[
  {
    "sku": "NK5-10-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK5/10-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 10,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.65,
    "static_load_kN": 1.92,
    "fatigue_load_limit_kN": 0.3,
    "limiting_speed_rpm": 39000,
    "max_rpm": 39000,
    "reference_speed_rpm": 55000,
    "weight_g": 3.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 5×10×10 mm: 5 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 2.5 mm radial section packed with small-diameter needle rollers C is 2.65 kN and C0 1.92 kN at the 5 mm seat; the C/C0 ratio of 1.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 10 mm outside diameter the fatigue load limit Cur is 0.3 kN, the limiting speed 39,000 r/min and the thermal reference speed 55,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.53 kN/mm and per millimetre of width 0.27 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.1 g, just 0.03 g per mm² of projected 10×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 5 mm bore this is one of the smallest HR1 executions — chosen where a 10 mm envelope must carry line-contact loads that no miniature ball bearing could take Omitting the inner ring frees radial space — at a 5 mm shaft the outer diameter is only 10 mm and the width 10 mm, yet C is 2.65 kN The thin 2.5 mm section makes the 3.1 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 39,000 r/min limit. With the -TV polyamide cage the rollers are positively separated, so the 5 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 10 mm outside diameter and 2.65 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 5 mm seat, and in agricultural machine pivots and linkages the 3.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 10 mm width and the published 1.92 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK5/10-TV-XL?",
        "a": "The NK5/10-TV-XL is a NK machined-ring needle roller bearing without inner ring with 10 mm outside diameter, 5 mm bore and 10 mm width, envelope 5×10×10 mm. Mass is 3.1 g."
      },
      {
        "q": "What does the NK5/10-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK5/10-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 5×10×10 mm and the catalogue ratings are C 2.65 kN, C0 1.92 kN, Cur 0.3 kN."
      },
      {
        "q": "What is the load capacity of the NK5/10-TV-XL?",
        "a": "The basic dynamic load rating C is 2.65 kN and the basic static load rating C0 is 1.92 kN; the fatigue load limit Cur is 0.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK5/10-TV-XL?",
        "a": "The limiting speed is 39,000 r/min and the thermal reference speed is 55,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK5/10-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK5/10-TV-XL has no inner ring, so the 5 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK5-10-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 5×10×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK5-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK5-10-TV-XL",
      "NK5/10-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK5-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK5/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 10,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.4,
    "static_load_kN": 2.65,
    "fatigue_load_limit_kN": 0.44,
    "limiting_speed_rpm": 39000,
    "max_rpm": 39000,
    "reference_speed_rpm": 54000,
    "weight_g": 3.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 5×10×12 mm: 5 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 2.5 mm radial section packed with small-diameter needle rollers C is 3.4 kN and C0 2.65 kN at the 5 mm seat; the C/C0 ratio of 1.28 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 10 mm outside diameter the fatigue load limit Cur is 0.44 kN, the limiting speed 39,000 r/min and the thermal reference speed 54,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.68 kN/mm and per millimetre of width 0.28 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.7 g, just 0.03 g per mm² of projected 10×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 5 mm bore and only 3.7 g: the smallest sizes demand accurate shaft geometry, because the 2.5 mm section leaves no tolerance for a soft or tapered seat The thin 2.5 mm section makes the 3.7 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 5×10×12 mm envelope. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 3.7 g in the 10 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 10 mm outside diameter and 3.4 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 5 mm seat, and in two-stroke and compressor piston pins the 3.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 12 mm width and the published 2.65 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK5/12-TV-XL?",
        "a": "The NK5/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 10 mm outside diameter, 5 mm bore and 12 mm width, envelope 5×10×12 mm. Mass is 3.7 g."
      },
      {
        "q": "What does the NK5/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK5/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 5×10×12 mm and the catalogue ratings are C 3.4 kN, C0 2.65 kN, Cur 0.44 kN."
      },
      {
        "q": "What is the load capacity of the NK5/12-TV-XL?",
        "a": "The basic dynamic load rating C is 3.4 kN and the basic static load rating C0 is 2.65 kN; the fatigue load limit Cur is 0.44 kN."
      },
      {
        "q": "What is the maximum speed of the NK5/12-TV-XL?",
        "a": "The limiting speed is 39,000 r/min and the thermal reference speed is 54,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK5/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK5/12-TV-XL has no inner ring, so the 5 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK5-10-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK5-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 5×10×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK5-12-TV-XL",
      "NK5/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK6-10-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK6/10-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 12,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.95,
    "static_load_kN": 2.28,
    "fatigue_load_limit_kN": 0.36,
    "limiting_speed_rpm": 36500,
    "max_rpm": 36500,
    "reference_speed_rpm": 48500,
    "weight_g": 4.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×12×10 mm: 6 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.0 mm radial section packed with small-diameter needle rollers C is 2.95 kN and C0 2.28 kN at the 6 mm seat; the C/C0 ratio of 1.29 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 12 mm outside diameter the fatigue load limit Cur is 0.36 kN, the limiting speed 36,500 r/min and the thermal reference speed 48,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.49 kN/mm and per millimetre of width 0.30 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 4.7 g, just 0.04 g per mm² of projected 12×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 6 mm bore and only 4.7 g: the smallest sizes demand accurate shaft geometry, because the 3.0 mm section leaves no tolerance for a soft or tapered seat The hardness requirement is unforgiving: below about 58 HRC the 6 mm journal brinels under the 2.28 kN static rating, and roughness above raceway finish accelerates roller wear Omitting the inner ring frees radial space — at a 6 mm shaft the outer diameter is only 12 mm and the width 10 mm, yet C is 2.95 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 2.95 kN C rating and longer nominal life come without an envelope change. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 36,500 r/min limiting speed without roller-to-roller sliding. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 12 mm outside diameter and 2.95 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 6 mm seat, and in motorcycle and light-vehicle transmissions the 4.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 10 mm width and the published 2.28 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK6/10-TV-XL?",
        "a": "The NK6/10-TV-XL is a NK machined-ring needle roller bearing without inner ring with 12 mm outside diameter, 6 mm bore and 10 mm width, envelope 6×12×10 mm. Mass is 4.7 g."
      },
      {
        "q": "What does the NK6/10-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK6/10-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×12×10 mm and the catalogue ratings are C 2.95 kN, C0 2.28 kN, Cur 0.36 kN."
      },
      {
        "q": "What is the load capacity of the NK6/10-TV-XL?",
        "a": "The basic dynamic load rating C is 2.95 kN and the basic static load rating C0 is 2.28 kN; the fatigue load limit Cur is 0.36 kN."
      },
      {
        "q": "What is the maximum speed of the NK6/10-TV-XL?",
        "a": "The limiting speed is 36,500 r/min and the thermal reference speed is 48,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK6/10-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK6/10-TV-XL has no inner ring, so the 6 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK6-10-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 6×12×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK6-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK6-10-TV-XL",
      "NK6/10-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK6-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK6/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 12,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.8,
    "static_load_kN": 3.15,
    "fatigue_load_limit_kN": 0.53,
    "limiting_speed_rpm": 36500,
    "max_rpm": 36500,
    "reference_speed_rpm": 47500,
    "weight_g": 5.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×12×12 mm: 6 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.0 mm radial section packed with small-diameter needle rollers C is 3.8 kN and C0 3.15 kN at the 6 mm seat; the C/C0 ratio of 1.21 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 12 mm outside diameter the fatigue load limit Cur is 0.53 kN, the limiting speed 36,500 r/min and the thermal reference speed 47,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.63 kN/mm and per millimetre of width 0.32 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.7 g, just 0.04 g per mm² of projected 12×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 6 mm bore sits in the miniature band; at 12 mm wide the NK6/12-TV-XL is built into compact cam drives, indexing pawls and light linkages The thin 3.0 mm section makes the 5.7 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.53 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 36,500 r/min. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 12 mm outside diameter and 3.8 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 6 mm seat, and in planetary gear bearings the 5.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 12 mm width and the published 3.15 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK6/12-TV-XL?",
        "a": "The NK6/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 12 mm outside diameter, 6 mm bore and 12 mm width, envelope 6×12×12 mm. Mass is 5.7 g."
      },
      {
        "q": "What does the NK6/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK6/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×12×12 mm and the catalogue ratings are C 3.8 kN, C0 3.15 kN, Cur 0.53 kN."
      },
      {
        "q": "What is the load capacity of the NK6/12-TV-XL?",
        "a": "The basic dynamic load rating C is 3.8 kN and the basic static load rating C0 is 3.15 kN; the fatigue load limit Cur is 0.53 kN."
      },
      {
        "q": "What is the maximum speed of the NK6/12-TV-XL?",
        "a": "The limiting speed is 36,500 r/min and the thermal reference speed is 47,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK6/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK6/12-TV-XL has no inner ring, so the 6 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK6-10-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK6-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 6×12×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK6-12-TV-XL",
      "NK6/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK7-10-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK7/10-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.25,
    "static_load_kN": 2.65,
    "fatigue_load_limit_kN": 0.42,
    "limiting_speed_rpm": 34500,
    "max_rpm": 34500,
    "reference_speed_rpm": 43000,
    "weight_g": 6.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 7×14×10 mm: 7 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 3.25 kN and C0 2.65 kN at the 7 mm seat; the C/C0 ratio of 1.23 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 14 mm outside diameter the fatigue load limit Cur is 0.42 kN, the limiting speed 34,500 r/min and the thermal reference speed 43,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.46 kN/mm and per millimetre of width 0.33 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 6.9 g, just 0.05 g per mm² of projected 14×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 7 mm bore this is one of the smallest HR1 executions — chosen where a 14 mm envelope must carry line-contact loads that no miniature ball bearing could take Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The thin 3.5 mm section makes the 6.9 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.42 kN Cur value. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 14 mm outside diameter and 3.25 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 7 mm seat, and in copying and printing machine mechanisms the 6.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 10 mm width and the published 2.65 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK7/10-TV-XL?",
        "a": "The NK7/10-TV-XL is a NK machined-ring needle roller bearing without inner ring with 14 mm outside diameter, 7 mm bore and 10 mm width, envelope 7×14×10 mm. Mass is 6.9 g."
      },
      {
        "q": "What does the NK7/10-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK7/10-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 7×14×10 mm and the catalogue ratings are C 3.25 kN, C0 2.65 kN, Cur 0.42 kN."
      },
      {
        "q": "What is the load capacity of the NK7/10-TV-XL?",
        "a": "The basic dynamic load rating C is 3.25 kN and the basic static load rating C0 is 2.65 kN; the fatigue load limit Cur is 0.42 kN."
      },
      {
        "q": "What is the maximum speed of the NK7/10-TV-XL?",
        "a": "The limiting speed is 34,500 r/min and the thermal reference speed is 43,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK7/10-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK7/10-TV-XL has no inner ring, so the 7 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK7-10-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 7×14×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK7-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK7-10-TV-XL",
      "NK7/10-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK7-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK7/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.15,
    "static_load_kN": 3.6,
    "fatigue_load_limit_kN": 0.61,
    "limiting_speed_rpm": 34500,
    "max_rpm": 34500,
    "reference_speed_rpm": 42000,
    "weight_g": 8.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 7×14×12 mm: 7 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 4.15 kN and C0 3.6 kN at the 7 mm seat; the C/C0 ratio of 1.15 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 14 mm outside diameter the fatigue load limit Cur is 0.61 kN, the limiting speed 34,500 r/min and the thermal reference speed 42,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.59 kN/mm and per millimetre of width 0.35 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 8.2 g, just 0.05 g per mm² of projected 14×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 7 mm bore and only 8.2 g: the smallest sizes demand accurate shaft geometry, because the 3.5 mm section leaves no tolerance for a soft or tapered seat Omitting the inner ring frees radial space — at a 7 mm shaft the outer diameter is only 14 mm and the width 12 mm, yet C is 4.15 kN With Cur 0.61 kN and a 34,500 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins X-life status (-XL) indicates the current Schaeffler premium execution at 7 mm bore; the 3.6 kN C0 rating reflects the improved rolling-contact geometry. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 14 mm outside diameter and 4.15 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 7 mm seat, and in connecting-rod small ends the 8.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 12 mm width and the published 3.6 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK7/12-TV-XL?",
        "a": "The NK7/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 14 mm outside diameter, 7 mm bore and 12 mm width, envelope 7×14×12 mm. Mass is 8.2 g."
      },
      {
        "q": "What does the NK7/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK7/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 7×14×12 mm and the catalogue ratings are C 4.15 kN, C0 3.6 kN, Cur 0.61 kN."
      },
      {
        "q": "What is the load capacity of the NK7/12-TV-XL?",
        "a": "The basic dynamic load rating C is 4.15 kN and the basic static load rating C0 is 3.6 kN; the fatigue load limit Cur is 0.61 kN."
      },
      {
        "q": "What is the maximum speed of the NK7/12-TV-XL?",
        "a": "The limiting speed is 34,500 r/min and the thermal reference speed is 42,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK7/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK7/12-TV-XL has no inner ring, so the 7 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK7-10-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK7-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 7×14×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK7-12-TV-XL",
      "NK7/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK8-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK8/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 15,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.45,
    "static_load_kN": 4.1,
    "fatigue_load_limit_kN": 0.7,
    "limiting_speed_rpm": 32500,
    "max_rpm": 32500,
    "reference_speed_rpm": 37000,
    "weight_g": 8.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 8×15×12 mm: 8 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 4.45 kN and C0 4.1 kN at the 8 mm seat; the C/C0 ratio of 1.09 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 15 mm outside diameter the fatigue load limit Cur is 0.7 kN, the limiting speed 32,500 r/min and the thermal reference speed 37,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.56 kN/mm and per millimetre of width 0.37 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 8.7 g, just 0.05 g per mm² of projected 15×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 8 mm bore sits in the miniature band; at 12 mm wide the NK8/12-TV-XL is built into compact cam drives, indexing pawls and light linkages This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Omitting the inner ring frees radial space — at a 8 mm shaft the outer diameter is only 15 mm and the width 12 mm, yet C is 4.45 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 8×15×12 mm envelope. With the -TV polyamide cage the rollers are positively separated, so the 8 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 15 mm outside diameter and 4.45 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 8 mm seat, and in rocker arms and valve trains the 8.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 12 mm width and the published 4.1 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK8/12-TV-XL?",
        "a": "The NK8/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 15 mm outside diameter, 8 mm bore and 12 mm width, envelope 8×15×12 mm. Mass is 8.7 g."
      },
      {
        "q": "What does the NK8/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK8/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 8×15×12 mm and the catalogue ratings are C 4.45 kN, C0 4.1 kN, Cur 0.7 kN."
      },
      {
        "q": "What is the load capacity of the NK8/12-TV-XL?",
        "a": "The basic dynamic load rating C is 4.45 kN and the basic static load rating C0 is 4.1 kN; the fatigue load limit Cur is 0.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK8/12-TV-XL?",
        "a": "The limiting speed is 32,500 r/min and the thermal reference speed is 37,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK8/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK8/12-TV-XL has no inner ring, so the 8 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK8-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 8×15×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK8-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK8-12-TV-XL",
      "NK8/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK8-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK8/16-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 15,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.8,
    "static_load_kN": 5.8,
    "fatigue_load_limit_kN": 0.99,
    "limiting_speed_rpm": 32500,
    "max_rpm": 32500,
    "reference_speed_rpm": 36500,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 8×15×16 mm: 8 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 5.8 kN and C0 5.8 kN at the 8 mm seat; the C/C0 ratio of 1.00 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 15 mm outside diameter the fatigue load limit Cur is 0.99 kN, the limiting speed 32,500 r/min and the thermal reference speed 36,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.72 kN/mm and per millimetre of width 0.36 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 12 g, just 0.05 g per mm² of projected 15×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 8 mm bore and only 12 g: the smallest sizes demand accurate shaft geometry, because the 3.5 mm section leaves no tolerance for a soft or tapered seat This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces NK8/16-TV-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 5.8 kN C rating and longer nominal life come without an envelope change. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 32,500 r/min limiting speed without roller-to-roller sliding. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 15 mm outside diameter and 5.8 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 8 mm seat, and in small electric motor accessory drives the 12 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 16 mm width and the published 5.8 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK8/16-TV-XL?",
        "a": "The NK8/16-TV-XL is a NK machined-ring needle roller bearing without inner ring with 15 mm outside diameter, 8 mm bore and 16 mm width, envelope 8×15×16 mm. Mass is 12 g."
      },
      {
        "q": "What does the NK8/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK8/16-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 8×15×16 mm and the catalogue ratings are C 5.8 kN, C0 5.8 kN, Cur 0.99 kN."
      },
      {
        "q": "What is the load capacity of the NK8/16-TV-XL?",
        "a": "The basic dynamic load rating C is 5.8 kN and the basic static load rating C0 is 5.8 kN; the fatigue load limit Cur is 0.99 kN."
      },
      {
        "q": "What is the maximum speed of the NK8/16-TV-XL?",
        "a": "The limiting speed is 32,500 r/min and the thermal reference speed is 36,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK8/16-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK8/16-TV-XL has no inner ring, so the 8 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK8-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK8-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 8×15×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK8-16-TV-XL",
      "NK8/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK9-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK9/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 16,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.1,
    "static_load_kN": 5,
    "fatigue_load_limit_kN": 0.86,
    "limiting_speed_rpm": 31000,
    "max_rpm": 31000,
    "reference_speed_rpm": 32000,
    "weight_g": 10.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 9×16×12 mm: 9 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 5.1 kN and C0 5 kN at the 9 mm seat; the C/C0 ratio of 1.02 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 16 mm outside diameter the fatigue load limit Cur is 0.86 kN, the limiting speed 31,000 r/min and the thermal reference speed 32,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.57 kN/mm and per millimetre of width 0.42 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 10.3 g, just 0.05 g per mm² of projected 16×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 9 mm bore this is one of the smallest HR1 executions — chosen where a 16 mm envelope must carry line-contact loads that no miniature ball bearing could take With Cur 0.86 kN and a 31,000 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins Omitting the inner ring frees radial space — at a 9 mm shaft the outer diameter is only 16 mm and the width 12 mm, yet C is 5.1 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 5.1 kN C rating and longer nominal life come without an envelope change. With the -TV polyamide cage the rollers are positively separated, so the 9 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 16 mm outside diameter and 5.1 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 9 mm seat, and in textile machine heald and cam shafts the 10.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 12 mm width and the published 5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK9/12-TV-XL?",
        "a": "The NK9/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 16 mm outside diameter, 9 mm bore and 12 mm width, envelope 9×16×12 mm. Mass is 10.3 g."
      },
      {
        "q": "What does the NK9/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK9/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 9×16×12 mm and the catalogue ratings are C 5.1 kN, C0 5 kN, Cur 0.86 kN."
      },
      {
        "q": "What is the load capacity of the NK9/12-TV-XL?",
        "a": "The basic dynamic load rating C is 5.1 kN and the basic static load rating C0 is 5 kN; the fatigue load limit Cur is 0.86 kN."
      },
      {
        "q": "What is the maximum speed of the NK9/12-TV-XL?",
        "a": "The limiting speed is 31,000 r/min and the thermal reference speed is 32,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK9/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK9/12-TV-XL has no inner ring, so the 9 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK9-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 9×16×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK9-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK9-12-TV-XL",
      "NK9/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK9-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK9/16-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 16,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 6.6,
    "static_load_kN": 7.1,
    "fatigue_load_limit_kN": 1.21,
    "limiting_speed_rpm": 31000,
    "max_rpm": 31000,
    "reference_speed_rpm": 32000,
    "weight_g": 12.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 9×16×16 mm: 9 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 6.6 kN and C0 7.1 kN at the 9 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 16 mm outside diameter the fatigue load limit Cur is 1.21 kN, the limiting speed 31,000 r/min and the thermal reference speed 32,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.73 kN/mm and per millimetre of width 0.41 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 12.8 g, just 0.05 g per mm² of projected 16×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 9 mm bore sits in the miniature band; at 16 mm wide the NK9/16-TV-XL is built into compact cam drives, indexing pawls and light linkages This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The thin 3.5 mm section makes the 12.8 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 1.21 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 31,000 r/min. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 16 mm outside diameter and 6.6 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 9 mm seat, and in connecting-rod small ends the 12.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 16 mm width and the published 7.1 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK9/16-TV-XL?",
        "a": "The NK9/16-TV-XL is a NK machined-ring needle roller bearing without inner ring with 16 mm outside diameter, 9 mm bore and 16 mm width, envelope 9×16×16 mm. Mass is 12.8 g."
      },
      {
        "q": "What does the NK9/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK9/16-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 9×16×16 mm and the catalogue ratings are C 6.6 kN, C0 7.1 kN, Cur 1.21 kN."
      },
      {
        "q": "What is the load capacity of the NK9/16-TV-XL?",
        "a": "The basic dynamic load rating C is 6.6 kN and the basic static load rating C0 is 7.1 kN; the fatigue load limit Cur is 1.21 kN."
      },
      {
        "q": "What is the maximum speed of the NK9/16-TV-XL?",
        "a": "The limiting speed is 31,000 r/min and the thermal reference speed is 32,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK9/16-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK9/16-TV-XL has no inner ring, so the 9 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK9-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK9-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 9×16×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK9-16-TV-XL",
      "NK9/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK10-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK10/12-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 17,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.3,
    "static_load_kN": 5.5,
    "fatigue_load_limit_kN": 0.94,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 29000,
    "weight_g": 10.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×17×12 mm: 10 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 5.3 kN and C0 5.5 kN at the 10 mm seat; the C/C0 ratio of 0.96 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 0.94 kN, the limiting speed 29,500 r/min and the thermal reference speed 29,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.53 kN/mm and per millimetre of width 0.44 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 10.1 g, just 0.05 g per mm² of projected 17×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 10 mm bore sits in the miniature band; at 12 mm wide the NK10/12-TV-XL is built into compact cam drives, indexing pawls and light linkages Omitting the inner ring frees radial space — at a 10 mm shaft the outer diameter is only 17 mm and the width 12 mm, yet C is 5.3 kN The hardness requirement is unforgiving: below about 58 HRC the 10 mm journal brinels under the 5.5 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 29,500 r/min limit. With the -TV polyamide cage the rollers are positively separated, so the 10 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 17 mm outside diameter and 5.3 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 10 mm seat, and in hydraulic and pneumatic pump eccentrics the 10.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 12 mm width and the published 5.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK10/12-TV-XL?",
        "a": "The NK10/12-TV-XL is a NK machined-ring needle roller bearing without inner ring with 17 mm outside diameter, 10 mm bore and 12 mm width, envelope 10×17×12 mm. Mass is 10.1 g."
      },
      {
        "q": "What does the NK10/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK10/12-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×17×12 mm and the catalogue ratings are C 5.3 kN, C0 5.5 kN, Cur 0.94 kN."
      },
      {
        "q": "What is the load capacity of the NK10/12-TV-XL?",
        "a": "The basic dynamic load rating C is 5.3 kN and the basic static load rating C0 is 5.5 kN; the fatigue load limit Cur is 0.94 kN."
      },
      {
        "q": "What is the maximum speed of the NK10/12-TV-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 29,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK10/12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK10/12-TV-XL has no inner ring, so the 10 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK10-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 10×17×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK10-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK10-12-TV-XL",
      "NK10/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK10-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK10/16-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 17,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 7,
    "static_load_kN": 7.8,
    "fatigue_load_limit_kN": 1.33,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 28500,
    "weight_g": 13.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×17×16 mm: 10 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 7 kN and C0 7.8 kN at the 10 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 1.33 kN, the limiting speed 29,500 r/min and the thermal reference speed 28,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.70 kN/mm and per millimetre of width 0.44 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 13.3 g, just 0.05 g per mm² of projected 17×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 10 mm bore and only 13.3 g: the smallest sizes demand accurate shaft geometry, because the 3.5 mm section leaves no tolerance for a soft or tapered seat With Cur 1.33 kN and a 29,500 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 3.5 mm section makes the 13.3 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 10×17×16 mm envelope. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 17 mm outside diameter and 7 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 10 mm seat, and in agricultural machine pivots and linkages the 13.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 16 mm width and the published 7.8 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK10/16-TV-XL?",
        "a": "The NK10/16-TV-XL is a NK machined-ring needle roller bearing without inner ring with 17 mm outside diameter, 10 mm bore and 16 mm width, envelope 10×17×16 mm. Mass is 13.3 g."
      },
      {
        "q": "What does the NK10/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK10/16-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×17×16 mm and the catalogue ratings are C 7 kN, C0 7.8 kN, Cur 1.33 kN."
      },
      {
        "q": "What is the load capacity of the NK10/16-TV-XL?",
        "a": "The basic dynamic load rating C is 7 kN and the basic static load rating C0 is 7.8 kN; the fatigue load limit Cur is 1.33 kN."
      },
      {
        "q": "What is the maximum speed of the NK10/16-TV-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 28,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK10/16-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK10/16-TV-XL has no inner ring, so the 10 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK10-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK10-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 10×17×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK10-16-TV-XL",
      "NK10/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK12-12-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK12/12-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 19,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 7.2,
    "static_load_kN": 7.1,
    "fatigue_load_limit_kN": 1.31,
    "limiting_speed_rpm": 26500,
    "max_rpm": 26500,
    "reference_speed_rpm": 22400,
    "weight_g": 12.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×19×12 mm: 12 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 7.2 kN and C0 7.1 kN at the 12 mm seat; the C/C0 ratio of 1.01 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 19 mm outside diameter the fatigue load limit Cur is 1.31 kN, the limiting speed 26,500 r/min and the thermal reference speed 22,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.60 kN/mm and per millimetre of width 0.60 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 12.1 g, just 0.05 g per mm² of projected 19×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 12 mm bore sits in the miniature band; at 12 mm wide the NK12/12-XL is built into compact cam drives, indexing pawls and light linkages Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 12 mm journal brinels under the 7.1 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 12×19×12 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 19 mm outside diameter and 7.2 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 12 mm seat, and in textile machine heald and cam shafts the 12.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 12 mm width and the published 7.1 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK12/12-XL?",
        "a": "The NK12/12-XL is a NK machined-ring needle roller bearing without inner ring with 19 mm outside diameter, 12 mm bore and 12 mm width, envelope 12×19×12 mm. Mass is 12.1 g."
      },
      {
        "q": "What does the NK12/12-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK12/12-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×19×12 mm and the catalogue ratings are C 7.2 kN, C0 7.1 kN, Cur 1.31 kN."
      },
      {
        "q": "What is the load capacity of the NK12/12-XL?",
        "a": "The basic dynamic load rating C is 7.2 kN and the basic static load rating C0 is 7.1 kN; the fatigue load limit Cur is 1.31 kN."
      },
      {
        "q": "What is the maximum speed of the NK12/12-XL?",
        "a": "The limiting speed is 26,500 r/min and the thermal reference speed is 22,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK12/12-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK12/12-XL has no inner ring, so the 12 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK12-12",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×19×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK12-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK12-12-XL",
      "NK12/12-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK12-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK12/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 19,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.1,
    "static_load_kN": 11,
    "fatigue_load_limit_kN": 1.95,
    "limiting_speed_rpm": 26500,
    "max_rpm": 26500,
    "reference_speed_rpm": 21600,
    "weight_g": 15.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×19×16 mm: 12 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 10.1 kN and C0 11 kN at the 12 mm seat; the C/C0 ratio of 0.92 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 19 mm outside diameter the fatigue load limit Cur is 1.95 kN, the limiting speed 26,500 r/min and the thermal reference speed 21,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 0.63 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 15.9 g, just 0.05 g per mm² of projected 19×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 12 mm bore this is one of the smallest HR1 executions — chosen where a 19 mm envelope must carry line-contact loads that no miniature ball bearing could take NK12/16-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Omitting the inner ring frees radial space — at a 12 mm shaft the outer diameter is only 19 mm and the width 16 mm, yet C is 10.1 kN The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 26,500 r/min limit. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 19 mm outside diameter and 10.1 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 12 mm seat, and in rocker arms and valve trains the 15.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 16 mm width and the published 11 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK12/16-XL?",
        "a": "The NK12/16-XL is a NK machined-ring needle roller bearing without inner ring with 19 mm outside diameter, 12 mm bore and 16 mm width, envelope 12×19×16 mm. Mass is 15.9 g."
      },
      {
        "q": "What does the NK12/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK12/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×19×16 mm and the catalogue ratings are C 10.1 kN, C0 11 kN, Cur 1.95 kN."
      },
      {
        "q": "What is the load capacity of the NK12/16-XL?",
        "a": "The basic dynamic load rating C is 10.1 kN and the basic static load rating C0 is 11 kN; the fatigue load limit Cur is 1.95 kN."
      },
      {
        "q": "What is the maximum speed of the NK12/16-XL?",
        "a": "The limiting speed is 26,500 r/min and the thermal reference speed is 21,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK12/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK12/16-XL has no inner ring, so the 12 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK12-12",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK12-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×19×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK12-16-XL",
      "NK12/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK14-16-D-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK14/16-D-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.4,
    "static_load_kN": 17.1,
    "fatigue_load_limit_kN": 2.9,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 16800,
    "weight_g": 21.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 14×22×16 mm: 14 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 15.4 kN and C0 17.1 kN at the 14 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 2.9 kN, the limiting speed 24,600 r/min and the thermal reference speed 16,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.10 kN/mm and per millimetre of width 0.96 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21.4 g, just 0.06 g per mm² of projected 22×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 14 mm bore this size balances the 22 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The thin 4.0 mm section makes the 21.4 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting NK14/16-D-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality X-life status (-XL) indicates the current Schaeffler premium execution at 14 mm bore; the 17.1 kN C0 rating reflects the improved rolling-contact geometry. The -D suffix supplies a radially split needle roller and cage assembly, so the cage can be fitted at bearing positions that cannot be reached over a shaft end. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 22 mm outside diameter and 15.4 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 14 mm seat, and in gearbox selector and change linkages the 21.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 16 mm width and the published 17.1 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK14/16-D-XL?",
        "a": "The NK14/16-D-XL is a NK machined-ring needle roller bearing without inner ring with 22 mm outside diameter, 14 mm bore and 16 mm width, envelope 14×22×16 mm. Mass is 21.4 g."
      },
      {
        "q": "What does the NK14/16-D-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK14/16-D-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 14×22×16 mm and the catalogue ratings are C 15.4 kN, C0 17.1 kN, Cur 2.9 kN."
      },
      {
        "q": "What is the load capacity of the NK14/16-D-XL?",
        "a": "The basic dynamic load rating C is 15.4 kN and the basic static load rating C0 is 17.1 kN; the fatigue load limit Cur is 2.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK14/16-D-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 16,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK14/16-D-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK14/16-D-XL has no inner ring, so the 14 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK14-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK14-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK14-16-D-XL",
      "NK14/16-D-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK14-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK14/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 11.5,
    "fatigue_load_limit_kN": 2.14,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 18600,
    "weight_g": 20.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 14×22×16 mm: 14 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 11.4 kN and C0 11.5 kN at the 14 mm seat; the C/C0 ratio of 0.99 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 2.14 kN, the limiting speed 24,600 r/min and the thermal reference speed 18,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 0.71 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 20.7 g, just 0.06 g per mm² of projected 22×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 14 mm bore the 16 mm width and 11.4 kN C rating suit high-cycle industrial machinery rather than instrument duty With Cur 2.14 kN and a 24,600 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 4.0 mm section makes the 20.7 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 14×22×16 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 22 mm outside diameter and 11.4 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 14 mm seat, and in copying and printing machine mechanisms the 20.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 16 mm width and the published 11.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK14/16-XL?",
        "a": "The NK14/16-XL is a NK machined-ring needle roller bearing without inner ring with 22 mm outside diameter, 14 mm bore and 16 mm width, envelope 14×22×16 mm. Mass is 20.7 g."
      },
      {
        "q": "What does the NK14/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK14/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 14×22×16 mm and the catalogue ratings are C 11.4 kN, C0 11.5 kN, Cur 2.14 kN."
      },
      {
        "q": "What is the load capacity of the NK14/16-XL?",
        "a": "The basic dynamic load rating C is 11.4 kN and the basic static load rating C0 is 11.5 kN; the fatigue load limit Cur is 2.14 kN."
      },
      {
        "q": "What is the maximum speed of the NK14/16-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 18,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK14/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK14/16-XL has no inner ring, so the 14 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK14-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK14-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK14-16-XL",
      "NK14/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK14-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK14/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.5,
    "static_load_kN": 15.6,
    "fatigue_load_limit_kN": 2.75,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 18300,
    "weight_g": 25.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 14×22×20 mm: 14 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 14.5 kN and C0 15.6 kN at the 14 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 2.75 kN, the limiting speed 24,600 r/min and the thermal reference speed 18,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 0.72 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 25.5 g, just 0.06 g per mm² of projected 22×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 14 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Omitting the inner ring frees radial space — at a 14 mm shaft the outer diameter is only 22 mm and the width 20 mm, yet C is 14.5 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 14.5 kN C rating and longer nominal life come without an envelope change. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 22 mm outside diameter and 14.5 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 14 mm seat, and in agricultural machine pivots and linkages the 25.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 15.6 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK14/20-XL?",
        "a": "The NK14/20-XL is a NK machined-ring needle roller bearing without inner ring with 22 mm outside diameter, 14 mm bore and 20 mm width, envelope 14×22×20 mm. Mass is 25.5 g."
      },
      {
        "q": "What does the NK14/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK14/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 14×22×20 mm and the catalogue ratings are C 14.5 kN, C0 15.6 kN, Cur 2.75 kN."
      },
      {
        "q": "What is the load capacity of the NK14/20-XL?",
        "a": "The basic dynamic load rating C is 14.5 kN and the basic static load rating C0 is 15.6 kN; the fatigue load limit Cur is 2.75 kN."
      },
      {
        "q": "What is the maximum speed of the NK14/20-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 18,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK14/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK14/20-XL has no inner ring, so the 14 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK14-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK14-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK14-20-XL",
      "NK14/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4900-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4900-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 9.6,
    "static_load_kN": 9.2,
    "fatigue_load_limit_kN": 1.66,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 17800,
    "weight_g": 16.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 14×22×13 mm: 14 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 9.6 kN and C0 9.2 kN at the 14 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 1.66 kN, the limiting speed 24,600 r/min and the thermal reference speed 17,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.69 kN/mm and per millimetre of width 0.74 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 16.5 g, just 0.06 g per mm² of projected 22×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 14 mm bore this size balances the 22 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The hardness requirement is unforgiving: below about 58 HRC the 14 mm journal brinels under the 9.2 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 1.66 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 22 mm outside diameter and 9.6 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 14 mm seat, and in motorcycle and light-vehicle transmissions the 16.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 13 mm width and the published 9.2 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4900-XL?",
        "a": "The RNA4900-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 22 mm outside diameter, 14 mm bore and 13 mm width, envelope 14×22×13 mm. Mass is 16.5 g."
      },
      {
        "q": "What does the RNA4900-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4900-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 14×22×13 mm and the catalogue ratings are C 9.6 kN, C0 9.2 kN, Cur 1.66 kN."
      },
      {
        "q": "What is the load capacity of the RNA4900-XL?",
        "a": "The basic dynamic load rating C is 9.6 kN and the basic static load rating C0 is 9.2 kN; the fatigue load limit Cur is 1.66 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4900-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 17,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4900-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4900-XL has no inner ring, so the 14 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4900",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4900-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4900-XL",
      "RNA4900-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK15-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK15/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 23,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12.1,
    "static_load_kN": 12.7,
    "fatigue_load_limit_kN": 2.36,
    "limiting_speed_rpm": 23900,
    "max_rpm": 23900,
    "reference_speed_rpm": 17300,
    "weight_g": 21.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×23×16 mm: 15 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 12.1 kN and C0 12.7 kN at the 15 mm seat; the C/C0 ratio of 0.95 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 23 mm outside diameter the fatigue load limit Cur is 2.36 kN, the limiting speed 23,900 r/min and the thermal reference speed 17,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 0.76 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21.8 g, just 0.06 g per mm² of projected 23×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 15 mm bore this size balances the 23 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The hardness requirement is unforgiving: below about 58 HRC the 15 mm journal brinels under the 12.7 kN static rating, and roughness above raceway finish accelerates roller wear NK15/16-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 15×23×16 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 23 mm outside diameter and 12.1 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 15 mm seat, and in planetary gear bearings the 21.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 16 mm width and the published 12.7 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK15/16-XL?",
        "a": "The NK15/16-XL is a NK machined-ring needle roller bearing without inner ring with 23 mm outside diameter, 15 mm bore and 16 mm width, envelope 15×23×16 mm. Mass is 21.8 g."
      },
      {
        "q": "What does the NK15/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK15/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×23×16 mm and the catalogue ratings are C 12.1 kN, C0 12.7 kN, Cur 2.36 kN."
      },
      {
        "q": "What is the load capacity of the NK15/16-XL?",
        "a": "The basic dynamic load rating C is 12.1 kN and the basic static load rating C0 is 12.7 kN; the fatigue load limit Cur is 2.36 kN."
      },
      {
        "q": "What is the maximum speed of the NK15/16-XL?",
        "a": "The limiting speed is 23,900 r/min and the thermal reference speed is 17,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK15/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK15/16-XL has no inner ring, so the 15 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK15-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK15-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK15-16-XL",
      "NK15/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK15-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK15/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 23,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.4,
    "static_load_kN": 17.2,
    "fatigue_load_limit_kN": 3.05,
    "limiting_speed_rpm": 23900,
    "max_rpm": 23900,
    "reference_speed_rpm": 17000,
    "weight_g": 26.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×23×20 mm: 15 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 15.4 kN and C0 17.2 kN at the 15 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 23 mm outside diameter the fatigue load limit Cur is 3.05 kN, the limiting speed 23,900 r/min and the thermal reference speed 17,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 0.77 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 26.6 g, just 0.06 g per mm² of projected 23×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 15 mm bore the 20 mm width and 15.4 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 15 mm journal brinels under the 17.2 kN static rating, and roughness above raceway finish accelerates roller wear -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 15.4 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 23 mm outside diameter and 15.4 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 15 mm seat, and in copying and printing machine mechanisms the 26.6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 17.2 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK15/20-XL?",
        "a": "The NK15/20-XL is a NK machined-ring needle roller bearing without inner ring with 23 mm outside diameter, 15 mm bore and 20 mm width, envelope 15×23×20 mm. Mass is 26.6 g."
      },
      {
        "q": "What does the NK15/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK15/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×23×20 mm and the catalogue ratings are C 15.4 kN, C0 17.2 kN, Cur 3.05 kN."
      },
      {
        "q": "What is the load capacity of the NK15/20-XL?",
        "a": "The basic dynamic load rating C is 15.4 kN and the basic static load rating C0 is 17.2 kN; the fatigue load limit Cur is 3.05 kN."
      },
      {
        "q": "What is the maximum speed of the NK15/20-XL?",
        "a": "The limiting speed is 23,900 r/min and the thermal reference speed is 17,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK15/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK15/20-XL has no inner ring, so the 15 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK15-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK15-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 15×23×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK15-20-XL",
      "NK15/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK16-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK16/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 13.9,
    "fatigue_load_limit_kN": 2.6,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 16200,
    "weight_g": 22.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×24×16 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 12.8 kN and C0 13.9 kN at the 16 mm seat; the C/C0 ratio of 0.92 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 2.6 kN, the limiting speed 23,200 r/min and the thermal reference speed 16,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.80 kN/mm and per millimetre of width 0.80 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 22.4 g, just 0.06 g per mm² of projected 24×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 16 mm bore this size balances the 24 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 16×24×16 mm envelope. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 24 mm outside diameter and 12.8 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 16 mm seat, and in small electric motor accessory drives the 22.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 16 mm width and the published 13.9 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK16/16-XL?",
        "a": "The NK16/16-XL is a NK machined-ring needle roller bearing without inner ring with 24 mm outside diameter, 16 mm bore and 16 mm width, envelope 16×24×16 mm. Mass is 22.4 g."
      },
      {
        "q": "What does the NK16/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK16/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×24×16 mm and the catalogue ratings are C 12.8 kN, C0 13.9 kN, Cur 2.6 kN."
      },
      {
        "q": "What is the load capacity of the NK16/16-XL?",
        "a": "The basic dynamic load rating C is 12.8 kN and the basic static load rating C0 is 13.9 kN; the fatigue load limit Cur is 2.6 kN."
      },
      {
        "q": "What is the maximum speed of the NK16/16-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 16,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK16/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK16/16-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK16-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK16-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK16-16-XL",
      "NK16/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK16-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK16/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.3,
    "static_load_kN": 18.8,
    "fatigue_load_limit_kN": 3.35,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 15900,
    "weight_g": 28.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×24×20 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 16.3 kN and C0 18.8 kN at the 16 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 3.35 kN, the limiting speed 23,200 r/min and the thermal reference speed 15,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.02 kN/mm and per millimetre of width 0.82 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 28.4 g, just 0.06 g per mm² of projected 24×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 16 mm bore the 20 mm width and 16.3 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 16 mm journal brinels under the 18.8 kN static rating, and roughness above raceway finish accelerates roller wear The thin 4.0 mm section makes the 28.4 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 16.3 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 24 mm outside diameter and 16.3 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 16 mm seat, and in gearbox selector and change linkages the 28.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 20 mm width and the published 18.8 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK16/20-XL?",
        "a": "The NK16/20-XL is a NK machined-ring needle roller bearing without inner ring with 24 mm outside diameter, 16 mm bore and 20 mm width, envelope 16×24×20 mm. Mass is 28.4 g."
      },
      {
        "q": "What does the NK16/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK16/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×24×20 mm and the catalogue ratings are C 16.3 kN, C0 18.8 kN, Cur 3.35 kN."
      },
      {
        "q": "What is the load capacity of the NK16/20-XL?",
        "a": "The basic dynamic load rating C is 16.3 kN and the basic static load rating C0 is 18.8 kN; the fatigue load limit Cur is 3.35 kN."
      },
      {
        "q": "What is the maximum speed of the NK16/20-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 15,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK16/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK16/20-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK16-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK16-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK16-20-XL",
      "NK16/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4901-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4901-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.6,
    "static_load_kN": 10.9,
    "fatigue_load_limit_kN": 1.97,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 15300,
    "weight_g": 17.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×24×13 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 10.6 kN and C0 10.9 kN at the 16 mm seat; the C/C0 ratio of 0.97 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 1.97 kN, the limiting speed 23,200 r/min and the thermal reference speed 15,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.66 kN/mm and per millimetre of width 0.82 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 17.4 g, just 0.06 g per mm² of projected 24×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 16 mm bore this size balances the 24 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 1.97 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 24 mm outside diameter and 10.6 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 16 mm seat, and in small electric motor accessory drives the 17.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 13 mm width and the published 10.9 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4901-XL?",
        "a": "The RNA4901-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 24 mm outside diameter, 16 mm bore and 13 mm width, envelope 16×24×13 mm. Mass is 17.4 g."
      },
      {
        "q": "What does the RNA4901-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4901-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×24×13 mm and the catalogue ratings are C 10.6 kN, C0 10.9 kN, Cur 1.97 kN."
      },
      {
        "q": "What is the load capacity of the RNA4901-XL?",
        "a": "The basic dynamic load rating C is 10.6 kN and the basic static load rating C0 is 10.9 kN; the fatigue load limit Cur is 1.97 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4901-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 15,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4901-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4901-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4901-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4901-XL",
      "RNA4901-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6901-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6901-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.1,
    "static_load_kN": 21.6,
    "fatigue_load_limit_kN": 3.85,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 14300,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×24×22 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 18.1 kN and C0 21.6 kN at the 16 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 3.85 kN, the limiting speed 23,200 r/min and the thermal reference speed 14,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 0.82 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 31 g, just 0.06 g per mm² of projected 24×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 16 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With Cur 3.85 kN and a 23,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 4.0 mm section makes the 31 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.85 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 24 mm outside diameter and 18.1 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 16 mm seat, and in motorcycle and light-vehicle transmissions the 31 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 22 mm width and the published 21.6 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6901-XL?",
        "a": "The RNA6901-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 24 mm outside diameter, 16 mm bore and 22 mm width, envelope 16×24×22 mm. Mass is 31 g."
      },
      {
        "q": "What does the RNA6901-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6901-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×24×22 mm and the catalogue ratings are C 18.1 kN, C0 21.6 kN, Cur 3.85 kN."
      },
      {
        "q": "What is the load capacity of the RNA6901-XL?",
        "a": "The basic dynamic load rating C is 18.1 kN and the basic static load rating C0 is 21.6 kN; the fatigue load limit Cur is 3.85 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6901-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 14,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6901-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6901-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6901-XL",
      "RNA6901-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK17-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK17/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 25,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 13.5,
    "static_load_kN": 15,
    "fatigue_load_limit_kN": 2.8,
    "limiting_speed_rpm": 22600,
    "max_rpm": 22600,
    "reference_speed_rpm": 15300,
    "weight_g": 23.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×25×16 mm: 17 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 13.5 kN and C0 15 kN at the 17 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 25 mm outside diameter the fatigue load limit Cur is 2.8 kN, the limiting speed 22,600 r/min and the thermal reference speed 15,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.79 kN/mm and per millimetre of width 0.84 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 23.7 g, just 0.06 g per mm² of projected 25×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 17 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces NK17/16-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 17×25×16 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 25 mm outside diameter and 13.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 17 mm seat, and in two-stroke and compressor piston pins the 23.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 16 mm width and the published 15 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK17/16-XL?",
        "a": "The NK17/16-XL is a NK machined-ring needle roller bearing without inner ring with 25 mm outside diameter, 17 mm bore and 16 mm width, envelope 17×25×16 mm. Mass is 23.7 g."
      },
      {
        "q": "What does the NK17/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK17/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×25×16 mm and the catalogue ratings are C 13.5 kN, C0 15 kN, Cur 2.8 kN."
      },
      {
        "q": "What is the load capacity of the NK17/16-XL?",
        "a": "The basic dynamic load rating C is 13.5 kN and the basic static load rating C0 is 15 kN; the fatigue load limit Cur is 2.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK17/16-XL?",
        "a": "The limiting speed is 22,600 r/min and the thermal reference speed is 15,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK17/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK17/16-XL has no inner ring, so the 17 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK17-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×25×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK17-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK17-16-XL",
      "NK17/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK17-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK17/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 25,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 17.1,
    "static_load_kN": 20.4,
    "fatigue_load_limit_kN": 3.6,
    "limiting_speed_rpm": 22600,
    "max_rpm": 22600,
    "reference_speed_rpm": 15000,
    "weight_g": 29.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×25×20 mm: 17 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 17.1 kN and C0 20.4 kN at the 17 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 25 mm outside diameter the fatigue load limit Cur is 3.6 kN, the limiting speed 22,600 r/min and the thermal reference speed 15,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 0.86 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 29.8 g, just 0.06 g per mm² of projected 25×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 17 mm bore this size balances the 25 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The hardness requirement is unforgiving: below about 58 HRC the 17 mm journal brinels under the 20.4 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.6 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 25 mm outside diameter and 17.1 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 17 mm seat, and in connecting-rod small ends the 29.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 20.4 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK17/20-XL?",
        "a": "The NK17/20-XL is a NK machined-ring needle roller bearing without inner ring with 25 mm outside diameter, 17 mm bore and 20 mm width, envelope 17×25×20 mm. Mass is 29.8 g."
      },
      {
        "q": "What does the NK17/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK17/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×25×20 mm and the catalogue ratings are C 17.1 kN, C0 20.4 kN, Cur 3.6 kN."
      },
      {
        "q": "What is the load capacity of the NK17/20-XL?",
        "a": "The basic dynamic load rating C is 17.1 kN and the basic static load rating C0 is 20.4 kN; the fatigue load limit Cur is 3.6 kN."
      },
      {
        "q": "What is the maximum speed of the NK17/20-XL?",
        "a": "The limiting speed is 22,600 r/min and the thermal reference speed is 15,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK17/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK17/20-XL has no inner ring, so the 17 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK17-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK17-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×25×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK17-20-XL",
      "NK17/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK18-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK18/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 26,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.1,
    "static_load_kN": 16.2,
    "fatigue_load_limit_kN": 3.05,
    "limiting_speed_rpm": 22100,
    "max_rpm": 22100,
    "reference_speed_rpm": 14400,
    "weight_g": 24.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 18×26×16 mm: 18 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 14.1 kN and C0 16.2 kN at the 18 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 26 mm outside diameter the fatigue load limit Cur is 3.05 kN, the limiting speed 22,100 r/min and the thermal reference speed 14,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.78 kN/mm and per millimetre of width 0.88 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 24.9 g, just 0.06 g per mm² of projected 26×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 18 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With Cur 3.05 kN and a 22,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 14.1 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 26 mm outside diameter and 14.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 18 mm seat, and in hydraulic and pneumatic pump eccentrics the 24.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 16 mm width and the published 16.2 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK18/16-XL?",
        "a": "The NK18/16-XL is a NK machined-ring needle roller bearing without inner ring with 26 mm outside diameter, 18 mm bore and 16 mm width, envelope 18×26×16 mm. Mass is 24.9 g."
      },
      {
        "q": "What does the NK18/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK18/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 18×26×16 mm and the catalogue ratings are C 14.1 kN, C0 16.2 kN, Cur 3.05 kN."
      },
      {
        "q": "What is the load capacity of the NK18/16-XL?",
        "a": "The basic dynamic load rating C is 14.1 kN and the basic static load rating C0 is 16.2 kN; the fatigue load limit Cur is 3.05 kN."
      },
      {
        "q": "What is the maximum speed of the NK18/16-XL?",
        "a": "The limiting speed is 22,100 r/min and the thermal reference speed is 14,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK18/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK18/16-XL has no inner ring, so the 18 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK18-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 18×26×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK18-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK18-16-XL",
      "NK18/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK18-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK18/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 26,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 17.9,
    "static_load_kN": 22,
    "fatigue_load_limit_kN": 3.9,
    "limiting_speed_rpm": 22100,
    "max_rpm": 22100,
    "reference_speed_rpm": 14100,
    "weight_g": 31.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 18×26×20 mm: 18 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 17.9 kN and C0 22 kN at the 18 mm seat; the C/C0 ratio of 0.81 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 26 mm outside diameter the fatigue load limit Cur is 3.9 kN, the limiting speed 22,100 r/min and the thermal reference speed 14,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.99 kN/mm and per millimetre of width 0.89 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 31.4 g, just 0.06 g per mm² of projected 26×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 18 mm bore this size balances the 26 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range NK18/20-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The hardness requirement is unforgiving: below about 58 HRC the 18 mm journal brinels under the 22 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.9 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 26 mm outside diameter and 17.9 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 18 mm seat, and in textile machine heald and cam shafts the 31.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 22 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK18/20-XL?",
        "a": "The NK18/20-XL is a NK machined-ring needle roller bearing without inner ring with 26 mm outside diameter, 18 mm bore and 20 mm width, envelope 18×26×20 mm. Mass is 31.4 g."
      },
      {
        "q": "What does the NK18/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK18/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 18×26×20 mm and the catalogue ratings are C 17.9 kN, C0 22 kN, Cur 3.9 kN."
      },
      {
        "q": "What is the load capacity of the NK18/20-XL?",
        "a": "The basic dynamic load rating C is 17.9 kN and the basic static load rating C0 is 22 kN; the fatigue load limit Cur is 3.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK18/20-XL?",
        "a": "The limiting speed is 22,100 r/min and the thermal reference speed is 14,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK18/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK18/20-XL has no inner ring, so the 18 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK18-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK18-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 18×26×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK18-20-XL",
      "NK18/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK19-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK19/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 19,
    "D_mm": 27,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.7,
    "static_load_kN": 17.4,
    "fatigue_load_limit_kN": 3.25,
    "limiting_speed_rpm": 21600,
    "max_rpm": 21600,
    "reference_speed_rpm": 13700,
    "weight_g": 26.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 19×27×16 mm: 19 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 14.7 kN and C0 17.4 kN at the 19 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 27 mm outside diameter the fatigue load limit Cur is 3.25 kN, the limiting speed 21,600 r/min and the thermal reference speed 13,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.77 kN/mm and per millimetre of width 0.92 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 26.1 g, just 0.06 g per mm² of projected 27×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 19 mm bore the 16 mm width and 14.7 kN C rating suit high-cycle industrial machinery rather than instrument duty Omitting the inner ring frees radial space — at a 19 mm shaft the outer diameter is only 27 mm and the width 16 mm, yet C is 14.7 kN This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 14.7 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 27 mm outside diameter and 14.7 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 19 mm seat, and in gearbox selector and change linkages the 26.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 16 mm width and the published 17.4 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK19/16-XL?",
        "a": "The NK19/16-XL is a NK machined-ring needle roller bearing without inner ring with 27 mm outside diameter, 19 mm bore and 16 mm width, envelope 19×27×16 mm. Mass is 26.1 g."
      },
      {
        "q": "What does the NK19/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK19/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 19×27×16 mm and the catalogue ratings are C 14.7 kN, C0 17.4 kN, Cur 3.25 kN."
      },
      {
        "q": "What is the load capacity of the NK19/16-XL?",
        "a": "The basic dynamic load rating C is 14.7 kN and the basic static load rating C0 is 17.4 kN; the fatigue load limit Cur is 3.25 kN."
      },
      {
        "q": "What is the maximum speed of the NK19/16-XL?",
        "a": "The limiting speed is 21,600 r/min and the thermal reference speed is 13,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK19/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK19/16-XL has no inner ring, so the 19 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK19-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK19-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK19-16-XL",
      "NK19/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK19-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK19/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 19,
    "D_mm": 27,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.7,
    "static_load_kN": 23.6,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 21600,
    "max_rpm": 21600,
    "reference_speed_rpm": 13400,
    "weight_g": 32.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 19×27×20 mm: 19 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 18.7 kN and C0 23.6 kN at the 19 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 27 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 21,600 r/min and the thermal reference speed 13,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 0.93 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 32.2 g, just 0.06 g per mm² of projected 27×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 19 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 19 mm shaft the outer diameter is only 27 mm and the width 20 mm, yet C is 18.7 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 4.2 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 27 mm outside diameter and 18.7 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 19 mm seat, and in hydraulic and pneumatic pump eccentrics the 32.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 23.6 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK19/20-XL?",
        "a": "The NK19/20-XL is a NK machined-ring needle roller bearing without inner ring with 27 mm outside diameter, 19 mm bore and 20 mm width, envelope 19×27×20 mm. Mass is 32.2 g."
      },
      {
        "q": "What does the NK19/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK19/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 19×27×20 mm and the catalogue ratings are C 18.7 kN, C0 23.6 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NK19/20-XL?",
        "a": "The basic dynamic load rating C is 18.7 kN and the basic static load rating C0 is 23.6 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NK19/20-XL?",
        "a": "The limiting speed is 21,600 r/min and the thermal reference speed is 13,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK19/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK19/20-XL has no inner ring, so the 19 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK19-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK19-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 19×27×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=947",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK19-20-XL",
      "NK19/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK20-16-D-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK20/16-D-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.5,
    "static_load_kN": 23.9,
    "fatigue_load_limit_kN": 4.1,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 12100,
    "weight_g": 28.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×16 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 18.5 kN and C0 23.9 kN at the 20 mm seat; the C/C0 ratio of 0.77 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 4.1 kN, the limiting speed 21,100 r/min and the thermal reference speed 12,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 1.16 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 28.4 g, just 0.06 g per mm² of projected 28×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Omitting the inner ring frees radial space — at a 20 mm shaft the outer diameter is only 28 mm and the width 16 mm, yet C is 18.5 kN With Cur 4.1 kN and a 21,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 21,100 r/min limit. The split -D cage targets positions where the shaft cannot be threaded through an intact bearing; seating and axial retention must follow the mounting instructions. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 28 mm outside diameter and 18.5 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 20 mm seat, and in agricultural machine pivots and linkages the 28.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 16 mm width and the published 23.9 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK20/16-D-XL?",
        "a": "The NK20/16-D-XL is a NK machined-ring needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 16 mm width, envelope 20×28×16 mm. Mass is 28.4 g."
      },
      {
        "q": "What does the NK20/16-D-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK20/16-D-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×16 mm and the catalogue ratings are C 18.5 kN, C0 23.9 kN, Cur 4.1 kN."
      },
      {
        "q": "What is the load capacity of the NK20/16-D-XL?",
        "a": "The basic dynamic load rating C is 18.5 kN and the basic static load rating C0 is 23.9 kN; the fatigue load limit Cur is 4.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK20/16-D-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 12,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK20/16-D-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK20/16-D-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK20-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK20-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK20-16-D-XL",
      "NK20/16-D-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK20-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK20/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.6,
    "static_load_kN": 17.5,
    "fatigue_load_limit_kN": 3.3,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 13200,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×16 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 14.6 kN and C0 17.5 kN at the 20 mm seat; the C/C0 ratio of 0.83 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 3.3 kN, the limiting speed 21,100 r/min and the thermal reference speed 13,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.73 kN/mm and per millimetre of width 0.91 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 27 g, just 0.06 g per mm² of projected 28×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The thin 4.0 mm section makes the 27 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The hardness requirement is unforgiving: below about 58 HRC the 20 mm journal brinels under the 17.5 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.3 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 28 mm outside diameter and 14.6 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 20 mm seat, and in motorcycle and light-vehicle transmissions the 27 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 16 mm width and the published 17.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK20/16-XL?",
        "a": "The NK20/16-XL is a NK machined-ring needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 16 mm width, envelope 20×28×16 mm. Mass is 27 g."
      },
      {
        "q": "What does the NK20/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK20/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×16 mm and the catalogue ratings are C 14.6 kN, C0 17.5 kN, Cur 3.3 kN."
      },
      {
        "q": "What is the load capacity of the NK20/16-XL?",
        "a": "The basic dynamic load rating C is 14.6 kN and the basic static load rating C0 is 17.5 kN; the fatigue load limit Cur is 3.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK20/16-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 13,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK20/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK20/16-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK20-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK20-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK20-16-XL",
      "NK20/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK20-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK20/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.6,
    "static_load_kN": 23.8,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 12900,
    "weight_g": 33.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×20 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 18.6 kN and C0 23.8 kN at the 20 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 21,100 r/min and the thermal reference speed 12,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 0.93 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 33.9 g, just 0.06 g per mm² of projected 28×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 20 mm bore this size balances the 28 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 20 mm journal brinels under the 23.8 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 21,100 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 28 mm outside diameter and 18.6 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 20 mm seat, and in textile machine heald and cam shafts the 33.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 23.8 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK20/20-XL?",
        "a": "The NK20/20-XL is a NK machined-ring needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 20 mm width, envelope 20×28×20 mm. Mass is 33.9 g."
      },
      {
        "q": "What does the NK20/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK20/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×20 mm and the catalogue ratings are C 18.6 kN, C0 23.8 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NK20/20-XL?",
        "a": "The basic dynamic load rating C is 18.6 kN and the basic static load rating C0 is 23.8 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NK20/20-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 12,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK20/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK20/20-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK20-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK20-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK20-20-XL",
      "NK20/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4902-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4902-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12,
    "static_load_kN": 13.6,
    "fatigue_load_limit_kN": 2.47,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 12000,
    "weight_g": 21.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×13 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 12 kN and C0 13.6 kN at the 20 mm seat; the C/C0 ratio of 0.88 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.47 kN, the limiting speed 21,100 r/min and the thermal reference speed 12,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.60 kN/mm and per millimetre of width 0.92 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21.7 g, just 0.06 g per mm² of projected 28×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 20 mm bore this size balances the 28 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range RNA4902-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 2.47 kN Cur value. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 28 mm outside diameter and 12 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 20 mm seat, and in copying and printing machine mechanisms the 21.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 13 mm width and the published 13.6 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4902-XL?",
        "a": "The RNA4902-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 13 mm width, envelope 20×28×13 mm. Mass is 21.7 g."
      },
      {
        "q": "What does the RNA4902-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4902-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×13 mm and the catalogue ratings are C 12 kN, C0 13.6 kN, Cur 2.47 kN."
      },
      {
        "q": "What is the load capacity of the RNA4902-XL?",
        "a": "The basic dynamic load rating C is 12 kN and the basic static load rating C0 is 13.6 kN; the fatigue load limit Cur is 2.47 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4902-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 12,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4902-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4902-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4902",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4902-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4902-XL",
      "RNA4902-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6902-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6902-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 19.5,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.55,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 11700,
    "weight_g": 39.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×23 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 19.5 kN and C0 25.5 kN at the 20 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 4.55 kN, the limiting speed 21,100 r/min and the thermal reference speed 11,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.97 kN/mm and per millimetre of width 0.85 kN/mm — the reason 23 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 39.7 g, just 0.06 g per mm² of projected 28×23 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Omitting the inner ring frees radial space — at a 20 mm shaft the outer diameter is only 28 mm and the width 23 mm, yet C is 19.5 kN This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 4.55 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 28 mm outside diameter and 19.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 20 mm seat, and in small electric motor accessory drives the 39.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 23 mm width and the published 25.5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6902-XL?",
        "a": "The RNA6902-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 23 mm width, envelope 20×28×23 mm. Mass is 39.7 g."
      },
      {
        "q": "What does the RNA6902-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6902-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×23 mm and the catalogue ratings are C 19.5 kN, C0 25.5 kN, Cur 4.55 kN."
      },
      {
        "q": "What is the load capacity of the RNA6902-XL?",
        "a": "The basic dynamic load rating C is 19.5 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.55 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6902-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 11,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6902-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6902-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6902",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6902-XL",
      "RNA6902-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS20-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26,
    "static_load_kN": 25,
    "fatigue_load_limit_kN": 4.5,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 11800,
    "weight_g": 48.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×32×20 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 25 kN at the 20 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 4.5 kN, the limiting speed 20,000 r/min and the thermal reference speed 11,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.30 kN/mm and per millimetre of width 1.30 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 48.7 g, just 0.08 g per mm² of projected 32×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 20 mm width and 26 kN C rating suit high-cycle industrial machinery rather than instrument duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The thin 6.0 mm section makes the 48.7 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 20,000 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 32 mm outside diameter and 26 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 20 mm seat, and in two-stroke and compressor piston pins the 48.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 25 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS20-XL?",
        "a": "The NKS20-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 32 mm outside diameter, 20 mm bore and 20 mm width, envelope 20×32×20 mm. Mass is 48.7 g."
      },
      {
        "q": "What does the NKS20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS20-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×32×20 mm and the catalogue ratings are C 26 kN, C0 25 kN, Cur 4.5 kN."
      },
      {
        "q": "What is the load capacity of the NKS20-XL?",
        "a": "The basic dynamic load rating C is 26 kN and the basic static load rating C0 is 25 kN; the fatigue load limit Cur is 4.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKS20-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 11,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS20-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS20-XL",
      "NKS20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK21-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK21/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 21,
    "D_mm": 29,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.2,
    "static_load_kN": 18.7,
    "fatigue_load_limit_kN": 3.5,
    "limiting_speed_rpm": 20600,
    "max_rpm": 20600,
    "reference_speed_rpm": 12600,
    "weight_g": 28.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 21×29×16 mm: 21 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 15.2 kN and C0 18.7 kN at the 21 mm seat; the C/C0 ratio of 0.81 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 29 mm outside diameter the fatigue load limit Cur is 3.5 kN, the limiting speed 20,600 r/min and the thermal reference speed 12,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.72 kN/mm and per millimetre of width 0.95 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 28.1 g, just 0.06 g per mm² of projected 29×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 21 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 3.5 kN and a 20,600 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins X-life status (-XL) indicates the current Schaeffler premium execution at 21 mm bore; the 18.7 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 29 mm outside diameter and 15.2 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 21 mm seat, and in copying and printing machine mechanisms the 28.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 16 mm width and the published 18.7 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK21/16-XL?",
        "a": "The NK21/16-XL is a NK machined-ring needle roller bearing without inner ring with 29 mm outside diameter, 21 mm bore and 16 mm width, envelope 21×29×16 mm. Mass is 28.1 g."
      },
      {
        "q": "What does the NK21/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK21/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 21×29×16 mm and the catalogue ratings are C 15.2 kN, C0 18.7 kN, Cur 3.5 kN."
      },
      {
        "q": "What is the load capacity of the NK21/16-XL?",
        "a": "The basic dynamic load rating C is 15.2 kN and the basic static load rating C0 is 18.7 kN; the fatigue load limit Cur is 3.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK21/16-XL?",
        "a": "The limiting speed is 20,600 r/min and the thermal reference speed is 12,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK21/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK21/16-XL has no inner ring, so the 21 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK21-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 21×29×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK21-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK21-16-XL",
      "NK21/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK21-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK21/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 21,
    "D_mm": 29,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 19.3,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.5,
    "limiting_speed_rpm": 20600,
    "max_rpm": 20600,
    "reference_speed_rpm": 12300,
    "weight_g": 35.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 21×29×20 mm: 21 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 19.3 kN and C0 25.5 kN at the 21 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 29 mm outside diameter the fatigue load limit Cur is 4.5 kN, the limiting speed 20,600 r/min and the thermal reference speed 12,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 0.97 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 35.2 g, just 0.06 g per mm² of projected 29×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 21 mm bore this size balances the 29 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range NK21/20-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 20,600 r/min limit. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 29 mm outside diameter and 19.3 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 21 mm seat, and in agricultural machine pivots and linkages the 35.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 25.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK21/20-XL?",
        "a": "The NK21/20-XL is a NK machined-ring needle roller bearing without inner ring with 29 mm outside diameter, 21 mm bore and 20 mm width, envelope 21×29×20 mm. Mass is 35.2 g."
      },
      {
        "q": "What does the NK21/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK21/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 21×29×20 mm and the catalogue ratings are C 19.3 kN, C0 25.5 kN, Cur 4.5 kN."
      },
      {
        "q": "What is the load capacity of the NK21/20-XL?",
        "a": "The basic dynamic load rating C is 19.3 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK21/20-XL?",
        "a": "The limiting speed is 20,600 r/min and the thermal reference speed is 12,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK21/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK21/20-XL has no inner ring, so the 21 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK21-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK21-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 21×29×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK21-20-XL",
      "NK21/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK22-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK22/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.8,
    "static_load_kN": 19.9,
    "fatigue_load_limit_kN": 3.75,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 12000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×30×16 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 15.8 kN and C0 19.9 kN at the 22 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 3.75 kN, the limiting speed 20,000 r/min and the thermal reference speed 12,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.72 kN/mm and per millimetre of width 0.99 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 30 g, just 0.06 g per mm² of projected 30×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 22 mm bore the 16 mm width and 15.8 kN C rating suit high-cycle industrial machinery rather than instrument duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Omitting the inner ring frees radial space — at a 22 mm shaft the outer diameter is only 30 mm and the width 16 mm, yet C is 15.8 kN X-life status (-XL) indicates the current Schaeffler premium execution at 22 mm bore; the 19.9 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 30 mm outside diameter and 15.8 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 22 mm seat, and in planetary gear bearings the 30 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 16 mm width and the published 19.9 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK22/16-XL?",
        "a": "The NK22/16-XL is a NK machined-ring needle roller bearing without inner ring with 30 mm outside diameter, 22 mm bore and 16 mm width, envelope 22×30×16 mm. Mass is 30 g."
      },
      {
        "q": "What does the NK22/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK22/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×30×16 mm and the catalogue ratings are C 15.8 kN, C0 19.9 kN, Cur 3.75 kN."
      },
      {
        "q": "What is the load capacity of the NK22/16-XL?",
        "a": "The basic dynamic load rating C is 15.8 kN and the basic static load rating C0 is 19.9 kN; the fatigue load limit Cur is 3.75 kN."
      },
      {
        "q": "What is the maximum speed of the NK22/16-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 12,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK22/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK22/16-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK22-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK22-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK22-16-XL",
      "NK22/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK22-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK22/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 20,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 4.8,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 11700,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×30×20 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 20 kN and C0 27 kN at the 22 mm seat; the C/C0 ratio of 0.74 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 4.8 kN, the limiting speed 20,000 r/min and the thermal reference speed 11,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.91 kN/mm and per millimetre of width 1.00 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 37 g, just 0.06 g per mm² of projected 30×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 22 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The thin 4.0 mm section makes the 37 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 20,000 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 30 mm outside diameter and 20 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 22 mm seat, and in copying and printing machine mechanisms the 37 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 27 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK22/20-XL?",
        "a": "The NK22/20-XL is a NK machined-ring needle roller bearing without inner ring with 30 mm outside diameter, 22 mm bore and 20 mm width, envelope 22×30×20 mm. Mass is 37 g."
      },
      {
        "q": "What does the NK22/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK22/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×30×20 mm and the catalogue ratings are C 20 kN, C0 27 kN, Cur 4.8 kN."
      },
      {
        "q": "What is the load capacity of the NK22/20-XL?",
        "a": "The basic dynamic load rating C is 20 kN and the basic static load rating C0 is 27 kN; the fatigue load limit Cur is 4.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK22/20-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 11,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK22/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK22/20-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK22-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK22-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK22-20-XL",
      "NK22/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4903-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4903-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12.4,
    "static_load_kN": 14.6,
    "fatigue_load_limit_kN": 2.65,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 10900,
    "weight_g": 22.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×30×13 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 12.4 kN and C0 14.6 kN at the 22 mm seat; the C/C0 ratio of 0.85 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 2.65 kN, the limiting speed 20,000 r/min and the thermal reference speed 10,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.56 kN/mm and per millimetre of width 0.95 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 22.2 g, just 0.06 g per mm² of projected 30×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 22 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty RNA4903-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality With Cur 2.65 kN and a 20,000 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 12.4 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 30 mm outside diameter and 12.4 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 22 mm seat, and in two-stroke and compressor piston pins the 22.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 13 mm width and the published 14.6 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4903-XL?",
        "a": "The RNA4903-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 30 mm outside diameter, 22 mm bore and 13 mm width, envelope 22×30×13 mm. Mass is 22.2 g."
      },
      {
        "q": "What does the RNA4903-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4903-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×30×13 mm and the catalogue ratings are C 12.4 kN, C0 14.6 kN, Cur 2.65 kN."
      },
      {
        "q": "What is the load capacity of the RNA4903-XL?",
        "a": "The basic dynamic load rating C is 12.4 kN and the basic static load rating C0 is 14.6 kN; the fatigue load limit Cur is 2.65 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4903-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 10,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4903-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4903-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4903",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4903-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4903-XL",
      "RNA4903-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6903-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6903-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.1,
    "static_load_kN": 29,
    "fatigue_load_limit_kN": 5.2,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 10500,
    "weight_g": 42.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×30×23 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 21.1 kN and C0 29 kN at the 22 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 5.2 kN, the limiting speed 20,000 r/min and the thermal reference speed 10,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 0.92 kN/mm — the reason 23 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42.4 g, just 0.06 g per mm² of projected 30×23 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 22 mm bore the 23 mm width and 21.1 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 22 mm journal brinels under the 29 kN static rating, and roughness above raceway finish accelerates roller wear Omitting the inner ring frees radial space — at a 22 mm shaft the outer diameter is only 30 mm and the width 23 mm, yet C is 21.1 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 5.2 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 30 mm outside diameter and 21.1 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 22 mm seat, and in gearbox selector and change linkages the 42.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 23 mm width and the published 29 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6903-XL?",
        "a": "The RNA6903-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 30 mm outside diameter, 22 mm bore and 23 mm width, envelope 22×30×23 mm. Mass is 42.4 g."
      },
      {
        "q": "What does the RNA6903-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6903-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×30×23 mm and the catalogue ratings are C 21.1 kN, C0 29 kN, Cur 5.2 kN."
      },
      {
        "q": "What is the load capacity of the RNA6903-XL?",
        "a": "The basic dynamic load rating C is 21.1 kN and the basic static load rating C0 is 29 kN; the fatigue load limit Cur is 5.2 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6903-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 10,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6903-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6903-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6903",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6903-XL",
      "RNA6903-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS22-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS22-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 35,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 5,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 10900,
    "weight_g": 61.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×35×20 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 28 kN at the 22 mm seat; the C/C0 ratio of 0.98 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 5 kN, the limiting speed 18,500 r/min and the thermal reference speed 10,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61.5 g, just 0.09 g per mm² of projected 35×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 22 mm bore this size balances the 35 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The thin 6.5 mm section makes the 61.5 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting With Cur 5 kN and a 18,500 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 18,500 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 35 mm outside diameter and 27.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 22 mm seat, and in copying and printing machine mechanisms the 61.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 28 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS22-XL?",
        "a": "The NKS22-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 35 mm outside diameter, 22 mm bore and 20 mm width, envelope 22×35×20 mm. Mass is 61.5 g."
      },
      {
        "q": "What does the NKS22-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS22-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×35×20 mm and the catalogue ratings are C 27.5 kN, C0 28 kN, Cur 5 kN."
      },
      {
        "q": "What is the load capacity of the NKS22-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 28 kN; the fatigue load limit Cur is 5 kN."
      },
      {
        "q": "What is the maximum speed of the NKS22-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 10,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS22-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS22-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS22-XL",
      "NKS22-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK24-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK24/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.9,
    "static_load_kN": 22.3,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 11000,
    "weight_g": 31.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 24×32×16 mm: 24 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 16.9 kN and C0 22.3 kN at the 24 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 18,500 r/min and the thermal reference speed 11,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.70 kN/mm and per millimetre of width 1.06 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 31.9 g, just 0.06 g per mm² of projected 32×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 24 mm bore this size balances the 32 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range With Cur 4.2 kN and a 18,500 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins Omitting the inner ring frees radial space — at a 24 mm shaft the outer diameter is only 32 mm and the width 16 mm, yet C is 16.9 kN X-life status (-XL) indicates the current Schaeffler premium execution at 24 mm bore; the 22.3 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 32 mm outside diameter and 16.9 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 24 mm seat, and in two-stroke and compressor piston pins the 31.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 16 mm width and the published 22.3 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK24/16-XL?",
        "a": "The NK24/16-XL is a NK machined-ring needle roller bearing without inner ring with 32 mm outside diameter, 24 mm bore and 16 mm width, envelope 24×32×16 mm. Mass is 31.9 g."
      },
      {
        "q": "What does the NK24/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK24/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 24×32×16 mm and the catalogue ratings are C 16.9 kN, C0 22.3 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NK24/16-XL?",
        "a": "The basic dynamic load rating C is 16.9 kN and the basic static load rating C0 is 22.3 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NK24/16-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 11,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK24/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK24/16-XL has no inner ring, so the 24 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK24-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK24-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK24-16-XL",
      "NK24/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK24-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK24/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.4,
    "static_load_kN": 30.5,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 10700,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 24×32×20 mm: 24 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 21.4 kN and C0 30.5 kN at the 24 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 18,500 r/min and the thermal reference speed 10,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 1.07 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 40 g, just 0.06 g per mm² of projected 32×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 24 mm bore the 20 mm width and 21.4 kN C rating suit high-cycle industrial machinery rather than instrument duty Omitting the inner ring frees radial space — at a 24 mm shaft the outer diameter is only 32 mm and the width 20 mm, yet C is 21.4 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 24×32×20 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 32 mm outside diameter and 21.4 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 24 mm seat, and in connecting-rod small ends the 40 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 30.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK24/20-XL?",
        "a": "The NK24/20-XL is a NK machined-ring needle roller bearing without inner ring with 32 mm outside diameter, 24 mm bore and 20 mm width, envelope 24×32×20 mm. Mass is 40 g."
      },
      {
        "q": "What does the NK24/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK24/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 24×32×20 mm and the catalogue ratings are C 21.4 kN, C0 30.5 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the NK24/20-XL?",
        "a": "The basic dynamic load rating C is 21.4 kN and the basic static load rating C0 is 30.5 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the NK24/20-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 10,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK24/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK24/20-XL has no inner ring, so the 24 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK24-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK24-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 24×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK24-20-XL",
      "NK24/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS24-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS24-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 29.5,
    "static_load_kN": 31,
    "fatigue_load_limit_kN": 5.5,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 10100,
    "weight_g": 65.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 24×37×20 mm: 24 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 29.5 kN and C0 31 kN at the 24 mm seat; the C/C0 ratio of 0.95 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 5.5 kN, the limiting speed 17,200 r/min and the thermal reference speed 10,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.23 kN/mm and per millimetre of width 1.48 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 65.5 g, just 0.09 g per mm² of projected 37×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 24 mm bore this size balances the 37 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range NKS24-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened X-life status (-XL) indicates the current Schaeffler premium execution at 24 mm bore; the 31 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 37 mm outside diameter and 29.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 24 mm seat, and in gearbox selector and change linkages the 65.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 20 mm width and the published 31 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS24-XL?",
        "a": "The NKS24-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 37 mm outside diameter, 24 mm bore and 20 mm width, envelope 24×37×20 mm. Mass is 65.5 g."
      },
      {
        "q": "What does the NKS24-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS24-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 24×37×20 mm and the catalogue ratings are C 29.5 kN, C0 31 kN, Cur 5.5 kN."
      },
      {
        "q": "What is the load capacity of the NKS24-XL?",
        "a": "The basic dynamic load rating C is 29.5 kN and the basic static load rating C0 is 31 kN; the fatigue load limit Cur is 5.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKS24-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 10,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS24-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS24-XL has no inner ring, so the 24 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS24",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 24×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS24-XL",
      "NKS24-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK25-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK25/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 33,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.8,
    "static_load_kN": 22.4,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 17800,
    "max_rpm": 17800,
    "reference_speed_rpm": 10700,
    "weight_g": 32.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×33×16 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 16.8 kN and C0 22.4 kN at the 25 mm seat; the C/C0 ratio of 0.75 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 33 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 17,800 r/min and the thermal reference speed 10,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.67 kN/mm and per millimetre of width 1.05 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 32.6 g, just 0.06 g per mm² of projected 33×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 25 mm bore this size balances the 33 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The hardness requirement is unforgiving: below about 58 HRC the 25 mm journal brinels under the 22.4 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 17,800 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 33 mm outside diameter and 16.8 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 25 mm seat, and in hydraulic and pneumatic pump eccentrics the 32.6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 16 mm width and the published 22.4 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK25/16-XL?",
        "a": "The NK25/16-XL is a NK machined-ring needle roller bearing without inner ring with 33 mm outside diameter, 25 mm bore and 16 mm width, envelope 25×33×16 mm. Mass is 32.6 g."
      },
      {
        "q": "What does the NK25/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK25/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×33×16 mm and the catalogue ratings are C 16.8 kN, C0 22.4 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NK25/16-XL?",
        "a": "The basic dynamic load rating C is 16.8 kN and the basic static load rating C0 is 22.4 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NK25/16-XL?",
        "a": "The limiting speed is 17,800 r/min and the thermal reference speed is 10,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK25/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK25/16-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK25-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×33×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK25-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK25-16-XL",
      "NK25/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK25-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK25/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 33,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.3,
    "static_load_kN": 30.5,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 17800,
    "max_rpm": 17800,
    "reference_speed_rpm": 10400,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×33×20 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 21.3 kN and C0 30.5 kN at the 25 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 33 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 17,800 r/min and the thermal reference speed 10,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.85 kN/mm and per millimetre of width 1.06 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42 g, just 0.06 g per mm² of projected 33×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 25 mm bore the 20 mm width and 21.3 kN C rating suit high-cycle industrial machinery rather than instrument duty The thin 4.0 mm section makes the 42 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 25×33×20 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 33 mm outside diameter and 21.3 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 25 mm seat, and in textile machine heald and cam shafts the 42 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 30.5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK25/20-XL?",
        "a": "The NK25/20-XL is a NK machined-ring needle roller bearing without inner ring with 33 mm outside diameter, 25 mm bore and 20 mm width, envelope 25×33×20 mm. Mass is 42 g."
      },
      {
        "q": "What does the NK25/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK25/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×33×20 mm and the catalogue ratings are C 21.3 kN, C0 30.5 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the NK25/20-XL?",
        "a": "The basic dynamic load rating C is 21.3 kN and the basic static load rating C0 is 30.5 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the NK25/20-XL?",
        "a": "The limiting speed is 17,800 r/min and the thermal reference speed is 10,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK25/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK25/20-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK25-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK25-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×33×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK25-20-XL",
      "NK25/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4904-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4904-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.7,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.7,
    "limiting_speed_rpm": 16900,
    "max_rpm": 16900,
    "reference_speed_rpm": 9900,
    "weight_g": 52.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×37×17 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 23.7 kN and C0 25.5 kN at the 25 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 4.7 kN, the limiting speed 16,900 r/min and the thermal reference speed 9,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 1.39 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 52.3 g, just 0.08 g per mm² of projected 37×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The hardness requirement is unforgiving: below about 58 HRC the 25 mm journal brinels under the 25.5 kN static rating, and roughness above raceway finish accelerates roller wear -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 23.7 kN C rating and longer nominal life come without an envelope change. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 37 mm outside diameter and 23.7 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 25 mm seat, and in planetary gear bearings the 52.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 17 mm width and the published 25.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4904-XL?",
        "a": "The RNA4904-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 37 mm outside diameter, 25 mm bore and 17 mm width, envelope 25×37×17 mm. Mass is 52.3 g."
      },
      {
        "q": "What does the RNA4904-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4904-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×37×17 mm and the catalogue ratings are C 23.7 kN, C0 25.5 kN, Cur 4.7 kN."
      },
      {
        "q": "What is the load capacity of the RNA4904-XL?",
        "a": "The basic dynamic load rating C is 23.7 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.7 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4904-XL?",
        "a": "The limiting speed is 16,900 r/min and the thermal reference speed is 9,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4904-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4904-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4904",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA4904-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×17 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4904-XL",
      "RNA4904-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6904-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6904-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 40.5,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 9.2,
    "limiting_speed_rpm": 16900,
    "max_rpm": 16900,
    "reference_speed_rpm": 9500,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×37×30 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 40.5 kN and C0 51 kN at the 25 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 9.2 kN, the limiting speed 16,900 r/min and the thermal reference speed 9,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.62 kN/mm and per millimetre of width 1.35 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 100 g, just 0.09 g per mm² of projected 37×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 25 mm bore the 30 mm width and 40.5 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 25 mm journal brinels under the 51 kN static rating, and roughness above raceway finish accelerates roller wear Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 40.5 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 37 mm outside diameter and 40.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 25 mm seat, and in two-stroke and compressor piston pins the 100 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 30 mm width and the published 51 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6904-XL?",
        "a": "The RNA6904-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 37 mm outside diameter, 25 mm bore and 30 mm width, envelope 25×37×30 mm. Mass is 100 g."
      },
      {
        "q": "What does the RNA6904-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6904-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×37×30 mm and the catalogue ratings are C 40.5 kN, C0 51 kN, Cur 9.2 kN."
      },
      {
        "q": "What is the load capacity of the RNA6904-XL?",
        "a": "The basic dynamic load rating C is 40.5 kN and the basic static load rating C0 is 51 kN; the fatigue load limit Cur is 9.2 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6904-XL?",
        "a": "The limiting speed is 16,900 r/min and the thermal reference speed is 9,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6904-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6904-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6904",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6904-XL",
      "RNA6904-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS25-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 31,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 5.9,
    "limiting_speed_rpm": 16600,
    "max_rpm": 16600,
    "reference_speed_rpm": 9700,
    "weight_g": 68.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×38×20 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 31 kN and C0 33.5 kN at the 25 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 5.9 kN, the limiting speed 16,600 r/min and the thermal reference speed 9,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.24 kN/mm and per millimetre of width 1.55 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 68.1 g, just 0.09 g per mm² of projected 38×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 25 mm bore this size balances the 38 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The thin 6.5 mm section makes the 68.1 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The hardness requirement is unforgiving: below about 58 HRC the 25 mm journal brinels under the 33.5 kN static rating, and roughness above raceway finish accelerates roller wear X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 33.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 38 mm outside diameter and 31 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 25 mm seat, and in agricultural machine pivots and linkages the 68.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 33.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS25-XL?",
        "a": "The NKS25-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 38 mm outside diameter, 25 mm bore and 20 mm width, envelope 25×38×20 mm. Mass is 68.1 g."
      },
      {
        "q": "What does the NKS25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS25-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×38×20 mm and the catalogue ratings are C 31 kN, C0 33.5 kN, Cur 5.9 kN."
      },
      {
        "q": "What is the load capacity of the NKS25-XL?",
        "a": "The basic dynamic load rating C is 31 kN and the basic static load rating C0 is 33.5 kN; the fatigue load limit Cur is 5.9 kN."
      },
      {
        "q": "What is the maximum speed of the NKS25-XL?",
        "a": "The limiting speed is 16,600 r/min and the thermal reference speed is 9,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS25-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS25-XL",
      "NKS25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK26-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK26/16-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 26,
    "D_mm": 34,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 17.3,
    "static_load_kN": 23.6,
    "fatigue_load_limit_kN": 4.45,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 10300,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 26×34×16 mm: 26 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 17.3 kN and C0 23.6 kN at the 26 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 34 mm outside diameter the fatigue load limit Cur is 4.45 kN, the limiting speed 17,200 r/min and the thermal reference speed 10,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.67 kN/mm and per millimetre of width 1.08 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 34 g, just 0.06 g per mm² of projected 34×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 26 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Omitting the inner ring frees radial space — at a 26 mm shaft the outer diameter is only 34 mm and the width 16 mm, yet C is 17.3 kN This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 17,200 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 34 mm outside diameter and 17.3 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 26 mm seat, and in gearbox selector and change linkages the 34 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 16 mm width and the published 23.6 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK26/16-XL?",
        "a": "The NK26/16-XL is a NK machined-ring needle roller bearing without inner ring with 34 mm outside diameter, 26 mm bore and 16 mm width, envelope 26×34×16 mm. Mass is 34 g."
      },
      {
        "q": "What does the NK26/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK26/16-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 26×34×16 mm and the catalogue ratings are C 17.3 kN, C0 23.6 kN, Cur 4.45 kN."
      },
      {
        "q": "What is the load capacity of the NK26/16-XL?",
        "a": "The basic dynamic load rating C is 17.3 kN and the basic static load rating C0 is 23.6 kN; the fatigue load limit Cur is 4.45 kN."
      },
      {
        "q": "What is the maximum speed of the NK26/16-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 10,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK26/16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK26/16-XL has no inner ring, so the 26 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK26-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 26×34×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK26-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK26-16-XL",
      "NK26/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK26-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK26/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 26,
    "D_mm": 34,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 5.7,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 10100,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 26×34×20 mm: 26 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 22 kN and C0 32 kN at the 26 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 34 mm outside diameter the fatigue load limit Cur is 5.7 kN, the limiting speed 17,200 r/min and the thermal reference speed 10,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.85 kN/mm and per millimetre of width 1.10 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42 g, just 0.06 g per mm² of projected 34×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 26 mm bore this size balances the 34 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 26 mm shaft the outer diameter is only 34 mm and the width 20 mm, yet C is 22 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 26×34×20 mm envelope. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 34 mm outside diameter and 22 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 26 mm seat, and in hydraulic and pneumatic pump eccentrics the 42 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 32 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK26/20-XL?",
        "a": "The NK26/20-XL is a NK machined-ring needle roller bearing without inner ring with 34 mm outside diameter, 26 mm bore and 20 mm width, envelope 26×34×20 mm. Mass is 42 g."
      },
      {
        "q": "What does the NK26/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK26/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 26×34×20 mm and the catalogue ratings are C 22 kN, C0 32 kN, Cur 5.7 kN."
      },
      {
        "q": "What is the load capacity of the NK26/20-XL?",
        "a": "The basic dynamic load rating C is 22 kN and the basic static load rating C0 is 32 kN; the fatigue load limit Cur is 5.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK26/20-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 10,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK26/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK26/20-XL has no inner ring, so the 26 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK26-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK26-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 26×34×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK26-20-XL",
      "NK26/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK28-20-D-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK28/20-D-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 29,
    "static_load_kN": 41.5,
    "fatigue_load_limit_kN": 7.5,
    "limiting_speed_rpm": 15800,
    "max_rpm": 15800,
    "reference_speed_rpm": 8800,
    "weight_g": 58,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×37×20 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 29 kN and C0 41.5 kN at the 28 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 7.5 kN, the limiting speed 15,800 r/min and the thermal reference speed 8,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 1.45 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 58 g, just 0.08 g per mm² of projected 37×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 28 mm bore this size balances the 37 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 28×37×20 mm envelope. The split -D cage targets positions where the shaft cannot be threaded through an intact bearing; seating and axial retention must follow the mounting instructions. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 37 mm outside diameter and 29 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 28 mm seat, and in two-stroke and compressor piston pins the 58 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 41.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK28/20-D-XL?",
        "a": "The NK28/20-D-XL is a NK machined-ring needle roller bearing without inner ring with 37 mm outside diameter, 28 mm bore and 20 mm width, envelope 28×37×20 mm. Mass is 58 g."
      },
      {
        "q": "What does the NK28/20-D-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK28/20-D-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×37×20 mm and the catalogue ratings are C 29 kN, C0 41.5 kN, Cur 7.5 kN."
      },
      {
        "q": "What is the load capacity of the NK28/20-D-XL?",
        "a": "The basic dynamic load rating C is 29 kN and the basic static load rating C0 is 41.5 kN; the fatigue load limit Cur is 7.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK28/20-D-XL?",
        "a": "The limiting speed is 15,800 r/min and the thermal reference speed is 8,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK28/20-D-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK28/20-D-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK28-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK28-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK28-20-D-XL",
      "NK28/20-D-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK28-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK28/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 24.8,
    "static_load_kN": 34,
    "fatigue_load_limit_kN": 6,
    "limiting_speed_rpm": 15800,
    "max_rpm": 15800,
    "reference_speed_rpm": 9300,
    "weight_g": 52.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×37×20 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 24.8 kN and C0 34 kN at the 28 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 6 kN, the limiting speed 15,800 r/min and the thermal reference speed 9,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 1.24 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 52.2 g, just 0.07 g per mm² of projected 37×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 28 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 28 mm shaft the outer diameter is only 37 mm and the width 20 mm, yet C is 24.8 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 24.8 kN C rating and longer nominal life come without an envelope change. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 37 mm outside diameter and 24.8 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 28 mm seat, and in motorcycle and light-vehicle transmissions the 52.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 20 mm width and the published 34 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK28/20-XL?",
        "a": "The NK28/20-XL is a NK machined-ring needle roller bearing without inner ring with 37 mm outside diameter, 28 mm bore and 20 mm width, envelope 28×37×20 mm. Mass is 52.2 g."
      },
      {
        "q": "What does the NK28/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK28/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×37×20 mm and the catalogue ratings are C 24.8 kN, C0 34 kN, Cur 6 kN."
      },
      {
        "q": "What is the load capacity of the NK28/20-XL?",
        "a": "The basic dynamic load rating C is 24.8 kN and the basic static load rating C0 is 34 kN; the fatigue load limit Cur is 6 kN."
      },
      {
        "q": "What is the maximum speed of the NK28/20-XL?",
        "a": "The limiting speed is 15,800 r/min and the thermal reference speed is 9,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK28/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK28/20-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK28-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK28-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK28-20-XL",
      "NK28/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK28-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK28/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 37,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 10.7,
    "limiting_speed_rpm": 15800,
    "max_rpm": 15800,
    "reference_speed_rpm": 9000,
    "weight_g": 82,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×37×30 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 28 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 10.7 kN, the limiting speed 15,800 r/min and the thermal reference speed 9,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.32 kN/mm and per millimetre of width 1.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 82 g, just 0.07 g per mm² of projected 37×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 28 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The thin 4.5 mm section makes the 82 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 28×37×30 mm envelope. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 37 mm outside diameter and 37 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 28 mm seat, and in gearbox selector and change linkages the 82 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 57 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK28/30-XL?",
        "a": "The NK28/30-XL is a NK machined-ring needle roller bearing without inner ring with 37 mm outside diameter, 28 mm bore and 30 mm width, envelope 28×37×30 mm. Mass is 82 g."
      },
      {
        "q": "What does the NK28/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK28/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×37×30 mm and the catalogue ratings are C 37 kN, C0 57 kN, Cur 10.7 kN."
      },
      {
        "q": "What is the load capacity of the NK28/30-XL?",
        "a": "The basic dynamic load rating C is 37 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 10.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK28/30-XL?",
        "a": "The limiting speed is 15,800 r/min and the thermal reference speed is 9,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK28/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK28/30-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK28-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK28-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK28-30-XL",
      "NK28/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-22-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA49/22-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 39,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26,
    "static_load_kN": 29.5,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8600,
    "weight_g": 50.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×39×17 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.5 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 29.5 kN at the 28 mm seat; the C/C0 ratio of 0.88 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 39 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 1.53 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 50.2 g, just 0.08 g per mm² of projected 39×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 28 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 5.4 kN and a 15,300 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 28×39×17 mm envelope. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 39 mm outside diameter and 26 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 28 mm seat, and in agricultural machine pivots and linkages the 50.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 17 mm width and the published 29.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA49/22-XL?",
        "a": "The RNA49/22-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 39 mm outside diameter, 28 mm bore and 17 mm width, envelope 28×39×17 mm. Mass is 50.2 g."
      },
      {
        "q": "What does the RNA49/22-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA49/22-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×39×17 mm and the catalogue ratings are C 26 kN, C0 29.5 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the RNA49/22-XL?",
        "a": "The basic dynamic load rating C is 26 kN and the basic static load rating C0 is 29.5 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the RNA49/22-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA49/22-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA49/22-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×39×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA49-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-22-XL",
      "RNA49/22-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-22-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA69/22-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 39,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 42,
    "static_load_kN": 55,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8400,
    "weight_g": 98,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×39×30 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.5 mm radial section packed with small-diameter needle rollers C is 42 kN and C0 55 kN at the 28 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 39 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.50 kN/mm and per millimetre of width 1.40 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 98 g, just 0.08 g per mm² of projected 39×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 28 mm bore this size balances the 39 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The hardness requirement is unforgiving: below about 58 HRC the 28 mm journal brinels under the 55 kN static rating, and roughness above raceway finish accelerates roller wear X-life status (-XL) indicates the current Schaeffler premium execution at 28 mm bore; the 55 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 39 mm outside diameter and 42 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 28 mm seat, and in two-stroke and compressor piston pins the 98 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 30 mm width and the published 55 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA69/22-XL?",
        "a": "The RNA69/22-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 39 mm outside diameter, 28 mm bore and 30 mm width, envelope 28×39×30 mm. Mass is 98 g."
      },
      {
        "q": "What does the RNA69/22-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA69/22-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×39×30 mm and the catalogue ratings are C 42 kN, C0 55 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the RNA69/22-XL?",
        "a": "The basic dynamic load rating C is 42 kN and the basic static load rating C0 is 55 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the RNA69/22-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA69/22-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA69/22-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×39×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA69-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-22-XL",
      "RNA69/22-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS28-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS28-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32.5,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 6.5,
    "limiting_speed_rpm": 15100,
    "max_rpm": 15100,
    "reference_speed_rpm": 8900,
    "weight_g": 83.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×42×20 mm: 28 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 32.5 kN and C0 36.5 kN at the 28 mm seat; the C/C0 ratio of 0.89 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 6.5 kN, the limiting speed 15,100 r/min and the thermal reference speed 8,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.16 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 83.6 g, just 0.10 g per mm² of projected 42×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 28 mm bore this size balances the 42 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The thin 7.0 mm section makes the 83.6 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 6.5 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 42 mm outside diameter and 32.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 28 mm seat, and in connecting-rod small ends the 83.6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 36.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS28-XL?",
        "a": "The NKS28-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 42 mm outside diameter, 28 mm bore and 20 mm width, envelope 28×42×20 mm. Mass is 83.6 g."
      },
      {
        "q": "What does the NKS28-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS28-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×42×20 mm and the catalogue ratings are C 32.5 kN, C0 36.5 kN, Cur 6.5 kN."
      },
      {
        "q": "What is the load capacity of the NKS28-XL?",
        "a": "The basic dynamic load rating C is 32.5 kN and the basic static load rating C0 is 36.5 kN; the fatigue load limit Cur is 6.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKS28-XL?",
        "a": "The limiting speed is 15,100 r/min and the thermal reference speed is 8,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS28-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS28-XL has no inner ring, so the 28 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS28",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS28-XL",
      "NKS28-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK29-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK29/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 29,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 7,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8700,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 29×38×20 mm: 29 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 39 kN at the 29 mm seat; the C/C0 ratio of 0.71 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 7 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 50 g, just 0.07 g per mm² of projected 38×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 29 mm bore the 20 mm width and 27.5 kN C rating suit high-cycle industrial machinery rather than instrument duty With Cur 7 kN and a 15,300 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The hardness requirement is unforgiving: below about 58 HRC the 29 mm journal brinels under the 39 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 29×38×20 mm envelope. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 50 g in the 38 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 38 mm outside diameter and 27.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 29 mm seat, and in connecting-rod small ends the 50 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 39 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK29/20-TV-XL?",
        "a": "The NK29/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 38 mm outside diameter, 29 mm bore and 20 mm width, envelope 29×38×20 mm. Mass is 50 g."
      },
      {
        "q": "What does the NK29/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK29/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 29×38×20 mm and the catalogue ratings are C 27.5 kN, C0 39 kN, Cur 7 kN."
      },
      {
        "q": "What is the load capacity of the NK29/20-TV-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 39 kN; the fatigue load limit Cur is 7 kN."
      },
      {
        "q": "What is the maximum speed of the NK29/20-TV-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK29/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK29/20-TV-XL has no inner ring, so the 29 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK29-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 29×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK29-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK29-20-TV-XL",
      "NK29/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK29-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK29/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 29,
    "D_mm": 38,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 37,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 10.7,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8800,
    "weight_g": 84.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 29×38×30 mm: 29 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 29 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 10.7 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.28 kN/mm and per millimetre of width 1.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 84.3 g, just 0.07 g per mm² of projected 38×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 29 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The hardness requirement is unforgiving: below about 58 HRC the 29 mm journal brinels under the 57 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 29×38×30 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 38 mm outside diameter and 37 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 29 mm seat, and in planetary gear bearings the 84.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 57 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK29/30-XL?",
        "a": "The NK29/30-XL is a NK machined-ring needle roller bearing without inner ring with 38 mm outside diameter, 29 mm bore and 30 mm width, envelope 29×38×30 mm. Mass is 84.3 g."
      },
      {
        "q": "What does the NK29/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK29/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 29×38×30 mm and the catalogue ratings are C 37 kN, C0 57 kN, Cur 10.7 kN."
      },
      {
        "q": "What is the load capacity of the NK29/30-XL?",
        "a": "The basic dynamic load rating C is 37 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 10.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK29/30-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK29/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK29/30-XL has no inner ring, so the 29 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK29-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK29-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 29×38×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=949",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK29-30-XL",
      "NK29/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK30-20-TW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK30/20-TW-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 35.5,
    "fatigue_load_limit_kN": 7.4,
    "limiting_speed_rpm": 14800,
    "max_rpm": 14800,
    "reference_speed_rpm": 8900,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×40×20 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 35.5 kN at the 30 mm seat; the C/C0 ratio of 0.77 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 40 mm outside diameter the fatigue load limit Cur is 7.4 kN, the limiting speed 14,800 r/min and the thermal reference speed 8,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61 g, just 0.08 g per mm² of projected 40×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 30 mm bore this size balances the 40 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 27.5 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 40 mm outside diameter and 27.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 30 mm seat, and in two-stroke and compressor piston pins the 61 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 35.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK30/20-TW-XL?",
        "a": "The NK30/20-TW-XL is a NK machined-ring needle roller bearing without inner ring with 40 mm outside diameter, 30 mm bore and 20 mm width, envelope 30×40×20 mm. Mass is 61 g."
      },
      {
        "q": "What does the NK30/20-TW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK30/20-TW-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×40×20 mm and the catalogue ratings are C 27.5 kN, C0 35.5 kN, Cur 7.4 kN."
      },
      {
        "q": "What is the load capacity of the NK30/20-TW-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 35.5 kN; the fatigue load limit Cur is 7.4 kN."
      },
      {
        "q": "What is the maximum speed of the NK30/20-TW-XL?",
        "a": "The limiting speed is 14,800 r/min and the thermal reference speed is 8,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK30/20-TW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK30/20-TW-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK30-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×40×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK30-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK30-20-TW-XL",
      "NK30/20-TW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK30-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK30/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 28,
    "static_load_kN": 41,
    "fatigue_load_limit_kN": 7.3,
    "limiting_speed_rpm": 14800,
    "max_rpm": 14800,
    "reference_speed_rpm": 8500,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×40×20 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 28 kN and C0 41 kN at the 30 mm seat; the C/C0 ratio of 0.68 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 40 mm outside diameter the fatigue load limit Cur is 7.3 kN, the limiting speed 14,800 r/min and the thermal reference speed 8,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 1.40 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61 g, just 0.08 g per mm² of projected 40×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 30 mm bore this size balances the 40 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range With Cur 7.3 kN and a 14,800 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 28 kN C rating and longer nominal life come without an envelope change. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 14,800 r/min. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 40 mm outside diameter and 28 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 30 mm seat, and in textile machine heald and cam shafts the 61 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 41 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK30/20-TV-XL?",
        "a": "The NK30/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 40 mm outside diameter, 30 mm bore and 20 mm width, envelope 30×40×20 mm. Mass is 61 g."
      },
      {
        "q": "What does the NK30/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK30/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×40×20 mm and the catalogue ratings are C 28 kN, C0 41 kN, Cur 7.3 kN."
      },
      {
        "q": "What is the load capacity of the NK30/20-TV-XL?",
        "a": "The basic dynamic load rating C is 28 kN and the basic static load rating C0 is 41 kN; the fatigue load limit Cur is 7.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK30/20-TV-XL?",
        "a": "The limiting speed is 14,800 r/min and the thermal reference speed is 8,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK30/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK30/20-TV-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK30-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×40×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK30-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK30-20-TV-XL",
      "NK30/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK30-30-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK30/30-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 42,
    "static_load_kN": 69,
    "fatigue_load_limit_kN": 12.9,
    "limiting_speed_rpm": 14800,
    "max_rpm": 14800,
    "reference_speed_rpm": 8200,
    "weight_g": 92.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×40×30 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 42 kN and C0 69 kN at the 30 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 40 mm outside diameter the fatigue load limit Cur is 12.9 kN, the limiting speed 14,800 r/min and the thermal reference speed 8,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.40 kN/mm and per millimetre of width 1.40 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 92.4 g, just 0.08 g per mm² of projected 40×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With Cur 12.9 kN and a 14,800 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins Omitting the inner ring frees radial space — at a 30 mm shaft the outer diameter is only 40 mm and the width 30 mm, yet C is 42 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 30×40×30 mm envelope. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 40 mm outside diameter and 42 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 30 mm seat, and in motorcycle and light-vehicle transmissions the 92.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 30 mm width and the published 69 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK30/30-TV-XL?",
        "a": "The NK30/30-TV-XL is a NK machined-ring needle roller bearing without inner ring with 40 mm outside diameter, 30 mm bore and 30 mm width, envelope 30×40×30 mm. Mass is 92.4 g."
      },
      {
        "q": "What does the NK30/30-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK30/30-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×40×30 mm and the catalogue ratings are C 42 kN, C0 69 kN, Cur 12.9 kN."
      },
      {
        "q": "What is the load capacity of the NK30/30-TV-XL?",
        "a": "The basic dynamic load rating C is 42 kN and the basic static load rating C0 is 69 kN; the fatigue load limit Cur is 12.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK30/30-TV-XL?",
        "a": "The limiting speed is 14,800 r/min and the thermal reference speed is 8,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK30/30-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK30/30-TV-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK30-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK30-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×40×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK30-30-TV-XL",
      "NK30/30-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4905-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4905-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26.5,
    "static_load_kN": 31.5,
    "fatigue_load_limit_kN": 5.8,
    "limiting_speed_rpm": 14400,
    "max_rpm": 14400,
    "reference_speed_rpm": 8100,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×42×17 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 26.5 kN and C0 31.5 kN at the 30 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 5.8 kN, the limiting speed 14,400 r/min and the thermal reference speed 8,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 1.56 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61 g, just 0.09 g per mm² of projected 42×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The thin 6.0 mm section makes the 61 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 30 mm shaft the outer diameter is only 42 mm and the width 17 mm, yet C is 26.5 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 26.5 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 42 mm outside diameter and 26.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 30 mm seat, and in hydraulic and pneumatic pump eccentrics the 61 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 17 mm width and the published 31.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4905-XL?",
        "a": "The RNA4905-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 42 mm outside diameter, 30 mm bore and 17 mm width, envelope 30×42×17 mm. Mass is 61 g."
      },
      {
        "q": "What does the RNA4905-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4905-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×42×17 mm and the catalogue ratings are C 26.5 kN, C0 31.5 kN, Cur 5.8 kN."
      },
      {
        "q": "What is the load capacity of the RNA4905-XL?",
        "a": "The basic dynamic load rating C is 26.5 kN and the basic static load rating C0 is 31.5 kN; the fatigue load limit Cur is 5.8 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4905-XL?",
        "a": "The limiting speed is 14,400 r/min and the thermal reference speed is 8,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4905-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4905-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4905",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA4905-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×17 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4905-XL",
      "RNA4905-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6905-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6905-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 59,
    "fatigue_load_limit_kN": 10.8,
    "limiting_speed_rpm": 14400,
    "max_rpm": 14400,
    "reference_speed_rpm": 7900,
    "weight_g": 112,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×42×30 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 59 kN at the 30 mm seat; the C/C0 ratio of 0.75 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 10.8 kN, the limiting speed 14,400 r/min and the thermal reference speed 7,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.47 kN/mm and per millimetre of width 1.47 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 112 g, just 0.09 g per mm² of projected 42×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 30 mm width and 44 kN C rating suit high-cycle industrial machinery rather than instrument duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 10.8 kN and a 14,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 44 kN C rating and longer nominal life come without an envelope change. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 42 mm outside diameter and 44 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 30 mm seat, and in planetary gear bearings the 112 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 59 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6905-XL?",
        "a": "The RNA6905-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 42 mm outside diameter, 30 mm bore and 30 mm width, envelope 30×42×30 mm. Mass is 112 g."
      },
      {
        "q": "What does the RNA6905-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6905-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×42×30 mm and the catalogue ratings are C 44 kN, C0 59 kN, Cur 10.8 kN."
      },
      {
        "q": "What is the load capacity of the RNA6905-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 59 kN; the fatigue load limit Cur is 10.8 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6905-XL?",
        "a": "The limiting speed is 14,400 r/min and the thermal reference speed is 7,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6905-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6905-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6905",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6905-XL",
      "RNA6905-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS30-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 36.5,
    "static_load_kN": 40,
    "fatigue_load_limit_kN": 7,
    "limiting_speed_rpm": 14000,
    "max_rpm": 14000,
    "reference_speed_rpm": 8500,
    "weight_g": 104,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×45×22 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 36.5 kN and C0 40 kN at the 30 mm seat; the C/C0 ratio of 0.91 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 7 kN, the limiting speed 14,000 r/min and the thermal reference speed 8,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.22 kN/mm and per millimetre of width 1.66 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 104 g, just 0.11 g per mm² of projected 45×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 22 mm width and 36.5 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 30 mm journal brinels under the 40 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 40 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 45 mm outside diameter and 36.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 30 mm seat, and in copying and printing machine mechanisms the 104 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 22 mm width and the published 40 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS30-XL?",
        "a": "The NKS30-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 45 mm outside diameter, 30 mm bore and 22 mm width, envelope 30×45×22 mm. Mass is 104 g."
      },
      {
        "q": "What does the NKS30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS30-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×45×22 mm and the catalogue ratings are C 36.5 kN, C0 40 kN, Cur 7 kN."
      },
      {
        "q": "What is the load capacity of the NKS30-XL?",
        "a": "The basic dynamic load rating C is 36.5 kN and the basic static load rating C0 is 40 kN; the fatigue load limit Cur is 7 kN."
      },
      {
        "q": "What is the maximum speed of the NKS30-XL?",
        "a": "The limiting speed is 14,000 r/min and the thermal reference speed is 8,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS30-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×45×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS30-XL",
      "NKS30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK32-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK32/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 29.5,
    "static_load_kN": 44.5,
    "fatigue_load_limit_kN": 8,
    "limiting_speed_rpm": 14000,
    "max_rpm": 14000,
    "reference_speed_rpm": 8000,
    "weight_g": 64,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×42×20 mm: 32 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 29.5 kN and C0 44.5 kN at the 32 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 8 kN, the limiting speed 14,000 r/min and the thermal reference speed 8,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 1.48 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 64 g, just 0.08 g per mm² of projected 42×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 32 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 32 mm shaft the outer diameter is only 42 mm and the width 20 mm, yet C is 29.5 kN The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 14,000 r/min limit. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 14,000 r/min. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 42 mm outside diameter and 29.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 32 mm seat, and in hydraulic and pneumatic pump eccentrics the 64 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 44.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK32/20-TV-XL?",
        "a": "The NK32/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 42 mm outside diameter, 32 mm bore and 20 mm width, envelope 32×42×20 mm. Mass is 64 g."
      },
      {
        "q": "What does the NK32/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK32/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×42×20 mm and the catalogue ratings are C 29.5 kN, C0 44.5 kN, Cur 8 kN."
      },
      {
        "q": "What is the load capacity of the NK32/20-TV-XL?",
        "a": "The basic dynamic load rating C is 29.5 kN and the basic static load rating C0 is 44.5 kN; the fatigue load limit Cur is 8 kN."
      },
      {
        "q": "What is the maximum speed of the NK32/20-TV-XL?",
        "a": "The limiting speed is 14,000 r/min and the thermal reference speed is 8,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK32/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK32/20-TV-XL has no inner ring, so the 32 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK32-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK32-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK32-20-TV-XL",
      "NK32/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK32-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK32/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 39,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 11.9,
    "limiting_speed_rpm": 14000,
    "max_rpm": 14000,
    "reference_speed_rpm": 8200,
    "weight_g": 102,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×42×30 mm: 32 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 39 kN and C0 63 kN at the 32 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 11.9 kN, the limiting speed 14,000 r/min and the thermal reference speed 8,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.22 kN/mm and per millimetre of width 1.30 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 102 g, just 0.08 g per mm² of projected 42×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 32 mm bore places this bearing in the medium band, where the 42 mm envelope already carries ratings in the tens of kilonewtons NK32/30-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11.9 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 42 mm outside diameter and 39 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 32 mm seat, and in small electric motor accessory drives the 102 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 30 mm width and the published 63 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK32/30-XL?",
        "a": "The NK32/30-XL is a NK machined-ring needle roller bearing without inner ring with 42 mm outside diameter, 32 mm bore and 30 mm width, envelope 32×42×30 mm. Mass is 102 g."
      },
      {
        "q": "What does the NK32/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK32/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×42×30 mm and the catalogue ratings are C 39 kN, C0 63 kN, Cur 11.9 kN."
      },
      {
        "q": "What is the load capacity of the NK32/30-XL?",
        "a": "The basic dynamic load rating C is 39 kN and the basic static load rating C0 is 63 kN; the fatigue load limit Cur is 11.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK32/30-XL?",
        "a": "The limiting speed is 14,000 r/min and the thermal reference speed is 8,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK32/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK32/30-XL has no inner ring, so the 32 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK32-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK32-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK32-30-XL",
      "NK32/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-28-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA49/28-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 6.2,
    "limiting_speed_rpm": 13600,
    "max_rpm": 13600,
    "reference_speed_rpm": 7600,
    "weight_g": 73.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×45×17 mm: 32 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 33.5 kN at the 32 mm seat; the C/C0 ratio of 0.82 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 6.2 kN, the limiting speed 13,600 r/min and the thermal reference speed 7,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.86 kN/mm and per millimetre of width 1.62 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 73.2 g, just 0.10 g per mm² of projected 45×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 32 mm bore marks the medium range: mounting forces and fits become critical, and the 73.2 g mass calls for proper induction or press tooling rather than hand fitting Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The thin 6.5 mm section makes the 73.2 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting X-life status (-XL) indicates the current Schaeffler premium execution at 32 mm bore; the 33.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 45 mm outside diameter and 27.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 32 mm seat, and in motorcycle and light-vehicle transmissions the 73.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 17 mm width and the published 33.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA49/28-XL?",
        "a": "The RNA49/28-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 45 mm outside diameter, 32 mm bore and 17 mm width, envelope 32×45×17 mm. Mass is 73.2 g."
      },
      {
        "q": "What does the RNA49/28-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA49/28-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×45×17 mm and the catalogue ratings are C 27.5 kN, C0 33.5 kN, Cur 6.2 kN."
      },
      {
        "q": "What is the load capacity of the RNA49/28-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 33.5 kN; the fatigue load limit Cur is 6.2 kN."
      },
      {
        "q": "What is the maximum speed of the RNA49/28-XL?",
        "a": "The limiting speed is 13,600 r/min and the thermal reference speed is 7,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA49/28-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA49/28-XL has no inner ring, so the 32 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-28",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA49-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-28-XL",
      "RNA49/28-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-28-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA69/28-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 11.6,
    "limiting_speed_rpm": 13600,
    "max_rpm": 13600,
    "reference_speed_rpm": 7400,
    "weight_g": 135,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×45×30 mm: 32 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 63 kN at the 32 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 11.6 kN, the limiting speed 13,600 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.42 kN/mm and per millimetre of width 1.52 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 135 g, just 0.10 g per mm² of projected 45×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 32 mm bore places this bearing in the medium band, where the 45 mm envelope already carries ratings in the tens of kilonewtons RNA69/28-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The hardness requirement is unforgiving: below about 58 HRC the 32 mm journal brinels under the 63 kN static rating, and roughness above raceway finish accelerates roller wear -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 45.5 kN C rating and longer nominal life come without an envelope change. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 45 mm outside diameter and 45.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 32 mm seat, and in planetary gear bearings the 135 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 63 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA69/28-XL?",
        "a": "The RNA69/28-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 45 mm outside diameter, 32 mm bore and 30 mm width, envelope 32×45×30 mm. Mass is 135 g."
      },
      {
        "q": "What does the RNA69/28-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA69/28-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×45×30 mm and the catalogue ratings are C 45.5 kN, C0 63 kN, Cur 11.6 kN."
      },
      {
        "q": "What is the load capacity of the RNA69/28-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 63 kN; the fatigue load limit Cur is 11.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNA69/28-XL?",
        "a": "The limiting speed is 13,600 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA69/28-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA69/28-XL has no inner ring, so the 32 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-28",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA69-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-28-XL",
      "RNA69/28-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS32-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS32-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 38,
    "static_load_kN": 43.5,
    "fatigue_load_limit_kN": 7.6,
    "limiting_speed_rpm": 13200,
    "max_rpm": 13200,
    "reference_speed_rpm": 8000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×47×22 mm: 32 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 38 kN and C0 43.5 kN at the 32 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.6 kN, the limiting speed 13,200 r/min and the thermal reference speed 8,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.19 kN/mm and per millimetre of width 1.73 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 110 g, just 0.11 g per mm² of projected 47×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 32 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space The hardness requirement is unforgiving: below about 58 HRC the 32 mm journal brinels under the 43.5 kN static rating, and roughness above raceway finish accelerates roller wear Omitting the inner ring frees radial space — at a 32 mm shaft the outer diameter is only 47 mm and the width 22 mm, yet C is 38 kN X-life status (-XL) indicates the current Schaeffler premium execution at 32 mm bore; the 43.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 47 mm outside diameter and 38 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 32 mm seat, and in motorcycle and light-vehicle transmissions the 110 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 22 mm width and the published 43.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS32-XL?",
        "a": "The NKS32-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 47 mm outside diameter, 32 mm bore and 22 mm width, envelope 32×47×22 mm. Mass is 110 g."
      },
      {
        "q": "What does the NKS32-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS32-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×47×22 mm and the catalogue ratings are C 38 kN, C0 43.5 kN, Cur 7.6 kN."
      },
      {
        "q": "What is the load capacity of the NKS32-XL?",
        "a": "The basic dynamic load rating C is 38 kN and the basic static load rating C0 is 43.5 kN; the fatigue load limit Cur is 7.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKS32-XL?",
        "a": "The limiting speed is 13,200 r/min and the thermal reference speed is 8,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS32-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS32-XL has no inner ring, so the 32 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS32",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×47×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS32-XL",
      "NKS32-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK35-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK35/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 31,
    "static_load_kN": 48.5,
    "fatigue_load_limit_kN": 8.6,
    "limiting_speed_rpm": 12900,
    "max_rpm": 12900,
    "reference_speed_rpm": 7400,
    "weight_g": 69.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×45×20 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 31 kN and C0 48.5 kN at the 35 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 8.6 kN, the limiting speed 12,900 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 1.55 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 69.4 g, just 0.08 g per mm² of projected 45×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 45 mm envelope already carries ratings in the tens of kilonewtons Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened NK35/20-TV-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,900 r/min limit. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 12,900 r/min. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 45 mm outside diameter and 31 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 35 mm seat, and in agricultural machine pivots and linkages the 69.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 48.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK35/20-TV-XL?",
        "a": "The NK35/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 45 mm outside diameter, 35 mm bore and 20 mm width, envelope 35×45×20 mm. Mass is 69.4 g."
      },
      {
        "q": "What does the NK35/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK35/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×45×20 mm and the catalogue ratings are C 31 kN, C0 48.5 kN, Cur 8.6 kN."
      },
      {
        "q": "What is the load capacity of the NK35/20-TV-XL?",
        "a": "The basic dynamic load rating C is 31 kN and the basic static load rating C0 is 48.5 kN; the fatigue load limit Cur is 8.6 kN."
      },
      {
        "q": "What is the maximum speed of the NK35/20-TV-XL?",
        "a": "The limiting speed is 12,900 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK35/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK35/20-TV-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK35-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×45×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK35-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK35-20-TV-XL",
      "NK35/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK35-30-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK35/30-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 46,
    "static_load_kN": 81,
    "fatigue_load_limit_kN": 15.3,
    "limiting_speed_rpm": 12900,
    "max_rpm": 12900,
    "reference_speed_rpm": 7100,
    "weight_g": 106,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×45×30 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 46 kN and C0 81 kN at the 35 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 15.3 kN, the limiting speed 12,900 r/min and the thermal reference speed 7,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.31 kN/mm and per millimetre of width 1.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 106 g, just 0.08 g per mm² of projected 45×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 35 mm bore marks the medium range: mounting forces and fits become critical, and the 106 g mass calls for proper induction or press tooling rather than hand fitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 15.3 kN and a 12,900 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins X-life status (-XL) indicates the current Schaeffler premium execution at 35 mm bore; the 81 kN C0 rating reflects the improved rolling-contact geometry. With the -TV polyamide cage the rollers are positively separated, so the 35 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 45 mm outside diameter and 46 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 35 mm seat, and in connecting-rod small ends the 106 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 81 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK35/30-TV-XL?",
        "a": "The NK35/30-TV-XL is a NK machined-ring needle roller bearing without inner ring with 45 mm outside diameter, 35 mm bore and 30 mm width, envelope 35×45×30 mm. Mass is 106 g."
      },
      {
        "q": "What does the NK35/30-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK35/30-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×45×30 mm and the catalogue ratings are C 46 kN, C0 81 kN, Cur 15.3 kN."
      },
      {
        "q": "What is the load capacity of the NK35/30-TV-XL?",
        "a": "The basic dynamic load rating C is 46 kN and the basic static load rating C0 is 81 kN; the fatigue load limit Cur is 15.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK35/30-TV-XL?",
        "a": "The limiting speed is 12,900 r/min and the thermal reference speed is 7,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK35/30-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK35/30-TV-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK35-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK35-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK35-30-TV-XL",
      "NK35/30-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4906-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4906-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 28.5,
    "static_load_kN": 35.5,
    "fatigue_load_limit_kN": 6.6,
    "limiting_speed_rpm": 12600,
    "max_rpm": 12600,
    "reference_speed_rpm": 6900,
    "weight_g": 69.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×47×17 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 28.5 kN and C0 35.5 kN at the 35 mm seat; the C/C0 ratio of 0.80 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 6.6 kN, the limiting speed 12,600 r/min and the thermal reference speed 6,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 1.68 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 69.4 g, just 0.09 g per mm² of projected 47×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 47 mm envelope already carries ratings in the tens of kilonewtons RNA4906-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The hardness requirement is unforgiving: below about 58 HRC the 35 mm journal brinels under the 35.5 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 35×47×17 mm envelope. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 47 mm outside diameter and 28.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 35 mm seat, and in small electric motor accessory drives the 69.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 17 mm width and the published 35.5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4906-XL?",
        "a": "The RNA4906-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 47 mm outside diameter, 35 mm bore and 17 mm width, envelope 35×47×17 mm. Mass is 69.4 g."
      },
      {
        "q": "What does the RNA4906-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4906-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×47×17 mm and the catalogue ratings are C 28.5 kN, C0 35.5 kN, Cur 6.6 kN."
      },
      {
        "q": "What is the load capacity of the RNA4906-XL?",
        "a": "The basic dynamic load rating C is 28.5 kN and the basic static load rating C0 is 35.5 kN; the fatigue load limit Cur is 6.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4906-XL?",
        "a": "The limiting speed is 12,600 r/min and the thermal reference speed is 6,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4906-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4906-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4906-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4906-XL",
      "RNA4906-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6906-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6906-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 49,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 13.1,
    "limiting_speed_rpm": 12600,
    "max_rpm": 12600,
    "reference_speed_rpm": 6600,
    "weight_g": 126,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×47×30 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 49 kN and C0 71 kN at the 35 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 13.1 kN, the limiting speed 12,600 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.40 kN/mm and per millimetre of width 1.63 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 126 g, just 0.09 g per mm² of projected 47×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 35 mm bore marks the medium range: mounting forces and fits become critical, and the 126 g mass calls for proper induction or press tooling rather than hand fitting Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened With Cur 13.1 kN and a 12,600 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 49 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 47 mm outside diameter and 49 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 35 mm seat, and in hydraulic and pneumatic pump eccentrics the 126 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 30 mm width and the published 71 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6906-XL?",
        "a": "The RNA6906-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 47 mm outside diameter, 35 mm bore and 30 mm width, envelope 35×47×30 mm. Mass is 126 g."
      },
      {
        "q": "What does the RNA6906-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6906-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×47×30 mm and the catalogue ratings are C 49 kN, C0 71 kN, Cur 13.1 kN."
      },
      {
        "q": "What is the load capacity of the RNA6906-XL?",
        "a": "The basic dynamic load rating C is 49 kN and the basic static load rating C0 is 71 kN; the fatigue load limit Cur is 13.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6906-XL?",
        "a": "The limiting speed is 12,600 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6906-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6906-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6906-XL",
      "RNA6906-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS35-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 39.5,
    "static_load_kN": 47,
    "fatigue_load_limit_kN": 8.2,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 7400,
    "weight_g": 118,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×50×22 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 39.5 kN and C0 47 kN at the 35 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 8.2 kN, the limiting speed 12,300 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 1.80 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 118 g, just 0.11 g per mm² of projected 50×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space With Cur 8.2 kN and a 12,300 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins Omitting the inner ring frees radial space — at a 35 mm shaft the outer diameter is only 50 mm and the width 22 mm, yet C is 39.5 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 8.2 kN Cur value. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 50 mm outside diameter and 39.5 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 35 mm seat, and in rocker arms and valve trains the 118 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 22 mm width and the published 47 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS35-XL?",
        "a": "The NKS35-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 50 mm outside diameter, 35 mm bore and 22 mm width, envelope 35×50×22 mm. Mass is 118 g."
      },
      {
        "q": "What does the NKS35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS35-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×50×22 mm and the catalogue ratings are C 39.5 kN, C0 47 kN, Cur 8.2 kN."
      },
      {
        "q": "What is the load capacity of the NKS35-XL?",
        "a": "The basic dynamic load rating C is 39.5 kN and the basic static load rating C0 is 47 kN; the fatigue load limit Cur is 8.2 kN."
      },
      {
        "q": "What is the maximum speed of the NKS35-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS35-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×50×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS35-XL",
      "NKS35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK37-20-D-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK37/20-D-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 34,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 6800,
    "weight_g": 83,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 37×47×20 mm: 37 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 34 kN and C0 56 kN at the 37 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 12,300 r/min and the thermal reference speed 6,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 1.70 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 83 g, just 0.09 g per mm² of projected 47×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 37 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 34 kN C rating and longer nominal life come without an envelope change. -D marks the split-cage execution of the NK37/20-D-XL: the needle-cage assembly opens around the shaft while retaining the 34 kN C rating. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 47 mm outside diameter and 34 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 37 mm seat, and in two-stroke and compressor piston pins the 83 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 56 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK37/20-D-XL?",
        "a": "The NK37/20-D-XL is a NK machined-ring needle roller bearing without inner ring with 47 mm outside diameter, 37 mm bore and 20 mm width, envelope 37×47×20 mm. Mass is 83 g."
      },
      {
        "q": "What does the NK37/20-D-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK37/20-D-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 37×47×20 mm and the catalogue ratings are C 34 kN, C0 56 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NK37/20-D-XL?",
        "a": "The basic dynamic load rating C is 34 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NK37/20-D-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 6,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK37/20-D-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK37/20-D-XL has no inner ring, so the 37 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK37-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 37×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK37-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK37-20-D-XL",
      "NK37/20-D-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK37-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK37/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 28,
    "static_load_kN": 43.5,
    "fatigue_load_limit_kN": 7.8,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 7400,
    "weight_g": 77,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 37×47×20 mm: 37 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 28 kN and C0 43.5 kN at the 37 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.8 kN, the limiting speed 12,300 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.76 kN/mm and per millimetre of width 1.40 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 77 g, just 0.08 g per mm² of projected 47×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 37 mm bore places this bearing in the medium band, where the 47 mm envelope already carries ratings in the tens of kilonewtons The hardness requirement is unforgiving: below about 58 HRC the 37 mm journal brinels under the 43.5 kN static rating, and roughness above raceway finish accelerates roller wear Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 37×47×20 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 47 mm outside diameter and 28 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 37 mm seat, and in planetary gear bearings the 77 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 20 mm width and the published 43.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK37/20-XL?",
        "a": "The NK37/20-XL is a NK machined-ring needle roller bearing without inner ring with 47 mm outside diameter, 37 mm bore and 20 mm width, envelope 37×47×20 mm. Mass is 77 g."
      },
      {
        "q": "What does the NK37/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK37/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 37×47×20 mm and the catalogue ratings are C 28 kN, C0 43.5 kN, Cur 7.8 kN."
      },
      {
        "q": "What is the load capacity of the NK37/20-XL?",
        "a": "The basic dynamic load rating C is 28 kN and the basic static load rating C0 is 43.5 kN; the fatigue load limit Cur is 7.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK37/20-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK37/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK37/20-XL has no inner ring, so the 37 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK37-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 37×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK37-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK37-20-XL",
      "NK37/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK37-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK37/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 42,
    "static_load_kN": 73,
    "fatigue_load_limit_kN": 13.7,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 7200,
    "weight_g": 113,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 37×47×30 mm: 37 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 42 kN and C0 73 kN at the 37 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 13.7 kN, the limiting speed 12,300 r/min and the thermal reference speed 7,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.14 kN/mm and per millimetre of width 1.40 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 113 g, just 0.08 g per mm² of projected 47×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 37 mm bore places this bearing in the medium band, where the 47 mm envelope already carries ratings in the tens of kilonewtons With Cur 13.7 kN and a 12,300 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The hardness requirement is unforgiving: below about 58 HRC the 37 mm journal brinels under the 73 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,300 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 47 mm outside diameter and 42 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 37 mm seat, and in textile machine heald and cam shafts the 113 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 73 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK37/30-XL?",
        "a": "The NK37/30-XL is a NK machined-ring needle roller bearing without inner ring with 47 mm outside diameter, 37 mm bore and 30 mm width, envelope 37×47×30 mm. Mass is 113 g."
      },
      {
        "q": "What does the NK37/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK37/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 37×47×30 mm and the catalogue ratings are C 42 kN, C0 73 kN, Cur 13.7 kN."
      },
      {
        "q": "What is the load capacity of the NK37/30-XL?",
        "a": "The basic dynamic load rating C is 42 kN and the basic static load rating C0 is 73 kN; the fatigue load limit Cur is 13.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK37/30-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 7,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK37/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK37/30-XL has no inner ring, so the 37 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK37-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK37-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 37×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK37-30-XL",
      "NK37/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS37-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS37-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 52,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 41.5,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 8.8,
    "limiting_speed_rpm": 11700,
    "max_rpm": 11700,
    "reference_speed_rpm": 7100,
    "weight_g": 123,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 37×52×22 mm: 37 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 41.5 kN and C0 50 kN at the 37 mm seat; the C/C0 ratio of 0.83 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 8.8 kN, the limiting speed 11,700 r/min and the thermal reference speed 7,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.12 kN/mm and per millimetre of width 1.89 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 123 g, just 0.11 g per mm² of projected 52×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 37 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space NKS37-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The thin 7.5 mm section makes the 123 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 41.5 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 52 mm outside diameter and 41.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 37 mm seat, and in two-stroke and compressor piston pins the 123 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 50 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS37-XL?",
        "a": "The NKS37-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 52 mm outside diameter, 37 mm bore and 22 mm width, envelope 37×52×22 mm. Mass is 123 g."
      },
      {
        "q": "What does the NKS37-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS37-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 37×52×22 mm and the catalogue ratings are C 41.5 kN, C0 50 kN, Cur 8.8 kN."
      },
      {
        "q": "What is the load capacity of the NKS37-XL?",
        "a": "The basic dynamic load rating C is 41.5 kN and the basic static load rating C0 is 50 kN; the fatigue load limit Cur is 8.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKS37-XL?",
        "a": "The limiting speed is 11,700 r/min and the thermal reference speed is 7,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS37-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS37-XL has no inner ring, so the 37 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS37",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 37×52×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS37-XL",
      "NKS37-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK38-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK38/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 48,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 29,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 8.1,
    "limiting_speed_rpm": 12000,
    "max_rpm": 12000,
    "reference_speed_rpm": 7200,
    "weight_g": 79.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 38×48×20 mm: 38 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 29 kN and C0 45 kN at the 38 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 48 mm outside diameter the fatigue load limit Cur is 8.1 kN, the limiting speed 12,000 r/min and the thermal reference speed 7,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.76 kN/mm and per millimetre of width 1.45 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 79.4 g, just 0.08 g per mm² of projected 48×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 38 mm bore marks the medium range: mounting forces and fits become critical, and the 79.4 g mass calls for proper induction or press tooling rather than hand fitting Omitting the inner ring frees radial space — at a 38 mm shaft the outer diameter is only 48 mm and the width 20 mm, yet C is 29 kN The hardness requirement is unforgiving: below about 58 HRC the 38 mm journal brinels under the 45 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 38×48×20 mm envelope. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 48 mm outside diameter and 29 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 38 mm seat, and in rocker arms and valve trains the 79.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 20 mm width and the published 45 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK38/20-XL?",
        "a": "The NK38/20-XL is a NK machined-ring needle roller bearing without inner ring with 48 mm outside diameter, 38 mm bore and 20 mm width, envelope 38×48×20 mm. Mass is 79.4 g."
      },
      {
        "q": "What does the NK38/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK38/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 38×48×20 mm and the catalogue ratings are C 29 kN, C0 45 kN, Cur 8.1 kN."
      },
      {
        "q": "What is the load capacity of the NK38/20-XL?",
        "a": "The basic dynamic load rating C is 29 kN and the basic static load rating C0 is 45 kN; the fatigue load limit Cur is 8.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK38/20-XL?",
        "a": "The limiting speed is 12,000 r/min and the thermal reference speed is 7,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK38/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK38/20-XL has no inner ring, so the 38 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK38-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 38×48×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK38-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK38-20-XL",
      "NK38/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK38-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK38/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 48,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 43,
    "static_load_kN": 76,
    "fatigue_load_limit_kN": 14.3,
    "limiting_speed_rpm": 12000,
    "max_rpm": 12000,
    "reference_speed_rpm": 7000,
    "weight_g": 116,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 38×48×30 mm: 38 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 43 kN and C0 76 kN at the 38 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 48 mm outside diameter the fatigue load limit Cur is 14.3 kN, the limiting speed 12,000 r/min and the thermal reference speed 7,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 1.43 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 116 g, just 0.08 g per mm² of projected 48×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 38 mm bore marks the medium range: mounting forces and fits become critical, and the 116 g mass calls for proper induction or press tooling rather than hand fitting The hardness requirement is unforgiving: below about 58 HRC the 38 mm journal brinels under the 76 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,000 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 48 mm outside diameter and 43 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 38 mm seat, and in hydraulic and pneumatic pump eccentrics the 116 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 30 mm width and the published 76 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK38/30-XL?",
        "a": "The NK38/30-XL is a NK machined-ring needle roller bearing without inner ring with 48 mm outside diameter, 38 mm bore and 30 mm width, envelope 38×48×30 mm. Mass is 116 g."
      },
      {
        "q": "What does the NK38/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK38/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 38×48×30 mm and the catalogue ratings are C 43 kN, C0 76 kN, Cur 14.3 kN."
      },
      {
        "q": "What is the load capacity of the NK38/30-XL?",
        "a": "The basic dynamic load rating C is 43 kN and the basic static load rating C0 is 76 kN; the fatigue load limit Cur is 14.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK38/30-XL?",
        "a": "The limiting speed is 12,000 r/min and the thermal reference speed is 7,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK38/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK38/30-XL has no inner ring, so the 38 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK38-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK38-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 38×48×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK38-30-XL",
      "NK38/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK40-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK40/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 33.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 11400,
    "max_rpm": 11400,
    "reference_speed_rpm": 6500,
    "weight_g": 78,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×50×20 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 33.5 kN and C0 56 kN at the 40 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 1.68 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 78 g, just 0.08 g per mm² of projected 50×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 50 mm envelope already carries ratings in the tens of kilonewtons This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 33.5 kN C rating and longer nominal life come without an envelope change. With the -TV polyamide cage the rollers are positively separated, so the 40 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 50 mm outside diameter and 33.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 40 mm seat, and in planetary gear bearings the 78 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 20 mm width and the published 56 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK40/20-TV-XL?",
        "a": "The NK40/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 50 mm outside diameter, 40 mm bore and 20 mm width, envelope 40×50×20 mm. Mass is 78 g."
      },
      {
        "q": "What does the NK40/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK40/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×50×20 mm and the catalogue ratings are C 33.5 kN, C0 56 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NK40/20-TV-XL?",
        "a": "The basic dynamic load rating C is 33.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NK40/20-TV-XL?",
        "a": "The limiting speed is 11,400 r/min and the thermal reference speed is 6,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK40/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK40/20-TV-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK40-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK40-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK40-20-TV-XL",
      "NK40/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK40-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK40/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 79,
    "fatigue_load_limit_kN": 14.9,
    "limiting_speed_rpm": 11400,
    "max_rpm": 11400,
    "reference_speed_rpm": 6700,
    "weight_g": 125,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×50×30 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 79 kN at the 40 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 14.9 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.10 kN/mm and per millimetre of width 1.47 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 125 g, just 0.08 g per mm² of projected 50×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 50 mm envelope already carries ratings in the tens of kilonewtons With Cur 14.9 kN and a 11,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 44 kN C rating and longer nominal life come without an envelope change. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 50 mm outside diameter and 44 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 40 mm seat, and in agricultural machine pivots and linkages the 125 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 79 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK40/30-XL?",
        "a": "The NK40/30-XL is a NK machined-ring needle roller bearing without inner ring with 50 mm outside diameter, 40 mm bore and 30 mm width, envelope 40×50×30 mm. Mass is 125 g."
      },
      {
        "q": "What does the NK40/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK40/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×50×30 mm and the catalogue ratings are C 44 kN, C0 79 kN, Cur 14.9 kN."
      },
      {
        "q": "What is the load capacity of the NK40/30-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 79 kN; the fatigue load limit Cur is 14.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK40/30-XL?",
        "a": "The limiting speed is 11,400 r/min and the thermal reference speed is 6,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK40/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK40/30-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK40-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK40-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×50×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK40-30-XL",
      "NK40/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-32-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA49/32-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 34.5,
    "static_load_kN": 47.5,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 11100,
    "max_rpm": 11100,
    "reference_speed_rpm": 6400,
    "weight_g": 89.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×52×20 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 34.5 kN and C0 47.5 kN at the 40 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 11,100 r/min and the thermal reference speed 6,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.86 kN/mm and per millimetre of width 1.73 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 89.1 g, just 0.09 g per mm² of projected 52×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 52 mm envelope already carries ratings in the tens of kilonewtons RNA49/32-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 11,100 r/min limit. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 52 mm outside diameter and 34.5 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 40 mm seat, and in rocker arms and valve trains the 89.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 20 mm width and the published 47.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA49/32-XL?",
        "a": "The RNA49/32-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 52 mm outside diameter, 40 mm bore and 20 mm width, envelope 40×52×20 mm. Mass is 89.1 g."
      },
      {
        "q": "What does the RNA49/32-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA49/32-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×52×20 mm and the catalogue ratings are C 34.5 kN, C0 47.5 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the RNA49/32-XL?",
        "a": "The basic dynamic load rating C is 34.5 kN and the basic static load rating C0 is 47.5 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNA49/32-XL?",
        "a": "The limiting speed is 11,100 r/min and the thermal reference speed is 6,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA49/32-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA49/32-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-32",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×52×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-32-XL",
      "RNA49/32-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-32-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA69/32-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 52,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 53,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 15.4,
    "limiting_speed_rpm": 11100,
    "max_rpm": 11100,
    "reference_speed_rpm": 6500,
    "weight_g": 162,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×52×36 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 82 kN at the 40 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 15.4 kN, the limiting speed 11,100 r/min and the thermal reference speed 6,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.32 kN/mm and per millimetre of width 1.47 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 162 g, just 0.09 g per mm² of projected 52×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 162 g mass calls for proper induction or press tooling rather than hand fitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 11,100 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 40×52 mm ring pair, giving the 53 kN C rating in a housing space sized for a wide single bearing. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 52 mm outside diameter and 53 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 40 mm seat, and in copying and printing machine mechanisms the 162 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 36 mm width and the published 82 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA69/32-ZW-XL?",
        "a": "The RNA69/32-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 52 mm outside diameter, 40 mm bore and 36 mm width, envelope 40×52×36 mm. Mass is 162 g."
      },
      {
        "q": "What does the RNA69/32-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA69/32-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×52×36 mm and the catalogue ratings are C 53 kN, C0 82 kN, Cur 15.4 kN."
      },
      {
        "q": "What is the load capacity of the RNA69/32-ZW-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 82 kN; the fatigue load limit Cur is 15.4 kN."
      },
      {
        "q": "What is the maximum speed of the RNA69/32-ZW-XL?",
        "a": "The limiting speed is 11,100 r/min and the thermal reference speed is 6,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA69/32-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA69/32-ZW-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-32",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×52×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-32-ZW-XL",
      "RNA69/32-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS40-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS40-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 42.5,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 9.4,
    "limiting_speed_rpm": 10900,
    "max_rpm": 10900,
    "reference_speed_rpm": 6600,
    "weight_g": 129,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×22 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 42.5 kN and C0 54 kN at the 40 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.4 kN, the limiting speed 10,900 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 1.93 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 129 g, just 0.11 g per mm² of projected 55×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 129 g mass calls for proper induction or press tooling rather than hand fitting Omitting the inner ring frees radial space — at a 40 mm shaft the outer diameter is only 55 mm and the width 22 mm, yet C is 42.5 kN Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 54 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 55 mm outside diameter and 42.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 40 mm seat, and in hydraulic and pneumatic pump eccentrics the 129 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 22 mm width and the published 54 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS40-XL?",
        "a": "The NKS40-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 55 mm outside diameter, 40 mm bore and 22 mm width, envelope 40×55×22 mm. Mass is 129 g."
      },
      {
        "q": "What does the NKS40-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS40-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×22 mm and the catalogue ratings are C 42.5 kN, C0 54 kN, Cur 9.4 kN."
      },
      {
        "q": "What is the load capacity of the NKS40-XL?",
        "a": "The basic dynamic load rating C is 42.5 kN and the basic static load rating C0 is 54 kN; the fatigue load limit Cur is 9.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKS40-XL?",
        "a": "The limiting speed is 10,900 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS40-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS40-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS40",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS40-XL",
      "NKS40-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK42-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK42/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 30,
    "static_load_kN": 49,
    "fatigue_load_limit_kN": 8.8,
    "limiting_speed_rpm": 10900,
    "max_rpm": 10900,
    "reference_speed_rpm": 6600,
    "weight_g": 85.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×52×20 mm: 42 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 30 kN and C0 49 kN at the 42 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 8.8 kN, the limiting speed 10,900 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.71 kN/mm and per millimetre of width 1.50 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 85.8 g, just 0.08 g per mm² of projected 52×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 42 mm bore marks the medium range: mounting forces and fits become critical, and the 85.8 g mass calls for proper induction or press tooling rather than hand fitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The hardness requirement is unforgiving: below about 58 HRC the 42 mm journal brinels under the 49 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 8.8 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 52 mm outside diameter and 30 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 42 mm seat, and in motorcycle and light-vehicle transmissions the 85.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 20 mm width and the published 49 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK42/20-XL?",
        "a": "The NK42/20-XL is a NK machined-ring needle roller bearing without inner ring with 52 mm outside diameter, 42 mm bore and 20 mm width, envelope 42×52×20 mm. Mass is 85.8 g."
      },
      {
        "q": "What does the NK42/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK42/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×52×20 mm and the catalogue ratings are C 30 kN, C0 49 kN, Cur 8.8 kN."
      },
      {
        "q": "What is the load capacity of the NK42/20-XL?",
        "a": "The basic dynamic load rating C is 30 kN and the basic static load rating C0 is 49 kN; the fatigue load limit Cur is 8.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK42/20-XL?",
        "a": "The limiting speed is 10,900 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK42/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK42/20-XL has no inner ring, so the 42 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK42-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×52×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK42-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK42-20-XL",
      "NK42/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK42-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK42/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 52,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44.5,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 15.5,
    "limiting_speed_rpm": 10900,
    "max_rpm": 10900,
    "reference_speed_rpm": 6400,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×52×30 mm: 42 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 44.5 kN and C0 82 kN at the 42 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 15.5 kN, the limiting speed 10,900 r/min and the thermal reference speed 6,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 1.48 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 130 g, just 0.08 g per mm² of projected 52×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 42 mm bore marks the medium range: mounting forces and fits become critical, and the 130 g mass calls for proper induction or press tooling rather than hand fitting The hardness requirement is unforgiving: below about 58 HRC the 42 mm journal brinels under the 82 kN static rating, and roughness above raceway finish accelerates roller wear Omitting the inner ring frees radial space — at a 42 mm shaft the outer diameter is only 52 mm and the width 30 mm, yet C is 44.5 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 44.5 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 52 mm outside diameter and 44.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 42 mm seat, and in gearbox selector and change linkages the 130 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 82 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK42/30-XL?",
        "a": "The NK42/30-XL is a NK machined-ring needle roller bearing without inner ring with 52 mm outside diameter, 42 mm bore and 30 mm width, envelope 42×52×30 mm. Mass is 130 g."
      },
      {
        "q": "What does the NK42/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK42/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×52×30 mm and the catalogue ratings are C 44.5 kN, C0 82 kN, Cur 15.5 kN."
      },
      {
        "q": "What is the load capacity of the NK42/30-XL?",
        "a": "The basic dynamic load rating C is 44.5 kN and the basic static load rating C0 is 82 kN; the fatigue load limit Cur is 15.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK42/30-XL?",
        "a": "The limiting speed is 10,900 r/min and the thermal reference speed is 6,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK42/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK42/30-XL has no inner ring, so the 42 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK42-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK42-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×52×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK42-30-XL",
      "NK42/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4907-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4907-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 35.5,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 9.6,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 6100,
    "weight_g": 107,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×55×20 mm: 42 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 35.5 kN and C0 50 kN at the 42 mm seat; the C/C0 ratio of 0.71 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.6 kN, the limiting speed 10,700 r/min and the thermal reference speed 6,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.85 kN/mm and per millimetre of width 1.77 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 107 g, just 0.10 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 42 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons The thin 6.5 mm section makes the 107 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 42×55×20 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 55 mm outside diameter and 35.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 42 mm seat, and in copying and printing machine mechanisms the 107 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 50 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4907-XL?",
        "a": "The RNA4907-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 55 mm outside diameter, 42 mm bore and 20 mm width, envelope 42×55×20 mm. Mass is 107 g."
      },
      {
        "q": "What does the RNA4907-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4907-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×55×20 mm and the catalogue ratings are C 35.5 kN, C0 50 kN, Cur 9.6 kN."
      },
      {
        "q": "What is the load capacity of the RNA4907-XL?",
        "a": "The basic dynamic load rating C is 35.5 kN and the basic static load rating C0 is 50 kN; the fatigue load limit Cur is 9.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4907-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 6,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4907-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4907-XL has no inner ring, so the 42 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4907-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4907-XL",
      "RNA4907-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6907-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6907-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 55,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 54,
    "static_load_kN": 86,
    "fatigue_load_limit_kN": 16.2,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 6200,
    "weight_g": 193,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×55×36 mm: 42 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 54 kN and C0 86 kN at the 42 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 16.2 kN, the limiting speed 10,700 r/min and the thermal reference speed 6,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.29 kN/mm and per millimetre of width 1.50 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 193 g, just 0.10 g per mm² of projected 55×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 42 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 36 mm width as a standard mounting space Omitting the inner ring frees radial space — at a 42 mm shaft the outer diameter is only 55 mm and the width 36 mm, yet C is 54 kN Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 16.2 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 55 mm outside diameter and 54 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 42 mm seat, and in copying and printing machine mechanisms the 193 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 36 mm width and the published 86 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6907-ZW-XL?",
        "a": "The RNA6907-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 55 mm outside diameter, 42 mm bore and 36 mm width, envelope 42×55×36 mm. Mass is 193 g."
      },
      {
        "q": "What does the RNA6907-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6907-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×55×36 mm and the catalogue ratings are C 54 kN, C0 86 kN, Cur 16.2 kN."
      },
      {
        "q": "What is the load capacity of the RNA6907-ZW-XL?",
        "a": "The basic dynamic load rating C is 54 kN and the basic static load rating C0 is 86 kN; the fatigue load limit Cur is 16.2 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6907-ZW-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 6,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6907-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6907-ZW-XL has no inner ring, so the 42 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×55×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=951",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6907-ZW-XL",
      "RNA6907-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK43-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK43/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 53,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 30.5,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 6500,
    "weight_g": 86,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 43×53×20 mm: 43 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 30.5 kN and C0 51 kN at the 43 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 53 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 10,700 r/min and the thermal reference speed 6,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.71 kN/mm and per millimetre of width 1.52 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 86 g, just 0.08 g per mm² of projected 53×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 43 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 9.1 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 53 mm outside diameter and 30.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 43 mm seat, and in textile machine heald and cam shafts the 86 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 51 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK43/20-XL?",
        "a": "The NK43/20-XL is a NK machined-ring needle roller bearing without inner ring with 53 mm outside diameter, 43 mm bore and 20 mm width, envelope 43×53×20 mm. Mass is 86 g."
      },
      {
        "q": "What does the NK43/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK43/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 43×53×20 mm and the catalogue ratings are C 30.5 kN, C0 51 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the NK43/20-XL?",
        "a": "The basic dynamic load rating C is 30.5 kN and the basic static load rating C0 is 51 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK43/20-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 6,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK43/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK43/20-XL has no inner ring, so the 43 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK43-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 43×53×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK43-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK43-20-XL",
      "NK43/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK43-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK43/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 53,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 16.1,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 6300,
    "weight_g": 133,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 43×53×30 mm: 43 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 85 kN at the 43 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 53 mm outside diameter the fatigue load limit Cur is 16.1 kN, the limiting speed 10,700 r/min and the thermal reference speed 6,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 1.52 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 133 g, just 0.08 g per mm² of projected 53×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 43 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 30 mm width as a standard mounting space The thin 5.0 mm section makes the 133 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 43 mm shaft the outer diameter is only 53 mm and the width 30 mm, yet C is 45.5 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 16.1 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 53 mm outside diameter and 45.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 43 mm seat, and in connecting-rod small ends the 133 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 85 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK43/30-XL?",
        "a": "The NK43/30-XL is a NK machined-ring needle roller bearing without inner ring with 53 mm outside diameter, 43 mm bore and 30 mm width, envelope 43×53×30 mm. Mass is 133 g."
      },
      {
        "q": "What does the NK43/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK43/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 43×53×30 mm and the catalogue ratings are C 45.5 kN, C0 85 kN, Cur 16.1 kN."
      },
      {
        "q": "What is the load capacity of the NK43/30-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 85 kN; the fatigue load limit Cur is 16.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK43/30-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 6,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK43/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK43/30-XL has no inner ring, so the 43 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK43-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK43-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 43×53×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK43-30-XL",
      "NK43/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS43-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS43-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 58,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 6200,
    "weight_g": 139,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 43×58×22 mm: 43 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 57 kN at the 43 mm seat; the C/C0 ratio of 0.77 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 58 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 10,200 r/min and the thermal reference speed 6,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.02 kN/mm and per millimetre of width 2.00 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 139 g, just 0.11 g per mm² of projected 58×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 43 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space Omitting the inner ring frees radial space — at a 43 mm shaft the outer diameter is only 58 mm and the width 22 mm, yet C is 44 kN NKS43-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 10 kN Cur value. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 58 mm outside diameter and 44 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 43 mm seat, and in agricultural machine pivots and linkages the 139 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 22 mm width and the published 57 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS43-XL?",
        "a": "The NKS43-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 58 mm outside diameter, 43 mm bore and 22 mm width, envelope 43×58×22 mm. Mass is 139 g."
      },
      {
        "q": "What does the NKS43-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS43-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 43×58×22 mm and the catalogue ratings are C 44 kN, C0 57 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NKS43-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NKS43-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 6,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS43-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS43-XL has no inner ring, so the 43 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS43",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 43×58×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS43-XL",
      "NKS43-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK45-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK45/20-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 35,
    "static_load_kN": 62,
    "fatigue_load_limit_kN": 11,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5900,
    "weight_g": 85.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×55×20 mm: 45 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 35 kN and C0 62 kN at the 45 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 11 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.78 kN/mm and per millimetre of width 1.75 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 85.3 g, just 0.08 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 45 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space The hardness requirement is unforgiving: below about 58 HRC the 45 mm journal brinels under the 62 kN static rating, and roughness above raceway finish accelerates roller wear With Cur 11 kN and a 10,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins X-life status (-XL) indicates the current Schaeffler premium execution at 45 mm bore; the 62 kN C0 rating reflects the improved rolling-contact geometry. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 55 mm outside diameter and 35 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 45 mm seat, and in copying and printing machine mechanisms the 85.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 62 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK45/20-TV-XL?",
        "a": "The NK45/20-TV-XL is a NK machined-ring needle roller bearing without inner ring with 55 mm outside diameter, 45 mm bore and 20 mm width, envelope 45×55×20 mm. Mass is 85.3 g."
      },
      {
        "q": "What does the NK45/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK45/20-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×55×20 mm and the catalogue ratings are C 35 kN, C0 62 kN, Cur 11 kN."
      },
      {
        "q": "What is the load capacity of the NK45/20-TV-XL?",
        "a": "The basic dynamic load rating C is 35 kN and the basic static load rating C0 is 62 kN; the fatigue load limit Cur is 11 kN."
      },
      {
        "q": "What is the maximum speed of the NK45/20-TV-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK45/20-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK45/20-TV-XL has no inner ring, so the 45 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK45-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK45-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK45-20-TV-XL",
      "NK45/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK45-30-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK45/30-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 52,
    "static_load_kN": 103,
    "fatigue_load_limit_kN": 19.5,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5700,
    "weight_g": 132,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×55×30 mm: 45 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 52 kN and C0 103 kN at the 45 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 19.5 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.16 kN/mm and per millimetre of width 1.73 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 132 g, just 0.08 g per mm² of projected 55×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 45 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 30 mm width as a standard mounting space NK45/30-TV-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality With Cur 19.5 kN and a 10,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 19.5 kN Cur value. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 132 g in the 55 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 55 mm outside diameter and 52 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 45 mm seat, and in textile machine heald and cam shafts the 132 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 103 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK45/30-TV-XL?",
        "a": "The NK45/30-TV-XL is a NK machined-ring needle roller bearing without inner ring with 55 mm outside diameter, 45 mm bore and 30 mm width, envelope 45×55×30 mm. Mass is 132 g."
      },
      {
        "q": "What does the NK45/30-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK45/30-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×55×30 mm and the catalogue ratings are C 52 kN, C0 103 kN, Cur 19.5 kN."
      },
      {
        "q": "What is the load capacity of the NK45/30-TV-XL?",
        "a": "The basic dynamic load rating C is 52 kN and the basic static load rating C0 is 103 kN; the fatigue load limit Cur is 19.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK45/30-TV-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK45/30-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK45/30-TV-XL has no inner ring, so the 45 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK45-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK45-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK45-30-TV-XL",
      "NK45/30-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS45-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS45-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 60,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 10.6,
    "limiting_speed_rpm": 9800,
    "max_rpm": 9800,
    "reference_speed_rpm": 6000,
    "weight_g": 145,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×60×22 mm: 45 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 60 kN at the 45 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 60 mm outside diameter the fatigue load limit Cur is 10.6 kN, the limiting speed 9,800 r/min and the thermal reference speed 6,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 2.07 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 145 g, just 0.11 g per mm² of projected 60×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 45 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 45.5 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 60 mm outside diameter and 45.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 45 mm seat, and in hydraulic and pneumatic pump eccentrics the 145 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 22 mm width and the published 60 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS45-XL?",
        "a": "The NKS45-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 60 mm outside diameter, 45 mm bore and 22 mm width, envelope 45×60×22 mm. Mass is 145 g."
      },
      {
        "q": "What does the NKS45-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS45-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×60×22 mm and the catalogue ratings are C 45.5 kN, C0 60 kN, Cur 10.6 kN."
      },
      {
        "q": "What is the load capacity of the NKS45-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 60 kN; the fatigue load limit Cur is 10.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKS45-XL?",
        "a": "The limiting speed is 9,800 r/min and the thermal reference speed is 6,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS45-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS45-XL has no inner ring, so the 45 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS45",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×60×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS45-XL",
      "NKS45-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK47-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK47/20-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 47,
    "D_mm": 57,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 10.1,
    "limiting_speed_rpm": 9800,
    "max_rpm": 9800,
    "reference_speed_rpm": 6000,
    "weight_g": 94.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 47×57×20 mm: 47 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 32.5 kN and C0 56 kN at the 47 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 57 mm outside diameter the fatigue load limit Cur is 10.1 kN, the limiting speed 9,800 r/min and the thermal reference speed 6,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.69 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 94.5 g, just 0.08 g per mm² of projected 57×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 47 mm bore marks the medium range: mounting forces and fits become critical, and the 94.5 g mass calls for proper induction or press tooling rather than hand fitting Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 47 mm journal brinels under the 56 kN static rating, and roughness above raceway finish accelerates roller wear X-life status (-XL) indicates the current Schaeffler premium execution at 47 mm bore; the 56 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 57 mm outside diameter and 32.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 47 mm seat, and in connecting-rod small ends the 94.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 56 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK47/20-XL?",
        "a": "The NK47/20-XL is a NK machined-ring needle roller bearing without inner ring with 57 mm outside diameter, 47 mm bore and 20 mm width, envelope 47×57×20 mm. Mass is 94.5 g."
      },
      {
        "q": "What does the NK47/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK47/20-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 47×57×20 mm and the catalogue ratings are C 32.5 kN, C0 56 kN, Cur 10.1 kN."
      },
      {
        "q": "What is the load capacity of the NK47/20-XL?",
        "a": "The basic dynamic load rating C is 32.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 10.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK47/20-XL?",
        "a": "The limiting speed is 9,800 r/min and the thermal reference speed is 6,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK47/20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK47/20-XL has no inner ring, so the 47 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK47-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 47×57×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK47-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK47-20-XL",
      "NK47/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK47-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK47/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 47,
    "D_mm": 57,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 94,
    "fatigue_load_limit_kN": 17.8,
    "limiting_speed_rpm": 9800,
    "max_rpm": 9800,
    "reference_speed_rpm": 5800,
    "weight_g": 142,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 47×57×30 mm: 47 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 94 kN at the 47 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 57 mm outside diameter the fatigue load limit Cur is 17.8 kN, the limiting speed 9,800 r/min and the thermal reference speed 5,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 1.62 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 142 g, just 0.08 g per mm² of projected 57×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 47 mm bore marks the medium range: mounting forces and fits become critical, and the 142 g mass calls for proper induction or press tooling rather than hand fitting With Cur 17.8 kN and a 9,800 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 5.0 mm section makes the 142 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting X-life status (-XL) indicates the current Schaeffler premium execution at 47 mm bore; the 94 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 57 mm outside diameter and 48.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 47 mm seat, and in motorcycle and light-vehicle transmissions the 142 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 30 mm width and the published 94 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK47/30-XL?",
        "a": "The NK47/30-XL is a NK machined-ring needle roller bearing without inner ring with 57 mm outside diameter, 47 mm bore and 30 mm width, envelope 47×57×30 mm. Mass is 142 g."
      },
      {
        "q": "What does the NK47/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK47/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 47×57×30 mm and the catalogue ratings are C 48.5 kN, C0 94 kN, Cur 17.8 kN."
      },
      {
        "q": "What is the load capacity of the NK47/30-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 94 kN; the fatigue load limit Cur is 17.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK47/30-XL?",
        "a": "The limiting speed is 9,800 r/min and the thermal reference speed is 5,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK47/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK47/30-XL has no inner ring, so the 47 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK47-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK47-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 47×57×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK47-30-XL",
      "NK47/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4908-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4908-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 48,
    "D_mm": 62,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.7,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5300,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 48×62×22 mm: 48 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 67 kN at the 48 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 11.7 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 2.20 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 140 g, just 0.10 g per mm² of projected 62×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 48 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 48×62×22 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 48 mm seat, and in textile machine heald and cam shafts the 140 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 22 mm width and the published 67 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4908-XL?",
        "a": "The RNA4908-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 62 mm outside diameter, 48 mm bore and 22 mm width, envelope 48×62×22 mm. Mass is 140 g."
      },
      {
        "q": "What does the RNA4908-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4908-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 48×62×22 mm and the catalogue ratings are C 48.5 kN, C0 67 kN, Cur 11.7 kN."
      },
      {
        "q": "What is the load capacity of the RNA4908-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.7 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4908-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4908-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4908-XL has no inner ring, so the 48 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4908",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4908-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4908-XL",
      "RNA4908-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6908-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6908-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 48,
    "D_mm": 62,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 74,
    "static_load_kN": 116,
    "fatigue_load_limit_kN": 19.8,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5400,
    "weight_g": 256,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 48×62×40 mm: 48 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 74 kN and C0 116 kN at the 48 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 19.8 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.54 kN/mm and per millimetre of width 1.85 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 256 g, just 0.10 g per mm² of projected 62×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 48 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons Omitting the inner ring frees radial space — at a 48 mm shaft the outer diameter is only 62 mm and the width 40 mm, yet C is 74 kN With Cur 19.8 kN and a 9,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 19.8 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 62 mm outside diameter and 74 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 48 mm seat, and in planetary gear bearings the 256 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 40 mm width and the published 116 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6908-ZW-XL?",
        "a": "The RNA6908-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 62 mm outside diameter, 48 mm bore and 40 mm width, envelope 48×62×40 mm. Mass is 256 g."
      },
      {
        "q": "What does the RNA6908-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6908-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 48×62×40 mm and the catalogue ratings are C 74 kN, C0 116 kN, Cur 19.8 kN."
      },
      {
        "q": "What is the load capacity of the RNA6908-ZW-XL?",
        "a": "The basic dynamic load rating C is 74 kN and the basic static load rating C0 is 116 kN; the fatigue load limit Cur is 19.8 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6908-ZW-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6908-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6908-ZW-XL has no inner ring, so the 48 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6908",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 48×62×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6908-ZW-XL",
      "RNA6908-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK50-25-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK50/25-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 62,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 87,
    "fatigue_load_limit_kN": 15,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5400,
    "weight_g": 146,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×62×25 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 87 kN at the 50 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 15 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.97 kN/mm and per millimetre of width 1.94 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 146 g, just 0.09 g per mm² of projected 62×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 50 mm bore marks the medium range: mounting forces and fits become critical, and the 146 g mass calls for proper induction or press tooling rather than hand fitting The thin 6.0 mm section makes the 146 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 15 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 9,200 r/min. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 50 mm seat, and in textile machine heald and cam shafts the 146 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 25 mm width and the published 87 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK50/25-TV-XL?",
        "a": "The NK50/25-TV-XL is a NK machined-ring needle roller bearing without inner ring with 62 mm outside diameter, 50 mm bore and 25 mm width, envelope 50×62×25 mm. Mass is 146 g."
      },
      {
        "q": "What does the NK50/25-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK50/25-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×62×25 mm and the catalogue ratings are C 48.5 kN, C0 87 kN, Cur 15 kN."
      },
      {
        "q": "What is the load capacity of the NK50/25-TV-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 87 kN; the fatigue load limit Cur is 15 kN."
      },
      {
        "q": "What is the maximum speed of the NK50/25-TV-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK50/25-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK50/25-TV-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK50-25-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK50-35-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK50-25-TV-XL",
      "NK50/25-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK50-35-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK50/35-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 62,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 67,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 24.3,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5200,
    "weight_g": 207,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×62×35 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 67 kN and C0 132 kN at the 50 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 24.3 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.34 kN/mm and per millimetre of width 1.91 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 207 g, just 0.10 g per mm² of projected 62×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 50 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 35 mm width as a standard mounting space This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 24.3 kN and a 9,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 67 kN C rating and longer nominal life come without an envelope change. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 9,200 r/min. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 62 mm outside diameter and 67 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 50 mm seat, and in motorcycle and light-vehicle transmissions the 207 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 35 mm width and the published 132 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK50/35-TV-XL?",
        "a": "The NK50/35-TV-XL is a NK machined-ring needle roller bearing without inner ring with 62 mm outside diameter, 50 mm bore and 35 mm width, envelope 50×62×35 mm. Mass is 207 g."
      },
      {
        "q": "What does the NK50/35-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK50/35-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×62×35 mm and the catalogue ratings are C 67 kN, C0 132 kN, Cur 24.3 kN."
      },
      {
        "q": "What is the load capacity of the NK50/35-TV-XL?",
        "a": "The basic dynamic load rating C is 67 kN and the basic static load rating C0 is 132 kN; the fatigue load limit Cur is 24.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK50/35-TV-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK50/35-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK50/35-TV-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK50-25-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK50-35-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK50-35-TV-XL",
      "NK50/35-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS50-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS50-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 65,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.8,
    "limiting_speed_rpm": 8900,
    "max_rpm": 8900,
    "reference_speed_rpm": 5500,
    "weight_g": 157,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×65×22 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 48 kN and C0 67 kN at the 50 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 65 mm outside diameter the fatigue load limit Cur is 11.8 kN, the limiting speed 8,900 r/min and the thermal reference speed 5,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 2.18 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 157 g, just 0.11 g per mm² of projected 65×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 50 mm bore marks the medium range: mounting forces and fits become critical, and the 157 g mass calls for proper induction or press tooling rather than hand fitting NKS50-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11.8 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 65 mm outside diameter and 48 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 50 mm seat, and in two-stroke and compressor piston pins the 157 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 67 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS50-XL?",
        "a": "The NKS50-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 65 mm outside diameter, 50 mm bore and 22 mm width, envelope 50×65×22 mm. Mass is 157 g."
      },
      {
        "q": "What does the NKS50-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS50-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×65×22 mm and the catalogue ratings are C 48 kN, C0 67 kN, Cur 11.8 kN."
      },
      {
        "q": "What is the load capacity of the NKS50-XL?",
        "a": "The basic dynamic load rating C is 48 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKS50-XL?",
        "a": "The limiting speed is 8,900 r/min and the thermal reference speed is 5,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS50-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS50-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS50",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×65×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS50-XL",
      "NKS50-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4909-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4909-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 52,
    "D_mm": 68,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 51,
    "static_load_kN": 73,
    "fatigue_load_limit_kN": 12.9,
    "limiting_speed_rpm": 8600,
    "max_rpm": 8600,
    "reference_speed_rpm": 4900,
    "weight_g": 182,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 52×68×22 mm: 52 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.0 mm radial section packed with small-diameter needle rollers C is 51 kN and C0 73 kN at the 52 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 12.9 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 2.32 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 182 g, just 0.12 g per mm² of projected 68×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 52 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons The hardness requirement is unforgiving: below about 58 HRC the 52 mm journal brinels under the 73 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 8,600 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 68 mm outside diameter and 51 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 52 mm seat, and in gearbox selector and change linkages the 182 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 22 mm width and the published 73 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4909-XL?",
        "a": "The RNA4909-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 68 mm outside diameter, 52 mm bore and 22 mm width, envelope 52×68×22 mm. Mass is 182 g."
      },
      {
        "q": "What does the RNA4909-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4909-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 52×68×22 mm and the catalogue ratings are C 51 kN, C0 73 kN, Cur 12.9 kN."
      },
      {
        "q": "What is the load capacity of the RNA4909-XL?",
        "a": "The basic dynamic load rating C is 51 kN and the basic static load rating C0 is 73 kN; the fatigue load limit Cur is 12.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4909-XL?",
        "a": "The limiting speed is 8,600 r/min and the thermal reference speed is 4,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4909-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4909-XL has no inner ring, so the 52 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4909",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4909-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4909-XL",
      "RNA4909-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6909-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6909-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 52,
    "D_mm": 68,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 79,
    "static_load_kN": 127,
    "fatigue_load_limit_kN": 21.8,
    "limiting_speed_rpm": 8600,
    "max_rpm": 8600,
    "reference_speed_rpm": 4950,
    "weight_g": 338,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 52×68×40 mm: 52 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.0 mm radial section packed with small-diameter needle rollers C is 79 kN and C0 127 kN at the 52 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.8 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.52 kN/mm and per millimetre of width 1.98 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 338 g, just 0.12 g per mm² of projected 68×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 52 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons The hardness requirement is unforgiving: below about 58 HRC the 52 mm journal brinels under the 127 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 21.8 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 68 mm outside diameter and 79 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 52 mm seat, and in small electric motor accessory drives the 338 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 40 mm width and the published 127 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6909-ZW-XL?",
        "a": "The RNA6909-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 68 mm outside diameter, 52 mm bore and 40 mm width, envelope 52×68×40 mm. Mass is 338 g."
      },
      {
        "q": "What does the RNA6909-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6909-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 52×68×40 mm and the catalogue ratings are C 79 kN, C0 127 kN, Cur 21.8 kN."
      },
      {
        "q": "What is the load capacity of the RNA6909-ZW-XL?",
        "a": "The basic dynamic load rating C is 79 kN and the basic static load rating C0 is 127 kN; the fatigue load limit Cur is 21.8 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6909-ZW-XL?",
        "a": "The limiting speed is 8,600 r/min and the thermal reference speed is 4,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6909-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6909-ZW-XL has no inner ring, so the 52 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6909",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 52×68×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6909-ZW-XL",
      "RNA6909-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK55-25-D-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK55/25-D-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 57,
    "static_load_kN": 111,
    "fatigue_load_limit_kN": 19.7,
    "limiting_speed_rpm": 8400,
    "max_rpm": 8400,
    "reference_speed_rpm": 4700,
    "weight_g": 195,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×68×25 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 57 kN and C0 111 kN at the 55 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 19.7 kN, the limiting speed 8,400 r/min and the thermal reference speed 4,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 2.28 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 195 g, just 0.11 g per mm² of projected 68×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 55 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 25 mm width as a standard mounting space NK55/25-D-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces X-life status (-XL) indicates the current Schaeffler premium execution at 55 mm bore; the 111 kN C0 rating reflects the improved rolling-contact geometry. The -D suffix supplies a radially split needle roller and cage assembly, so the cage can be fitted at bearing positions that cannot be reached over a shaft end. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 68 mm outside diameter and 57 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 55 mm seat, and in rocker arms and valve trains the 195 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 25 mm width and the published 111 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK55/25-D-XL?",
        "a": "The NK55/25-D-XL is a NK machined-ring needle roller bearing without inner ring with 68 mm outside diameter, 55 mm bore and 25 mm width, envelope 55×68×25 mm. Mass is 195 g."
      },
      {
        "q": "What does the NK55/25-D-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK55/25-D-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×68×25 mm and the catalogue ratings are C 57 kN, C0 111 kN, Cur 19.7 kN."
      },
      {
        "q": "What is the load capacity of the NK55/25-D-XL?",
        "a": "The basic dynamic load rating C is 57 kN and the basic static load rating C0 is 111 kN; the fatigue load limit Cur is 19.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK55/25-D-XL?",
        "a": "The limiting speed is 8,400 r/min and the thermal reference speed is 4,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK55/25-D-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK55/25-D-XL has no inner ring, so the 55 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK55-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK55-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK55-25-D-XL",
      "NK55/25-D-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK55-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK55/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 14.3,
    "limiting_speed_rpm": 8400,
    "max_rpm": 8400,
    "reference_speed_rpm": 5200,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×68×25 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 82 kN at the 55 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 14.3 kN, the limiting speed 8,400 r/min and the thermal reference speed 5,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.83 kN/mm and per millimetre of width 1.82 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 180 g, just 0.11 g per mm² of projected 68×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 180 g mass calls for proper induction or press tooling rather than hand fitting The hardness requirement is unforgiving: below about 58 HRC the 55 mm journal brinels under the 82 kN static rating, and roughness above raceway finish accelerates roller wear Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 55×68×25 mm envelope. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 68 mm outside diameter and 45.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 55 mm seat, and in gearbox selector and change linkages the 180 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 25 mm width and the published 82 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK55/25-XL?",
        "a": "The NK55/25-XL is a NK machined-ring needle roller bearing without inner ring with 68 mm outside diameter, 55 mm bore and 25 mm width, envelope 55×68×25 mm. Mass is 180 g."
      },
      {
        "q": "What does the NK55/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK55/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×68×25 mm and the catalogue ratings are C 45.5 kN, C0 82 kN, Cur 14.3 kN."
      },
      {
        "q": "What is the load capacity of the NK55/25-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 82 kN; the fatigue load limit Cur is 14.3 kN."
      },
      {
        "q": "What is the maximum speed of the NK55/25-XL?",
        "a": "The limiting speed is 8,400 r/min and the thermal reference speed is 5,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK55/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK55/25-XL has no inner ring, so the 55 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK55-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK55-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK55-25-XL",
      "NK55/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK55-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK55/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 60,
    "static_load_kN": 118,
    "fatigue_load_limit_kN": 21.6,
    "limiting_speed_rpm": 8400,
    "max_rpm": 8400,
    "reference_speed_rpm": 5200,
    "weight_g": 250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×68×35 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 60 kN and C0 118 kN at the 55 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.6 kN, the limiting speed 8,400 r/min and the thermal reference speed 5,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.09 kN/mm and per millimetre of width 1.71 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 250 g, just 0.11 g per mm² of projected 68×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 250 g mass calls for proper induction or press tooling rather than hand fitting Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 55 mm shaft the outer diameter is only 68 mm and the width 35 mm, yet C is 60 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 55×68×35 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 68 mm outside diameter and 60 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 55 mm seat, and in copying and printing machine mechanisms the 250 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 35 mm width and the published 118 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK55/35-XL?",
        "a": "The NK55/35-XL is a NK machined-ring needle roller bearing without inner ring with 68 mm outside diameter, 55 mm bore and 35 mm width, envelope 55×68×35 mm. Mass is 250 g."
      },
      {
        "q": "What does the NK55/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK55/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×68×35 mm and the catalogue ratings are C 60 kN, C0 118 kN, Cur 21.6 kN."
      },
      {
        "q": "What is the load capacity of the NK55/35-XL?",
        "a": "The basic dynamic load rating C is 60 kN and the basic static load rating C0 is 118 kN; the fatigue load limit Cur is 21.6 kN."
      },
      {
        "q": "What is the maximum speed of the NK55/35-XL?",
        "a": "The limiting speed is 8,400 r/min and the thermal reference speed is 5,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK55/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK55/35-XL has no inner ring, so the 55 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK55-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK55-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×68×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK55-35-XL",
      "NK55/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS55-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS55-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 51,
    "static_load_kN": 74,
    "fatigue_load_limit_kN": 13,
    "limiting_speed_rpm": 8200,
    "max_rpm": 8200,
    "reference_speed_rpm": 5100,
    "weight_g": 221,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×72×22 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 51 kN and C0 74 kN at the 55 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 13 kN, the limiting speed 8,200 r/min and the thermal reference speed 5,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 2.32 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 221 g, just 0.14 g per mm² of projected 72×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 55 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 55 mm journal brinels under the 74 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 55×72×22 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 72 mm outside diameter and 51 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 55 mm seat, and in two-stroke and compressor piston pins the 221 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 74 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS55-XL?",
        "a": "The NKS55-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 72 mm outside diameter, 55 mm bore and 22 mm width, envelope 55×72×22 mm. Mass is 221 g."
      },
      {
        "q": "What does the NKS55-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS55-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×72×22 mm and the catalogue ratings are C 51 kN, C0 74 kN, Cur 13 kN."
      },
      {
        "q": "What is the load capacity of the NKS55-XL?",
        "a": "The basic dynamic load rating C is 51 kN and the basic static load rating C0 is 74 kN; the fatigue load limit Cur is 13 kN."
      },
      {
        "q": "What is the maximum speed of the NKS55-XL?",
        "a": "The limiting speed is 8,200 r/min and the thermal reference speed is 5,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS55-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS55-XL has no inner ring, so the 55 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS55",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS55-XL",
      "NKS55-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4910-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4910-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 58,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 53,
    "static_load_kN": 80,
    "fatigue_load_limit_kN": 14.1,
    "limiting_speed_rpm": 7800,
    "max_rpm": 7800,
    "reference_speed_rpm": 4350,
    "weight_g": 163,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 58×72×22 mm: 58 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 80 kN at the 58 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 14.1 kN, the limiting speed 7,800 r/min and the thermal reference speed 4,350 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.91 kN/mm and per millimetre of width 2.41 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 163 g, just 0.10 g per mm² of projected 72×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 58 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space The hardness requirement is unforgiving: below about 58 HRC the 58 mm journal brinels under the 80 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 14.1 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 72 mm outside diameter and 53 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 58 mm seat, and in two-stroke and compressor piston pins the 163 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 80 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4910-XL?",
        "a": "The RNA4910-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 72 mm outside diameter, 58 mm bore and 22 mm width, envelope 58×72×22 mm. Mass is 163 g."
      },
      {
        "q": "What does the RNA4910-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4910-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 58×72×22 mm and the catalogue ratings are C 53 kN, C0 80 kN, Cur 14.1 kN."
      },
      {
        "q": "What is the load capacity of the RNA4910-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 80 kN; the fatigue load limit Cur is 14.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4910-XL?",
        "a": "The limiting speed is 7,800 r/min and the thermal reference speed is 4,350 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4910-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4910-XL has no inner ring, so the 58 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4910",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4910-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4910-XL",
      "RNA4910-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6910-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6910-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 58,
    "D_mm": 72,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 82,
    "static_load_kN": 139,
    "fatigue_load_limit_kN": 23.8,
    "limiting_speed_rpm": 7800,
    "max_rpm": 7800,
    "reference_speed_rpm": 4400,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 58×72×40 mm: 58 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 82 kN and C0 139 kN at the 58 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 23.8 kN, the limiting speed 7,800 r/min and the thermal reference speed 4,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.41 kN/mm and per millimetre of width 2.05 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 310 g, just 0.11 g per mm² of projected 72×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 58 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 40 mm width as a standard mounting space The thin 7.0 mm section makes the 310 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 58 mm shaft the outer diameter is only 72 mm and the width 40 mm, yet C is 82 kN The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,800 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 58×72 mm ring pair, giving the 82 kN C rating in a housing space sized for a wide single bearing. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 72 mm outside diameter and 82 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 58 mm seat, and in gearbox selector and change linkages the 310 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 40 mm width and the published 139 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6910-ZW-XL?",
        "a": "The RNA6910-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 72 mm outside diameter, 58 mm bore and 40 mm width, envelope 58×72×40 mm. Mass is 310 g."
      },
      {
        "q": "What does the RNA6910-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6910-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 58×72×40 mm and the catalogue ratings are C 82 kN, C0 139 kN, Cur 23.8 kN."
      },
      {
        "q": "What is the load capacity of the RNA6910-ZW-XL?",
        "a": "The basic dynamic load rating C is 82 kN and the basic static load rating C0 is 139 kN; the fatigue load limit Cur is 23.8 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6910-ZW-XL?",
        "a": "The limiting speed is 7,800 r/min and the thermal reference speed is 4,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6910-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6910-ZW-XL has no inner ring, so the 58 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6910",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 58×72×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6910-ZW-XL",
      "RNA6910-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK60-25-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK60/25-TV-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 72,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 53,
    "static_load_kN": 103,
    "fatigue_load_limit_kN": 17.8,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4600,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×72×25 mm: 60 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 103 kN at the 60 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 17.8 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 2.12 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 170 g, just 0.09 g per mm² of projected 72×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 60 mm bore places this bearing in the medium band, where the 72 mm envelope already carries ratings in the tens of kilonewtons With Cur 17.8 kN and a 7,700 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins NK60/25-TV-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 53 kN C rating and longer nominal life come without an envelope change. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 7,700 r/min. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 72 mm outside diameter and 53 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 60 mm seat, and in hydraulic and pneumatic pump eccentrics the 170 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 25 mm width and the published 103 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK60/25-TV-XL?",
        "a": "The NK60/25-TV-XL is a NK machined-ring needle roller bearing without inner ring with 72 mm outside diameter, 60 mm bore and 25 mm width, envelope 60×72×25 mm. Mass is 170 g."
      },
      {
        "q": "What does the NK60/25-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK60/25-TV-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×72×25 mm and the catalogue ratings are C 53 kN, C0 103 kN, Cur 17.8 kN."
      },
      {
        "q": "What is the load capacity of the NK60/25-TV-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 103 kN; the fatigue load limit Cur is 17.8 kN."
      },
      {
        "q": "What is the maximum speed of the NK60/25-TV-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK60/25-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK60/25-TV-XL has no inner ring, so the 60 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK60-25-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK60-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK60-25-TV-XL",
      "NK60/25-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK60-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK60/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 72,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 63,
    "static_load_kN": 130,
    "fatigue_load_limit_kN": 23.9,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4800,
    "weight_g": 258,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×72×35 mm: 60 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 63 kN and C0 130 kN at the 60 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 23.9 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.05 kN/mm and per millimetre of width 1.80 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 258 g, just 0.10 g per mm² of projected 72×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 60 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 35 mm width as a standard mounting space The thin 6.0 mm section makes the 258 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting With Cur 23.9 kN and a 7,700 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 23.9 kN Cur value. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 72 mm outside diameter and 63 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 60 mm seat, and in rocker arms and valve trains the 258 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 35 mm width and the published 130 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK60/35-XL?",
        "a": "The NK60/35-XL is a NK machined-ring needle roller bearing without inner ring with 72 mm outside diameter, 60 mm bore and 35 mm width, envelope 60×72×35 mm. Mass is 258 g."
      },
      {
        "q": "What does the NK60/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK60/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×72×35 mm and the catalogue ratings are C 63 kN, C0 130 kN, Cur 23.9 kN."
      },
      {
        "q": "What is the load capacity of the NK60/35-XL?",
        "a": "The basic dynamic load rating C is 63 kN and the basic static load rating C0 is 130 kN; the fatigue load limit Cur is 23.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK60/35-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK60/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK60/35-XL has no inner ring, so the 60 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK60-25-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK60-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×72×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK60-35-XL",
      "NK60/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS60-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS60-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 80,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 71,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 17.6,
    "limiting_speed_rpm": 7400,
    "max_rpm": 7400,
    "reference_speed_rpm": 4750,
    "weight_g": 335,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×80×28 mm: 60 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 71 kN and C0 98 kN at the 60 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 17.6 kN, the limiting speed 7,400 r/min and the thermal reference speed 4,750 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.18 kN/mm and per millimetre of width 2.54 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 335 g, just 0.15 g per mm² of projected 80×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 60 mm bore marks the medium range: mounting forces and fits become critical, and the 335 g mass calls for proper induction or press tooling rather than hand fitting NKS60-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The thin 10.0 mm section makes the 335 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 71 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 80 mm outside diameter and 71 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 60 mm seat, and in copying and printing machine mechanisms the 335 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 28 mm width and the published 98 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS60-XL?",
        "a": "The NKS60-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 80 mm outside diameter, 60 mm bore and 28 mm width, envelope 60×80×28 mm. Mass is 335 g."
      },
      {
        "q": "What does the NKS60-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS60-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×80×28 mm and the catalogue ratings are C 71 kN, C0 98 kN, Cur 17.6 kN."
      },
      {
        "q": "What is the load capacity of the NKS60-XL?",
        "a": "The basic dynamic load rating C is 71 kN and the basic static load rating C0 is 98 kN; the fatigue load limit Cur is 17.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKS60-XL?",
        "a": "The limiting speed is 7,400 r/min and the thermal reference speed is 4,750 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS60-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS60-XL has no inner ring, so the 60 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS60",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×80×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS60-XL",
      "NKS60-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4911-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4911-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 63,
    "D_mm": 80,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 65,
    "static_load_kN": 100,
    "fatigue_load_limit_kN": 17.6,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4150,
    "weight_g": 255,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 63×80×25 mm: 63 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 65 kN and C0 100 kN at the 63 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 17.6 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 2.60 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 255 g, just 0.13 g per mm² of projected 80×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 63 mm bore the 80 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 7,200 r/min This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 17.6 kN and a 7,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 65 kN C rating and longer nominal life come without an envelope change. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 80 mm outside diameter and 65 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 63 mm seat, and in agricultural machine pivots and linkages the 255 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 25 mm width and the published 100 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4911-XL?",
        "a": "The RNA4911-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 80 mm outside diameter, 63 mm bore and 25 mm width, envelope 63×80×25 mm. Mass is 255 g."
      },
      {
        "q": "What does the RNA4911-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4911-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 63×80×25 mm and the catalogue ratings are C 65 kN, C0 100 kN, Cur 17.6 kN."
      },
      {
        "q": "What is the load capacity of the RNA4911-XL?",
        "a": "The basic dynamic load rating C is 65 kN and the basic static load rating C0 is 100 kN; the fatigue load limit Cur is 17.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4911-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4911-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4911-XL has no inner ring, so the 63 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4911",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 63×80×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4911-XL",
      "RNA4911-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6911-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6911-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 63,
    "D_mm": 80,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 102,
    "static_load_kN": 176,
    "fatigue_load_limit_kN": 30.5,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4200,
    "weight_g": 470,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 63×80×45 mm: 63 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 102 kN and C0 176 kN at the 63 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 30.5 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.62 kN/mm and per millimetre of width 2.27 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 470 g, just 0.13 g per mm² of projected 80×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 63 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened RNA6911-ZW-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,200 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 63×80 mm ring pair, giving the 102 kN C rating in a housing space sized for a wide single bearing. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 80 mm outside diameter and 102 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 63 mm seat, and in small electric motor accessory drives the 470 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 45 mm width and the published 176 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6911-ZW-XL?",
        "a": "The RNA6911-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 80 mm outside diameter, 63 mm bore and 45 mm width, envelope 63×80×45 mm. Mass is 470 g."
      },
      {
        "q": "What does the RNA6911-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6911-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 63×80×45 mm and the catalogue ratings are C 102 kN, C0 176 kN, Cur 30.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA6911-ZW-XL?",
        "a": "The basic dynamic load rating C is 102 kN and the basic static load rating C0 is 176 kN; the fatigue load limit Cur is 30.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6911-ZW-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6911-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6911-ZW-XL has no inner ring, so the 63 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6911",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 63×80×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6911-ZW-XL",
      "RNA6911-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK65-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK65/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 78,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 50,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 17,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4500,
    "weight_g": 221,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×78×25 mm: 65 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 50 kN and C0 98 kN at the 65 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 78 mm outside diameter the fatigue load limit Cur is 17 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.77 kN/mm and per millimetre of width 2.00 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 221 g, just 0.11 g per mm² of projected 78×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 65 mm bore the 78 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 7,200 r/min The thin 6.5 mm section makes the 221 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 65 mm shaft the outer diameter is only 78 mm and the width 25 mm, yet C is 50 kN The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,200 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 78 mm outside diameter and 50 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 65 mm seat, and in hydraulic and pneumatic pump eccentrics the 221 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 25 mm width and the published 98 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK65/25-XL?",
        "a": "The NK65/25-XL is a NK machined-ring needle roller bearing without inner ring with 78 mm outside diameter, 65 mm bore and 25 mm width, envelope 65×78×25 mm. Mass is 221 g."
      },
      {
        "q": "What does the NK65/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK65/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×78×25 mm and the catalogue ratings are C 50 kN, C0 98 kN, Cur 17 kN."
      },
      {
        "q": "What is the load capacity of the NK65/25-XL?",
        "a": "The basic dynamic load rating C is 50 kN and the basic static load rating C0 is 98 kN; the fatigue load limit Cur is 17 kN."
      },
      {
        "q": "What is the maximum speed of the NK65/25-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK65/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK65/25-XL has no inner ring, so the 65 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK65-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×78×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK65-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK65-25-XL",
      "NK65/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK65-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK65/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 78,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 66,
    "static_load_kN": 142,
    "fatigue_load_limit_kN": 26,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4450,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×78×35 mm: 65 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 66 kN and C0 142 kN at the 65 mm seat; the C/C0 ratio of 0.46 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 78 mm outside diameter the fatigue load limit Cur is 26 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,450 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.02 kN/mm and per millimetre of width 1.89 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 310 g, just 0.11 g per mm² of projected 78×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 65 mm bore the 78 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 7,200 r/min NK65/35-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Omitting the inner ring frees radial space — at a 65 mm shaft the outer diameter is only 78 mm and the width 35 mm, yet C is 66 kN X-life status (-XL) indicates the current Schaeffler premium execution at 65 mm bore; the 142 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 78 mm outside diameter and 66 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 65 mm seat, and in two-stroke and compressor piston pins the 310 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 35 mm width and the published 142 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK65/35-XL?",
        "a": "The NK65/35-XL is a NK machined-ring needle roller bearing without inner ring with 78 mm outside diameter, 65 mm bore and 35 mm width, envelope 65×78×35 mm. Mass is 310 g."
      },
      {
        "q": "What does the NK65/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK65/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×78×35 mm and the catalogue ratings are C 66 kN, C0 142 kN, Cur 26 kN."
      },
      {
        "q": "What is the load capacity of the NK65/35-XL?",
        "a": "The basic dynamic load rating C is 66 kN and the basic static load rating C0 is 142 kN; the fatigue load limit Cur is 26 kN."
      },
      {
        "q": "What is the maximum speed of the NK65/35-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,450 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK65/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK65/35-XL has no inner ring, so the 65 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK65-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK65-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×78×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK65-35-XL",
      "NK65/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS65-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS65-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 85,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 75,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 19.4,
    "limiting_speed_rpm": 6900,
    "max_rpm": 6900,
    "reference_speed_rpm": 4400,
    "weight_g": 356,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×85×28 mm: 65 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 75 kN and C0 108 kN at the 65 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 19.4 kN, the limiting speed 6,900 r/min and the thermal reference speed 4,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.15 kN/mm and per millimetre of width 2.68 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 356 g, just 0.15 g per mm² of projected 85×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 65 mm bore the 85 mm outside diameter and 28 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,900 r/min Reading the NKS prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 65 mm journal brinels under the 108 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 65×85×28 mm envelope. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 85 mm outside diameter and 75 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 65 mm seat, and in rocker arms and valve trains the 356 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 28 mm width and the published 108 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS65-XL?",
        "a": "The NKS65-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 85 mm outside diameter, 65 mm bore and 28 mm width, envelope 65×85×28 mm. Mass is 356 g."
      },
      {
        "q": "What does the NKS65-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS65-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×85×28 mm and the catalogue ratings are C 75 kN, C0 108 kN, Cur 19.4 kN."
      },
      {
        "q": "What is the load capacity of the NKS65-XL?",
        "a": "The basic dynamic load rating C is 75 kN and the basic static load rating C0 is 108 kN; the fatigue load limit Cur is 19.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKS65-XL?",
        "a": "The limiting speed is 6,900 r/min and the thermal reference speed is 4,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS65-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS65-XL has no inner ring, so the 65 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS65",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×85×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=953",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS65-XL",
      "NKS65-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK68-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK68/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 82,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 49.5,
    "static_load_kN": 89,
    "fatigue_load_limit_kN": 15.5,
    "limiting_speed_rpm": 6800,
    "max_rpm": 6800,
    "reference_speed_rpm": 4500,
    "weight_g": 241,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 68×82×25 mm: 68 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 49.5 kN and C0 89 kN at the 68 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 82 mm outside diameter the fatigue load limit Cur is 15.5 kN, the limiting speed 6,800 r/min and the thermal reference speed 4,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.73 kN/mm and per millimetre of width 1.98 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 241 g, just 0.12 g per mm² of projected 82×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 68 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Omitting the inner ring frees radial space — at a 68 mm shaft the outer diameter is only 82 mm and the width 25 mm, yet C is 49.5 kN The thin 7.0 mm section makes the 241 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 68×82×25 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 82 mm outside diameter and 49.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 68 mm seat, and in connecting-rod small ends the 241 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 25 mm width and the published 89 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK68/25-XL?",
        "a": "The NK68/25-XL is a NK machined-ring needle roller bearing without inner ring with 82 mm outside diameter, 68 mm bore and 25 mm width, envelope 68×82×25 mm. Mass is 241 g."
      },
      {
        "q": "What does the NK68/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK68/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 68×82×25 mm and the catalogue ratings are C 49.5 kN, C0 89 kN, Cur 15.5 kN."
      },
      {
        "q": "What is the load capacity of the NK68/25-XL?",
        "a": "The basic dynamic load rating C is 49.5 kN and the basic static load rating C0 is 89 kN; the fatigue load limit Cur is 15.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK68/25-XL?",
        "a": "The limiting speed is 6,800 r/min and the thermal reference speed is 4,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK68/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK68/25-XL has no inner ring, so the 68 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK68-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 68×82×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK68-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK68-25-XL",
      "NK68/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK68-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK68/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 82,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 70,
    "static_load_kN": 139,
    "fatigue_load_limit_kN": 26,
    "limiting_speed_rpm": 6800,
    "max_rpm": 6800,
    "reference_speed_rpm": 4350,
    "weight_g": 338,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 68×82×35 mm: 68 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 70 kN and C0 139 kN at the 68 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 82 mm outside diameter the fatigue load limit Cur is 26 kN, the limiting speed 6,800 r/min and the thermal reference speed 4,350 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 2.00 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 338 g, just 0.12 g per mm² of projected 82×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 68 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NK68/35-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,800 r/min limit. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 82 mm outside diameter and 70 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 68 mm seat, and in planetary gear bearings the 338 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 139 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK68/35-XL?",
        "a": "The NK68/35-XL is a NK machined-ring needle roller bearing without inner ring with 82 mm outside diameter, 68 mm bore and 35 mm width, envelope 68×82×35 mm. Mass is 338 g."
      },
      {
        "q": "What does the NK68/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK68/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 68×82×35 mm and the catalogue ratings are C 70 kN, C0 139 kN, Cur 26 kN."
      },
      {
        "q": "What is the load capacity of the NK68/35-XL?",
        "a": "The basic dynamic load rating C is 70 kN and the basic static load rating C0 is 139 kN; the fatigue load limit Cur is 26 kN."
      },
      {
        "q": "What is the maximum speed of the NK68/35-XL?",
        "a": "The limiting speed is 6,800 r/min and the thermal reference speed is 4,350 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK68/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK68/35-XL has no inner ring, so the 68 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK68-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK68-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 68×82×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK68-35-XL",
      "NK68/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4912-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4912-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 68,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 19.1,
    "limiting_speed_rpm": 6700,
    "max_rpm": 6700,
    "reference_speed_rpm": 3850,
    "weight_g": 275,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 68×85×25 mm: 68 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 68 kN and C0 108 kN at the 68 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 19.1 kN, the limiting speed 6,700 r/min and the thermal reference speed 3,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.00 kN/mm and per millimetre of width 2.72 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 275 g, just 0.13 g per mm² of projected 85×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 68 mm bore the 85 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,700 r/min This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces RNA4912-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 68 kN C rating and longer nominal life come without an envelope change. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 85 mm outside diameter and 68 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 68 mm seat, and in motorcycle and light-vehicle transmissions the 275 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 25 mm width and the published 108 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4912-XL?",
        "a": "The RNA4912-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 85 mm outside diameter, 68 mm bore and 25 mm width, envelope 68×85×25 mm. Mass is 275 g."
      },
      {
        "q": "What does the RNA4912-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4912-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 68×85×25 mm and the catalogue ratings are C 68 kN, C0 108 kN, Cur 19.1 kN."
      },
      {
        "q": "What is the load capacity of the RNA4912-XL?",
        "a": "The basic dynamic load rating C is 68 kN and the basic static load rating C0 is 108 kN; the fatigue load limit Cur is 19.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4912-XL?",
        "a": "The limiting speed is 6,700 r/min and the thermal reference speed is 3,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4912-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4912-XL has no inner ring, so the 68 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4912",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 68×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4912-XL",
      "RNA4912-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6912-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6912-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 85,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 106,
    "static_load_kN": 191,
    "fatigue_load_limit_kN": 33,
    "limiting_speed_rpm": 6700,
    "max_rpm": 6700,
    "reference_speed_rpm": 3850,
    "weight_g": 488,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 68×85×45 mm: 68 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 106 kN and C0 191 kN at the 68 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 33 kN, the limiting speed 6,700 r/min and the thermal reference speed 3,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.56 kN/mm and per millimetre of width 2.36 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 488 g, just 0.13 g per mm² of projected 85×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 68 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The thin 8.5 mm section makes the 488 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting RNA6912-ZW-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,700 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 68×85 mm ring pair, giving the 106 kN C rating in a housing space sized for a wide single bearing. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 85 mm outside diameter and 106 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 68 mm seat, and in rocker arms and valve trains the 488 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 45 mm width and the published 191 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6912-ZW-XL?",
        "a": "The RNA6912-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 85 mm outside diameter, 68 mm bore and 45 mm width, envelope 68×85×45 mm. Mass is 488 g."
      },
      {
        "q": "What does the RNA6912-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6912-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 68×85×45 mm and the catalogue ratings are C 106 kN, C0 191 kN, Cur 33 kN."
      },
      {
        "q": "What is the load capacity of the RNA6912-ZW-XL?",
        "a": "The basic dynamic load rating C is 106 kN and the basic static load rating C0 is 191 kN; the fatigue load limit Cur is 33 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6912-ZW-XL?",
        "a": "The limiting speed is 6,700 r/min and the thermal reference speed is 3,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6912-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6912-ZW-XL has no inner ring, so the 68 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6912",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 68×85×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6912-ZW-XL",
      "RNA6912-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK70-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK70/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 50,
    "static_load_kN": 92,
    "fatigue_load_limit_kN": 16,
    "limiting_speed_rpm": 6600,
    "max_rpm": 6600,
    "reference_speed_rpm": 4450,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×85×25 mm: 70 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 50 kN and C0 92 kN at the 70 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 16 kN, the limiting speed 6,600 r/min and the thermal reference speed 4,450 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.71 kN/mm and per millimetre of width 2.00 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 260 g, just 0.12 g per mm² of projected 85×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 70 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The hardness requirement is unforgiving: below about 58 HRC the 70 mm journal brinels under the 92 kN static rating, and roughness above raceway finish accelerates roller wear The thin 7.5 mm section makes the 260 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 16 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 85 mm outside diameter and 50 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 70 mm seat, and in connecting-rod small ends the 260 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 25 mm width and the published 92 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK70/25-XL?",
        "a": "The NK70/25-XL is a NK machined-ring needle roller bearing without inner ring with 85 mm outside diameter, 70 mm bore and 25 mm width, envelope 70×85×25 mm. Mass is 260 g."
      },
      {
        "q": "What does the NK70/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK70/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×85×25 mm and the catalogue ratings are C 50 kN, C0 92 kN, Cur 16 kN."
      },
      {
        "q": "What is the load capacity of the NK70/25-XL?",
        "a": "The basic dynamic load rating C is 50 kN and the basic static load rating C0 is 92 kN; the fatigue load limit Cur is 16 kN."
      },
      {
        "q": "What is the maximum speed of the NK70/25-XL?",
        "a": "The limiting speed is 6,600 r/min and the thermal reference speed is 4,450 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK70/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK70/25-XL has no inner ring, so the 70 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK70-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK70-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK70-25-XL",
      "NK70/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK70-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK70/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 85,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 71,
    "static_load_kN": 144,
    "fatigue_load_limit_kN": 27,
    "limiting_speed_rpm": 6600,
    "max_rpm": 6600,
    "reference_speed_rpm": 4300,
    "weight_g": 370,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×85×35 mm: 70 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 71 kN and C0 144 kN at the 70 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 27 kN, the limiting speed 6,600 r/min and the thermal reference speed 4,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 2.03 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 370 g, just 0.12 g per mm² of projected 85×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 70 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The thin 7.5 mm section makes the 370 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 71 kN C rating and longer nominal life come without an envelope change. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 85 mm outside diameter and 71 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 70 mm seat, and in planetary gear bearings the 370 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 144 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK70/35-XL?",
        "a": "The NK70/35-XL is a NK machined-ring needle roller bearing without inner ring with 85 mm outside diameter, 70 mm bore and 35 mm width, envelope 70×85×35 mm. Mass is 370 g."
      },
      {
        "q": "What does the NK70/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK70/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×85×35 mm and the catalogue ratings are C 71 kN, C0 144 kN, Cur 27 kN."
      },
      {
        "q": "What is the load capacity of the NK70/35-XL?",
        "a": "The basic dynamic load rating C is 71 kN and the basic static load rating C0 is 144 kN; the fatigue load limit Cur is 27 kN."
      },
      {
        "q": "What is the maximum speed of the NK70/35-XL?",
        "a": "The limiting speed is 6,600 r/min and the thermal reference speed is 4,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK70/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK70/35-XL has no inner ring, so the 70 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK70-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK70-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×85×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK70-35-XL",
      "NK70/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS70-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS70-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 90,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 77,
    "static_load_kN": 113,
    "fatigue_load_limit_kN": 20.4,
    "limiting_speed_rpm": 6400,
    "max_rpm": 6400,
    "reference_speed_rpm": 4200,
    "weight_g": 380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×90×28 mm: 70 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 77 kN and C0 113 kN at the 70 mm seat; the C/C0 ratio of 0.68 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 20.4 kN, the limiting speed 6,400 r/min and the thermal reference speed 4,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.10 kN/mm and per millimetre of width 2.75 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 380 g, just 0.15 g per mm² of projected 90×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 70 mm bore this is a heavy-industrial bearing: 380 g of stiff ring and roller set, specified where rigidity matters more than speed Omitting the inner ring frees radial space — at a 70 mm shaft the outer diameter is only 90 mm and the width 28 mm, yet C is 77 kN NKS70-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 77 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 90 mm outside diameter and 77 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 70 mm seat, and in hydraulic and pneumatic pump eccentrics the 380 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 28 mm width and the published 113 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS70-XL?",
        "a": "The NKS70-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 90 mm outside diameter, 70 mm bore and 28 mm width, envelope 70×90×28 mm. Mass is 380 g."
      },
      {
        "q": "What does the NKS70-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS70-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×90×28 mm and the catalogue ratings are C 77 kN, C0 113 kN, Cur 20.4 kN."
      },
      {
        "q": "What is the load capacity of the NKS70-XL?",
        "a": "The basic dynamic load rating C is 77 kN and the basic static load rating C0 is 113 kN; the fatigue load limit Cur is 20.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKS70-XL?",
        "a": "The limiting speed is 6,400 r/min and the thermal reference speed is 4,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS70-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS70-XL has no inner ring, so the 70 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS70",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×90×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS70-XL",
      "NKS70-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4913-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4913-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 72,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 69,
    "static_load_kN": 112,
    "fatigue_load_limit_kN": 19.9,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3650,
    "weight_g": 312,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 72×90×25 mm: 72 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 69 kN and C0 112 kN at the 72 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 19.9 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 2.76 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 312 g, just 0.14 g per mm² of projected 90×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 72 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened RNA4913-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 69 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 90 mm outside diameter and 69 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 72 mm seat, and in rocker arms and valve trains the 312 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 25 mm width and the published 112 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4913-XL?",
        "a": "The RNA4913-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 90 mm outside diameter, 72 mm bore and 25 mm width, envelope 72×90×25 mm. Mass is 312 g."
      },
      {
        "q": "What does the RNA4913-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4913-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 72×90×25 mm and the catalogue ratings are C 69 kN, C0 112 kN, Cur 19.9 kN."
      },
      {
        "q": "What is the load capacity of the RNA4913-XL?",
        "a": "The basic dynamic load rating C is 69 kN and the basic static load rating C0 is 112 kN; the fatigue load limit Cur is 19.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4913-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4913-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4913-XL has no inner ring, so the 72 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4913",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 72×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4913-XL",
      "RNA4913-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6913-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6913-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 72,
    "D_mm": 90,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 108,
    "static_load_kN": 198,
    "fatigue_load_limit_kN": 34.5,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3650,
    "weight_g": 580,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 72×90×45 mm: 72 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 108 kN and C0 198 kN at the 72 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 34.5 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.50 kN/mm and per millimetre of width 2.40 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 580 g, just 0.14 g per mm² of projected 90×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 72 mm bore this is a heavy-industrial bearing: 580 g of stiff ring and roller set, specified where rigidity matters more than speed The thin 9.0 mm section makes the 580 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 72×90×45 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 45 mm width while the outside diameter stays a compact 90 mm. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 90 mm outside diameter and 108 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 72 mm seat, and in hydraulic and pneumatic pump eccentrics the 580 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 45 mm width and the published 198 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6913-ZW-XL?",
        "a": "The RNA6913-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 90 mm outside diameter, 72 mm bore and 45 mm width, envelope 72×90×45 mm. Mass is 580 g."
      },
      {
        "q": "What does the RNA6913-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6913-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 72×90×45 mm and the catalogue ratings are C 108 kN, C0 198 kN, Cur 34.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA6913-ZW-XL?",
        "a": "The basic dynamic load rating C is 108 kN and the basic static load rating C0 is 198 kN; the fatigue load limit Cur is 34.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6913-ZW-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6913-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6913-ZW-XL has no inner ring, so the 72 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6913",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 72×90×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6913-ZW-XL",
      "RNA6913-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK73-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK73/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 73,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 60,
    "static_load_kN": 100,
    "fatigue_load_limit_kN": 17.9,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 4150,
    "weight_g": 302,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 73×90×25 mm: 73 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 60 kN and C0 100 kN at the 73 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 17.9 kN, the limiting speed 6,300 r/min and the thermal reference speed 4,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.82 kN/mm and per millimetre of width 2.40 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 302 g, just 0.13 g per mm² of projected 90×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 73 mm bore this is a heavy-industrial bearing: 302 g of stiff ring and roller set, specified where rigidity matters more than speed Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened Omitting the inner ring frees radial space — at a 73 mm shaft the outer diameter is only 90 mm and the width 25 mm, yet C is 60 kN X-life status (-XL) indicates the current Schaeffler premium execution at 73 mm bore; the 100 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 90 mm outside diameter and 60 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 73 mm seat, and in rocker arms and valve trains the 302 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 25 mm width and the published 100 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK73/25-XL?",
        "a": "The NK73/25-XL is a NK machined-ring needle roller bearing without inner ring with 90 mm outside diameter, 73 mm bore and 25 mm width, envelope 73×90×25 mm. Mass is 302 g."
      },
      {
        "q": "What does the NK73/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK73/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 73×90×25 mm and the catalogue ratings are C 60 kN, C0 100 kN, Cur 17.9 kN."
      },
      {
        "q": "What is the load capacity of the NK73/25-XL?",
        "a": "The basic dynamic load rating C is 60 kN and the basic static load rating C0 is 100 kN; the fatigue load limit Cur is 17.9 kN."
      },
      {
        "q": "What is the maximum speed of the NK73/25-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 4,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK73/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK73/25-XL has no inner ring, so the 73 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK73-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 73×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK73-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK73-25-XL",
      "NK73/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK73-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK73/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 73,
    "D_mm": 90,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 85,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 27.5,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 4050,
    "weight_g": 428,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 73×90×35 mm: 73 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 85 kN and C0 156 kN at the 73 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 27.5 kN, the limiting speed 6,300 r/min and the thermal reference speed 4,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.16 kN/mm and per millimetre of width 2.43 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 428 g, just 0.14 g per mm² of projected 90×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 73 mm bore this is a heavy-industrial bearing: 428 g of stiff ring and roller set, specified where rigidity matters more than speed The thin 8.5 mm section makes the 428 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 27.5 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 90 mm outside diameter and 85 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 73 mm seat, and in hydraulic and pneumatic pump eccentrics the 428 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 35 mm width and the published 156 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK73/35-XL?",
        "a": "The NK73/35-XL is a NK machined-ring needle roller bearing without inner ring with 90 mm outside diameter, 73 mm bore and 35 mm width, envelope 73×90×35 mm. Mass is 428 g."
      },
      {
        "q": "What does the NK73/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK73/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 73×90×35 mm and the catalogue ratings are C 85 kN, C0 156 kN, Cur 27.5 kN."
      },
      {
        "q": "What is the load capacity of the NK73/35-XL?",
        "a": "The basic dynamic load rating C is 85 kN and the basic static load rating C0 is 156 kN; the fatigue load limit Cur is 27.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK73/35-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 4,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK73/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK73/35-XL has no inner ring, so the 73 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK73-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK73-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 73×90×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK73-35-XL",
      "NK73/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK75-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK75/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 92,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 61,
    "static_load_kN": 104,
    "fatigue_load_limit_kN": 18.5,
    "limiting_speed_rpm": 6100,
    "max_rpm": 6100,
    "reference_speed_rpm": 4050,
    "weight_g": 315,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×92×25 mm: 75 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 61 kN and C0 104 kN at the 75 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 92 mm outside diameter the fatigue load limit Cur is 18.5 kN, the limiting speed 6,100 r/min and the thermal reference speed 4,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 2.44 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 315 g, just 0.14 g per mm² of projected 92×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 92 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,100 r/min With Cur 18.5 kN and a 6,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The hardness requirement is unforgiving: below about 58 HRC the 75 mm journal brinels under the 104 kN static rating, and roughness above raceway finish accelerates roller wear X-life status (-XL) indicates the current Schaeffler premium execution at 75 mm bore; the 104 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 92 mm outside diameter and 61 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 75 mm seat, and in connecting-rod small ends the 315 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 25 mm width and the published 104 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK75/25-XL?",
        "a": "The NK75/25-XL is a NK machined-ring needle roller bearing without inner ring with 92 mm outside diameter, 75 mm bore and 25 mm width, envelope 75×92×25 mm. Mass is 315 g."
      },
      {
        "q": "What does the NK75/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK75/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×92×25 mm and the catalogue ratings are C 61 kN, C0 104 kN, Cur 18.5 kN."
      },
      {
        "q": "What is the load capacity of the NK75/25-XL?",
        "a": "The basic dynamic load rating C is 61 kN and the basic static load rating C0 is 104 kN; the fatigue load limit Cur is 18.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK75/25-XL?",
        "a": "The limiting speed is 6,100 r/min and the thermal reference speed is 4,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK75/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK75/25-XL has no inner ring, so the 75 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK75-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×92×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK75-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK75-25-XL",
      "NK75/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK75-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK75/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 92,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 87,
    "static_load_kN": 162,
    "fatigue_load_limit_kN": 28.5,
    "limiting_speed_rpm": 6100,
    "max_rpm": 6100,
    "reference_speed_rpm": 3950,
    "weight_g": 445,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×92×35 mm: 75 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 87 kN and C0 162 kN at the 75 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 92 mm outside diameter the fatigue load limit Cur is 28.5 kN, the limiting speed 6,100 r/min and the thermal reference speed 3,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.16 kN/mm and per millimetre of width 2.49 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 445 g, just 0.14 g per mm² of projected 92×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 92 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,100 r/min The thin 8.5 mm section makes the 445 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The hardness requirement is unforgiving: below about 58 HRC the 75 mm journal brinels under the 162 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 28.5 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 92 mm outside diameter and 87 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 75 mm seat, and in planetary gear bearings the 445 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 162 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK75/35-XL?",
        "a": "The NK75/35-XL is a NK machined-ring needle roller bearing without inner ring with 92 mm outside diameter, 75 mm bore and 35 mm width, envelope 75×92×35 mm. Mass is 445 g."
      },
      {
        "q": "What does the NK75/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK75/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×92×35 mm and the catalogue ratings are C 87 kN, C0 162 kN, Cur 28.5 kN."
      },
      {
        "q": "What is the load capacity of the NK75/35-XL?",
        "a": "The basic dynamic load rating C is 87 kN and the basic static load rating C0 is 162 kN; the fatigue load limit Cur is 28.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK75/35-XL?",
        "a": "The limiting speed is 6,100 r/min and the thermal reference speed is 3,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK75/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK75/35-XL has no inner ring, so the 75 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK75-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK75-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×92×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK75-35-XL",
      "NK75/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS75-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKS75-XL",
    "series": "nks-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 95,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 81,
    "static_load_kN": 123,
    "fatigue_load_limit_kN": 22.2,
    "limiting_speed_rpm": 6000,
    "max_rpm": 6000,
    "reference_speed_rpm": 3950,
    "weight_g": 402,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×95×28 mm: 75 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 81 kN and C0 123 kN at the 75 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 22.2 kN, the limiting speed 6,000 r/min and the thermal reference speed 3,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.08 kN/mm and per millimetre of width 2.89 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 402 g, just 0.15 g per mm² of projected 95×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 95 mm outside diameter and 28 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,000 r/min The hardness requirement is unforgiving: below about 58 HRC the 75 mm journal brinels under the 123 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,000 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 95 mm outside diameter and 81 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 75 mm seat, and in hydraulic and pneumatic pump eccentrics the 402 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 28 mm width and the published 123 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKS75-XL?",
        "a": "The NKS75-XL is a NKS heavy-section machined-ring needle roller bearing without inner ring with 95 mm outside diameter, 75 mm bore and 28 mm width, envelope 75×95×28 mm. Mass is 402 g."
      },
      {
        "q": "What does the NKS75-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKS75-XL identifies this NKS heavy-section machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×95×28 mm and the catalogue ratings are C 81 kN, C0 123 kN, Cur 22.2 kN."
      },
      {
        "q": "What is the load capacity of the NKS75-XL?",
        "a": "The basic dynamic load rating C is 81 kN and the basic static load rating C0 is 123 kN; the fatigue load limit Cur is 22.2 kN."
      },
      {
        "q": "What is the maximum speed of the NKS75-XL?",
        "a": "The limiting speed is 6,000 r/min and the thermal reference speed is 3,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NKS75-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NKS75-XL has no inner ring, so the 75 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS75",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×95×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS75-XL",
      "NKS75-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK80-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK80/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 95,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 63,
    "static_load_kN": 119,
    "fatigue_load_limit_kN": 20,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3750,
    "weight_g": 301,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×95×25 mm: 80 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 63 kN and C0 119 kN at the 80 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 20 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,750 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.79 kN/mm and per millimetre of width 2.52 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 301 g, just 0.13 g per mm² of projected 95×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 80 mm bore this is a heavy-industrial bearing: 301 g of stiff ring and roller set, specified where rigidity matters more than speed NK80/25-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The thin 7.5 mm section makes the 301 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 63 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 95 mm outside diameter and 63 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 80 mm seat, and in two-stroke and compressor piston pins the 301 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 25 mm width and the published 119 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK80/25-XL?",
        "a": "The NK80/25-XL is a NK machined-ring needle roller bearing without inner ring with 95 mm outside diameter, 80 mm bore and 25 mm width, envelope 80×95×25 mm. Mass is 301 g."
      },
      {
        "q": "What does the NK80/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK80/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×95×25 mm and the catalogue ratings are C 63 kN, C0 119 kN, Cur 20 kN."
      },
      {
        "q": "What is the load capacity of the NK80/25-XL?",
        "a": "The basic dynamic load rating C is 63 kN and the basic static load rating C0 is 119 kN; the fatigue load limit Cur is 20 kN."
      },
      {
        "q": "What is the maximum speed of the NK80/25-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,750 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK80/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK80/25-XL has no inner ring, so the 80 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK80-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×95×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK80-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK80-25-XL",
      "NK80/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK80-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK80/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 95,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 89,
    "static_load_kN": 184,
    "fatigue_load_limit_kN": 33,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3650,
    "weight_g": 425,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×95×35 mm: 80 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 89 kN and C0 184 kN at the 80 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 33 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.11 kN/mm and per millimetre of width 2.54 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 425 g, just 0.13 g per mm² of projected 95×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 80 mm bore this is a heavy-industrial bearing: 425 g of stiff ring and roller set, specified where rigidity matters more than speed The hardness requirement is unforgiving: below about 58 HRC the 80 mm journal brinels under the 184 kN static rating, and roughness above raceway finish accelerates roller wear Omitting the inner ring frees radial space — at a 80 mm shaft the outer diameter is only 95 mm and the width 35 mm, yet C is 89 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 80×95×35 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 95 mm outside diameter and 89 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 80 mm seat, and in copying and printing machine mechanisms the 425 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 35 mm width and the published 184 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK80/35-XL?",
        "a": "The NK80/35-XL is a NK machined-ring needle roller bearing without inner ring with 95 mm outside diameter, 80 mm bore and 35 mm width, envelope 80×95×35 mm. Mass is 425 g."
      },
      {
        "q": "What does the NK80/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK80/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×95×35 mm and the catalogue ratings are C 89 kN, C0 184 kN, Cur 33 kN."
      },
      {
        "q": "What is the load capacity of the NK80/35-XL?",
        "a": "The basic dynamic load rating C is 89 kN and the basic static load rating C0 is 184 kN; the fatigue load limit Cur is 33 kN."
      },
      {
        "q": "What is the maximum speed of the NK80/35-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK80/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK80/35-XL has no inner ring, so the 80 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK80-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK80-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×95×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK80-35-XL",
      "NK80/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4914-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4914-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 95,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 28,
    "limiting_speed_rpm": 5700,
    "max_rpm": 5700,
    "reference_speed_rpm": 3400,
    "weight_g": 460,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×100×30 mm: 80 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 95 kN and C0 156 kN at the 80 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 28 kN, the limiting speed 5,700 r/min and the thermal reference speed 3,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.19 kN/mm and per millimetre of width 3.17 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 460 g, just 0.15 g per mm² of projected 100×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 80 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Omitting the inner ring frees radial space — at a 80 mm shaft the outer diameter is only 100 mm and the width 30 mm, yet C is 95 kN RNA4914-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 80×100×30 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 100 mm outside diameter and 95 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 80 mm seat, and in textile machine heald and cam shafts the 460 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 156 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4914-XL?",
        "a": "The RNA4914-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 100 mm outside diameter, 80 mm bore and 30 mm width, envelope 80×100×30 mm. Mass is 460 g."
      },
      {
        "q": "What does the RNA4914-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4914-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×100×30 mm and the catalogue ratings are C 95 kN, C0 156 kN, Cur 28 kN."
      },
      {
        "q": "What is the load capacity of the RNA4914-XL?",
        "a": "The basic dynamic load rating C is 95 kN and the basic static load rating C0 is 156 kN; the fatigue load limit Cur is 28 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4914-XL?",
        "a": "The limiting speed is 5,700 r/min and the thermal reference speed is 3,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4914-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4914-XL has no inner ring, so the 80 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4914",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×100×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4914-XL",
      "RNA4914-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6914-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6914-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 100,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 145,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 48,
    "limiting_speed_rpm": 5700,
    "max_rpm": 5700,
    "reference_speed_rpm": 3450,
    "weight_g": 857,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×100×54 mm: 80 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 145 kN and C0 265 kN at the 80 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 48 kN, the limiting speed 5,700 r/min and the thermal reference speed 3,450 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.81 kN/mm and per millimetre of width 2.69 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 857 g, just 0.16 g per mm² of projected 100×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 80 mm bore this is a heavy-industrial bearing: 857 g of stiff ring and roller set, specified where rigidity matters more than speed RNA6914-ZW-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Omitting the inner ring frees radial space — at a 80 mm shaft the outer diameter is only 100 mm and the width 54 mm, yet C is 145 kN The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 80×100×54 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 54 mm width while the outside diameter stays a compact 100 mm. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 100 mm outside diameter and 145 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 80 mm seat, and in copying and printing machine mechanisms the 857 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 54 mm width and the published 265 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6914-ZW-XL?",
        "a": "The RNA6914-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 100 mm outside diameter, 80 mm bore and 54 mm width, envelope 80×100×54 mm. Mass is 857 g."
      },
      {
        "q": "What does the RNA6914-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6914-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×100×54 mm and the catalogue ratings are C 145 kN, C0 265 kN, Cur 48 kN."
      },
      {
        "q": "What is the load capacity of the RNA6914-ZW-XL?",
        "a": "The basic dynamic load rating C is 145 kN and the basic static load rating C0 is 265 kN; the fatigue load limit Cur is 48 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6914-ZW-XL?",
        "a": "The limiting speed is 5,700 r/min and the thermal reference speed is 3,450 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6914-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6914-ZW-XL has no inner ring, so the 80 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6914",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×100×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6914-ZW-XL",
      "RNA6914-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK85-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK85/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 78,
    "static_load_kN": 123,
    "fatigue_load_limit_kN": 22.1,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3550,
    "weight_g": 425,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×105×25 mm: 85 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 78 kN and C0 123 kN at the 85 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 22.1 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 3.12 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 425 g, just 0.16 g per mm² of projected 105×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 85 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces With Cur 22.1 kN and a 5,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 22.1 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 105 mm outside diameter and 78 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 85 mm seat, and in two-stroke and compressor piston pins the 425 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 25 mm width and the published 123 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK85/25-XL?",
        "a": "The NK85/25-XL is a NK machined-ring needle roller bearing without inner ring with 105 mm outside diameter, 85 mm bore and 25 mm width, envelope 85×105×25 mm. Mass is 425 g."
      },
      {
        "q": "What does the NK85/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK85/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×105×25 mm and the catalogue ratings are C 78 kN, C0 123 kN, Cur 22.1 kN."
      },
      {
        "q": "What is the load capacity of the NK85/25-XL?",
        "a": "The basic dynamic load rating C is 78 kN and the basic static load rating C0 is 123 kN; the fatigue load limit Cur is 22.1 kN."
      },
      {
        "q": "What is the maximum speed of the NK85/25-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK85/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK85/25-XL has no inner ring, so the 85 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK85-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×105×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK85-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK85-25-XL",
      "NK85/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK85-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK85/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 111,
    "static_load_kN": 193,
    "fatigue_load_limit_kN": 35,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3450,
    "weight_g": 600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×105×35 mm: 85 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 111 kN and C0 193 kN at the 85 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 35 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,450 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.31 kN/mm and per millimetre of width 3.17 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 600 g, just 0.16 g per mm² of projected 105×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 85 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The thin 10.0 mm section makes the 600 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 111 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 105 mm outside diameter and 111 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 85 mm seat, and in copying and printing machine mechanisms the 600 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 35 mm width and the published 193 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK85/35-XL?",
        "a": "The NK85/35-XL is a NK machined-ring needle roller bearing without inner ring with 105 mm outside diameter, 85 mm bore and 35 mm width, envelope 85×105×35 mm. Mass is 600 g."
      },
      {
        "q": "What does the NK85/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK85/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×105×35 mm and the catalogue ratings are C 111 kN, C0 193 kN, Cur 35 kN."
      },
      {
        "q": "What is the load capacity of the NK85/35-XL?",
        "a": "The basic dynamic load rating C is 111 kN and the basic static load rating C0 is 193 kN; the fatigue load limit Cur is 35 kN."
      },
      {
        "q": "What is the maximum speed of the NK85/35-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,450 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK85/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK85/35-XL has no inner ring, so the 85 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK85-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK85-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×105×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK85-35-XL",
      "NK85/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4915-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4915-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 97,
    "static_load_kN": 162,
    "fatigue_load_limit_kN": 29,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3200,
    "weight_g": 489,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×105×30 mm: 85 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 97 kN and C0 162 kN at the 85 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 29 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.14 kN/mm and per millimetre of width 3.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 489 g, just 0.16 g per mm² of projected 105×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 85 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 85 mm journal brinels under the 162 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 85×105×30 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 105 mm outside diameter and 97 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 85 mm seat, and in two-stroke and compressor piston pins the 489 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 30 mm width and the published 162 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4915-XL?",
        "a": "The RNA4915-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 105 mm outside diameter, 85 mm bore and 30 mm width, envelope 85×105×30 mm. Mass is 489 g."
      },
      {
        "q": "What does the RNA4915-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4915-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×105×30 mm and the catalogue ratings are C 97 kN, C0 162 kN, Cur 29 kN."
      },
      {
        "q": "What is the load capacity of the RNA4915-XL?",
        "a": "The basic dynamic load rating C is 97 kN and the basic static load rating C0 is 162 kN; the fatigue load limit Cur is 29 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4915-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4915-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4915-XL has no inner ring, so the 85 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4915",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×105×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4915-XL",
      "RNA4915-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6915-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6915-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 147,
    "static_load_kN": 275,
    "fatigue_load_limit_kN": 50,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3250,
    "weight_g": 935,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×105×54 mm: 85 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 147 kN and C0 275 kN at the 85 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 50 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.73 kN/mm and per millimetre of width 2.72 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 935 g, just 0.16 g per mm² of projected 105×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 85 mm bore the 105 mm outside diameter and 54 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,400 r/min Omitting the inner ring frees radial space — at a 85 mm shaft the outer diameter is only 105 mm and the width 54 mm, yet C is 147 kN With Cur 50 kN and a 5,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 85×105×54 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 54 mm width while the outside diameter stays a compact 105 mm. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 105 mm outside diameter and 147 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 85 mm seat, and in planetary gear bearings the 935 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 54 mm width and the published 275 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6915-ZW-XL?",
        "a": "The RNA6915-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 105 mm outside diameter, 85 mm bore and 54 mm width, envelope 85×105×54 mm. Mass is 935 g."
      },
      {
        "q": "What does the RNA6915-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6915-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×105×54 mm and the catalogue ratings are C 147 kN, C0 275 kN, Cur 50 kN."
      },
      {
        "q": "What is the load capacity of the RNA6915-ZW-XL?",
        "a": "The basic dynamic load rating C is 147 kN and the basic static load rating C0 is 275 kN; the fatigue load limit Cur is 50 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6915-ZW-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6915-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6915-ZW-XL has no inner ring, so the 85 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6915",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×105×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6915-ZW-XL",
      "RNA6915-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK90-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK90/25-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 81,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 23.7,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3400,
    "weight_g": 450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×110×25 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 81 kN and C0 132 kN at the 90 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 23.7 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.90 kN/mm and per millimetre of width 3.24 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 450 g, just 0.16 g per mm² of projected 110×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 90 mm bore this is a heavy-industrial bearing: 450 g of stiff ring and roller set, specified where rigidity matters more than speed Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 90×110×25 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 110 mm outside diameter and 81 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 90 mm seat, and in planetary gear bearings the 450 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 25 mm width and the published 132 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK90/25-XL?",
        "a": "The NK90/25-XL is a NK machined-ring needle roller bearing without inner ring with 110 mm outside diameter, 90 mm bore and 25 mm width, envelope 90×110×25 mm. Mass is 450 g."
      },
      {
        "q": "What does the NK90/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK90/25-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×110×25 mm and the catalogue ratings are C 81 kN, C0 132 kN, Cur 23.7 kN."
      },
      {
        "q": "What is the load capacity of the NK90/25-XL?",
        "a": "The basic dynamic load rating C is 81 kN and the basic static load rating C0 is 132 kN; the fatigue load limit Cur is 23.7 kN."
      },
      {
        "q": "What is the maximum speed of the NK90/25-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK90/25-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK90/25-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK90-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×110×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK90-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK90-25-XL",
      "NK90/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK90-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK90/35-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 116,
    "static_load_kN": 208,
    "fatigue_load_limit_kN": 38,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3250,
    "weight_g": 630,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×110×35 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 116 kN and C0 208 kN at the 90 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 38 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.29 kN/mm and per millimetre of width 3.31 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 630 g, just 0.16 g per mm² of projected 110×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 90 mm bore this is a heavy-industrial bearing: 630 g of stiff ring and roller set, specified where rigidity matters more than speed The hardness requirement is unforgiving: below about 58 HRC the 90 mm journal brinels under the 208 kN static rating, and roughness above raceway finish accelerates roller wear This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 5,100 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 110 mm outside diameter and 116 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 90 mm seat, and in textile machine heald and cam shafts the 630 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 35 mm width and the published 208 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK90/35-XL?",
        "a": "The NK90/35-XL is a NK machined-ring needle roller bearing without inner ring with 110 mm outside diameter, 90 mm bore and 35 mm width, envelope 90×110×35 mm. Mass is 630 g."
      },
      {
        "q": "What does the NK90/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK90/35-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×110×35 mm and the catalogue ratings are C 116 kN, C0 208 kN, Cur 38 kN."
      },
      {
        "q": "What is the load capacity of the NK90/35-XL?",
        "a": "The basic dynamic load rating C is 116 kN and the basic static load rating C0 is 208 kN; the fatigue load limit Cur is 38 kN."
      },
      {
        "q": "What is the maximum speed of the NK90/35-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK90/35-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK90/35-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK90-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK90-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×110×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK90-35-XL",
      "NK90/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4916-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4916-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 101,
    "static_load_kN": 174,
    "fatigue_load_limit_kN": 31,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3000,
    "weight_g": 516,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×110×30 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 101 kN and C0 174 kN at the 90 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 31 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.12 kN/mm and per millimetre of width 3.37 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 516 g, just 0.16 g per mm² of projected 110×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened With Cur 31 kN and a 5,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 90×110×30 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 110 mm outside diameter and 101 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 90 mm seat, and in planetary gear bearings the 516 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 174 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4916-XL?",
        "a": "The RNA4916-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 110 mm outside diameter, 90 mm bore and 30 mm width, envelope 90×110×30 mm. Mass is 516 g."
      },
      {
        "q": "What does the RNA4916-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4916-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×110×30 mm and the catalogue ratings are C 101 kN, C0 174 kN, Cur 31 kN."
      },
      {
        "q": "What is the load capacity of the RNA4916-XL?",
        "a": "The basic dynamic load rating C is 101 kN and the basic static load rating C0 is 174 kN; the fatigue load limit Cur is 31 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4916-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4916-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4916-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4916",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×110×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4916-XL",
      "RNA4916-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6916-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6916-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 153,
    "static_load_kN": 300,
    "fatigue_load_limit_kN": 54,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3050,
    "weight_g": 987,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×110×54 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 153 kN and C0 300 kN at the 90 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 54 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.70 kN/mm and per millimetre of width 2.83 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 987 g, just 0.17 g per mm² of projected 110×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 90 mm bore the 110 mm outside diameter and 54 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,100 r/min With Cur 54 kN and a 5,100 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 90×110×54 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 54 mm width while the outside diameter stays a compact 110 mm. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 110 mm outside diameter and 153 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 90 mm seat, and in small electric motor accessory drives the 987 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 54 mm width and the published 300 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6916-ZW-XL?",
        "a": "The RNA6916-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 110 mm outside diameter, 90 mm bore and 54 mm width, envelope 90×110×54 mm. Mass is 987 g."
      },
      {
        "q": "What does the RNA6916-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6916-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×110×54 mm and the catalogue ratings are C 153 kN, C0 300 kN, Cur 54 kN."
      },
      {
        "q": "What is the load capacity of the RNA6916-ZW-XL?",
        "a": "The basic dynamic load rating C is 153 kN and the basic static load rating C0 is 300 kN; the fatigue load limit Cur is 54 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6916-ZW-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6916-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6916-ZW-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6916",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×110×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6916-ZW-XL",
      "RNA6916-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK95-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK95/26-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 115,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 83,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 24.5,
    "limiting_speed_rpm": 4850,
    "max_rpm": 4850,
    "reference_speed_rpm": 3300,
    "weight_g": 490,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×115×26 mm: 95 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 83 kN and C0 137 kN at the 95 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 115 mm outside diameter the fatigue load limit Cur is 24.5 kN, the limiting speed 4,850 r/min and the thermal reference speed 3,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.87 kN/mm and per millimetre of width 3.19 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 490 g, just 0.16 g per mm² of projected 115×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 95 mm bore this is a heavy-industrial bearing: 490 g of stiff ring and roller set, specified where rigidity matters more than speed The hardness requirement is unforgiving: below about 58 HRC the 95 mm journal brinels under the 137 kN static rating, and roughness above raceway finish accelerates roller wear Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 83 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 115 mm outside diameter and 83 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 95 mm seat, and in copying and printing machine mechanisms the 490 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 26 mm width and the published 137 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK95/26-XL?",
        "a": "The NK95/26-XL is a NK machined-ring needle roller bearing without inner ring with 115 mm outside diameter, 95 mm bore and 26 mm width, envelope 95×115×26 mm. Mass is 490 g."
      },
      {
        "q": "What does the NK95/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK95/26-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×115×26 mm and the catalogue ratings are C 83 kN, C0 137 kN, Cur 24.5 kN."
      },
      {
        "q": "What is the load capacity of the NK95/26-XL?",
        "a": "The basic dynamic load rating C is 83 kN and the basic static load rating C0 is 137 kN; the fatigue load limit Cur is 24.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK95/26-XL?",
        "a": "The limiting speed is 4,850 r/min and the thermal reference speed is 3,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK95/26-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK95/26-XL has no inner ring, so the 95 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK95-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×115×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK95-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK95-26-XL",
      "NK95/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK95-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK95/36-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 115,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 121,
    "static_load_kN": 223,
    "fatigue_load_limit_kN": 40.5,
    "limiting_speed_rpm": 4850,
    "max_rpm": 4850,
    "reference_speed_rpm": 3150,
    "weight_g": 680,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×115×36 mm: 95 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 121 kN and C0 223 kN at the 95 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 115 mm outside diameter the fatigue load limit Cur is 40.5 kN, the limiting speed 4,850 r/min and the thermal reference speed 3,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.27 kN/mm and per millimetre of width 3.36 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 680 g, just 0.16 g per mm² of projected 115×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 95 mm bore this is a heavy-industrial bearing: 680 g of stiff ring and roller set, specified where rigidity matters more than speed This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 95×115×36 mm envelope. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 115 mm outside diameter and 121 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 95 mm seat, and in motorcycle and light-vehicle transmissions the 680 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 36 mm width and the published 223 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK95/36-XL?",
        "a": "The NK95/36-XL is a NK machined-ring needle roller bearing without inner ring with 115 mm outside diameter, 95 mm bore and 36 mm width, envelope 95×115×36 mm. Mass is 680 g."
      },
      {
        "q": "What does the NK95/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK95/36-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×115×36 mm and the catalogue ratings are C 121 kN, C0 223 kN, Cur 40.5 kN."
      },
      {
        "q": "What is the load capacity of the NK95/36-XL?",
        "a": "The basic dynamic load rating C is 121 kN and the basic static load rating C0 is 223 kN; the fatigue load limit Cur is 40.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK95/36-XL?",
        "a": "The limiting speed is 4,850 r/min and the thermal reference speed is 3,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK95/36-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK95/36-XL has no inner ring, so the 95 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK95-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK95-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×115×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=955",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK95-36-XL",
      "NK95/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK100-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK100/26-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 86,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 25.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 3150,
    "weight_g": 515,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×120×26 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 86 kN and C0 146 kN at the 100 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 25.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 3,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.86 kN/mm and per millimetre of width 3.31 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 515 g, just 0.17 g per mm² of projected 120×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 100 mm bore the 120 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min NK100/26-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 25.5 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 120 mm outside diameter and 86 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 100 mm seat, and in planetary gear bearings the 515 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 26 mm width and the published 146 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK100/26-XL?",
        "a": "The NK100/26-XL is a NK machined-ring needle roller bearing without inner ring with 120 mm outside diameter, 100 mm bore and 26 mm width, envelope 100×120×26 mm. Mass is 515 g."
      },
      {
        "q": "What does the NK100/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK100/26-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×120×26 mm and the catalogue ratings are C 86 kN, C0 146 kN, Cur 25.5 kN."
      },
      {
        "q": "What is the load capacity of the NK100/26-XL?",
        "a": "The basic dynamic load rating C is 86 kN and the basic static load rating C0 is 146 kN; the fatigue load limit Cur is 25.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK100/26-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 3,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK100/26-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK100/26-XL has no inner ring, so the 100 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK100-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×120×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK100-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK100-26-XL",
      "NK100/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK100-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK100/36-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 125,
    "static_load_kN": 237,
    "fatigue_load_limit_kN": 42.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 3000,
    "weight_g": 715,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×120×36 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 100 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 3,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 3.47 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 715 g, just 0.17 g per mm² of projected 120×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 100 mm bore the 120 mm outside diameter and 36 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min Omitting the inner ring frees radial space — at a 100 mm shaft the outer diameter is only 120 mm and the width 36 mm, yet C is 125 kN The hardness requirement is unforgiving: below about 58 HRC the 100 mm journal brinels under the 237 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 42.5 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 100 mm seat, and in gearbox selector and change linkages the 715 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 36 mm width and the published 237 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK100/36-XL?",
        "a": "The NK100/36-XL is a NK machined-ring needle roller bearing without inner ring with 120 mm outside diameter, 100 mm bore and 36 mm width, envelope 100×120×36 mm. Mass is 715 g."
      },
      {
        "q": "What does the NK100/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK100/36-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×120×36 mm and the catalogue ratings are C 125 kN, C0 237 kN, Cur 42.5 kN."
      },
      {
        "q": "What is the load capacity of the NK100/36-XL?",
        "a": "The basic dynamic load rating C is 125 kN and the basic static load rating C0 is 237 kN; the fatigue load limit Cur is 42.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK100/36-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 3,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK100/36-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK100/36-XL has no inner ring, so the 100 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK100-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK100-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×120×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK100-36-XL",
      "NK100/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4917-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4917-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 125,
    "static_load_kN": 237,
    "fatigue_load_limit_kN": 42.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2800,
    "weight_g": 657,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×120×35 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 100 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 3.57 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 657 g, just 0.16 g per mm² of projected 120×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 100 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Omitting the inner ring frees radial space — at a 100 mm shaft the outer diameter is only 120 mm and the width 35 mm, yet C is 125 kN With Cur 42.5 kN and a 4,600 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,600 r/min limit. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 100 mm seat, and in motorcycle and light-vehicle transmissions the 657 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 35 mm width and the published 237 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4917-XL?",
        "a": "The RNA4917-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 120 mm outside diameter, 100 mm bore and 35 mm width, envelope 100×120×35 mm. Mass is 657 g."
      },
      {
        "q": "What does the RNA4917-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4917-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×120×35 mm and the catalogue ratings are C 125 kN, C0 237 kN, Cur 42.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA4917-XL?",
        "a": "The basic dynamic load rating C is 125 kN and the basic static load rating C0 is 237 kN; the fatigue load limit Cur is 42.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4917-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4917-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4917-XL has no inner ring, so the 100 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4917",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×120×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4917-XL",
      "RNA4917-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6917-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6917-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 188,
    "static_load_kN": 400,
    "fatigue_load_limit_kN": 72,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2850,
    "weight_g": 1200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×120×63 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 188 kN and C0 400 kN at the 100 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 72 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.88 kN/mm and per millimetre of width 2.98 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.2 kg (1200 g), just 0.16 g per mm² of projected 120×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 100 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The thin 10.0 mm section makes the 1200 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 188 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 400 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 120 mm outside diameter and 188 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 100 mm seat, and in agricultural machine pivots and linkages the 1.2 kg mass is part of the rotor inertia calculation. Designers also specify it for connecting-rod small ends, relying on the 63 mm width and the published 400 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6917-ZW-XL?",
        "a": "The RNA6917-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 120 mm outside diameter, 100 mm bore and 63 mm width, envelope 100×120×63 mm. Mass is 1.2 kg."
      },
      {
        "q": "What does the RNA6917-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6917-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×120×63 mm and the catalogue ratings are C 188 kN, C0 400 kN, Cur 72 kN."
      },
      {
        "q": "What is the load capacity of the RNA6917-ZW-XL?",
        "a": "The basic dynamic load rating C is 188 kN and the basic static load rating C0 is 400 kN; the fatigue load limit Cur is 72 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6917-ZW-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6917-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6917-ZW-XL has no inner ring, so the 100 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6917",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×120×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6917-ZW-XL",
      "RNA6917-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK105-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK105/26-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 89,
    "static_load_kN": 155,
    "fatigue_load_limit_kN": 27,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 3050,
    "weight_g": 540,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 105×125×26 mm: 105 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 89 kN and C0 155 kN at the 105 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 27 kN, the limiting speed 4,400 r/min and the thermal reference speed 3,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.85 kN/mm and per millimetre of width 3.42 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 540 g, just 0.17 g per mm² of projected 125×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 105 mm bore the 125 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened NK105/26-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,400 r/min limit. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 125 mm outside diameter and 89 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 105 mm seat, and in connecting-rod small ends the 540 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 26 mm width and the published 155 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK105/26-XL?",
        "a": "The NK105/26-XL is a NK machined-ring needle roller bearing without inner ring with 125 mm outside diameter, 105 mm bore and 26 mm width, envelope 105×125×26 mm. Mass is 540 g."
      },
      {
        "q": "What does the NK105/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK105/26-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 105×125×26 mm and the catalogue ratings are C 89 kN, C0 155 kN, Cur 27 kN."
      },
      {
        "q": "What is the load capacity of the NK105/26-XL?",
        "a": "The basic dynamic load rating C is 89 kN and the basic static load rating C0 is 155 kN; the fatigue load limit Cur is 27 kN."
      },
      {
        "q": "What is the maximum speed of the NK105/26-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 3,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK105/26-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK105/26-XL has no inner ring, so the 105 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK105-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 105×125×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK105-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK105-26-XL",
      "NK105/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK105-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK105/36-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 129,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 44.5,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2850,
    "weight_g": 713,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 105×125×36 mm: 105 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 129 kN and C0 250 kN at the 105 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 44.5 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.23 kN/mm and per millimetre of width 3.58 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 713 g, just 0.16 g per mm² of projected 125×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 105 mm bore the 125 mm outside diameter and 36 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min Omitting the inner ring frees radial space — at a 105 mm shaft the outer diameter is only 125 mm and the width 36 mm, yet C is 129 kN With Cur 44.5 kN and a 4,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins X-life status (-XL) indicates the current Schaeffler premium execution at 105 mm bore; the 250 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 125 mm outside diameter and 129 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 105 mm seat, and in planetary gear bearings the 713 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 36 mm width and the published 250 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK105/36-XL?",
        "a": "The NK105/36-XL is a NK machined-ring needle roller bearing without inner ring with 125 mm outside diameter, 105 mm bore and 36 mm width, envelope 105×125×36 mm. Mass is 713 g."
      },
      {
        "q": "What does the NK105/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK105/36-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 105×125×36 mm and the catalogue ratings are C 129 kN, C0 250 kN, Cur 44.5 kN."
      },
      {
        "q": "What is the load capacity of the NK105/36-XL?",
        "a": "The basic dynamic load rating C is 129 kN and the basic static load rating C0 is 250 kN; the fatigue load limit Cur is 44.5 kN."
      },
      {
        "q": "What is the maximum speed of the NK105/36-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK105/36-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK105/36-XL has no inner ring, so the 105 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK105-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK105-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 105×125×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK105-36-XL",
      "NK105/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4918-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4918-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 129,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 44.5,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2650,
    "weight_g": 745,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 105×125×35 mm: 105 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 129 kN and C0 250 kN at the 105 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 44.5 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.23 kN/mm and per millimetre of width 3.69 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 745 g, just 0.17 g per mm² of projected 125×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 105 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery With Cur 44.5 kN and a 4,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,400 r/min limit. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 125 mm outside diameter and 129 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 105 mm seat, and in small electric motor accessory drives the 745 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 35 mm width and the published 250 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4918-XL?",
        "a": "The RNA4918-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 125 mm outside diameter, 105 mm bore and 35 mm width, envelope 105×125×35 mm. Mass is 745 g."
      },
      {
        "q": "What does the RNA4918-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4918-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 105×125×35 mm and the catalogue ratings are C 129 kN, C0 250 kN, Cur 44.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA4918-XL?",
        "a": "The basic dynamic load rating C is 129 kN and the basic static load rating C0 is 250 kN; the fatigue load limit Cur is 44.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4918-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4918-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4918-XL has no inner ring, so the 105 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4918",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 105×125×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4918-XL",
      "RNA4918-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6918-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6918-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 195,
    "static_load_kN": 425,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2700,
    "weight_g": 1330,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 105×125×63 mm: 105 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 195 kN and C0 425 kN at the 105 mm seat; the C/C0 ratio of 0.46 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.86 kN/mm and per millimetre of width 3.10 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.33 kg (1330 g), just 0.17 g per mm² of projected 125×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 105 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 195 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 425 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 125 mm outside diameter and 195 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 105 mm seat, and in hydraulic and pneumatic pump eccentrics the 1.33 kg mass is part of the rotor inertia calculation. Designers also specify it for textile machine heald and cam shafts, relying on the 63 mm width and the published 425 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6918-ZW-XL?",
        "a": "The RNA6918-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 125 mm outside diameter, 105 mm bore and 63 mm width, envelope 105×125×63 mm. Mass is 1.33 kg."
      },
      {
        "q": "What does the RNA6918-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6918-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 105×125×63 mm and the catalogue ratings are C 195 kN, C0 425 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the RNA6918-ZW-XL?",
        "a": "The basic dynamic load rating C is 195 kN and the basic static load rating C0 is 425 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6918-ZW-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6918-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6918-ZW-XL has no inner ring, so the 105 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6918",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 105×125×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6918-ZW-XL",
      "RNA6918-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK110-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK110/30-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 111,
    "static_load_kN": 210,
    "fatigue_load_limit_kN": 36,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2800,
    "weight_g": 650,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×130×30 mm: 110 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 111 kN and C0 210 kN at the 110 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 36 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 3.70 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 650 g, just 0.17 g per mm² of projected 130×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 110 mm bore the 130 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,200 r/min The thin 10.0 mm section makes the 650 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 110 mm shaft the outer diameter is only 130 mm and the width 30 mm, yet C is 111 kN X-life status (-XL) indicates the current Schaeffler premium execution at 110 mm bore; the 210 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 130 mm outside diameter and 111 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 110 mm seat, and in planetary gear bearings the 650 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 210 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK110/30-XL?",
        "a": "The NK110/30-XL is a NK machined-ring needle roller bearing without inner ring with 130 mm outside diameter, 110 mm bore and 30 mm width, envelope 110×130×30 mm. Mass is 650 g."
      },
      {
        "q": "What does the NK110/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK110/30-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×130×30 mm and the catalogue ratings are C 111 kN, C0 210 kN, Cur 36 kN."
      },
      {
        "q": "What is the load capacity of the NK110/30-XL?",
        "a": "The basic dynamic load rating C is 111 kN and the basic static load rating C0 is 210 kN; the fatigue load limit Cur is 36 kN."
      },
      {
        "q": "What is the maximum speed of the NK110/30-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK110/30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK110/30-XL has no inner ring, so the 110 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK110-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×130×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK110-40",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK110-30-XL",
      "NK110/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK110-40-XL",
    "brand": "FAG",
    "manufacturer_designation": "NK110/40-XL",
    "series": "nk-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 143,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 51,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2750,
    "weight_g": 830,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×130×40 mm: 110 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 143 kN and C0 290 kN at the 110 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 51 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,750 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.30 kN/mm and per millimetre of width 3.58 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 830 g, just 0.16 g per mm² of projected 130×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 110 mm bore the 130 mm outside diameter and 40 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,200 r/min With Cur 51 kN and a 4,200 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The thin 10.0 mm section makes the 830 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 51 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 130 mm outside diameter and 143 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 110 mm seat, and in textile machine heald and cam shafts the 830 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 40 mm width and the published 290 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NK110/40-XL?",
        "a": "The NK110/40-XL is a NK machined-ring needle roller bearing without inner ring with 130 mm outside diameter, 110 mm bore and 40 mm width, envelope 110×130×40 mm. Mass is 830 g."
      },
      {
        "q": "What does the NK110/40-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NK110/40-XL identifies this NK machined-ring needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×130×40 mm and the catalogue ratings are C 143 kN, C0 290 kN, Cur 51 kN."
      },
      {
        "q": "What is the load capacity of the NK110/40-XL?",
        "a": "The basic dynamic load rating C is 143 kN and the basic static load rating C0 is 290 kN; the fatigue load limit Cur is 51 kN."
      },
      {
        "q": "What is the maximum speed of the NK110/40-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,750 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the NK110/40-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The NK110/40-XL has no inner ring, so the 110 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK110-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK110-40",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×130×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK110-40-XL",
      "NK110/40-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4919-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4919-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 131,
    "static_load_kN": 260,
    "fatigue_load_limit_kN": 45,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2500,
    "weight_g": 719,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×130×35 mm: 110 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 131 kN and C0 260 kN at the 110 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 45 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.19 kN/mm and per millimetre of width 3.74 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 719 g, just 0.16 g per mm² of projected 130×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 110 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The thin 10.0 mm section makes the 719 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting RNA4919-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,200 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 130 mm outside diameter and 131 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 110 mm seat, and in copying and printing machine mechanisms the 719 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 35 mm width and the published 260 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4919-XL?",
        "a": "The RNA4919-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 130 mm outside diameter, 110 mm bore and 35 mm width, envelope 110×130×35 mm. Mass is 719 g."
      },
      {
        "q": "What does the RNA4919-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4919-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×130×35 mm and the catalogue ratings are C 131 kN, C0 260 kN, Cur 45 kN."
      },
      {
        "q": "What is the load capacity of the RNA4919-XL?",
        "a": "The basic dynamic load rating C is 131 kN and the basic static load rating C0 is 260 kN; the fatigue load limit Cur is 45 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4919-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4919-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4919-XL has no inner ring, so the 110 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4919",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×130×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4919-XL",
      "RNA4919-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6919-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA6919-ZW-XL",
    "series": "rna69-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 197,
    "static_load_kN": 440,
    "fatigue_load_limit_kN": 77,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2550,
    "weight_g": 1460,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×130×63 mm: 110 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 197 kN and C0 440 kN at the 110 mm seat; the C/C0 ratio of 0.45 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 77 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.79 kN/mm and per millimetre of width 3.13 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.46 kg (1460 g), just 0.18 g per mm² of projected 130×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 110 mm bore this is a heavy-industrial bearing: 1.46 kg of stiff ring and roller set, specified where rigidity matters more than speed Omitting the inner ring frees radial space — at a 110 mm shaft the outer diameter is only 130 mm and the width 63 mm, yet C is 197 kN This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 197 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 440 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 130 mm outside diameter and 197 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 110 mm seat, and in gearbox selector and change linkages the 1.46 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 63 mm width and the published 440 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA6919-ZW-XL?",
        "a": "The RNA6919-ZW-XL is a RNA69 double-row dimension-series 69 needle roller bearing without inner ring with 130 mm outside diameter, 110 mm bore and 63 mm width, envelope 110×130×63 mm. Mass is 1.46 kg."
      },
      {
        "q": "What does the RNA6919-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA6919-ZW-XL identifies this RNA69 double-row dimension-series 69 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×130×63 mm and the catalogue ratings are C 197 kN, C0 440 kN, Cur 77 kN."
      },
      {
        "q": "What is the load capacity of the RNA6919-ZW-XL?",
        "a": "The basic dynamic load rating C is 197 kN and the basic static load rating C0 is 440 kN; the fatigue load limit Cur is 77 kN."
      },
      {
        "q": "What is the maximum speed of the RNA6919-ZW-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA6919-ZW-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA6919-ZW-XL has no inner ring, so the 110 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6919",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×130×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6919-ZW-XL",
      "RNA6919-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4920-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4920-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 115,
    "D_mm": 140,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 144,
    "static_load_kN": 270,
    "fatigue_load_limit_kN": 46,
    "limiting_speed_rpm": 4000,
    "max_rpm": 4000,
    "reference_speed_rpm": 2650,
    "weight_g": 1150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 115×140×40 mm: 115 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 144 kN and C0 270 kN at the 115 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 140 mm outside diameter the fatigue load limit Cur is 46 kN, the limiting speed 4,000 r/min and the thermal reference speed 2,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 3.60 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.15 kg (1150 g), just 0.21 g per mm² of projected 140×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 115 mm bore the 140 mm outside diameter and 40 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,000 r/min The thin 12.5 mm section makes the 1150 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting With Cur 46 kN and a 4,000 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 144 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 140 mm outside diameter and 144 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 115 mm seat, and in copying and printing machine mechanisms the 1.15 kg mass is part of the rotor inertia calculation. Designers also specify it for agricultural machine pivots and linkages, relying on the 40 mm width and the published 270 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4920-XL?",
        "a": "The RNA4920-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 140 mm outside diameter, 115 mm bore and 40 mm width, envelope 115×140×40 mm. Mass is 1.15 kg."
      },
      {
        "q": "What does the RNA4920-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4920-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 115×140×40 mm and the catalogue ratings are C 144 kN, C0 270 kN, Cur 46 kN."
      },
      {
        "q": "What is the load capacity of the RNA4920-XL?",
        "a": "The basic dynamic load rating C is 144 kN and the basic static load rating C0 is 270 kN; the fatigue load limit Cur is 46 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4920-XL?",
        "a": "The limiting speed is 4,000 r/min and the thermal reference speed is 2,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4920-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4920-XL has no inner ring, so the 115 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4920",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 115×140×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4920-XL",
      "RNA4920-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4822-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4822-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 140,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 106,
    "static_load_kN": 216,
    "fatigue_load_limit_kN": 36.5,
    "limiting_speed_rpm": 3900,
    "max_rpm": 3900,
    "reference_speed_rpm": 2340,
    "weight_g": 670,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 120×140×30 mm: 120 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 106 kN and C0 216 kN at the 120 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 140 mm outside diameter the fatigue load limit Cur is 36.5 kN, the limiting speed 3,900 r/min and the thermal reference speed 2,340 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 3.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 670 g, just 0.16 g per mm² of projected 140×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 120 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The hardness requirement is unforgiving: below about 58 HRC the 120 mm journal brinels under the 216 kN static rating, and roughness above raceway finish accelerates roller wear RNA4822-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality X-life status (-XL) indicates the current Schaeffler premium execution at 120 mm bore; the 216 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 140 mm outside diameter and 106 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 120 mm seat, and in gearbox selector and change linkages the 670 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 216 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4822-XL?",
        "a": "The RNA4822-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 140 mm outside diameter, 120 mm bore and 30 mm width, envelope 120×140×30 mm. Mass is 670 g."
      },
      {
        "q": "What does the RNA4822-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4822-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 120×140×30 mm and the catalogue ratings are C 106 kN, C0 216 kN, Cur 36.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA4822-XL?",
        "a": "The basic dynamic load rating C is 106 kN and the basic static load rating C0 is 216 kN; the fatigue load limit Cur is 36.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4822-XL?",
        "a": "The limiting speed is 3,900 r/min and the thermal reference speed is 2,340 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4822-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4822-XL has no inner ring, so the 120 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4822",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 120×140×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4822-XL",
      "RNA4822-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4922-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4922-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 125,
    "D_mm": 150,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 149,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 48,
    "limiting_speed_rpm": 3700,
    "max_rpm": 3700,
    "reference_speed_rpm": 2430,
    "weight_g": 1240,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 125×150×40 mm: 125 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 149 kN and C0 290 kN at the 125 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 150 mm outside diameter the fatigue load limit Cur is 48 kN, the limiting speed 3,700 r/min and the thermal reference speed 2,430 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.19 kN/mm and per millimetre of width 3.73 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.24 kg (1240 g), just 0.21 g per mm² of projected 150×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 125 mm bore this is among the largest catalogue sizes; the 3,700 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 125×150×40 mm envelope. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 150 mm outside diameter and 149 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 125 mm seat, and in gearbox selector and change linkages the 1.24 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 40 mm width and the published 290 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4922-XL?",
        "a": "The RNA4922-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 150 mm outside diameter, 125 mm bore and 40 mm width, envelope 125×150×40 mm. Mass is 1.24 kg."
      },
      {
        "q": "What does the RNA4922-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4922-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 125×150×40 mm and the catalogue ratings are C 149 kN, C0 290 kN, Cur 48 kN."
      },
      {
        "q": "What is the load capacity of the RNA4922-XL?",
        "a": "The basic dynamic load rating C is 149 kN and the basic static load rating C0 is 290 kN; the fatigue load limit Cur is 48 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4922-XL?",
        "a": "The limiting speed is 3,700 r/min and the thermal reference speed is 2,430 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4922-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4922-XL has no inner ring, so the 125 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4922",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 125×150×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4922-XL",
      "RNA4922-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4824-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4824-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 150,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 112,
    "static_load_kN": 239,
    "fatigue_load_limit_kN": 39.5,
    "limiting_speed_rpm": 3600,
    "max_rpm": 3600,
    "reference_speed_rpm": 2120,
    "weight_g": 730,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 130×150×30 mm: 130 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 112 kN and C0 239 kN at the 130 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 150 mm outside diameter the fatigue load limit Cur is 39.5 kN, the limiting speed 3,600 r/min and the thermal reference speed 2,120 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.86 kN/mm and per millimetre of width 3.73 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 730 g, just 0.16 g per mm² of projected 150×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 130 mm bore, 150 mm outside diameter: at this size the 239 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs Omitting the inner ring frees radial space — at a 130 mm shaft the outer diameter is only 150 mm and the width 30 mm, yet C is 112 kN Reading the RNA48 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened X-life status (-XL) indicates the current Schaeffler premium execution at 130 mm bore; the 239 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 150 mm outside diameter and 112 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 130 mm seat, and in connecting-rod small ends the 730 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 239 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4824-XL?",
        "a": "The RNA4824-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 150 mm outside diameter, 130 mm bore and 30 mm width, envelope 130×150×30 mm. Mass is 730 g."
      },
      {
        "q": "What does the RNA4824-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4824-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 130×150×30 mm and the catalogue ratings are C 112 kN, C0 239 kN, Cur 39.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA4824-XL?",
        "a": "The basic dynamic load rating C is 112 kN and the basic static load rating C0 is 239 kN; the fatigue load limit Cur is 39.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4824-XL?",
        "a": "The limiting speed is 3,600 r/min and the thermal reference speed is 2,120 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4824-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4824-XL has no inner ring, so the 130 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4824",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 130×150×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4824-XL",
      "RNA4824-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4924-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4924-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 135,
    "D_mm": 165,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 205,
    "static_load_kN": 390,
    "fatigue_load_limit_kN": 65,
    "limiting_speed_rpm": 3400,
    "max_rpm": 3400,
    "reference_speed_rpm": 2250,
    "weight_g": 1860,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 135×165×45 mm: 135 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 205 kN and C0 390 kN at the 135 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 165 mm outside diameter the fatigue load limit Cur is 65 kN, the limiting speed 3,400 r/min and the thermal reference speed 2,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.52 kN/mm and per millimetre of width 4.56 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.86 kg (1860 g), just 0.25 g per mm² of projected 165×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 135 mm bore puts this execution at the top of the HR1 range — the 165 mm outside diameter, 45 mm width and 1.86 kg mass are built for primary-industry load cases The thin 15.0 mm section makes the 1860 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting With Cur 65 kN and a 3,400 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 135×165×45 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 165 mm outside diameter and 205 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 135 mm seat, and in connecting-rod small ends the 1.86 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 45 mm width and the published 390 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4924-XL?",
        "a": "The RNA4924-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 165 mm outside diameter, 135 mm bore and 45 mm width, envelope 135×165×45 mm. Mass is 1.86 kg."
      },
      {
        "q": "What does the RNA4924-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4924-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 135×165×45 mm and the catalogue ratings are C 205 kN, C0 390 kN, Cur 65 kN."
      },
      {
        "q": "What is the load capacity of the RNA4924-XL?",
        "a": "The basic dynamic load rating C is 205 kN and the basic static load rating C0 is 390 kN; the fatigue load limit Cur is 65 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4924-XL?",
        "a": "The limiting speed is 3,400 r/min and the thermal reference speed is 2,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4924-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4924-XL has no inner ring, so the 135 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4924",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 135×165×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4924-XL",
      "RNA4924-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4826-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4826-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 145,
    "D_mm": 165,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 134,
    "static_load_kN": 310,
    "fatigue_load_limit_kN": 49.5,
    "limiting_speed_rpm": 3250,
    "max_rpm": 3250,
    "reference_speed_rpm": 2000,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 145×165×35 mm: 145 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 134 kN and C0 310 kN at the 145 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 165 mm outside diameter the fatigue load limit Cur is 49.5 kN, the limiting speed 3,250 r/min and the thermal reference speed 2,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 3.83 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 990 g, just 0.17 g per mm² of projected 165×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 145 mm bore, 165 mm outside diameter: at this size the 310 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces Omitting the inner ring frees radial space — at a 145 mm shaft the outer diameter is only 165 mm and the width 35 mm, yet C is 134 kN As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 49.5 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 165 mm outside diameter and 134 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 145 mm seat, and in textile machine heald and cam shafts the 990 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 35 mm width and the published 310 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4826-XL?",
        "a": "The RNA4826-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 165 mm outside diameter, 145 mm bore and 35 mm width, envelope 145×165×35 mm. Mass is 990 g."
      },
      {
        "q": "What does the RNA4826-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4826-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 145×165×35 mm and the catalogue ratings are C 134 kN, C0 310 kN, Cur 49.5 kN."
      },
      {
        "q": "What is the load capacity of the RNA4826-XL?",
        "a": "The basic dynamic load rating C is 134 kN and the basic static load rating C0 is 310 kN; the fatigue load limit Cur is 49.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4826-XL?",
        "a": "The limiting speed is 3,250 r/min and the thermal reference speed is 2,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4826-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4826-XL has no inner ring, so the 145 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4826",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 145×165×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4826-XL",
      "RNA4826-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4926-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4926-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 150,
    "D_mm": 180,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 229,
    "static_load_kN": 470,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 3100,
    "max_rpm": 3100,
    "reference_speed_rpm": 2080,
    "weight_g": 2210,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 150×180×50 mm: 150 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 229 kN and C0 470 kN at the 150 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 180 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 3,100 r/min and the thermal reference speed 2,080 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.53 kN/mm and per millimetre of width 4.58 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.21 kg (2210 g), just 0.25 g per mm² of projected 180×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 150 mm bore puts this execution at the top of the HR1 range — the 180 mm outside diameter, 50 mm width and 2.21 kg mass are built for primary-industry load cases RNA4926-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 3,100 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 180 mm outside diameter and 229 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 150 mm seat, and in textile machine heald and cam shafts the 2.21 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 50 mm width and the published 470 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4926-XL?",
        "a": "The RNA4926-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 180 mm outside diameter, 150 mm bore and 50 mm width, envelope 150×180×50 mm. Mass is 2.21 kg."
      },
      {
        "q": "What does the RNA4926-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4926-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 150×180×50 mm and the catalogue ratings are C 229 kN, C0 470 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the RNA4926-XL?",
        "a": "The basic dynamic load rating C is 229 kN and the basic static load rating C0 is 470 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4926-XL?",
        "a": "The limiting speed is 3,100 r/min and the thermal reference speed is 2,080 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4926-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4926-XL has no inner ring, so the 150 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4926",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 150×180×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4926-XL",
      "RNA4926-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4828-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4828-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 155,
    "D_mm": 175,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 136,
    "static_load_kN": 325,
    "fatigue_load_limit_kN": 51,
    "limiting_speed_rpm": 3050,
    "max_rpm": 3050,
    "reference_speed_rpm": 1870,
    "weight_g": 1050,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 155×175×35 mm: 155 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 136 kN and C0 325 kN at the 155 mm seat; the C/C0 ratio of 0.42 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 175 mm outside diameter the fatigue load limit Cur is 51 kN, the limiting speed 3,050 r/min and the thermal reference speed 1,870 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 3.89 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.05 kg (1050 g), just 0.17 g per mm² of projected 175×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 155 mm bore, 175 mm outside diameter: at this size the 325 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 136 kN C rating and longer nominal life come without an envelope change. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 175 mm outside diameter and 136 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 155 mm seat, and in agricultural machine pivots and linkages the 1.05 kg mass is part of the rotor inertia calculation. Designers also specify it for connecting-rod small ends, relying on the 35 mm width and the published 325 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4828-XL?",
        "a": "The RNA4828-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 175 mm outside diameter, 155 mm bore and 35 mm width, envelope 155×175×35 mm. Mass is 1.05 kg."
      },
      {
        "q": "What does the RNA4828-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4828-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 155×175×35 mm and the catalogue ratings are C 136 kN, C0 325 kN, Cur 51 kN."
      },
      {
        "q": "What is the load capacity of the RNA4828-XL?",
        "a": "The basic dynamic load rating C is 136 kN and the basic static load rating C0 is 325 kN; the fatigue load limit Cur is 51 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4828-XL?",
        "a": "The limiting speed is 3,050 r/min and the thermal reference speed is 1,870 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4828-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4828-XL has no inner ring, so the 155 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4828",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 155×175×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4828-XL",
      "RNA4828-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4928-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4928-XL",
    "series": "rna49-series",
    "type": "needle",
    "d_mm": 160,
    "D_mm": 190,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 237,
    "static_load_kN": 500,
    "fatigue_load_limit_kN": 79,
    "limiting_speed_rpm": 2900,
    "max_rpm": 2900,
    "reference_speed_rpm": 1910,
    "weight_g": 2350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 160×190×50 mm: 160 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 237 kN and C0 500 kN at the 160 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 190 mm outside diameter the fatigue load limit Cur is 79 kN, the limiting speed 2,900 r/min and the thermal reference speed 1,910 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.48 kN/mm and per millimetre of width 4.74 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.35 kg (2350 g), just 0.25 g per mm² of projected 190×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 160 mm bore puts this execution at the top of the HR1 range — the 190 mm outside diameter, 50 mm width and 2.35 kg mass are built for primary-industry load cases Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened RNA4928-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality X-life status (-XL) indicates the current Schaeffler premium execution at 160 mm bore; the 500 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 190 mm outside diameter and 237 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 160 mm seat, and in agricultural machine pivots and linkages the 2.35 kg mass is part of the rotor inertia calculation. Designers also specify it for connecting-rod small ends, relying on the 50 mm width and the published 500 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4928-XL?",
        "a": "The RNA4928-XL is a RNA49 dimension-series 49 needle roller bearing without inner ring with 190 mm outside diameter, 160 mm bore and 50 mm width, envelope 160×190×50 mm. Mass is 2.35 kg."
      },
      {
        "q": "What does the RNA4928-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4928-XL identifies this RNA49 dimension-series 49 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 160×190×50 mm and the catalogue ratings are C 237 kN, C0 500 kN, Cur 79 kN."
      },
      {
        "q": "What is the load capacity of the RNA4928-XL?",
        "a": "The basic dynamic load rating C is 237 kN and the basic static load rating C0 is 500 kN; the fatigue load limit Cur is 79 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4928-XL?",
        "a": "The limiting speed is 2,900 r/min and the thermal reference speed is 1,910 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4928-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4928-XL has no inner ring, so the 160 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4928",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 160×190×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4928-XL",
      "RNA4928-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4830-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4830-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 165,
    "D_mm": 190,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 172,
    "static_load_kN": 400,
    "fatigue_load_limit_kN": 63,
    "limiting_speed_rpm": 2850,
    "max_rpm": 2850,
    "reference_speed_rpm": 1830,
    "weight_g": 1600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 165×190×40 mm: 165 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 172 kN and C0 400 kN at the 165 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 190 mm outside diameter the fatigue load limit Cur is 63 kN, the limiting speed 2,850 r/min and the thermal reference speed 1,830 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 4.30 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.6 kg (1600 g), just 0.21 g per mm² of projected 190×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 165 mm bore puts this execution at the top of the HR1 range — the 190 mm outside diameter, 40 mm width and 1.6 kg mass are built for primary-industry load cases This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces X-life status (-XL) indicates the current Schaeffler premium execution at 165 mm bore; the 400 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 190 mm outside diameter and 172 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 165 mm seat, and in motorcycle and light-vehicle transmissions the 1.6 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 40 mm width and the published 400 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4830-XL?",
        "a": "The RNA4830-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 190 mm outside diameter, 165 mm bore and 40 mm width, envelope 165×190×40 mm. Mass is 1.6 kg."
      },
      {
        "q": "What does the RNA4830-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4830-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 165×190×40 mm and the catalogue ratings are C 172 kN, C0 400 kN, Cur 63 kN."
      },
      {
        "q": "What is the load capacity of the RNA4830-XL?",
        "a": "The basic dynamic load rating C is 172 kN and the basic static load rating C0 is 400 kN; the fatigue load limit Cur is 63 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4830-XL?",
        "a": "The limiting speed is 2,850 r/min and the thermal reference speed is 1,830 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4830-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4830-XL has no inner ring, so the 165 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4830",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 165×190×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4830-XL",
      "RNA4830-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4832-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4832-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 175,
    "D_mm": 200,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 181,
    "static_load_kN": 435,
    "fatigue_load_limit_kN": 67,
    "limiting_speed_rpm": 2700,
    "max_rpm": 2700,
    "reference_speed_rpm": 1700,
    "weight_g": 1700,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 175×200×40 mm: 175 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 181 kN and C0 435 kN at the 175 mm seat; the C/C0 ratio of 0.42 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 200 mm outside diameter the fatigue load limit Cur is 67 kN, the limiting speed 2,700 r/min and the thermal reference speed 1,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 4.53 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.7 kg (1700 g), just 0.21 g per mm² of projected 200×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 175 mm bore puts this execution at the top of the HR1 range — the 200 mm outside diameter, 40 mm width and 1.7 kg mass are built for primary-industry load cases The thin 12.5 mm section makes the 1700 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Reading the RNA48 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 67 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 200 mm outside diameter and 181 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 175 mm seat, and in connecting-rod small ends the 1.7 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 40 mm width and the published 435 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4832-XL?",
        "a": "The RNA4832-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 200 mm outside diameter, 175 mm bore and 40 mm width, envelope 175×200×40 mm. Mass is 1.7 kg."
      },
      {
        "q": "What does the RNA4832-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4832-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 175×200×40 mm and the catalogue ratings are C 181 kN, C0 435 kN, Cur 67 kN."
      },
      {
        "q": "What is the load capacity of the RNA4832-XL?",
        "a": "The basic dynamic load rating C is 181 kN and the basic static load rating C0 is 435 kN; the fatigue load limit Cur is 67 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4832-XL?",
        "a": "The limiting speed is 2,700 r/min and the thermal reference speed is 1,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4832-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4832-XL has no inner ring, so the 175 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4832",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 175×200×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4832-XL",
      "RNA4832-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4834-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4834-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 185,
    "D_mm": 215,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 209,
    "static_load_kN": 510,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 2550,
    "max_rpm": 2550,
    "reference_speed_rpm": 1640,
    "weight_g": 2540,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 185×215×45 mm: 185 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 209 kN and C0 510 kN at the 185 mm seat; the C/C0 ratio of 0.41 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 215 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 2,550 r/min and the thermal reference speed 1,640 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 4.64 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.54 kg (2540 g), just 0.26 g per mm² of projected 215×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 185 mm bore, 215 mm outside diameter: at this size the 510 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs Reading the RNA48 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 76 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 215 mm outside diameter and 209 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 185 mm seat, and in planetary gear bearings the 2.54 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 45 mm width and the published 510 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4834-XL?",
        "a": "The RNA4834-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 215 mm outside diameter, 185 mm bore and 45 mm width, envelope 185×215×45 mm. Mass is 2.54 kg."
      },
      {
        "q": "What does the RNA4834-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4834-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 185×215×45 mm and the catalogue ratings are C 209 kN, C0 510 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the RNA4834-XL?",
        "a": "The basic dynamic load rating C is 209 kN and the basic static load rating C0 is 510 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4834-XL?",
        "a": "The limiting speed is 2,550 r/min and the thermal reference speed is 1,640 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4834-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4834-XL has no inner ring, so the 185 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4834",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 185×215×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4834-XL",
      "RNA4834-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4836-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4836-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 195,
    "D_mm": 225,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 219,
    "static_load_kN": 550,
    "fatigue_load_limit_kN": 81,
    "limiting_speed_rpm": 2420,
    "max_rpm": 2420,
    "reference_speed_rpm": 1510,
    "weight_g": 2680,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 195×225×45 mm: 195 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 219 kN and C0 550 kN at the 195 mm seat; the C/C0 ratio of 0.40 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 225 mm outside diameter the fatigue load limit Cur is 81 kN, the limiting speed 2,420 r/min and the thermal reference speed 1,510 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.12 kN/mm and per millimetre of width 4.87 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.68 kg (2680 g), just 0.26 g per mm² of projected 225×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 195 mm bore, 225 mm outside diameter: at this size the 550 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs The hardness requirement is unforgiving: below about 58 HRC the 195 mm journal brinels under the 550 kN static rating, and roughness above raceway finish accelerates roller wear The thin 15.0 mm section makes the 2680 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 219 kN C rating and longer nominal life come without an envelope change. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 225 mm outside diameter and 219 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 195 mm seat, and in small electric motor accessory drives the 2.68 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 45 mm width and the published 550 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4836-XL?",
        "a": "The RNA4836-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 225 mm outside diameter, 195 mm bore and 45 mm width, envelope 195×225×45 mm. Mass is 2.68 kg."
      },
      {
        "q": "What does the RNA4836-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4836-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 195×225×45 mm and the catalogue ratings are C 219 kN, C0 550 kN, Cur 81 kN."
      },
      {
        "q": "What is the load capacity of the RNA4836-XL?",
        "a": "The basic dynamic load rating C is 219 kN and the basic static load rating C0 is 550 kN; the fatigue load limit Cur is 81 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4836-XL?",
        "a": "The limiting speed is 2,420 r/min and the thermal reference speed is 1,510 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4836-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4836-XL has no inner ring, so the 195 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4836",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 195×225×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4836-XL",
      "RNA4836-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4838-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4838-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 210,
    "D_mm": 240,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 255,
    "static_load_kN": 690,
    "fatigue_load_limit_kN": 102,
    "limiting_speed_rpm": 2250,
    "max_rpm": 2250,
    "reference_speed_rpm": 1360,
    "weight_g": 3210,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 210×240×50 mm: 210 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 255 kN and C0 690 kN at the 210 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 240 mm outside diameter the fatigue load limit Cur is 102 kN, the limiting speed 2,250 r/min and the thermal reference speed 1,360 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.21 kN/mm and per millimetre of width 5.10 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.21 kg (3210 g), just 0.27 g per mm² of projected 240×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 210 mm bore, 240 mm outside diameter: at this size the 690 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs Omitting the inner ring frees radial space — at a 210 mm shaft the outer diameter is only 240 mm and the width 50 mm, yet C is 255 kN -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 255 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 240 mm outside diameter and 255 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 210 mm seat, and in textile machine heald and cam shafts the 3.21 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 50 mm width and the published 690 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4838-XL?",
        "a": "The RNA4838-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 240 mm outside diameter, 210 mm bore and 50 mm width, envelope 210×240×50 mm. Mass is 3.21 kg."
      },
      {
        "q": "What does the RNA4838-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4838-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 210×240×50 mm and the catalogue ratings are C 255 kN, C0 690 kN, Cur 102 kN."
      },
      {
        "q": "What is the load capacity of the RNA4838-XL?",
        "a": "The basic dynamic load rating C is 255 kN and the basic static load rating C0 is 690 kN; the fatigue load limit Cur is 102 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4838-XL?",
        "a": "The limiting speed is 2,250 r/min and the thermal reference speed is 1,360 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4838-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4838-XL has no inner ring, so the 210 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4838",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 210×240×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4838-XL",
      "RNA4838-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4840-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4840-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 220,
    "D_mm": 250,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 260,
    "static_load_kN": 720,
    "fatigue_load_limit_kN": 104,
    "limiting_speed_rpm": 2150,
    "max_rpm": 2150,
    "reference_speed_rpm": 1280,
    "weight_g": 3350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 220×250×50 mm: 220 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 260 kN and C0 720 kN at the 220 mm seat; the C/C0 ratio of 0.36 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 250 mm outside diameter the fatigue load limit Cur is 104 kN, the limiting speed 2,150 r/min and the thermal reference speed 1,280 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.18 kN/mm and per millimetre of width 5.20 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.35 kg (3350 g), just 0.27 g per mm² of projected 250×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 220 mm bore puts this execution at the top of the HR1 range — the 250 mm outside diameter, 50 mm width and 3.35 kg mass are built for primary-industry load cases Omitting the inner ring frees radial space — at a 220 mm shaft the outer diameter is only 250 mm and the width 50 mm, yet C is 260 kN RNA4840-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 104 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 250 mm outside diameter and 260 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 220 mm seat, and in gearbox selector and change linkages the 3.35 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 50 mm width and the published 720 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4840-XL?",
        "a": "The RNA4840-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 250 mm outside diameter, 220 mm bore and 50 mm width, envelope 220×250×50 mm. Mass is 3.35 kg."
      },
      {
        "q": "What does the RNA4840-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4840-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 220×250×50 mm and the catalogue ratings are C 260 kN, C0 720 kN, Cur 104 kN."
      },
      {
        "q": "What is the load capacity of the RNA4840-XL?",
        "a": "The basic dynamic load rating C is 260 kN and the basic static load rating C0 is 720 kN; the fatigue load limit Cur is 104 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4840-XL?",
        "a": "The limiting speed is 2,150 r/min and the thermal reference speed is 1,280 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4840-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4840-XL has no inner ring, so the 220 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4840",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 220×250×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4840-XL",
      "RNA4840-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4844-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4844-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 240,
    "D_mm": 270,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 275,
    "static_load_kN": 790,
    "fatigue_load_limit_kN": 112,
    "limiting_speed_rpm": 1980,
    "max_rpm": 1980,
    "reference_speed_rpm": 1130,
    "weight_g": 3620,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 240×270×50 mm: 240 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 275 kN and C0 790 kN at the 240 mm seat; the C/C0 ratio of 0.35 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 270 mm outside diameter the fatigue load limit Cur is 112 kN, the limiting speed 1,980 r/min and the thermal reference speed 1,130 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.15 kN/mm and per millimetre of width 5.50 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.62 kg (3620 g), just 0.27 g per mm² of projected 270×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 240 mm bore, 270 mm outside diameter: at this size the 790 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The hardness requirement is unforgiving: below about 58 HRC the 240 mm journal brinels under the 790 kN static rating, and roughness above raceway finish accelerates roller wear -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 275 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 270 mm outside diameter and 275 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 240 mm seat, and in textile machine heald and cam shafts the 3.62 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 50 mm width and the published 790 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4844-XL?",
        "a": "The RNA4844-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 270 mm outside diameter, 240 mm bore and 50 mm width, envelope 240×270×50 mm. Mass is 3.62 kg."
      },
      {
        "q": "What does the RNA4844-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4844-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 240×270×50 mm and the catalogue ratings are C 275 kN, C0 790 kN, Cur 112 kN."
      },
      {
        "q": "What is the load capacity of the RNA4844-XL?",
        "a": "The basic dynamic load rating C is 275 kN and the basic static load rating C0 is 790 kN; the fatigue load limit Cur is 112 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4844-XL?",
        "a": "The limiting speed is 1,980 r/min and the thermal reference speed is 1,130 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4844-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4844-XL has no inner ring, so the 240 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4844",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 240×270×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=956",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4844-XL",
      "RNA4844-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4848-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4848-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 265,
    "D_mm": 300,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 400,
    "static_load_kN": 1080,
    "fatigue_load_limit_kN": 153,
    "limiting_speed_rpm": 1780,
    "max_rpm": 1780,
    "reference_speed_rpm": 980,
    "weight_g": 5400,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 265×300×60 mm: 265 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 400 kN and C0 1080 kN at the 265 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 300 mm outside diameter the fatigue load limit Cur is 153 kN, the limiting speed 1,780 r/min and the thermal reference speed 980 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.51 kN/mm and per millimetre of width 6.67 kN/mm — the reason 60 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.4 kg (5400 g), just 0.30 g per mm² of projected 300×60 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 265 mm bore, 300 mm outside diameter: at this size the 1080 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs RNA4848-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality The thin 17.5 mm section makes the 5400 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 265×300×60 mm envelope. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 300 mm outside diameter and 400 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 265 mm seat, and in small electric motor accessory drives the 5.4 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 60 mm width and the published 1080 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4848-XL?",
        "a": "The RNA4848-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 300 mm outside diameter, 265 mm bore and 60 mm width, envelope 265×300×60 mm. Mass is 5.4 kg."
      },
      {
        "q": "What does the RNA4848-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4848-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 265×300×60 mm and the catalogue ratings are C 400 kN, C0 1080 kN, Cur 153 kN."
      },
      {
        "q": "What is the load capacity of the RNA4848-XL?",
        "a": "The basic dynamic load rating C is 400 kN and the basic static load rating C0 is 1080 kN; the fatigue load limit Cur is 153 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4848-XL?",
        "a": "The limiting speed is 1,780 r/min and the thermal reference speed is 980 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4848-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4848-XL has no inner ring, so the 265 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4848",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 265×300×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4848-XL",
      "RNA4848-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4852-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4852-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 285,
    "D_mm": 320,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 415,
    "static_load_kN": 1160,
    "fatigue_load_limit_kN": 161,
    "limiting_speed_rpm": 1660,
    "max_rpm": 1660,
    "reference_speed_rpm": 890,
    "weight_g": 5800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 285×320×60 mm: 285 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 415 kN and C0 1160 kN at the 285 mm seat; the C/C0 ratio of 0.36 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 320 mm outside diameter the fatigue load limit Cur is 161 kN, the limiting speed 1,660 r/min and the thermal reference speed 890 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.46 kN/mm and per millimetre of width 6.92 kN/mm — the reason 60 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.8 kg (5800 g), just 0.30 g per mm² of projected 320×60 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 285 mm bore puts this execution at the top of the HR1 range — the 320 mm outside diameter, 60 mm width and 5.8 kg mass are built for primary-industry load cases With Cur 161 kN and a 1,660 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins RNA4852-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 415 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 320 mm outside diameter and 415 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 285 mm seat, and in gearbox selector and change linkages the 5.8 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 60 mm width and the published 1160 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4852-XL?",
        "a": "The RNA4852-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 320 mm outside diameter, 285 mm bore and 60 mm width, envelope 285×320×60 mm. Mass is 5.8 kg."
      },
      {
        "q": "What does the RNA4852-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4852-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 285×320×60 mm and the catalogue ratings are C 415 kN, C0 1160 kN, Cur 161 kN."
      },
      {
        "q": "What is the load capacity of the RNA4852-XL?",
        "a": "The basic dynamic load rating C is 415 kN and the basic static load rating C0 is 1160 kN; the fatigue load limit Cur is 161 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4852-XL?",
        "a": "The limiting speed is 1,660 r/min and the thermal reference speed is 890 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4852-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4852-XL has no inner ring, so the 285 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4852",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 285×320×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4852-XL",
      "RNA4852-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4856-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4856-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 305,
    "D_mm": 350,
    "B_mm": 69,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 510,
    "static_load_kN": 1300,
    "fatigue_load_limit_kN": 178,
    "limiting_speed_rpm": 1540,
    "max_rpm": 1540,
    "reference_speed_rpm": 850,
    "weight_g": 9300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 305×350×69 mm: 305 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 22.5 mm radial section packed with small-diameter needle rollers C is 510 kN and C0 1300 kN at the 305 mm seat; the C/C0 ratio of 0.39 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 350 mm outside diameter the fatigue load limit Cur is 178 kN, the limiting speed 1,540 r/min and the thermal reference speed 850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.67 kN/mm and per millimetre of width 7.39 kN/mm — the reason 69 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 9.3 kg (9300 g), just 0.39 g per mm² of projected 350×69 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 305 mm bore, 350 mm outside diameter: at this size the 1300 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces The thin 22.5 mm section makes the 9300 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 305×350×69 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 350 mm outside diameter and 510 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 305 mm seat, and in textile machine heald and cam shafts the 9.3 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 69 mm width and the published 1300 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4856-XL?",
        "a": "The RNA4856-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 350 mm outside diameter, 305 mm bore and 69 mm width, envelope 305×350×69 mm. Mass is 9.3 kg."
      },
      {
        "q": "What does the RNA4856-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4856-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 305×350×69 mm and the catalogue ratings are C 510 kN, C0 1300 kN, Cur 178 kN."
      },
      {
        "q": "What is the load capacity of the RNA4856-XL?",
        "a": "The basic dynamic load rating C is 510 kN and the basic static load rating C0 is 1300 kN; the fatigue load limit Cur is 178 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4856-XL?",
        "a": "The limiting speed is 1,540 r/min and the thermal reference speed is 850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4856-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4856-XL has no inner ring, so the 305 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4856",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 305×350×69 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4856-XL",
      "RNA4856-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4860-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4860-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 330,
    "D_mm": 380,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 700,
    "static_load_kN": 1770,
    "fatigue_load_limit_kN": 239,
    "limiting_speed_rpm": 1420,
    "max_rpm": 1420,
    "reference_speed_rpm": 740,
    "weight_g": 12700,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 330×380×80 mm: 330 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 700 kN and C0 1770 kN at the 330 mm seat; the C/C0 ratio of 0.40 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 380 mm outside diameter the fatigue load limit Cur is 239 kN, the limiting speed 1,420 r/min and the thermal reference speed 740 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.12 kN/mm and per millimetre of width 8.75 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 12.7 kg (12700 g), just 0.42 g per mm² of projected 380×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 330 mm bore puts this execution at the top of the HR1 range — the 380 mm outside diameter, 80 mm width and 12.7 kg mass are built for primary-industry load cases With Cur 239 kN and a 1,420 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The hardness requirement is unforgiving: below about 58 HRC the 330 mm journal brinels under the 1770 kN static rating, and roughness above raceway finish accelerates roller wear -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 700 kN C rating and longer nominal life come without an envelope change. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 380 mm outside diameter and 700 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 330 mm seat, and in motorcycle and light-vehicle transmissions the 12.7 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 80 mm width and the published 1770 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4860-XL?",
        "a": "The RNA4860-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 380 mm outside diameter, 330 mm bore and 80 mm width, envelope 330×380×80 mm. Mass is 12.7 kg."
      },
      {
        "q": "What does the RNA4860-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4860-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 330×380×80 mm and the catalogue ratings are C 700 kN, C0 1770 kN, Cur 239 kN."
      },
      {
        "q": "What is the load capacity of the RNA4860-XL?",
        "a": "The basic dynamic load rating C is 700 kN and the basic static load rating C0 is 1770 kN; the fatigue load limit Cur is 239 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4860-XL?",
        "a": "The limiting speed is 1,420 r/min and the thermal reference speed is 740 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4860-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4860-XL has no inner ring, so the 330 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4860",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 330×380×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4860-XL",
      "RNA4860-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4864-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4864-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 350,
    "D_mm": 400,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 710,
    "static_load_kN": 1850,
    "fatigue_load_limit_kN": 246,
    "limiting_speed_rpm": 1340,
    "max_rpm": 1340,
    "reference_speed_rpm": 680,
    "weight_g": 13400,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 350×400×80 mm: 350 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 710 kN and C0 1850 kN at the 350 mm seat; the C/C0 ratio of 0.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 400 mm outside diameter the fatigue load limit Cur is 246 kN, the limiting speed 1,340 r/min and the thermal reference speed 680 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.03 kN/mm and per millimetre of width 8.88 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 13.4 kg (13400 g), just 0.42 g per mm² of projected 400×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 350 mm bore, 400 mm outside diameter: at this size the 1850 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs RNA4864-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality With Cur 246 kN and a 1,340 r/min limiting speed the unit suits pivots, rocker arms, pumps and compact gear trains running on hardened pins The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 350×400×80 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 400 mm outside diameter and 710 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 350 mm seat, and in planetary gear bearings the 13.4 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 80 mm width and the published 1850 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4864-XL?",
        "a": "The RNA4864-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 400 mm outside diameter, 350 mm bore and 80 mm width, envelope 350×400×80 mm. Mass is 13.4 kg."
      },
      {
        "q": "What does the RNA4864-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4864-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 350×400×80 mm and the catalogue ratings are C 710 kN, C0 1850 kN, Cur 246 kN."
      },
      {
        "q": "What is the load capacity of the RNA4864-XL?",
        "a": "The basic dynamic load rating C is 710 kN and the basic static load rating C0 is 1850 kN; the fatigue load limit Cur is 246 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4864-XL?",
        "a": "The limiting speed is 1,340 r/min and the thermal reference speed is 680 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4864-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4864-XL has no inner ring, so the 350 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4864",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4864-XL",
      "RNA4864-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4868-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4868-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 370,
    "D_mm": 420,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 730,
    "static_load_kN": 1940,
    "fatigue_load_limit_kN": 255,
    "limiting_speed_rpm": 1270,
    "max_rpm": 1270,
    "reference_speed_rpm": 640,
    "weight_g": 14000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 370×420×80 mm: 370 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 730 kN and C0 1940 kN at the 370 mm seat; the C/C0 ratio of 0.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 420 mm outside diameter the fatigue load limit Cur is 255 kN, the limiting speed 1,270 r/min and the thermal reference speed 640 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.97 kN/mm and per millimetre of width 9.13 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 14 kg (14000 g), just 0.42 g per mm² of projected 420×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 370 mm bore, 420 mm outside diameter: at this size the 1940 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs The hardness requirement is unforgiving: below about 58 HRC the 370 mm journal brinels under the 1940 kN static rating, and roughness above raceway finish accelerates roller wear RNA4868-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality X-life status (-XL) indicates the current Schaeffler premium execution at 370 mm bore; the 1940 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 420 mm outside diameter and 730 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 370 mm seat, and in rocker arms and valve trains the 14 kg mass is part of the rotor inertia calculation. Designers also specify it for planetary gear bearings, relying on the 80 mm width and the published 1940 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4868-XL?",
        "a": "The RNA4868-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 420 mm outside diameter, 370 mm bore and 80 mm width, envelope 370×420×80 mm. Mass is 14 kg."
      },
      {
        "q": "What does the RNA4868-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4868-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 370×420×80 mm and the catalogue ratings are C 730 kN, C0 1940 kN, Cur 255 kN."
      },
      {
        "q": "What is the load capacity of the RNA4868-XL?",
        "a": "The basic dynamic load rating C is 730 kN and the basic static load rating C0 is 1940 kN; the fatigue load limit Cur is 255 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4868-XL?",
        "a": "The limiting speed is 1,270 r/min and the thermal reference speed is 640 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4868-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4868-XL has no inner ring, so the 370 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4868",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4868-XL",
      "RNA4868-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4872-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4872-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 390,
    "D_mm": 440,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 740,
    "static_load_kN": 2020,
    "fatigue_load_limit_kN": 260,
    "limiting_speed_rpm": 1210,
    "max_rpm": 1210,
    "reference_speed_rpm": 600,
    "weight_g": 14800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 390×440×80 mm: 390 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 740 kN and C0 2020 kN at the 390 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 440 mm outside diameter the fatigue load limit Cur is 260 kN, the limiting speed 1,210 r/min and the thermal reference speed 600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.90 kN/mm and per millimetre of width 9.25 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 14.8 kg (14800 g), just 0.42 g per mm² of projected 440×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 390 mm bore puts this execution at the top of the HR1 range — the 440 mm outside diameter, 80 mm width and 14.8 kg mass are built for primary-industry load cases Reading the RNA48 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened The hardness requirement is unforgiving: below about 58 HRC the 390 mm journal brinels under the 2020 kN static rating, and roughness above raceway finish accelerates roller wear The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 390×440×80 mm envelope. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 440 mm outside diameter and 740 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 390 mm seat, and in motorcycle and light-vehicle transmissions the 14.8 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 80 mm width and the published 2020 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4872-XL?",
        "a": "The RNA4872-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 440 mm outside diameter, 390 mm bore and 80 mm width, envelope 390×440×80 mm. Mass is 14.8 kg."
      },
      {
        "q": "What does the RNA4872-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4872-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 390×440×80 mm and the catalogue ratings are C 740 kN, C0 2020 kN, Cur 260 kN."
      },
      {
        "q": "What is the load capacity of the RNA4872-XL?",
        "a": "The basic dynamic load rating C is 740 kN and the basic static load rating C0 is 2020 kN; the fatigue load limit Cur is 260 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4872-XL?",
        "a": "The limiting speed is 1,210 r/min and the thermal reference speed is 600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4872-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4872-XL has no inner ring, so the 390 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4872",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4872-XL",
      "RNA4872-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4876-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNA4876-XL",
    "series": "rna48-series",
    "type": "needle",
    "d_mm": 415,
    "D_mm": 480,
    "B_mm": 100,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 1130,
    "static_load_kN": 2900,
    "fatigue_load_limit_kN": 375,
    "limiting_speed_rpm": 1130,
    "max_rpm": 1130,
    "reference_speed_rpm": 520,
    "weight_g": 26000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 415×480×100 mm: 415 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 32.5 mm radial section packed with small-diameter needle rollers C is 1130 kN and C0 2900 kN at the 415 mm seat; the C/C0 ratio of 0.39 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 480 mm outside diameter the fatigue load limit Cur is 375 kN, the limiting speed 1,130 r/min and the thermal reference speed 520 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.72 kN/mm and per millimetre of width 11.30 kN/mm — the reason 100 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 26 kg (26000 g), just 0.54 g per mm² of projected 480×100 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 415 mm bore, 480 mm outside diameter: at this size the 2900 kN C0 rating and rigid full-complement pack replace multi-bearing arrangements in compact heavy-duty designs The thin 32.5 mm section makes the 26000 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting X-life status (-XL) indicates the current Schaeffler premium execution at 415 mm bore; the 2900 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 480 mm outside diameter and 1130 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 415 mm seat, and in agricultural machine pivots and linkages the 26 kg mass is part of the rotor inertia calculation. Designers also specify it for connecting-rod small ends, relying on the 100 mm width and the published 2900 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNA4876-XL?",
        "a": "The RNA4876-XL is a RNA48 dimension-series 48 needle roller bearing without inner ring with 480 mm outside diameter, 415 mm bore and 100 mm width, envelope 415×480×100 mm. Mass is 26 kg."
      },
      {
        "q": "What does the RNA4876-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNA4876-XL identifies this RNA48 dimension-series 48 needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 415×480×100 mm and the catalogue ratings are C 1130 kN, C0 2900 kN, Cur 375 kN."
      },
      {
        "q": "What is the load capacity of the RNA4876-XL?",
        "a": "The basic dynamic load rating C is 1130 kN and the basic static load rating C0 is 2900 kN; the fatigue load limit Cur is 375 kN."
      },
      {
        "q": "What is the maximum speed of the RNA4876-XL?",
        "a": "The limiting speed is 1,130 r/min and the thermal reference speed is 520 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNA4876-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNA4876-XL has no inner ring, so the 415 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4876",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=957",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4876-XL",
      "RNA4876-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI5-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI5/12-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 15,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.45,
    "static_load_kN": 4.1,
    "fatigue_load_limit_kN": 0.7,
    "limiting_speed_rpm": 32500,
    "max_rpm": 32500,
    "reference_speed_rpm": 32500,
    "weight_g": 11.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 5×15×12 mm: 5 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 4.45 kN and C0 4.1 kN at the 5 mm seat; the C/C0 ratio of 1.09 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 15 mm outside diameter the fatigue load limit Cur is 0.7 kN, the limiting speed 32,500 r/min and the thermal reference speed 32,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 0.37 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 11.5 g, just 0.06 g per mm² of projected 15×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 5 mm bore and only 11.5 g: the smallest sizes demand accurate shaft geometry, because the 5.0 mm section leaves no tolerance for a soft or tapered seat The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 4.1 kN C0 rating still assumes full rigid support under both rings The 5.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 5×15×12 mm envelope. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 32,500 r/min limiting speed without roller-to-roller sliding. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 15 mm outside diameter and 4.45 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 5 mm seat, and in textile machine heald and cam shafts the 11.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 12 mm width and the published 4.1 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI5/12-TV-XL?",
        "a": "The NKI5/12-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 15 mm outside diameter, 5 mm bore and 12 mm width, envelope 5×15×12 mm. Mass is 11.5 g."
      },
      {
        "q": "What does the NKI5/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI5/12-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 5×15×12 mm and the catalogue ratings are C 4.45 kN, C0 4.1 kN, Cur 0.7 kN."
      },
      {
        "q": "What is the load capacity of the NKI5/12-TV-XL?",
        "a": "The basic dynamic load rating C is 4.45 kN and the basic static load rating C0 is 4.1 kN; the fatigue load limit Cur is 0.7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI5/12-TV-XL?",
        "a": "The limiting speed is 32,500 r/min and the thermal reference speed is 32,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI5/12-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 5 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI5-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 5×15×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI5-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI5-12-TV-XL",
      "NKI5/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI5-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI5/16-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 15,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.8,
    "static_load_kN": 5.8,
    "fatigue_load_limit_kN": 0.99,
    "limiting_speed_rpm": 32500,
    "max_rpm": 32500,
    "reference_speed_rpm": 32000,
    "weight_g": 15.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 5×15×16 mm: 5 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 5.8 kN and C0 5.8 kN at the 5 mm seat; the C/C0 ratio of 1.00 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 15 mm outside diameter the fatigue load limit Cur is 0.99 kN, the limiting speed 32,500 r/min and the thermal reference speed 32,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.16 kN/mm and per millimetre of width 0.36 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 15.3 g, just 0.06 g per mm² of projected 15×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 5 mm bore this is one of the smallest HR1 executions — chosen where a 15 mm envelope must carry line-contact loads that no miniature ball bearing could take NKI5/16-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 5.8 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 5.8 kN C rating and longer nominal life come without an envelope change. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 32,500 r/min limiting speed without roller-to-roller sliding. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 15 mm outside diameter and 5.8 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 5 mm seat, and in connecting-rod small ends the 15.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 16 mm width and the published 5.8 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI5/16-TV-XL?",
        "a": "The NKI5/16-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 15 mm outside diameter, 5 mm bore and 16 mm width, envelope 5×15×16 mm. Mass is 15.3 g."
      },
      {
        "q": "What does the NKI5/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI5/16-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 5×15×16 mm and the catalogue ratings are C 5.8 kN, C0 5.8 kN, Cur 0.99 kN."
      },
      {
        "q": "What is the load capacity of the NKI5/16-TV-XL?",
        "a": "The basic dynamic load rating C is 5.8 kN and the basic static load rating C0 is 5.8 kN; the fatigue load limit Cur is 0.99 kN."
      },
      {
        "q": "What is the maximum speed of the NKI5/16-TV-XL?",
        "a": "The limiting speed is 32,500 r/min and the thermal reference speed is 32,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI5/16-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 5 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI5-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI5-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 5×15×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI5-16-TV-XL",
      "NKI5/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI6-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI6/12-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 16,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.1,
    "static_load_kN": 5,
    "fatigue_load_limit_kN": 0.86,
    "limiting_speed_rpm": 31000,
    "max_rpm": 31000,
    "reference_speed_rpm": 28500,
    "weight_g": 13.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×16×12 mm: 6 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 5.1 kN and C0 5 kN at the 6 mm seat; the C/C0 ratio of 1.02 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 16 mm outside diameter the fatigue load limit Cur is 0.86 kN, the limiting speed 31,000 r/min and the thermal reference speed 28,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.85 kN/mm and per millimetre of width 0.42 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 13.5 g, just 0.07 g per mm² of projected 16×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 6 mm bore sits in the miniature band; at 12 mm wide the NKI6/12-TV-XL is built into compact cam drives, indexing pawls and light linkages NKI6/12-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 5 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.86 kN Cur value. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 16 mm outside diameter and 5.1 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 6 mm seat, and in two-stroke and compressor piston pins the 13.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 12 mm width and the published 5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI6/12-TV-XL?",
        "a": "The NKI6/12-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 16 mm outside diameter, 6 mm bore and 12 mm width, envelope 6×16×12 mm. Mass is 13.5 g."
      },
      {
        "q": "What does the NKI6/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI6/12-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×16×12 mm and the catalogue ratings are C 5.1 kN, C0 5 kN, Cur 0.86 kN."
      },
      {
        "q": "What is the load capacity of the NKI6/12-TV-XL?",
        "a": "The basic dynamic load rating C is 5.1 kN and the basic static load rating C0 is 5 kN; the fatigue load limit Cur is 0.86 kN."
      },
      {
        "q": "What is the maximum speed of the NKI6/12-TV-XL?",
        "a": "The limiting speed is 31,000 r/min and the thermal reference speed is 28,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI6/12-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 6 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI6-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 6×16×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI6-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI6-12-TV-XL",
      "NKI6/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI6-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI6/16-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 16,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 6.6,
    "static_load_kN": 7.1,
    "fatigue_load_limit_kN": 1.21,
    "limiting_speed_rpm": 31000,
    "max_rpm": 31000,
    "reference_speed_rpm": 28000,
    "weight_g": 17.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×16×16 mm: 6 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 6.6 kN and C0 7.1 kN at the 6 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 16 mm outside diameter the fatigue load limit Cur is 1.21 kN, the limiting speed 31,000 r/min and the thermal reference speed 28,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.10 kN/mm and per millimetre of width 0.41 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 17.4 g, just 0.07 g per mm² of projected 16×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 6 mm bore and only 17.4 g: the smallest sizes demand accurate shaft geometry, because the 5.0 mm section leaves no tolerance for a soft or tapered seat NKI6/16-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 6.6 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 6 mm bore; the 7.1 kN C0 rating reflects the improved rolling-contact geometry. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 31,000 r/min limiting speed without roller-to-roller sliding. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 16 mm outside diameter and 6.6 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 6 mm seat, and in rocker arms and valve trains the 17.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 16 mm width and the published 7.1 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI6/16-TV-XL?",
        "a": "The NKI6/16-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 16 mm outside diameter, 6 mm bore and 16 mm width, envelope 6×16×16 mm. Mass is 17.4 g."
      },
      {
        "q": "What does the NKI6/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI6/16-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×16×16 mm and the catalogue ratings are C 6.6 kN, C0 7.1 kN, Cur 1.21 kN."
      },
      {
        "q": "What is the load capacity of the NKI6/16-TV-XL?",
        "a": "The basic dynamic load rating C is 6.6 kN and the basic static load rating C0 is 7.1 kN; the fatigue load limit Cur is 1.21 kN."
      },
      {
        "q": "What is the maximum speed of the NKI6/16-TV-XL?",
        "a": "The limiting speed is 31,000 r/min and the thermal reference speed is 28,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI6/16-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 6 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI6-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI6-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 6×16×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI6-16-TV-XL",
      "NKI6/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI7-12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI7/12-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 17,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.3,
    "static_load_kN": 5.5,
    "fatigue_load_limit_kN": 0.94,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 26000,
    "weight_g": 13.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 7×17×12 mm: 7 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 5.3 kN and C0 5.5 kN at the 7 mm seat; the C/C0 ratio of 0.96 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 0.94 kN, the limiting speed 29,500 r/min and the thermal reference speed 26,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.76 kN/mm and per millimetre of width 0.44 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 13.7 g, just 0.07 g per mm² of projected 17×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 7 mm bore and only 13.7 g: the smallest sizes demand accurate shaft geometry, because the 5.0 mm section leaves no tolerance for a soft or tapered seat This is the choice for OEM production on soft shafts: machine the 7 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway NKI7/12-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required X-life status (-XL) indicates the current Schaeffler premium execution at 7 mm bore; the 5.5 kN C0 rating reflects the improved rolling-contact geometry. With the -TV polyamide cage the rollers are positively separated, so the 7 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 17 mm outside diameter and 5.3 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 7 mm seat, and in hydraulic and pneumatic pump eccentrics the 13.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 12 mm width and the published 5.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI7/12-TV-XL?",
        "a": "The NKI7/12-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 17 mm outside diameter, 7 mm bore and 12 mm width, envelope 7×17×12 mm. Mass is 13.7 g."
      },
      {
        "q": "What does the NKI7/12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI7/12-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 7×17×12 mm and the catalogue ratings are C 5.3 kN, C0 5.5 kN, Cur 0.94 kN."
      },
      {
        "q": "What is the load capacity of the NKI7/12-TV-XL?",
        "a": "The basic dynamic load rating C is 5.3 kN and the basic static load rating C0 is 5.5 kN; the fatigue load limit Cur is 0.94 kN."
      },
      {
        "q": "What is the maximum speed of the NKI7/12-TV-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 26,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI7/12-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 7 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI7-12-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 7×17×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI7-16-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI7-12-TV-XL",
      "NKI7/12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI7-16-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI7/16-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 17,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 7,
    "static_load_kN": 7.8,
    "fatigue_load_limit_kN": 1.33,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 25500,
    "weight_g": 18.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 7×17×16 mm: 7 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 7 kN and C0 7.8 kN at the 7 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 1.33 kN, the limiting speed 29,500 r/min and the thermal reference speed 25,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.00 kN/mm and per millimetre of width 0.44 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 18.2 g, just 0.07 g per mm² of projected 17×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 7 mm bore this is one of the smallest HR1 executions — chosen where a 17 mm envelope must carry line-contact loads that no miniature ball bearing could take Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 7 kN C The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 7.8 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 29,500 r/min limit. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 17 mm outside diameter and 7 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 7 mm seat, and in agricultural machine pivots and linkages the 18.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 16 mm width and the published 7.8 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI7/16-TV-XL?",
        "a": "The NKI7/16-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 17 mm outside diameter, 7 mm bore and 16 mm width, envelope 7×17×16 mm. Mass is 18.2 g."
      },
      {
        "q": "What does the NKI7/16-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI7/16-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 7×17×16 mm and the catalogue ratings are C 7 kN, C0 7.8 kN, Cur 1.33 kN."
      },
      {
        "q": "What is the load capacity of the NKI7/16-TV-XL?",
        "a": "The basic dynamic load rating C is 7 kN and the basic static load rating C0 is 7.8 kN; the fatigue load limit Cur is 1.33 kN."
      },
      {
        "q": "What is the maximum speed of the NKI7/16-TV-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 25,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI7/16-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 7 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI7-12-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI7-16-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 7×17×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI7-16-TV-XL",
      "NKI7/16-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI9-12-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI9/12-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 19,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 7.2,
    "static_load_kN": 7.1,
    "fatigue_load_limit_kN": 1.31,
    "limiting_speed_rpm": 26500,
    "max_rpm": 26500,
    "reference_speed_rpm": 20200,
    "weight_g": 16.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 9×19×12 mm: 9 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 7.2 kN and C0 7.1 kN at the 9 mm seat; the C/C0 ratio of 1.01 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 19 mm outside diameter the fatigue load limit Cur is 1.31 kN, the limiting speed 26,500 r/min and the thermal reference speed 20,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.80 kN/mm and per millimetre of width 0.60 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 16.6 g, just 0.07 g per mm² of projected 19×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 9 mm bore and only 16.6 g: the smallest sizes demand accurate shaft geometry, because the 5.0 mm section leaves no tolerance for a soft or tapered seat The integral inner ring brings the bore to 9 mm inside the 19×12 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing This is the choice for OEM production on soft shafts: machine the 9 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 1.31 kN Cur value. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 19 mm outside diameter and 7.2 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 9 mm seat, and in copying and printing machine mechanisms the 16.6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 12 mm width and the published 7.1 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI9/12-XL?",
        "a": "The NKI9/12-XL is a NKI machined-ring needle roller bearing with inner ring with 19 mm outside diameter, 9 mm bore and 12 mm width, envelope 9×19×12 mm. Mass is 16.6 g."
      },
      {
        "q": "What does the NKI9/12-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI9/12-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 9×19×12 mm and the catalogue ratings are C 7.2 kN, C0 7.1 kN, Cur 1.31 kN."
      },
      {
        "q": "What is the load capacity of the NKI9/12-XL?",
        "a": "The basic dynamic load rating C is 7.2 kN and the basic static load rating C0 is 7.1 kN; the fatigue load limit Cur is 1.31 kN."
      },
      {
        "q": "What is the maximum speed of the NKI9/12-XL?",
        "a": "The limiting speed is 26,500 r/min and the thermal reference speed is 20,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI9/12-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 9 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI9-12",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 9×19×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI9-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI9-12-XL",
      "NKI9/12-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI9-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI9/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 19,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.1,
    "static_load_kN": 11,
    "fatigue_load_limit_kN": 1.95,
    "limiting_speed_rpm": 26500,
    "max_rpm": 26500,
    "reference_speed_rpm": 19500,
    "weight_g": 21.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 9×19×16 mm: 9 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 10.1 kN and C0 11 kN at the 9 mm seat; the C/C0 ratio of 0.92 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 19 mm outside diameter the fatigue load limit Cur is 1.95 kN, the limiting speed 26,500 r/min and the thermal reference speed 19,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.12 kN/mm and per millimetre of width 0.63 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21.9 g, just 0.07 g per mm² of projected 19×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 9 mm bore sits in the miniature band; at 16 mm wide the NKI9/16-XL is built into compact cam drives, indexing pawls and light linkages The 5.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 11 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 10.1 kN C rating and longer nominal life come without an envelope change. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 19 mm outside diameter and 10.1 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 9 mm seat, and in connecting-rod small ends the 21.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 16 mm width and the published 11 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI9/16-XL?",
        "a": "The NKI9/16-XL is a NKI machined-ring needle roller bearing with inner ring with 19 mm outside diameter, 9 mm bore and 16 mm width, envelope 9×19×16 mm. Mass is 21.9 g."
      },
      {
        "q": "What does the NKI9/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI9/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 9×19×16 mm and the catalogue ratings are C 10.1 kN, C0 11 kN, Cur 1.95 kN."
      },
      {
        "q": "What is the load capacity of the NKI9/16-XL?",
        "a": "The basic dynamic load rating C is 10.1 kN and the basic static load rating C0 is 11 kN; the fatigue load limit Cur is 1.95 kN."
      },
      {
        "q": "What is the maximum speed of the NKI9/16-XL?",
        "a": "The limiting speed is 26,500 r/min and the thermal reference speed is 19,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI9/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 9 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI9-12",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI9-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 9×19×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI9-16-XL",
      "NKI9/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI10-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI10/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 11.5,
    "fatigue_load_limit_kN": 2.14,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 16400,
    "weight_g": 29.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×22×16 mm: 10 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 11.4 kN and C0 11.5 kN at the 10 mm seat; the C/C0 ratio of 0.99 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 2.14 kN, the limiting speed 24,600 r/min and the thermal reference speed 16,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.14 kN/mm and per millimetre of width 0.71 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 29.4 g, just 0.08 g per mm² of projected 22×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 10 mm bore this is one of the smallest HR1 executions — chosen where a 22 mm envelope must carry line-contact loads that no miniature ball bearing could take Cur 2.14 kN, limiting speed 24,600 r/min, reference speed 16,400 r/min — the inner ring adds a few grams (total 29.4 g) but removes the hardening requirement The integral inner ring brings the bore to 10 mm inside the 22×16 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 10×22×16 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 22 mm outside diameter and 11.4 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 10 mm seat, and in two-stroke and compressor piston pins the 29.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 16 mm width and the published 11.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI10/16-XL?",
        "a": "The NKI10/16-XL is a NKI machined-ring needle roller bearing with inner ring with 22 mm outside diameter, 10 mm bore and 16 mm width, envelope 10×22×16 mm. Mass is 29.4 g."
      },
      {
        "q": "What does the NKI10/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI10/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×22×16 mm and the catalogue ratings are C 11.4 kN, C0 11.5 kN, Cur 2.14 kN."
      },
      {
        "q": "What is the load capacity of the NKI10/16-XL?",
        "a": "The basic dynamic load rating C is 11.4 kN and the basic static load rating C0 is 11.5 kN; the fatigue load limit Cur is 2.14 kN."
      },
      {
        "q": "What is the maximum speed of the NKI10/16-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 16,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI10/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 10 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI10-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 10×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI10-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI10-16-XL",
      "NKI10/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI10-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI10/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.5,
    "static_load_kN": 15.6,
    "fatigue_load_limit_kN": 2.75,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 16100,
    "weight_g": 37.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×22×20 mm: 10 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 14.5 kN and C0 15.6 kN at the 10 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 2.75 kN, the limiting speed 24,600 r/min and the thermal reference speed 16,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.45 kN/mm and per millimetre of width 0.72 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 37.1 g, just 0.08 g per mm² of projected 22×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 10 mm bore sits in the miniature band; at 20 mm wide the NKI10/20-XL is built into compact cam drives, indexing pawls and light linkages This is the choice for OEM production on soft shafts: machine the 10 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The 6.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 2.75 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 22 mm outside diameter and 14.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 10 mm seat, and in connecting-rod small ends the 37.1 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 15.6 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI10/20-XL?",
        "a": "The NKI10/20-XL is a NKI machined-ring needle roller bearing with inner ring with 22 mm outside diameter, 10 mm bore and 20 mm width, envelope 10×22×20 mm. Mass is 37.1 g."
      },
      {
        "q": "What does the NKI10/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI10/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×22×20 mm and the catalogue ratings are C 14.5 kN, C0 15.6 kN, Cur 2.75 kN."
      },
      {
        "q": "What is the load capacity of the NKI10/20-XL?",
        "a": "The basic dynamic load rating C is 14.5 kN and the basic static load rating C0 is 15.6 kN; the fatigue load limit Cur is 2.75 kN."
      },
      {
        "q": "What is the maximum speed of the NKI10/20-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 16,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI10/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 10 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI10-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI10-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 10×22×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI10-20-XL",
      "NKI10/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4900-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4900-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 9.6,
    "static_load_kN": 9.2,
    "fatigue_load_limit_kN": 1.66,
    "limiting_speed_rpm": 24600,
    "max_rpm": 24600,
    "reference_speed_rpm": 16400,
    "weight_g": 23,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×22×13 mm: 10 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 9.6 kN and C0 9.2 kN at the 10 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 1.66 kN, the limiting speed 24,600 r/min and the thermal reference speed 16,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 0.74 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 23 g, just 0.08 g per mm² of projected 22×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 10 mm bore and only 23 g: the smallest sizes demand accurate shaft geometry, because the 6.0 mm section leaves no tolerance for a soft or tapered seat Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 9.6 kN C The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 9.2 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 10×22×13 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 22 mm outside diameter and 9.6 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 10 mm seat, and in two-stroke and compressor piston pins the 23 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 13 mm width and the published 9.2 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4900-XL?",
        "a": "The NA4900-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 22 mm outside diameter, 10 mm bore and 13 mm width, envelope 10×22×13 mm. Mass is 23 g."
      },
      {
        "q": "What does the NA4900-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4900-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×22×13 mm and the catalogue ratings are C 9.6 kN, C0 9.2 kN, Cur 1.66 kN."
      },
      {
        "q": "What is the load capacity of the NA4900-XL?",
        "a": "The basic dynamic load rating C is 9.6 kN and the basic static load rating C0 is 9.2 kN; the fatigue load limit Cur is 1.66 kN."
      },
      {
        "q": "What is the maximum speed of the NA4900-XL?",
        "a": "The limiting speed is 24,600 r/min and the thermal reference speed is 16,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4900-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 10 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4900",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 10×22×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4900-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4900-XL",
      "NA4900-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI12-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI12/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 13.9,
    "fatigue_load_limit_kN": 2.6,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 14500,
    "weight_g": 33.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×24×16 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 12.8 kN and C0 13.9 kN at the 12 mm seat; the C/C0 ratio of 0.92 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 2.6 kN, the limiting speed 23,200 r/min and the thermal reference speed 14,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.07 kN/mm and per millimetre of width 0.80 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 33.3 g, just 0.09 g per mm² of projected 24×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 12 mm bore and only 33.3 g: the smallest sizes demand accurate shaft geometry, because the 6.0 mm section leaves no tolerance for a soft or tapered seat The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 13.9 kN C0 rating still assumes full rigid support under both rings NKI12/16-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 12.8 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 24 mm outside diameter and 12.8 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 12 mm seat, and in gearbox selector and change linkages the 33.3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 16 mm width and the published 13.9 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI12/16-XL?",
        "a": "The NKI12/16-XL is a NKI machined-ring needle roller bearing with inner ring with 24 mm outside diameter, 12 mm bore and 16 mm width, envelope 12×24×16 mm. Mass is 33.3 g."
      },
      {
        "q": "What does the NKI12/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI12/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×24×16 mm and the catalogue ratings are C 12.8 kN, C0 13.9 kN, Cur 2.6 kN."
      },
      {
        "q": "What is the load capacity of the NKI12/16-XL?",
        "a": "The basic dynamic load rating C is 12.8 kN and the basic static load rating C0 is 13.9 kN; the fatigue load limit Cur is 2.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKI12/16-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 14,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI12/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI12-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI12-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI12-16-XL",
      "NKI12/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI12-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI12/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.3,
    "static_load_kN": 18.8,
    "fatigue_load_limit_kN": 3.35,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 14200,
    "weight_g": 41.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×24×20 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 16.3 kN and C0 18.8 kN at the 12 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 3.35 kN, the limiting speed 23,200 r/min and the thermal reference speed 14,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.36 kN/mm and per millimetre of width 0.82 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 41.9 g, just 0.09 g per mm² of projected 24×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 12 mm bore this is one of the smallest HR1 executions — chosen where a 24 mm envelope must carry line-contact loads that no miniature ball bearing could take Cur 3.35 kN, limiting speed 23,200 r/min, reference speed 14,200 r/min — the inner ring adds a few grams (total 41.9 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.35 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 24 mm outside diameter and 16.3 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 12 mm seat, and in hydraulic and pneumatic pump eccentrics the 41.9 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 18.8 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI12/20-XL?",
        "a": "The NKI12/20-XL is a NKI machined-ring needle roller bearing with inner ring with 24 mm outside diameter, 12 mm bore and 20 mm width, envelope 12×24×20 mm. Mass is 41.9 g."
      },
      {
        "q": "What does the NKI12/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI12/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×24×20 mm and the catalogue ratings are C 16.3 kN, C0 18.8 kN, Cur 3.35 kN."
      },
      {
        "q": "What is the load capacity of the NKI12/20-XL?",
        "a": "The basic dynamic load rating C is 16.3 kN and the basic static load rating C0 is 18.8 kN; the fatigue load limit Cur is 3.35 kN."
      },
      {
        "q": "What is the maximum speed of the NKI12/20-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 14,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI12/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI12-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI12-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×24×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI12-20-XL",
      "NKI12/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4901-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4901-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.6,
    "static_load_kN": 10.9,
    "fatigue_load_limit_kN": 1.97,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 14200,
    "weight_g": 26,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×24×13 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 10.6 kN and C0 10.9 kN at the 12 mm seat; the C/C0 ratio of 0.97 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 1.97 kN, the limiting speed 23,200 r/min and the thermal reference speed 14,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 0.82 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 26 g, just 0.08 g per mm² of projected 24×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 12 mm bore and only 26 g: the smallest sizes demand accurate shaft geometry, because the 6.0 mm section leaves no tolerance for a soft or tapered seat NA4901-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 10.9 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 12×24×13 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 24 mm outside diameter and 10.6 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 12 mm seat, and in planetary gear bearings the 26 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 13 mm width and the published 10.9 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4901-XL?",
        "a": "The NA4901-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 24 mm outside diameter, 12 mm bore and 13 mm width, envelope 12×24×13 mm. Mass is 26 g."
      },
      {
        "q": "What does the NA4901-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4901-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×24×13 mm and the catalogue ratings are C 10.6 kN, C0 10.9 kN, Cur 1.97 kN."
      },
      {
        "q": "What is the load capacity of the NA4901-XL?",
        "a": "The basic dynamic load rating C is 10.6 kN and the basic static load rating C0 is 10.9 kN; the fatigue load limit Cur is 1.97 kN."
      },
      {
        "q": "What is the maximum speed of the NA4901-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 14,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4901-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×24×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4901-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4901-XL",
      "NA4901-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6901-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6901-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.1,
    "static_load_kN": 21.6,
    "fatigue_load_limit_kN": 3.85,
    "limiting_speed_rpm": 23200,
    "max_rpm": 23200,
    "reference_speed_rpm": 13300,
    "weight_g": 46,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×24×22 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 18.1 kN and C0 21.6 kN at the 12 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 3.85 kN, the limiting speed 23,200 r/min and the thermal reference speed 13,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.51 kN/mm and per millimetre of width 0.82 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 46 g, just 0.09 g per mm² of projected 24×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 12 mm bore sits in the miniature band; at 22 mm wide the NA6901-XL is built into compact cam drives, indexing pawls and light linkages The 6.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The integral inner ring brings the bore to 12 mm inside the 24×22 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 12×24×22 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 24 mm outside diameter and 18.1 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 12 mm seat, and in two-stroke and compressor piston pins the 46 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 21.6 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6901-XL?",
        "a": "The NA6901-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 24 mm outside diameter, 12 mm bore and 22 mm width, envelope 12×24×22 mm. Mass is 46 g."
      },
      {
        "q": "What does the NA6901-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6901-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×24×22 mm and the catalogue ratings are C 18.1 kN, C0 21.6 kN, Cur 3.85 kN."
      },
      {
        "q": "What is the load capacity of the NA6901-XL?",
        "a": "The basic dynamic load rating C is 18.1 kN and the basic static load rating C0 is 21.6 kN; the fatigue load limit Cur is 3.85 kN."
      },
      {
        "q": "What is the maximum speed of the NA6901-XL?",
        "a": "The limiting speed is 23,200 r/min and the thermal reference speed is 13,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6901-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×24×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6901-XL",
      "NA6901-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI15-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI15/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 27,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 14.7,
    "static_load_kN": 17.4,
    "fatigue_load_limit_kN": 3.25,
    "limiting_speed_rpm": 21600,
    "max_rpm": 21600,
    "reference_speed_rpm": 12400,
    "weight_g": 38.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×27×16 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 14.7 kN and C0 17.4 kN at the 15 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 27 mm outside diameter the fatigue load limit Cur is 3.25 kN, the limiting speed 21,600 r/min and the thermal reference speed 12,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 0.92 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 38.8 g, just 0.09 g per mm² of projected 27×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 15 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 17.4 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.25 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 27 mm outside diameter and 14.7 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 15 mm seat, and in hydraulic and pneumatic pump eccentrics the 38.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 16 mm width and the published 17.4 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI15/16-XL?",
        "a": "The NKI15/16-XL is a NKI machined-ring needle roller bearing with inner ring with 27 mm outside diameter, 15 mm bore and 16 mm width, envelope 15×27×16 mm. Mass is 38.8 g."
      },
      {
        "q": "What does the NKI15/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI15/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×27×16 mm and the catalogue ratings are C 14.7 kN, C0 17.4 kN, Cur 3.25 kN."
      },
      {
        "q": "What is the load capacity of the NKI15/16-XL?",
        "a": "The basic dynamic load rating C is 14.7 kN and the basic static load rating C0 is 17.4 kN; the fatigue load limit Cur is 3.25 kN."
      },
      {
        "q": "What is the maximum speed of the NKI15/16-XL?",
        "a": "The limiting speed is 21,600 r/min and the thermal reference speed is 12,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI15/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI15-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI15-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI15-16-XL",
      "NKI15/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI15-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI15/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 27,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.7,
    "static_load_kN": 23.6,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 21600,
    "max_rpm": 21600,
    "reference_speed_rpm": 12100,
    "weight_g": 48.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×27×20 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 18.7 kN and C0 23.6 kN at the 15 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 27 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 21,600 r/min and the thermal reference speed 12,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 0.93 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 48.7 g, just 0.09 g per mm² of projected 27×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 15 mm bore this size balances the 27 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The 6.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 18.7 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 15 mm bore; the 23.6 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 27 mm outside diameter and 18.7 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 15 mm seat, and in textile machine heald and cam shafts the 48.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 23.6 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI15/20-XL?",
        "a": "The NKI15/20-XL is a NKI machined-ring needle roller bearing with inner ring with 27 mm outside diameter, 15 mm bore and 20 mm width, envelope 15×27×20 mm. Mass is 48.7 g."
      },
      {
        "q": "What does the NKI15/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI15/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×27×20 mm and the catalogue ratings are C 18.7 kN, C0 23.6 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NKI15/20-XL?",
        "a": "The basic dynamic load rating C is 18.7 kN and the basic static load rating C0 is 23.6 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NKI15/20-XL?",
        "a": "The limiting speed is 21,600 r/min and the thermal reference speed is 12,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI15/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI15-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI15-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 15×27×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI15-20-XL",
      "NKI15/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4902-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4902-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12,
    "static_load_kN": 13.6,
    "fatigue_load_limit_kN": 2.47,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 11200,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×28×13 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 12 kN and C0 13.6 kN at the 15 mm seat; the C/C0 ratio of 0.88 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.47 kN, the limiting speed 21,100 r/min and the thermal reference speed 11,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.80 kN/mm and per millimetre of width 0.92 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 34 g, just 0.09 g per mm² of projected 28×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 15 mm bore the 13 mm width and 12 kN C rating suit high-cycle industrial machinery rather than instrument duty This is the choice for OEM production on soft shafts: machine the 15 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 12 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 21,100 r/min limit. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 28 mm outside diameter and 12 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 15 mm seat, and in motorcycle and light-vehicle transmissions the 34 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 13 mm width and the published 13.6 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4902-XL?",
        "a": "The NA4902-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 28 mm outside diameter, 15 mm bore and 13 mm width, envelope 15×28×13 mm. Mass is 34 g."
      },
      {
        "q": "What does the NA4902-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4902-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×28×13 mm and the catalogue ratings are C 12 kN, C0 13.6 kN, Cur 2.47 kN."
      },
      {
        "q": "What is the load capacity of the NA4902-XL?",
        "a": "The basic dynamic load rating C is 12 kN and the basic static load rating C0 is 13.6 kN; the fatigue load limit Cur is 2.47 kN."
      },
      {
        "q": "What is the maximum speed of the NA4902-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 11,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4902-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4902",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 15×28×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4902-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4902-XL",
      "NA4902-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6902-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6902-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 19.5,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.55,
    "limiting_speed_rpm": 21100,
    "max_rpm": 21100,
    "reference_speed_rpm": 10900,
    "weight_g": 63.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×28×23 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 19.5 kN and C0 25.5 kN at the 15 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 4.55 kN, the limiting speed 21,100 r/min and the thermal reference speed 10,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.30 kN/mm and per millimetre of width 0.85 kN/mm — the reason 23 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 63.6 g, just 0.10 g per mm² of projected 28×23 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 15 mm bore this size balances the 28 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range NA6902-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Cur 4.55 kN, limiting speed 21,100 r/min, reference speed 10,900 r/min — the inner ring adds a few grams (total 63.6 g) but removes the hardening requirement The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 15×28×23 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 28 mm outside diameter and 19.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 15 mm seat, and in planetary gear bearings the 63.6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 23 mm width and the published 25.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6902-XL?",
        "a": "The NA6902-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 28 mm outside diameter, 15 mm bore and 23 mm width, envelope 15×28×23 mm. Mass is 63.6 g."
      },
      {
        "q": "What does the NA6902-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6902-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×28×23 mm and the catalogue ratings are C 19.5 kN, C0 25.5 kN, Cur 4.55 kN."
      },
      {
        "q": "What is the load capacity of the NA6902-XL?",
        "a": "The basic dynamic load rating C is 19.5 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.55 kN."
      },
      {
        "q": "What is the maximum speed of the NA6902-XL?",
        "a": "The limiting speed is 21,100 r/min and the thermal reference speed is 10,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6902-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6902",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 15×28×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6902-XL",
      "NA6902-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS15-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS15-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 35,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 5,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 9400,
    "weight_g": 92,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×35×20 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 28 kN at the 15 mm seat; the C/C0 ratio of 0.98 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 5 kN, the limiting speed 18,500 r/min and the thermal reference speed 9,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.83 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 92 g, just 0.13 g per mm² of projected 35×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 15 mm bore the 20 mm width and 27.5 kN C rating suit high-cycle industrial machinery rather than instrument duty NKIS15-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required This is the choice for OEM production on soft shafts: machine the 15 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 18,500 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 35 mm outside diameter and 27.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 15 mm seat, and in two-stroke and compressor piston pins the 92 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 28 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS15-XL?",
        "a": "The NKIS15-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 35 mm outside diameter, 15 mm bore and 20 mm width, envelope 15×35×20 mm. Mass is 92 g."
      },
      {
        "q": "What does the NKIS15-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS15-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×35×20 mm and the catalogue ratings are C 27.5 kN, C0 28 kN, Cur 5 kN."
      },
      {
        "q": "What is the load capacity of the NKIS15-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 28 kN; the fatigue load limit Cur is 5 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS15-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 9,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS15-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS15",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 15×35×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS15-XL",
      "NKIS15-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI17-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI17/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 29,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.2,
    "static_load_kN": 18.7,
    "fatigue_load_limit_kN": 3.5,
    "limiting_speed_rpm": 20600,
    "max_rpm": 20600,
    "reference_speed_rpm": 11400,
    "weight_g": 42.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×29×16 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 15.2 kN and C0 18.7 kN at the 17 mm seat; the C/C0 ratio of 0.81 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 29 mm outside diameter the fatigue load limit Cur is 3.5 kN, the limiting speed 20,600 r/min and the thermal reference speed 11,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 0.95 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42.4 g, just 0.09 g per mm² of projected 29×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 17 mm bore the 16 mm width and 15.2 kN C rating suit high-cycle industrial machinery rather than instrument duty Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 15.2 kN C The integral inner ring brings the bore to 17 mm inside the 29×16 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 3.5 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 29 mm outside diameter and 15.2 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 17 mm seat, and in planetary gear bearings the 42.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 16 mm width and the published 18.7 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI17/16-XL?",
        "a": "The NKI17/16-XL is a NKI machined-ring needle roller bearing with inner ring with 29 mm outside diameter, 17 mm bore and 16 mm width, envelope 17×29×16 mm. Mass is 42.4 g."
      },
      {
        "q": "What does the NKI17/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI17/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×29×16 mm and the catalogue ratings are C 15.2 kN, C0 18.7 kN, Cur 3.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI17/16-XL?",
        "a": "The basic dynamic load rating C is 15.2 kN and the basic static load rating C0 is 18.7 kN; the fatigue load limit Cur is 3.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI17/16-XL?",
        "a": "The limiting speed is 20,600 r/min and the thermal reference speed is 11,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI17/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI17-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×29×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI17-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI17-16-XL",
      "NKI17/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI17-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI17/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 29,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 19.3,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.5,
    "limiting_speed_rpm": 20600,
    "max_rpm": 20600,
    "reference_speed_rpm": 11200,
    "weight_g": 53.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×29×20 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 19.3 kN and C0 25.5 kN at the 17 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 29 mm outside diameter the fatigue load limit Cur is 4.5 kN, the limiting speed 20,600 r/min and the thermal reference speed 11,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.14 kN/mm and per millimetre of width 0.97 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 53.4 g, just 0.09 g per mm² of projected 29×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 17 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty NKI17/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 19.3 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 17 mm bore; the 25.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 29 mm outside diameter and 19.3 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 17 mm seat, and in copying and printing machine mechanisms the 53.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 25.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI17/20-XL?",
        "a": "The NKI17/20-XL is a NKI machined-ring needle roller bearing with inner ring with 29 mm outside diameter, 17 mm bore and 20 mm width, envelope 17×29×20 mm. Mass is 53.4 g."
      },
      {
        "q": "What does the NKI17/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI17/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×29×20 mm and the catalogue ratings are C 19.3 kN, C0 25.5 kN, Cur 4.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI17/20-XL?",
        "a": "The basic dynamic load rating C is 19.3 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI17/20-XL?",
        "a": "The limiting speed is 20,600 r/min and the thermal reference speed is 11,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI17/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI17-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI17-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×29×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI17-20-XL",
      "NKI17/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4903-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4903-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 12.4,
    "static_load_kN": 14.6,
    "fatigue_load_limit_kN": 2.65,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 10200,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×30×13 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 12.4 kN and C0 14.6 kN at the 17 mm seat; the C/C0 ratio of 0.85 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 2.65 kN, the limiting speed 20,000 r/min and the thermal reference speed 10,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.73 kN/mm and per millimetre of width 0.95 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 37 g, just 0.09 g per mm² of projected 30×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 17 mm bore the 13 mm width and 12.4 kN C rating suit high-cycle industrial machinery rather than instrument duty Cur 2.65 kN, limiting speed 20,000 r/min, reference speed 10,200 r/min — the inner ring adds a few grams (total 37 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 14.6 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 20,000 r/min limit. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 30 mm outside diameter and 12.4 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 17 mm seat, and in small electric motor accessory drives the 37 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 13 mm width and the published 14.6 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4903-XL?",
        "a": "The NA4903-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 30 mm outside diameter, 17 mm bore and 13 mm width, envelope 17×30×13 mm. Mass is 37 g."
      },
      {
        "q": "What does the NA4903-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4903-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×30×13 mm and the catalogue ratings are C 12.4 kN, C0 14.6 kN, Cur 2.65 kN."
      },
      {
        "q": "What is the load capacity of the NA4903-XL?",
        "a": "The basic dynamic load rating C is 12.4 kN and the basic static load rating C0 is 14.6 kN; the fatigue load limit Cur is 2.65 kN."
      },
      {
        "q": "What is the maximum speed of the NA4903-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 10,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4903-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4903",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×30×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4903-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4903-XL",
      "NA4903-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6903-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6903-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.1,
    "static_load_kN": 29,
    "fatigue_load_limit_kN": 5.2,
    "limiting_speed_rpm": 20000,
    "max_rpm": 20000,
    "reference_speed_rpm": 9800,
    "weight_g": 72,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×30×23 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 21.1 kN and C0 29 kN at the 17 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 5.2 kN, the limiting speed 20,000 r/min and the thermal reference speed 9,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.24 kN/mm and per millimetre of width 0.92 kN/mm — the reason 23 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 72 g, just 0.10 g per mm² of projected 30×23 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 17 mm bore this size balances the 30 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range This is the choice for OEM production on soft shafts: machine the 17 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Cur 5.2 kN, limiting speed 20,000 r/min, reference speed 9,800 r/min — the inner ring adds a few grams (total 72 g) but removes the hardening requirement The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 17×30×23 mm envelope. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 30 mm outside diameter and 21.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 17 mm seat, and in hydraulic and pneumatic pump eccentrics the 72 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 23 mm width and the published 29 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6903-XL?",
        "a": "The NA6903-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 30 mm outside diameter, 17 mm bore and 23 mm width, envelope 17×30×23 mm. Mass is 72 g."
      },
      {
        "q": "What does the NA6903-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6903-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×30×23 mm and the catalogue ratings are C 21.1 kN, C0 29 kN, Cur 5.2 kN."
      },
      {
        "q": "What is the load capacity of the NA6903-XL?",
        "a": "The basic dynamic load rating C is 21.1 kN and the basic static load rating C0 is 29 kN; the fatigue load limit Cur is 5.2 kN."
      },
      {
        "q": "What is the maximum speed of the NA6903-XL?",
        "a": "The limiting speed is 20,000 r/min and the thermal reference speed is 9,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6903-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6903",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×30×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6903-XL",
      "NA6903-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS17-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 29.5,
    "static_load_kN": 31,
    "fatigue_load_limit_kN": 5.5,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 8800,
    "weight_g": 98,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×37×20 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 29.5 kN and C0 31 kN at the 17 mm seat; the C/C0 ratio of 0.95 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 5.5 kN, the limiting speed 17,200 r/min and the thermal reference speed 8,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.74 kN/mm and per millimetre of width 1.48 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 98 g, just 0.13 g per mm² of projected 37×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 17 mm bore the 20 mm width and 29.5 kN C rating suit high-cycle industrial machinery rather than instrument duty Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 29.5 kN C Cur 5.5 kN, limiting speed 17,200 r/min, reference speed 8,800 r/min — the inner ring adds a few grams (total 98 g) but removes the hardening requirement The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 17,200 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 37 mm outside diameter and 29.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 17 mm seat, and in hydraulic and pneumatic pump eccentrics the 98 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 31 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS17-XL?",
        "a": "The NKIS17-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 37 mm outside diameter, 17 mm bore and 20 mm width, envelope 17×37×20 mm. Mass is 98 g."
      },
      {
        "q": "What does the NKIS17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS17-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×37×20 mm and the catalogue ratings are C 29.5 kN, C0 31 kN, Cur 5.5 kN."
      },
      {
        "q": "What is the load capacity of the NKIS17-XL?",
        "a": "The basic dynamic load rating C is 29.5 kN and the basic static load rating C0 is 31 kN; the fatigue load limit Cur is 5.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS17-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 8,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS17",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 17×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS17-XL",
      "NKIS17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI20-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI20/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.9,
    "static_load_kN": 22.3,
    "fatigue_load_limit_kN": 4.2,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 10100,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×32×16 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 16.9 kN and C0 22.3 kN at the 20 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 4.2 kN, the limiting speed 18,500 r/min and the thermal reference speed 10,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 1.06 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 49 g, just 0.10 g per mm² of projected 32×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 16 mm width and 16.9 kN C rating suit high-cycle industrial machinery rather than instrument duty This is the choice for OEM production on soft shafts: machine the 20 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 18,500 r/min limit. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 32 mm outside diameter and 16.9 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 20 mm seat, and in small electric motor accessory drives the 49 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 16 mm width and the published 22.3 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI20/16-XL?",
        "a": "The NKI20/16-XL is a NKI machined-ring needle roller bearing with inner ring with 32 mm outside diameter, 20 mm bore and 16 mm width, envelope 20×32×16 mm. Mass is 49 g."
      },
      {
        "q": "What does the NKI20/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI20/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×32×16 mm and the catalogue ratings are C 16.9 kN, C0 22.3 kN, Cur 4.2 kN."
      },
      {
        "q": "What is the load capacity of the NKI20/16-XL?",
        "a": "The basic dynamic load rating C is 16.9 kN and the basic static load rating C0 is 22.3 kN; the fatigue load limit Cur is 4.2 kN."
      },
      {
        "q": "What is the maximum speed of the NKI20/16-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 10,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI20/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI20-16",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI20-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI20-16-XL",
      "NKI20/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI20-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI20/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.4,
    "static_load_kN": 30.5,
    "fatigue_load_limit_kN": 8.1,
    "limiting_speed_rpm": 18500,
    "max_rpm": 18500,
    "reference_speed_rpm": 9900,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×32×20 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 21.4 kN and C0 30.5 kN at the 20 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 8.1 kN, the limiting speed 18,500 r/min and the thermal reference speed 9,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.07 kN/mm and per millimetre of width 1.07 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 61 g, just 0.10 g per mm² of projected 32×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The integral inner ring brings the bore to 20 mm inside the 32×20 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing This is the choice for OEM production on soft shafts: machine the 20 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 21.4 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 32 mm outside diameter and 21.4 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 20 mm seat, and in two-stroke and compressor piston pins the 61 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 30.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI20/20-XL?",
        "a": "The NKI20/20-XL is a NKI machined-ring needle roller bearing with inner ring with 32 mm outside diameter, 20 mm bore and 20 mm width, envelope 20×32×20 mm. Mass is 61 g."
      },
      {
        "q": "What does the NKI20/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI20/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×32×20 mm and the catalogue ratings are C 21.4 kN, C0 30.5 kN, Cur 8.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI20/20-XL?",
        "a": "The basic dynamic load rating C is 21.4 kN and the basic static load rating C0 is 30.5 kN; the fatigue load limit Cur is 8.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI20/20-XL?",
        "a": "The limiting speed is 18,500 r/min and the thermal reference speed is 9,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI20/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI20-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI20-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI20-20-XL",
      "NKI20/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4904-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4904-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.7,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.7,
    "limiting_speed_rpm": 16900,
    "max_rpm": 16900,
    "reference_speed_rpm": 9400,
    "weight_g": 75.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×37×17 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 23.7 kN and C0 25.5 kN at the 20 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 4.7 kN, the limiting speed 16,900 r/min and the thermal reference speed 9,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.19 kN/mm and per millimetre of width 1.39 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 75.2 g, just 0.12 g per mm² of projected 37×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 20 mm bore this size balances the 37 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The 8.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel NA4904-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 16,900 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 37 mm outside diameter and 23.7 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 20 mm seat, and in gearbox selector and change linkages the 75.2 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 17 mm width and the published 25.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4904-XL?",
        "a": "The NA4904-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 37 mm outside diameter, 20 mm bore and 17 mm width, envelope 20×37×17 mm. Mass is 75.2 g."
      },
      {
        "q": "What does the NA4904-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4904-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×37×17 mm and the catalogue ratings are C 23.7 kN, C0 25.5 kN, Cur 4.7 kN."
      },
      {
        "q": "What is the load capacity of the NA4904-XL?",
        "a": "The basic dynamic load rating C is 23.7 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.7 kN."
      },
      {
        "q": "What is the maximum speed of the NA4904-XL?",
        "a": "The limiting speed is 16,900 r/min and the thermal reference speed is 9,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4904-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4904",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA4904-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4904-XL",
      "NA4904-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6904-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6904-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 40.5,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 9.2,
    "limiting_speed_rpm": 16900,
    "max_rpm": 16900,
    "reference_speed_rpm": 8900,
    "weight_g": 141,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×37×30 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 40.5 kN and C0 51 kN at the 20 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 9.2 kN, the limiting speed 16,900 r/min and the thermal reference speed 8,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.02 kN/mm and per millimetre of width 1.35 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 141 g, just 0.13 g per mm² of projected 37×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 40.5 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 16,900 r/min limit. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 37 mm outside diameter and 40.5 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 20 mm seat, and in rocker arms and valve trains the 141 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 30 mm width and the published 51 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6904-XL?",
        "a": "The NA6904-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 37 mm outside diameter, 20 mm bore and 30 mm width, envelope 20×37×30 mm. Mass is 141 g."
      },
      {
        "q": "What does the NA6904-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6904-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×37×30 mm and the catalogue ratings are C 40.5 kN, C0 51 kN, Cur 9.2 kN."
      },
      {
        "q": "What is the load capacity of the NA6904-XL?",
        "a": "The basic dynamic load rating C is 40.5 kN and the basic static load rating C0 is 51 kN; the fatigue load limit Cur is 9.2 kN."
      },
      {
        "q": "What is the maximum speed of the NA6904-XL?",
        "a": "The limiting speed is 16,900 r/min and the thermal reference speed is 8,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6904-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6904",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6904-XL",
      "NA6904-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS20-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32.5,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 6.5,
    "limiting_speed_rpm": 15100,
    "max_rpm": 15100,
    "reference_speed_rpm": 7700,
    "weight_g": 129,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×42×20 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 32.5 kN and C0 36.5 kN at the 20 mm seat; the C/C0 ratio of 0.89 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 6.5 kN, the limiting speed 15,100 r/min and the thermal reference speed 7,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.63 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 129 g, just 0.15 g per mm² of projected 42×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 20 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The 11.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 32.5 kN C The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 20×42×20 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 42 mm outside diameter and 32.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 20 mm seat, and in copying and printing machine mechanisms the 129 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 36.5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS20-XL?",
        "a": "The NKIS20-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 42 mm outside diameter, 20 mm bore and 20 mm width, envelope 20×42×20 mm. Mass is 129 g."
      },
      {
        "q": "What does the NKIS20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS20-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×42×20 mm and the catalogue ratings are C 32.5 kN, C0 36.5 kN, Cur 6.5 kN."
      },
      {
        "q": "What is the load capacity of the NKIS20-XL?",
        "a": "The basic dynamic load rating C is 32.5 kN and the basic static load rating C0 is 36.5 kN; the fatigue load limit Cur is 6.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS20-XL?",
        "a": "The limiting speed is 15,100 r/min and the thermal reference speed is 7,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=959",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS20-XL",
      "NKIS20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI22-16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI22/16-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 34,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 17.3,
    "static_load_kN": 23.6,
    "fatigue_load_limit_kN": 4.45,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 9500,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×34×16 mm: 22 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 17.3 kN and C0 23.6 kN at the 22 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 34 mm outside diameter the fatigue load limit Cur is 4.45 kN, the limiting speed 17,200 r/min and the thermal reference speed 9,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.79 kN/mm and per millimetre of width 1.08 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 52 g, just 0.10 g per mm² of projected 34×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 22 mm bore this size balances the 34 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The 6.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 22×34×16 mm envelope. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 34 mm outside diameter and 17.3 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 22 mm seat, and in hydraulic and pneumatic pump eccentrics the 52 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 16 mm width and the published 23.6 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI22/16-XL?",
        "a": "The NKI22/16-XL is a NKI machined-ring needle roller bearing with inner ring with 34 mm outside diameter, 22 mm bore and 16 mm width, envelope 22×34×16 mm. Mass is 52 g."
      },
      {
        "q": "What does the NKI22/16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI22/16-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×34×16 mm and the catalogue ratings are C 17.3 kN, C0 23.6 kN, Cur 4.45 kN."
      },
      {
        "q": "What is the load capacity of the NKI22/16-XL?",
        "a": "The basic dynamic load rating C is 17.3 kN and the basic static load rating C0 is 23.6 kN; the fatigue load limit Cur is 4.45 kN."
      },
      {
        "q": "What is the maximum speed of the NKI22/16-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 9,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI22/16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 22 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI22-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×34×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI22-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI22-16-XL",
      "NKI22/16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI22-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI22/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 34,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 5.7,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 9300,
    "weight_g": 65.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×34×20 mm: 22 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 22 kN and C0 32 kN at the 22 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 34 mm outside diameter the fatigue load limit Cur is 5.7 kN, the limiting speed 17,200 r/min and the thermal reference speed 9,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.00 kN/mm and per millimetre of width 1.10 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 65.4 g, just 0.10 g per mm² of projected 34×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 22 mm bore the 20 mm width and 22 kN C rating suit high-cycle industrial machinery rather than instrument duty NKI22/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 32 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 22 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 34 mm outside diameter and 22 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 22 mm seat, and in textile machine heald and cam shafts the 65.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 20 mm width and the published 32 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI22/20-XL?",
        "a": "The NKI22/20-XL is a NKI machined-ring needle roller bearing with inner ring with 34 mm outside diameter, 22 mm bore and 20 mm width, envelope 22×34×20 mm. Mass is 65.4 g."
      },
      {
        "q": "What does the NKI22/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI22/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×34×20 mm and the catalogue ratings are C 22 kN, C0 32 kN, Cur 5.7 kN."
      },
      {
        "q": "What is the load capacity of the NKI22/20-XL?",
        "a": "The basic dynamic load rating C is 22 kN and the basic static load rating C0 is 32 kN; the fatigue load limit Cur is 5.7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI22/20-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 9,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI22/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 22 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI22-16",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI22-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×34×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI22-20-XL",
      "NKI22/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-22-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA49/22-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26,
    "static_load_kN": 29.5,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8100,
    "weight_g": 80,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×39×17 mm: 22 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 29.5 kN at the 22 mm seat; the C/C0 ratio of 0.88 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 39 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.18 kN/mm and per millimetre of width 1.53 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 80 g, just 0.12 g per mm² of projected 39×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 22 mm bore the 17 mm width and 26 kN C rating suit high-cycle industrial machinery rather than instrument duty Cur 5.4 kN, limiting speed 15,300 r/min, reference speed 8,100 r/min — the inner ring adds a few grams (total 80 g) but removes the hardening requirement The integral inner ring brings the bore to 22 mm inside the 39×17 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 22×39×17 mm envelope. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 39 mm outside diameter and 26 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 22 mm seat, and in gearbox selector and change linkages the 80 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 17 mm width and the published 29.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA49/22-XL?",
        "a": "The NA49/22-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 39 mm outside diameter, 22 mm bore and 17 mm width, envelope 22×39×17 mm. Mass is 80 g."
      },
      {
        "q": "What does the NA49/22-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA49/22-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×39×17 mm and the catalogue ratings are C 26 kN, C0 29.5 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the NA49/22-XL?",
        "a": "The basic dynamic load rating C is 26 kN and the basic static load rating C0 is 29.5 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the NA49/22-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA49/22-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 22 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×39×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA49-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-22-XL",
      "NA49/22-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-22-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA69/22-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 42,
    "static_load_kN": 55,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 7900,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×39×30 mm: 22 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 42 kN and C0 55 kN at the 22 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 39 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 15,300 r/min and the thermal reference speed 7,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.91 kN/mm and per millimetre of width 1.40 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 150 g, just 0.13 g per mm² of projected 39×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 22 mm bore this size balances the 39 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range NA69/22-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 55 kN C0 rating still assumes full rigid support under both rings X-life status (-XL) indicates the current Schaeffler premium execution at 22 mm bore; the 55 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 39 mm outside diameter and 42 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 22 mm seat, and in connecting-rod small ends the 150 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 55 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA69/22-XL?",
        "a": "The NA69/22-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 39 mm outside diameter, 22 mm bore and 30 mm width, envelope 22×39×30 mm. Mass is 150 g."
      },
      {
        "q": "What does the NA69/22-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA69/22-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×39×30 mm and the catalogue ratings are C 42 kN, C0 55 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NA69/22-XL?",
        "a": "The basic dynamic load rating C is 42 kN and the basic static load rating C0 is 55 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NA69/22-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 7,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA69/22-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 22 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×39×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA69-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-22-XL",
      "NA69/22-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI25-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI25/20-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 7,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8100,
    "weight_g": 75.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×38×20 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 39 kN at the 25 mm seat; the C/C0 ratio of 0.71 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 7 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.10 kN/mm and per millimetre of width 1.38 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 75.8 g, just 0.10 g per mm² of projected 38×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 39 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 7 kN Cur value. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 15,300 r/min limiting speed without roller-to-roller sliding. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 38 mm outside diameter and 27.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 25 mm seat, and in copying and printing machine mechanisms the 75.8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 39 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI25/20-TV-XL?",
        "a": "The NKI25/20-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 38 mm outside diameter, 25 mm bore and 20 mm width, envelope 25×38×20 mm. Mass is 75.8 g."
      },
      {
        "q": "What does the NKI25/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI25/20-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×38×20 mm and the catalogue ratings are C 27.5 kN, C0 39 kN, Cur 7 kN."
      },
      {
        "q": "What is the load capacity of the NKI25/20-TV-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 39 kN; the fatigue load limit Cur is 7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI25/20-TV-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI25/20-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI25-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI25-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI25-20-TV-XL",
      "NKI25/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI25-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI25/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 37,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 10.7,
    "limiting_speed_rpm": 15300,
    "max_rpm": 15300,
    "reference_speed_rpm": 8200,
    "weight_g": 124,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×38×30 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 25 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 38 mm outside diameter the fatigue load limit Cur is 10.7 kN, the limiting speed 15,300 r/min and the thermal reference speed 8,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.48 kN/mm and per millimetre of width 1.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 124 g, just 0.11 g per mm² of projected 38×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This is the choice for OEM production on soft shafts: machine the 25 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 57 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 37 kN C rating and longer nominal life come without an envelope change. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 38 mm outside diameter and 37 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 25 mm seat, and in gearbox selector and change linkages the 124 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 57 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI25/30-XL?",
        "a": "The NKI25/30-XL is a NKI machined-ring needle roller bearing with inner ring with 38 mm outside diameter, 25 mm bore and 30 mm width, envelope 25×38×30 mm. Mass is 124 g."
      },
      {
        "q": "What does the NKI25/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI25/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×38×30 mm and the catalogue ratings are C 37 kN, C0 57 kN, Cur 10.7 kN."
      },
      {
        "q": "What is the load capacity of the NKI25/30-XL?",
        "a": "The basic dynamic load rating C is 37 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 10.7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI25/30-XL?",
        "a": "The limiting speed is 15,300 r/min and the thermal reference speed is 8,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI25/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI25-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI25-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×38×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI25-30-XL",
      "NKI25/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4905-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4905-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26.5,
    "static_load_kN": 31.5,
    "fatigue_load_limit_kN": 5.8,
    "limiting_speed_rpm": 14400,
    "max_rpm": 14400,
    "reference_speed_rpm": 7700,
    "weight_g": 88,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×42×17 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 26.5 kN and C0 31.5 kN at the 25 mm seat; the C/C0 ratio of 0.84 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 5.8 kN, the limiting speed 14,400 r/min and the thermal reference speed 7,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 1.56 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 88 g, just 0.12 g per mm² of projected 42×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 25 mm bore this size balances the 42 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 26.5 kN C Cur 5.8 kN, limiting speed 14,400 r/min, reference speed 7,700 r/min — the inner ring adds a few grams (total 88 g) but removes the hardening requirement X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 31.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 42 mm outside diameter and 26.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 25 mm seat, and in two-stroke and compressor piston pins the 88 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 17 mm width and the published 31.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4905-XL?",
        "a": "The NA4905-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 42 mm outside diameter, 25 mm bore and 17 mm width, envelope 25×42×17 mm. Mass is 88 g."
      },
      {
        "q": "What does the NA4905-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4905-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×42×17 mm and the catalogue ratings are C 26.5 kN, C0 31.5 kN, Cur 5.8 kN."
      },
      {
        "q": "What is the load capacity of the NA4905-XL?",
        "a": "The basic dynamic load rating C is 26.5 kN and the basic static load rating C0 is 31.5 kN; the fatigue load limit Cur is 5.8 kN."
      },
      {
        "q": "What is the maximum speed of the NA4905-XL?",
        "a": "The limiting speed is 14,400 r/min and the thermal reference speed is 7,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4905-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4905",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA4905-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4905-XL",
      "NA4905-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6905-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6905-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 59,
    "fatigue_load_limit_kN": 10.8,
    "limiting_speed_rpm": 14400,
    "max_rpm": 14400,
    "reference_speed_rpm": 7500,
    "weight_g": 161,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×42×30 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 59 kN at the 25 mm seat; the C/C0 ratio of 0.75 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 10.8 kN, the limiting speed 14,400 r/min and the thermal reference speed 7,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.76 kN/mm and per millimetre of width 1.47 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 161 g, just 0.13 g per mm² of projected 42×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty NA6905-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 44 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 14,400 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 42 mm outside diameter and 44 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 25 mm seat, and in gearbox selector and change linkages the 161 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 59 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6905-XL?",
        "a": "The NA6905-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 42 mm outside diameter, 25 mm bore and 30 mm width, envelope 25×42×30 mm. Mass is 161 g."
      },
      {
        "q": "What does the NA6905-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6905-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×42×30 mm and the catalogue ratings are C 44 kN, C0 59 kN, Cur 10.8 kN."
      },
      {
        "q": "What is the load capacity of the NA6905-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 59 kN; the fatigue load limit Cur is 10.8 kN."
      },
      {
        "q": "What is the maximum speed of the NA6905-XL?",
        "a": "The limiting speed is 14,400 r/min and the thermal reference speed is 7,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6905-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6905",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6905-XL",
      "NA6905-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS25-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 47,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 38,
    "static_load_kN": 43.5,
    "fatigue_load_limit_kN": 7.6,
    "limiting_speed_rpm": 13200,
    "max_rpm": 13200,
    "reference_speed_rpm": 7100,
    "weight_g": 162,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×47×22 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 38 kN and C0 43.5 kN at the 25 mm seat; the C/C0 ratio of 0.87 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.6 kN, the limiting speed 13,200 r/min and the thermal reference speed 7,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.52 kN/mm and per millimetre of width 1.73 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 162 g, just 0.16 g per mm² of projected 47×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 25 mm bore the 22 mm width and 38 kN C rating suit high-cycle industrial machinery rather than instrument duty NKIS25-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required This is the choice for OEM production on soft shafts: machine the 25 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 13,200 r/min limit. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 47 mm outside diameter and 38 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 25 mm seat, and in rocker arms and valve trains the 162 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 22 mm width and the published 43.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS25-XL?",
        "a": "The NKIS25-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 47 mm outside diameter, 25 mm bore and 22 mm width, envelope 25×47×22 mm. Mass is 162 g."
      },
      {
        "q": "What does the NKIS25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS25-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×47×22 mm and the catalogue ratings are C 38 kN, C0 43.5 kN, Cur 7.6 kN."
      },
      {
        "q": "What is the load capacity of the NKIS25-XL?",
        "a": "The basic dynamic load rating C is 38 kN and the basic static load rating C0 is 43.5 kN; the fatigue load limit Cur is 7.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS25-XL?",
        "a": "The limiting speed is 13,200 r/min and the thermal reference speed is 7,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×47×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS25-XL",
      "NKIS25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI28-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI28/20-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 29.5,
    "static_load_kN": 44.5,
    "fatigue_load_limit_kN": 8,
    "limiting_speed_rpm": 14000,
    "max_rpm": 14000,
    "reference_speed_rpm": 7500,
    "weight_g": 92.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×42×20 mm: 28 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 29.5 kN and C0 44.5 kN at the 28 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 8 kN, the limiting speed 14,000 r/min and the thermal reference speed 7,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.05 kN/mm and per millimetre of width 1.48 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 92.4 g, just 0.11 g per mm² of projected 42×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 28 mm bore the 20 mm width and 29.5 kN C rating suit high-cycle industrial machinery rather than instrument duty The integral inner ring brings the bore to 28 mm inside the 42×20 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing NKI28/20-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 8 kN Cur value. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 42 mm outside diameter and 29.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 28 mm seat, and in hydraulic and pneumatic pump eccentrics the 92.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 44.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI28/20-TV-XL?",
        "a": "The NKI28/20-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 42 mm outside diameter, 28 mm bore and 20 mm width, envelope 28×42×20 mm. Mass is 92.4 g."
      },
      {
        "q": "What does the NKI28/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI28/20-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×42×20 mm and the catalogue ratings are C 29.5 kN, C0 44.5 kN, Cur 8 kN."
      },
      {
        "q": "What is the load capacity of the NKI28/20-TV-XL?",
        "a": "The basic dynamic load rating C is 29.5 kN and the basic static load rating C0 is 44.5 kN; the fatigue load limit Cur is 8 kN."
      },
      {
        "q": "What is the maximum speed of the NKI28/20-TV-XL?",
        "a": "The limiting speed is 14,000 r/min and the thermal reference speed is 7,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI28/20-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 28 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI28-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI28-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI28-20-TV-XL",
      "NKI28/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI28-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI28/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 39,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 11.9,
    "limiting_speed_rpm": 14000,
    "max_rpm": 14000,
    "reference_speed_rpm": 7600,
    "weight_g": 146,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×42×30 mm: 28 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 39 kN and C0 63 kN at the 28 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 11.9 kN, the limiting speed 14,000 r/min and the thermal reference speed 7,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.39 kN/mm and per millimetre of width 1.30 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 146 g, just 0.12 g per mm² of projected 42×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 28 mm bore the 30 mm width and 39 kN C rating suit high-cycle industrial machinery rather than instrument duty The integral inner ring brings the bore to 28 mm inside the 42×30 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 39 kN C As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11.9 kN Cur value. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 42 mm outside diameter and 39 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 28 mm seat, and in agricultural machine pivots and linkages the 146 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 63 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI28/30-XL?",
        "a": "The NKI28/30-XL is a NKI machined-ring needle roller bearing with inner ring with 42 mm outside diameter, 28 mm bore and 30 mm width, envelope 28×42×30 mm. Mass is 146 g."
      },
      {
        "q": "What does the NKI28/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI28/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×42×30 mm and the catalogue ratings are C 39 kN, C0 63 kN, Cur 11.9 kN."
      },
      {
        "q": "What is the load capacity of the NKI28/30-XL?",
        "a": "The basic dynamic load rating C is 39 kN and the basic static load rating C0 is 63 kN; the fatigue load limit Cur is 11.9 kN."
      },
      {
        "q": "What is the maximum speed of the NKI28/30-XL?",
        "a": "The limiting speed is 14,000 r/min and the thermal reference speed is 7,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI28/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 28 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI28-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI28-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI28-30-XL",
      "NKI28/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-28-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA49/28-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 6.2,
    "limiting_speed_rpm": 13600,
    "max_rpm": 13600,
    "reference_speed_rpm": 7400,
    "weight_g": 97.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×45×17 mm: 28 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 33.5 kN at the 28 mm seat; the C/C0 ratio of 0.82 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 6.2 kN, the limiting speed 13,600 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 1.62 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 97.7 g, just 0.13 g per mm² of projected 45×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 28 mm bore the 17 mm width and 27.5 kN C rating suit high-cycle industrial machinery rather than instrument duty This is the choice for OEM production on soft shafts: machine the 28 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway X-life status (-XL) indicates the current Schaeffler premium execution at 28 mm bore; the 33.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 45 mm outside diameter and 27.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 28 mm seat, and in textile machine heald and cam shafts the 97.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 17 mm width and the published 33.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA49/28-XL?",
        "a": "The NA49/28-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 45 mm outside diameter, 28 mm bore and 17 mm width, envelope 28×45×17 mm. Mass is 97.7 g."
      },
      {
        "q": "What does the NA49/28-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA49/28-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×45×17 mm and the catalogue ratings are C 27.5 kN, C0 33.5 kN, Cur 6.2 kN."
      },
      {
        "q": "What is the load capacity of the NA49/28-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 33.5 kN; the fatigue load limit Cur is 6.2 kN."
      },
      {
        "q": "What is the maximum speed of the NA49/28-XL?",
        "a": "The limiting speed is 13,600 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA49/28-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 28 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-28",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA49-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-28-XL",
      "NA49/28-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-28-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA69/28-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 11.6,
    "limiting_speed_rpm": 13600,
    "max_rpm": 13600,
    "reference_speed_rpm": 7100,
    "weight_g": 182,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 28×45×30 mm: 28 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 63 kN at the 28 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 11.6 kN, the limiting speed 13,600 r/min and the thermal reference speed 7,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.63 kN/mm and per millimetre of width 1.52 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 182 g, just 0.13 g per mm² of projected 45×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 28 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This is the choice for OEM production on soft shafts: machine the 28 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Cur 11.6 kN, limiting speed 13,600 r/min, reference speed 7,100 r/min — the inner ring adds a few grams (total 182 g) but removes the hardening requirement -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 45.5 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 45 mm outside diameter and 45.5 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 28 mm seat, and in rocker arms and valve trains the 182 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 30 mm width and the published 63 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA69/28-XL?",
        "a": "The NA69/28-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 45 mm outside diameter, 28 mm bore and 30 mm width, envelope 28×45×30 mm. Mass is 182 g."
      },
      {
        "q": "What does the NA69/28-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA69/28-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 28×45×30 mm and the catalogue ratings are C 45.5 kN, C0 63 kN, Cur 11.6 kN."
      },
      {
        "q": "What is the load capacity of the NA69/28-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 63 kN; the fatigue load limit Cur is 11.6 kN."
      },
      {
        "q": "What is the maximum speed of the NA69/28-XL?",
        "a": "The limiting speed is 13,600 r/min and the thermal reference speed is 7,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA69/28-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 28 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-28",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA69-32",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-28-XL",
      "NA69/28-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI30-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI30/20-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 31,
    "static_load_kN": 48.5,
    "fatigue_load_limit_kN": 8.6,
    "limiting_speed_rpm": 12900,
    "max_rpm": 12900,
    "reference_speed_rpm": 6800,
    "weight_g": 108,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×45×20 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 31 kN and C0 48.5 kN at the 30 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 8.6 kN, the limiting speed 12,900 r/min and the thermal reference speed 6,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 1.55 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 108 g, just 0.12 g per mm² of projected 45×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 31 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,900 r/min limit. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 12,900 r/min. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 45 mm outside diameter and 31 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 30 mm seat, and in rocker arms and valve trains the 108 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 20 mm width and the published 48.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI30/20-TV-XL?",
        "a": "The NKI30/20-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 45 mm outside diameter, 30 mm bore and 20 mm width, envelope 30×45×20 mm. Mass is 108 g."
      },
      {
        "q": "What does the NKI30/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI30/20-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×45×20 mm and the catalogue ratings are C 31 kN, C0 48.5 kN, Cur 8.6 kN."
      },
      {
        "q": "What is the load capacity of the NKI30/20-TV-XL?",
        "a": "The basic dynamic load rating C is 31 kN and the basic static load rating C0 is 48.5 kN; the fatigue load limit Cur is 8.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKI30/20-TV-XL?",
        "a": "The limiting speed is 12,900 r/min and the thermal reference speed is 6,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI30/20-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI30-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×45×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI30-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI30-20-TV-XL",
      "NKI30/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI30-30-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI30/30-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 46,
    "static_load_kN": 81,
    "fatigue_load_limit_kN": 15.3,
    "limiting_speed_rpm": 12900,
    "max_rpm": 12900,
    "reference_speed_rpm": 6600,
    "weight_g": 165,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×45×30 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 46 kN and C0 81 kN at the 30 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 15.3 kN, the limiting speed 12,900 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.53 kN/mm and per millimetre of width 1.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 165 g, just 0.12 g per mm² of projected 45×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 30 mm width and 46 kN C rating suit high-cycle industrial machinery rather than instrument duty This is the choice for OEM production on soft shafts: machine the 30 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The integral inner ring brings the bore to 30 mm inside the 45×30 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 81 kN C0 rating reflects the improved rolling-contact geometry. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 165 g in the 45 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 45 mm outside diameter and 46 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 30 mm seat, and in planetary gear bearings the 165 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 81 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI30/30-TV-XL?",
        "a": "The NKI30/30-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 45 mm outside diameter, 30 mm bore and 30 mm width, envelope 30×45×30 mm. Mass is 165 g."
      },
      {
        "q": "What does the NKI30/30-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI30/30-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×45×30 mm and the catalogue ratings are C 46 kN, C0 81 kN, Cur 15.3 kN."
      },
      {
        "q": "What is the load capacity of the NKI30/30-TV-XL?",
        "a": "The basic dynamic load rating C is 46 kN and the basic static load rating C0 is 81 kN; the fatigue load limit Cur is 15.3 kN."
      },
      {
        "q": "What is the maximum speed of the NKI30/30-TV-XL?",
        "a": "The limiting speed is 12,900 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI30/30-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI30-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI30-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI30-30-TV-XL",
      "NKI30/30-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4906-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4906-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 28.5,
    "static_load_kN": 35.5,
    "fatigue_load_limit_kN": 6.6,
    "limiting_speed_rpm": 12600,
    "max_rpm": 12600,
    "reference_speed_rpm": 6600,
    "weight_g": 101,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×47×17 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 28.5 kN and C0 35.5 kN at the 30 mm seat; the C/C0 ratio of 0.80 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 6.6 kN, the limiting speed 12,600 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 1.68 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 101 g, just 0.13 g per mm² of projected 47×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 30 mm bore this size balances the 47 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range This is the choice for OEM production on soft shafts: machine the 30 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 28.5 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 35.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 47 mm outside diameter and 28.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 30 mm seat, and in planetary gear bearings the 101 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 17 mm width and the published 35.5 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4906-XL?",
        "a": "The NA4906-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 47 mm outside diameter, 30 mm bore and 17 mm width, envelope 30×47×17 mm. Mass is 101 g."
      },
      {
        "q": "What does the NA4906-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4906-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×47×17 mm and the catalogue ratings are C 28.5 kN, C0 35.5 kN, Cur 6.6 kN."
      },
      {
        "q": "What is the load capacity of the NA4906-XL?",
        "a": "The basic dynamic load rating C is 28.5 kN and the basic static load rating C0 is 35.5 kN; the fatigue load limit Cur is 6.6 kN."
      },
      {
        "q": "What is the maximum speed of the NA4906-XL?",
        "a": "The limiting speed is 12,600 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4906-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×47×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4906-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4906-XL",
      "NA4906-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6906-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6906-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 49,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 13.1,
    "limiting_speed_rpm": 12600,
    "max_rpm": 12600,
    "reference_speed_rpm": 6300,
    "weight_g": 192,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×47×30 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 49 kN and C0 71 kN at the 30 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 13.1 kN, the limiting speed 12,600 r/min and the thermal reference speed 6,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.63 kN/mm and per millimetre of width 1.63 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 192 g, just 0.14 g per mm² of projected 47×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The 8.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 71 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,600 r/min limit. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 47 mm outside diameter and 49 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 30 mm seat, and in agricultural machine pivots and linkages the 192 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 71 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6906-XL?",
        "a": "The NA6906-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 47 mm outside diameter, 30 mm bore and 30 mm width, envelope 30×47×30 mm. Mass is 192 g."
      },
      {
        "q": "What does the NA6906-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6906-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×47×30 mm and the catalogue ratings are C 49 kN, C0 71 kN, Cur 13.1 kN."
      },
      {
        "q": "What is the load capacity of the NA6906-XL?",
        "a": "The basic dynamic load rating C is 49 kN and the basic static load rating C0 is 71 kN; the fatigue load limit Cur is 13.1 kN."
      },
      {
        "q": "What is the maximum speed of the NA6906-XL?",
        "a": "The limiting speed is 12,600 r/min and the thermal reference speed is 6,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6906-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6906-XL",
      "NA6906-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS30-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 52,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 41.5,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 8.8,
    "limiting_speed_rpm": 11700,
    "max_rpm": 11700,
    "reference_speed_rpm": 6400,
    "weight_g": 184,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×52×22 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 41.5 kN and C0 50 kN at the 30 mm seat; the C/C0 ratio of 0.83 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 8.8 kN, the limiting speed 11,700 r/min and the thermal reference speed 6,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.38 kN/mm and per millimetre of width 1.89 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 184 g, just 0.16 g per mm² of projected 52×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty NKIS30-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 41.5 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 11,700 r/min limit. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 52 mm outside diameter and 41.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 30 mm seat, and in motorcycle and light-vehicle transmissions the 184 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 22 mm width and the published 50 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS30-XL?",
        "a": "The NKIS30-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 52 mm outside diameter, 30 mm bore and 22 mm width, envelope 30×52×22 mm. Mass is 184 g."
      },
      {
        "q": "What does the NKIS30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS30-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×52×22 mm and the catalogue ratings are C 41.5 kN, C0 50 kN, Cur 8.8 kN."
      },
      {
        "q": "What is the load capacity of the NKIS30-XL?",
        "a": "The basic dynamic load rating C is 41.5 kN and the basic static load rating C0 is 50 kN; the fatigue load limit Cur is 8.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS30-XL?",
        "a": "The limiting speed is 11,700 r/min and the thermal reference speed is 6,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×52×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS30-XL",
      "NKIS30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI32-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI32/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 28,
    "static_load_kN": 43.5,
    "fatigue_load_limit_kN": 7.8,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 6900,
    "weight_g": 118,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×47×20 mm: 32 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 28 kN and C0 43.5 kN at the 32 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.8 kN, the limiting speed 12,300 r/min and the thermal reference speed 6,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 1.40 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 118 g, just 0.13 g per mm² of projected 47×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 32 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space NKI32/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The 7.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 32×47×20 mm envelope. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 47 mm outside diameter and 28 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 32 mm seat, and in motorcycle and light-vehicle transmissions the 118 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 20 mm width and the published 43.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI32/20-XL?",
        "a": "The NKI32/20-XL is a NKI machined-ring needle roller bearing with inner ring with 47 mm outside diameter, 32 mm bore and 20 mm width, envelope 32×47×20 mm. Mass is 118 g."
      },
      {
        "q": "What does the NKI32/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI32/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×47×20 mm and the catalogue ratings are C 28 kN, C0 43.5 kN, Cur 7.8 kN."
      },
      {
        "q": "What is the load capacity of the NKI32/20-XL?",
        "a": "The basic dynamic load rating C is 28 kN and the basic static load rating C0 is 43.5 kN; the fatigue load limit Cur is 7.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKI32/20-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 6,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI32/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 32 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI32-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI32-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI32-20-XL",
      "NKI32/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI32-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI32/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 42,
    "static_load_kN": 73,
    "fatigue_load_limit_kN": 13.7,
    "limiting_speed_rpm": 12300,
    "max_rpm": 12300,
    "reference_speed_rpm": 6600,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×47×30 mm: 32 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 42 kN and C0 73 kN at the 32 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 13.7 kN, the limiting speed 12,300 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.31 kN/mm and per millimetre of width 1.40 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 180 g, just 0.13 g per mm² of projected 47×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 32 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 30 mm width as a standard mounting space Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 42 kN C NKI32/30-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 12,300 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 47 mm outside diameter and 42 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 32 mm seat, and in gearbox selector and change linkages the 180 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 73 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI32/30-XL?",
        "a": "The NKI32/30-XL is a NKI machined-ring needle roller bearing with inner ring with 47 mm outside diameter, 32 mm bore and 30 mm width, envelope 32×47×30 mm. Mass is 180 g."
      },
      {
        "q": "What does the NKI32/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI32/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×47×30 mm and the catalogue ratings are C 42 kN, C0 73 kN, Cur 13.7 kN."
      },
      {
        "q": "What is the load capacity of the NKI32/30-XL?",
        "a": "The basic dynamic load rating C is 42 kN and the basic static load rating C0 is 73 kN; the fatigue load limit Cur is 13.7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI32/30-XL?",
        "a": "The limiting speed is 12,300 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI32/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 32 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI32-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI32-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI32-30-XL",
      "NKI32/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-32-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA49/32-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 34.5,
    "static_load_kN": 47.5,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 11100,
    "max_rpm": 11100,
    "reference_speed_rpm": 6000,
    "weight_g": 158,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×52×20 mm: 32 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 34.5 kN and C0 47.5 kN at the 32 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 11,100 r/min and the thermal reference speed 6,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.08 kN/mm and per millimetre of width 1.73 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 158 g, just 0.15 g per mm² of projected 52×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 32 mm bore marks the medium range: mounting forces and fits become critical, and the 158 g mass calls for proper induction or press tooling rather than hand fitting The 10.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 34.5 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 11,100 r/min limit. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 52 mm outside diameter and 34.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 32 mm seat, and in connecting-rod small ends the 158 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 20 mm width and the published 47.5 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA49/32-XL?",
        "a": "The NA49/32-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 52 mm outside diameter, 32 mm bore and 20 mm width, envelope 32×52×20 mm. Mass is 158 g."
      },
      {
        "q": "What does the NA49/32-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA49/32-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×52×20 mm and the catalogue ratings are C 34.5 kN, C0 47.5 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the NA49/32-XL?",
        "a": "The basic dynamic load rating C is 34.5 kN and the basic static load rating C0 is 47.5 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the NA49/32-XL?",
        "a": "The limiting speed is 11,100 r/min and the thermal reference speed is 6,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA49/32-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 32 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-32",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×52×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-32-XL",
      "NA49/32-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-32-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA69/32-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 52,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 53,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 15.4,
    "limiting_speed_rpm": 11100,
    "max_rpm": 11100,
    "reference_speed_rpm": 6100,
    "weight_g": 288,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 32×52×36 mm: 32 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 82 kN at the 32 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 52 mm outside diameter the fatigue load limit Cur is 15.4 kN, the limiting speed 11,100 r/min and the thermal reference speed 6,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.66 kN/mm and per millimetre of width 1.47 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 288 g, just 0.15 g per mm² of projected 52×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 32 mm bore marks the medium range: mounting forces and fits become critical, and the 288 g mass calls for proper induction or press tooling rather than hand fitting The 10.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Cur 15.4 kN, limiting speed 11,100 r/min, reference speed 6,100 r/min — the inner ring adds a few grams (total 288 g) but removes the hardening requirement X-life status (-XL) indicates the current Schaeffler premium execution at 32 mm bore; the 82 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 36 mm-wide envelope for higher capacity at the same bore. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 52 mm outside diameter and 53 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 32 mm seat, and in motorcycle and light-vehicle transmissions the 288 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 36 mm width and the published 82 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA69/32-ZW-XL?",
        "a": "The NA69/32-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 52 mm outside diameter, 32 mm bore and 36 mm width, envelope 32×52×36 mm. Mass is 288 g."
      },
      {
        "q": "What does the NA69/32-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA69/32-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 32×52×36 mm and the catalogue ratings are C 53 kN, C0 82 kN, Cur 15.4 kN."
      },
      {
        "q": "What is the load capacity of the NA69/32-ZW-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 82 kN; the fatigue load limit Cur is 15.4 kN."
      },
      {
        "q": "What is the maximum speed of the NA69/32-ZW-XL?",
        "a": "The limiting speed is 11,100 r/min and the thermal reference speed is 6,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA69/32-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 32 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-28",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-32",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 32×52×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-32-ZW-XL",
      "NA69/32-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI35-20-TW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI35/20-TW-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32.5,
    "static_load_kN": 48.5,
    "fatigue_load_limit_kN": 10.1,
    "limiting_speed_rpm": 11400,
    "max_rpm": 11400,
    "reference_speed_rpm": 6900,
    "weight_g": 122,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×50×20 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 32.5 kN and C0 48.5 kN at the 35 mm seat; the C/C0 ratio of 0.67 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 10.1 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 122 g, just 0.12 g per mm² of projected 50×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space NKI35/20-TW-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The 7.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 32.5 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 50 mm outside diameter and 32.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 35 mm seat, and in hydraulic and pneumatic pump eccentrics the 122 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 48.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI35/20-TW-XL?",
        "a": "The NKI35/20-TW-XL is a NKI machined-ring needle roller bearing with inner ring with 50 mm outside diameter, 35 mm bore and 20 mm width, envelope 35×50×20 mm. Mass is 122 g."
      },
      {
        "q": "What does the NKI35/20-TW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI35/20-TW-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×50×20 mm and the catalogue ratings are C 32.5 kN, C0 48.5 kN, Cur 10.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI35/20-TW-XL?",
        "a": "The basic dynamic load rating C is 32.5 kN and the basic static load rating C0 is 48.5 kN; the fatigue load limit Cur is 10.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI35/20-TW-XL?",
        "a": "The limiting speed is 11,400 r/min and the thermal reference speed is 6,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI35/20-TW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI35-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI35-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI35-20-TW-XL",
      "NKI35/20-TW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI35-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI35/20-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 33.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 11400,
    "max_rpm": 11400,
    "reference_speed_rpm": 6100,
    "weight_g": 122,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×50×20 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 33.5 kN and C0 56 kN at the 35 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 1.68 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 122 g, just 0.12 g per mm² of projected 50×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space The integral inner ring brings the bore to 35 mm inside the 50×20 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The 7.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 10 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 11,400 r/min. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 50 mm outside diameter and 33.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 35 mm seat, and in motorcycle and light-vehicle transmissions the 122 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 20 mm width and the published 56 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI35/20-TV-XL?",
        "a": "The NKI35/20-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 50 mm outside diameter, 35 mm bore and 20 mm width, envelope 35×50×20 mm. Mass is 122 g."
      },
      {
        "q": "What does the NKI35/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI35/20-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×50×20 mm and the catalogue ratings are C 33.5 kN, C0 56 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NKI35/20-TV-XL?",
        "a": "The basic dynamic load rating C is 33.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NKI35/20-TV-XL?",
        "a": "The limiting speed is 11,400 r/min and the thermal reference speed is 6,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI35/20-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI35-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI35-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI35-20-TV-XL",
      "NKI35/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI35-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI35/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 79,
    "fatigue_load_limit_kN": 14.9,
    "limiting_speed_rpm": 11400,
    "max_rpm": 11400,
    "reference_speed_rpm": 6200,
    "weight_g": 193,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×50×30 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 79 kN at the 35 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 14.9 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.26 kN/mm and per millimetre of width 1.47 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 193 g, just 0.13 g per mm² of projected 50×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 50 mm envelope already carries ratings in the tens of kilonewtons Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 44 kN C The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 79 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 35×50×30 mm envelope. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 50 mm outside diameter and 44 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 35 mm seat, and in agricultural machine pivots and linkages the 193 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 79 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI35/30-XL?",
        "a": "The NKI35/30-XL is a NKI machined-ring needle roller bearing with inner ring with 50 mm outside diameter, 35 mm bore and 30 mm width, envelope 35×50×30 mm. Mass is 193 g."
      },
      {
        "q": "What does the NKI35/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI35/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×50×30 mm and the catalogue ratings are C 44 kN, C0 79 kN, Cur 14.9 kN."
      },
      {
        "q": "What is the load capacity of the NKI35/30-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 79 kN; the fatigue load limit Cur is 14.9 kN."
      },
      {
        "q": "What is the maximum speed of the NKI35/30-XL?",
        "a": "The limiting speed is 11,400 r/min and the thermal reference speed is 6,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI35/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI35-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI35-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×50×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI35-30-XL",
      "NKI35/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4907-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4907-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 35.5,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 9.6,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 5800,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×55×20 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 35.5 kN and C0 50 kN at the 35 mm seat; the C/C0 ratio of 0.71 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.6 kN, the limiting speed 10,700 r/min and the thermal reference speed 5,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 1.77 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 170 g, just 0.15 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space This is the choice for OEM production on soft shafts: machine the 35 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Cur 9.6 kN, limiting speed 10,700 r/min, reference speed 5,800 r/min — the inner ring adds a few grams (total 170 g) but removes the hardening requirement X-life status (-XL) indicates the current Schaeffler premium execution at 35 mm bore; the 50 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 55 mm outside diameter and 35.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 35 mm seat, and in hydraulic and pneumatic pump eccentrics the 170 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 50 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4907-XL?",
        "a": "The NA4907-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 55 mm outside diameter, 35 mm bore and 20 mm width, envelope 35×55×20 mm. Mass is 170 g."
      },
      {
        "q": "What does the NA4907-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4907-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×55×20 mm and the catalogue ratings are C 35.5 kN, C0 50 kN, Cur 9.6 kN."
      },
      {
        "q": "What is the load capacity of the NA4907-XL?",
        "a": "The basic dynamic load rating C is 35.5 kN and the basic static load rating C0 is 50 kN; the fatigue load limit Cur is 9.6 kN."
      },
      {
        "q": "What is the maximum speed of the NA4907-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 5,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4907-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4907-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4907-XL",
      "NA4907-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6907-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6907-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 54,
    "static_load_kN": 86,
    "fatigue_load_limit_kN": 16.2,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 5900,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×55×36 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 54 kN and C0 86 kN at the 35 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 16.2 kN, the limiting speed 10,700 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.54 kN/mm and per millimetre of width 1.50 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 310 g, just 0.16 g per mm² of projected 55×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 36 mm width as a standard mounting space The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 86 kN C0 rating still assumes full rigid support under both rings Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 54 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 35 mm bore; the 86 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 36 mm-wide envelope for higher capacity at the same bore. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 55 mm outside diameter and 54 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 35 mm seat, and in small electric motor accessory drives the 310 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 36 mm width and the published 86 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6907-ZW-XL?",
        "a": "The NA6907-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 55 mm outside diameter, 35 mm bore and 36 mm width, envelope 35×55×36 mm. Mass is 310 g."
      },
      {
        "q": "What does the NA6907-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6907-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×55×36 mm and the catalogue ratings are C 54 kN, C0 86 kN, Cur 16.2 kN."
      },
      {
        "q": "What is the load capacity of the NA6907-ZW-XL?",
        "a": "The basic dynamic load rating C is 54 kN and the basic static load rating C0 is 86 kN; the fatigue load limit Cur is 16.2 kN."
      },
      {
        "q": "What is the maximum speed of the NA6907-ZW-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6907-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×55×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6907-ZW-XL",
      "NA6907-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS35-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 58,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 44,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5600,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×58×22 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.5 mm radial section packed with small-diameter needle rollers C is 44 kN and C0 57 kN at the 35 mm seat; the C/C0 ratio of 0.77 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 58 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.26 kN/mm and per millimetre of width 2.00 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 220 g, just 0.17 g per mm² of projected 58×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 35 mm bore marks the medium range: mounting forces and fits become critical, and the 220 g mass calls for proper induction or press tooling rather than hand fitting The 11.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 57 kN C0 rating still assumes full rigid support under both rings X-life status (-XL) indicates the current Schaeffler premium execution at 35 mm bore; the 57 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 58 mm outside diameter and 44 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 35 mm seat, and in hydraulic and pneumatic pump eccentrics the 220 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 22 mm width and the published 57 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS35-XL?",
        "a": "The NKIS35-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 58 mm outside diameter, 35 mm bore and 22 mm width, envelope 35×58×22 mm. Mass is 220 g."
      },
      {
        "q": "What does the NKIS35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS35-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×58×22 mm and the catalogue ratings are C 44 kN, C0 57 kN, Cur 10 kN."
      },
      {
        "q": "What is the load capacity of the NKIS35-XL?",
        "a": "The basic dynamic load rating C is 44 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 10 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS35-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×58×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=960",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS35-XL",
      "NKIS35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI38-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI38/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 53,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 30.5,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 6000,
    "weight_g": 136,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 38×53×20 mm: 38 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 30.5 kN and C0 51 kN at the 38 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 53 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 10,700 r/min and the thermal reference speed 6,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.80 kN/mm and per millimetre of width 1.52 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 136 g, just 0.13 g per mm² of projected 53×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 38 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 30.5 kN C NKI38/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 9.1 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 53 mm outside diameter and 30.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 38 mm seat, and in gearbox selector and change linkages the 136 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 20 mm width and the published 51 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI38/20-XL?",
        "a": "The NKI38/20-XL is a NKI machined-ring needle roller bearing with inner ring with 53 mm outside diameter, 38 mm bore and 20 mm width, envelope 38×53×20 mm. Mass is 136 g."
      },
      {
        "q": "What does the NKI38/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI38/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 38×53×20 mm and the catalogue ratings are C 30.5 kN, C0 51 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI38/20-XL?",
        "a": "The basic dynamic load rating C is 30.5 kN and the basic static load rating C0 is 51 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI38/20-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 6,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI38/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 38 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI38-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 38×53×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI38-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI38-20-XL",
      "NKI38/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI38-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI38/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 53,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 16.1,
    "limiting_speed_rpm": 10700,
    "max_rpm": 10700,
    "reference_speed_rpm": 5900,
    "weight_g": 207,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 38×53×30 mm: 38 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 85 kN at the 38 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 53 mm outside diameter the fatigue load limit Cur is 16.1 kN, the limiting speed 10,700 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.20 kN/mm and per millimetre of width 1.52 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 207 g, just 0.13 g per mm² of projected 53×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 38 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 30 mm width as a standard mounting space This is the choice for OEM production on soft shafts: machine the 38 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 45.5 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 45.5 kN C rating and longer nominal life come without an envelope change. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 53 mm outside diameter and 45.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 38 mm seat, and in connecting-rod small ends the 207 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 85 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI38/30-XL?",
        "a": "The NKI38/30-XL is a NKI machined-ring needle roller bearing with inner ring with 53 mm outside diameter, 38 mm bore and 30 mm width, envelope 38×53×30 mm. Mass is 207 g."
      },
      {
        "q": "What does the NKI38/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI38/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 38×53×30 mm and the catalogue ratings are C 45.5 kN, C0 85 kN, Cur 16.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI38/30-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 85 kN; the fatigue load limit Cur is 16.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI38/30-XL?",
        "a": "The limiting speed is 10,700 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI38/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 38 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI38-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI38-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 38×53×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI38-30-XL",
      "NKI38/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI40-20-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI40/20-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 35,
    "static_load_kN": 62,
    "fatigue_load_limit_kN": 11,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5600,
    "weight_g": 136,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×20 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 35 kN and C0 62 kN at the 40 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 11 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 1.75 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 136 g, just 0.12 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 40 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space Cur 11 kN, limiting speed 10,200 r/min, reference speed 5,600 r/min — the inner ring adds a few grams (total 136 g) but removes the hardening requirement Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 35 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 10,200 r/min limit. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 55 mm outside diameter and 35 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 40 mm seat, and in hydraulic and pneumatic pump eccentrics the 136 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 62 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI40/20-TV-XL?",
        "a": "The NKI40/20-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 55 mm outside diameter, 40 mm bore and 20 mm width, envelope 40×55×20 mm. Mass is 136 g."
      },
      {
        "q": "What does the NKI40/20-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI40/20-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×20 mm and the catalogue ratings are C 35 kN, C0 62 kN, Cur 11 kN."
      },
      {
        "q": "What is the load capacity of the NKI40/20-TV-XL?",
        "a": "The basic dynamic load rating C is 35 kN and the basic static load rating C0 is 62 kN; the fatigue load limit Cur is 11 kN."
      },
      {
        "q": "What is the maximum speed of the NKI40/20-TV-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI40/20-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI40-30-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI40-20-TV-XL",
      "NKI40/20-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI40-30-TW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI40/30-TW-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 54,
    "static_load_kN": 97,
    "fatigue_load_limit_kN": 18.6,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5900,
    "weight_g": 216,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×30 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 54 kN and C0 97 kN at the 40 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 18.6 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.35 kN/mm and per millimetre of width 1.80 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 216 g, just 0.13 g per mm² of projected 55×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons NKI40/30-TW-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 54 kN C As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 18.6 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 55 mm outside diameter and 54 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 40 mm seat, and in gearbox selector and change linkages the 216 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 97 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI40/30-TW-XL?",
        "a": "The NKI40/30-TW-XL is a NKI machined-ring needle roller bearing with inner ring with 55 mm outside diameter, 40 mm bore and 30 mm width, envelope 40×55×30 mm. Mass is 216 g."
      },
      {
        "q": "What does the NKI40/30-TW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI40/30-TW-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×30 mm and the catalogue ratings are C 54 kN, C0 97 kN, Cur 18.6 kN."
      },
      {
        "q": "What is the load capacity of the NKI40/30-TW-XL?",
        "a": "The basic dynamic load rating C is 54 kN and the basic static load rating C0 is 97 kN; the fatigue load limit Cur is 18.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKI40/30-TW-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI40/30-TW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI40-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI40-30-TW-XL",
      "NKI40/30-TW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI40-30-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI40/30-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 52,
    "static_load_kN": 103,
    "fatigue_load_limit_kN": 19.5,
    "limiting_speed_rpm": 10200,
    "max_rpm": 10200,
    "reference_speed_rpm": 5400,
    "weight_g": 216,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×30 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 52 kN and C0 103 kN at the 40 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 19.5 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.30 kN/mm and per millimetre of width 1.73 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 216 g, just 0.13 g per mm² of projected 55×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons Cur 19.5 kN, limiting speed 10,200 r/min, reference speed 5,400 r/min — the inner ring adds a few grams (total 216 g) but removes the hardening requirement This is the choice for OEM production on soft shafts: machine the 40 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 103 kN C0 rating reflects the improved rolling-contact geometry. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 55 mm outside diameter and 52 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 40 mm seat, and in textile machine heald and cam shafts the 216 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 103 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI40/30-TV-XL?",
        "a": "The NKI40/30-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 55 mm outside diameter, 40 mm bore and 30 mm width, envelope 40×55×30 mm. Mass is 216 g."
      },
      {
        "q": "What does the NKI40/30-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI40/30-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×30 mm and the catalogue ratings are C 52 kN, C0 103 kN, Cur 19.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI40/30-TV-XL?",
        "a": "The basic dynamic load rating C is 52 kN and the basic static load rating C0 is 103 kN; the fatigue load limit Cur is 19.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI40/30-TV-XL?",
        "a": "The limiting speed is 10,200 r/min and the thermal reference speed is 5,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI40/30-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI40-30-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI40-30-TV-XL",
      "NKI40/30-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4908-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4908-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.7,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5000,
    "weight_g": 230,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×62×22 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 67 kN at the 40 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 11.7 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.21 kN/mm and per millimetre of width 2.20 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 230 g, just 0.17 g per mm² of projected 62×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 40 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 67 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11.7 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 40 mm seat, and in small electric motor accessory drives the 230 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 22 mm width and the published 67 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4908-XL?",
        "a": "The NA4908-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 62 mm outside diameter, 40 mm bore and 22 mm width, envelope 40×62×22 mm. Mass is 230 g."
      },
      {
        "q": "What does the NA4908-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4908-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×62×22 mm and the catalogue ratings are C 48.5 kN, C0 67 kN, Cur 11.7 kN."
      },
      {
        "q": "What is the load capacity of the NA4908-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.7 kN."
      },
      {
        "q": "What is the maximum speed of the NA4908-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4908-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4908",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×62×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4908-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4908-XL",
      "NA4908-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6908-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6908-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 74,
    "static_load_kN": 116,
    "fatigue_load_limit_kN": 19.8,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5100,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×62×40 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 74 kN and C0 116 kN at the 40 mm seat; the C/C0 ratio of 0.64 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 19.8 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.85 kN/mm and per millimetre of width 1.85 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 430 g, just 0.17 g per mm² of projected 62×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons Cur 19.8 kN, limiting speed 9,200 r/min, reference speed 5,100 r/min — the inner ring adds a few grams (total 430 g) but removes the hardening requirement The 11.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 116 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 40 mm-wide envelope for higher capacity at the same bore. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 62 mm outside diameter and 74 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 40 mm seat, and in two-stroke and compressor piston pins the 430 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 40 mm width and the published 116 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6908-ZW-XL?",
        "a": "The NA6908-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 62 mm outside diameter, 40 mm bore and 40 mm width, envelope 40×62×40 mm. Mass is 430 g."
      },
      {
        "q": "What does the NA6908-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6908-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×62×40 mm and the catalogue ratings are C 74 kN, C0 116 kN, Cur 19.8 kN."
      },
      {
        "q": "What is the load capacity of the NA6908-ZW-XL?",
        "a": "The basic dynamic load rating C is 74 kN and the basic static load rating C0 is 116 kN; the fatigue load limit Cur is 19.8 kN."
      },
      {
        "q": "What is the maximum speed of the NA6908-ZW-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6908-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6908",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×62×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6908-ZW-XL",
      "NA6908-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS40-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS40-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 65,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.8,
    "limiting_speed_rpm": 8900,
    "max_rpm": 8900,
    "reference_speed_rpm": 4850,
    "weight_g": 281,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×65×22 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 48 kN and C0 67 kN at the 40 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 65 mm outside diameter the fatigue load limit Cur is 11.8 kN, the limiting speed 8,900 r/min and the thermal reference speed 4,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.20 kN/mm and per millimetre of width 2.18 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 281 g, just 0.20 g per mm² of projected 65×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 65 mm envelope already carries ratings in the tens of kilonewtons Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 48 kN C Cur 11.8 kN, limiting speed 8,900 r/min, reference speed 4,850 r/min — the inner ring adds a few grams (total 281 g) but removes the hardening requirement The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 8,900 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 65 mm outside diameter and 48 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 40 mm seat, and in two-stroke and compressor piston pins the 281 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 67 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS40-XL?",
        "a": "The NKIS40-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 65 mm outside diameter, 40 mm bore and 22 mm width, envelope 40×65×22 mm. Mass is 281 g."
      },
      {
        "q": "What does the NKIS40-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS40-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×65×22 mm and the catalogue ratings are C 48 kN, C0 67 kN, Cur 11.8 kN."
      },
      {
        "q": "What is the load capacity of the NKIS40-XL?",
        "a": "The basic dynamic load rating C is 48 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS40-XL?",
        "a": "The limiting speed is 8,900 r/min and the thermal reference speed is 4,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS40-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS40",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×65×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS40-XL",
      "NKIS40-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI42-20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI42/20-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 57,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 10.1,
    "limiting_speed_rpm": 9800,
    "max_rpm": 9800,
    "reference_speed_rpm": 5600,
    "weight_g": 148,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×57×20 mm: 42 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 32.5 kN and C0 56 kN at the 42 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 57 mm outside diameter the fatigue load limit Cur is 10.1 kN, the limiting speed 9,800 r/min and the thermal reference speed 5,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.77 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 148 g, just 0.13 g per mm² of projected 57×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 42 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space This is the choice for OEM production on soft shafts: machine the 42 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway NKI42/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 9,800 r/min limit. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 57 mm outside diameter and 32.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 42 mm seat, and in small electric motor accessory drives the 148 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 20 mm width and the published 56 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI42/20-XL?",
        "a": "The NKI42/20-XL is a NKI machined-ring needle roller bearing with inner ring with 57 mm outside diameter, 42 mm bore and 20 mm width, envelope 42×57×20 mm. Mass is 148 g."
      },
      {
        "q": "What does the NKI42/20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI42/20-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×57×20 mm and the catalogue ratings are C 32.5 kN, C0 56 kN, Cur 10.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI42/20-XL?",
        "a": "The basic dynamic load rating C is 32.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 10.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI42/20-XL?",
        "a": "The limiting speed is 9,800 r/min and the thermal reference speed is 5,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI42/20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 42 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI42-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×57×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI42-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI42-20-XL",
      "NKI42/20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI42-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI42/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 57,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 94,
    "fatigue_load_limit_kN": 17.8,
    "limiting_speed_rpm": 9800,
    "max_rpm": 9800,
    "reference_speed_rpm": 5400,
    "weight_g": 222,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 42×57×30 mm: 42 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 94 kN at the 42 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 57 mm outside diameter the fatigue load limit Cur is 17.8 kN, the limiting speed 9,800 r/min and the thermal reference speed 5,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.15 kN/mm and per millimetre of width 1.62 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 222 g, just 0.13 g per mm² of projected 57×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 42 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 30 mm width as a standard mounting space This is the choice for OEM production on soft shafts: machine the 42 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The 7.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 42 mm bore; the 94 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 57 mm outside diameter and 48.5 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 42 mm seat, and in agricultural machine pivots and linkages the 222 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 94 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI42/30-XL?",
        "a": "The NKI42/30-XL is a NKI machined-ring needle roller bearing with inner ring with 57 mm outside diameter, 42 mm bore and 30 mm width, envelope 42×57×30 mm. Mass is 222 g."
      },
      {
        "q": "What does the NKI42/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI42/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 42×57×30 mm and the catalogue ratings are C 48.5 kN, C0 94 kN, Cur 17.8 kN."
      },
      {
        "q": "What is the load capacity of the NKI42/30-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 94 kN; the fatigue load limit Cur is 17.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKI42/30-XL?",
        "a": "The limiting speed is 9,800 r/min and the thermal reference speed is 5,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI42/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 42 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI42-20",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI42-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×57×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI42-30-XL",
      "NKI42/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI45-25-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI45/25-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 48.5,
    "static_load_kN": 87,
    "fatigue_load_limit_kN": 15,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 5100,
    "weight_g": 217,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×62×25 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 87 kN at the 45 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 15 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.08 kN/mm and per millimetre of width 1.94 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 217 g, just 0.14 g per mm² of projected 62×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons The integral inner ring brings the bore to 45 mm inside the 62×25 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The 8.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 45 mm bore; the 87 kN C0 rating reflects the improved rolling-contact geometry. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 9,200 r/min limiting speed without roller-to-roller sliding. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 45 mm seat, and in gearbox selector and change linkages the 217 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 25 mm width and the published 87 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI45/25-TV-XL?",
        "a": "The NKI45/25-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 62 mm outside diameter, 45 mm bore and 25 mm width, envelope 45×62×25 mm. Mass is 217 g."
      },
      {
        "q": "What does the NKI45/25-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI45/25-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×62×25 mm and the catalogue ratings are C 48.5 kN, C0 87 kN, Cur 15 kN."
      },
      {
        "q": "What is the load capacity of the NKI45/25-TV-XL?",
        "a": "The basic dynamic load rating C is 48.5 kN and the basic static load rating C0 is 87 kN; the fatigue load limit Cur is 15 kN."
      },
      {
        "q": "What is the maximum speed of the NKI45/25-TV-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 5,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI45/25-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 45 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI45-25-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×62×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI45-35-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI45-25-TV-XL",
      "NKI45/25-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI45-35-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI45/35-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 67,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 24.3,
    "limiting_speed_rpm": 9200,
    "max_rpm": 9200,
    "reference_speed_rpm": 4950,
    "weight_g": 308,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×62×35 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 67 kN and C0 132 kN at the 45 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 24.3 kN, the limiting speed 9,200 r/min and the thermal reference speed 4,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.49 kN/mm and per millimetre of width 1.91 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 308 g, just 0.14 g per mm² of projected 62×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons NKI45/35-TV-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 67 kN C rating and longer nominal life come without an envelope change. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 308 g in the 62 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 62 mm outside diameter and 67 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 45 mm seat, and in two-stroke and compressor piston pins the 308 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 35 mm width and the published 132 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI45/35-TV-XL?",
        "a": "The NKI45/35-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 62 mm outside diameter, 45 mm bore and 35 mm width, envelope 45×62×35 mm. Mass is 308 g."
      },
      {
        "q": "What does the NKI45/35-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI45/35-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×62×35 mm and the catalogue ratings are C 67 kN, C0 132 kN, Cur 24.3 kN."
      },
      {
        "q": "What is the load capacity of the NKI45/35-TV-XL?",
        "a": "The basic dynamic load rating C is 67 kN and the basic static load rating C0 is 132 kN; the fatigue load limit Cur is 24.3 kN."
      },
      {
        "q": "What is the maximum speed of the NKI45/35-TV-XL?",
        "a": "The limiting speed is 9,200 r/min and the thermal reference speed is 4,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI45/35-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 45 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI45-25-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI45-35-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×62×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI45-35-TV-XL",
      "NKI45/35-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4909-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4909-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 51,
    "static_load_kN": 73,
    "fatigue_load_limit_kN": 12.9,
    "limiting_speed_rpm": 8600,
    "max_rpm": 8600,
    "reference_speed_rpm": 4700,
    "weight_g": 271,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×68×22 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.5 mm radial section packed with small-diameter needle rollers C is 51 kN and C0 73 kN at the 45 mm seat; the C/C0 ratio of 0.70 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 12.9 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 2.32 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 271 g, just 0.18 g per mm² of projected 68×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 45 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 22 mm width as a standard mounting space This is the choice for OEM production on soft shafts: machine the 45 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway NA4909-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 12.9 kN Cur value. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 68 mm outside diameter and 51 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 45 mm seat, and in copying and printing machine mechanisms the 271 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 22 mm width and the published 73 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4909-XL?",
        "a": "The NA4909-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 68 mm outside diameter, 45 mm bore and 22 mm width, envelope 45×68×22 mm. Mass is 271 g."
      },
      {
        "q": "What does the NA4909-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4909-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×68×22 mm and the catalogue ratings are C 51 kN, C0 73 kN, Cur 12.9 kN."
      },
      {
        "q": "What is the load capacity of the NA4909-XL?",
        "a": "The basic dynamic load rating C is 51 kN and the basic static load rating C0 is 73 kN; the fatigue load limit Cur is 12.9 kN."
      },
      {
        "q": "What is the maximum speed of the NA4909-XL?",
        "a": "The limiting speed is 8,600 r/min and the thermal reference speed is 4,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4909-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 45 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4909",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×68×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4909-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4909-XL",
      "NA4909-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6909-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6909-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 79,
    "static_load_kN": 127,
    "fatigue_load_limit_kN": 21.8,
    "limiting_speed_rpm": 8600,
    "max_rpm": 8600,
    "reference_speed_rpm": 4750,
    "weight_g": 495,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×68×40 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.5 mm radial section packed with small-diameter needle rollers C is 79 kN and C0 127 kN at the 45 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.8 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,750 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.76 kN/mm and per millimetre of width 1.98 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 495 g, just 0.18 g per mm² of projected 68×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 79 kN C NA6909-ZW-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required X-life status (-XL) indicates the current Schaeffler premium execution at 45 mm bore; the 127 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 40 mm-wide envelope for higher capacity at the same bore. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 68 mm outside diameter and 79 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 45 mm seat, and in motorcycle and light-vehicle transmissions the 495 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 40 mm width and the published 127 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6909-ZW-XL?",
        "a": "The NA6909-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 68 mm outside diameter, 45 mm bore and 40 mm width, envelope 45×68×40 mm. Mass is 495 g."
      },
      {
        "q": "What does the NA6909-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6909-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×68×40 mm and the catalogue ratings are C 79 kN, C0 127 kN, Cur 21.8 kN."
      },
      {
        "q": "What is the load capacity of the NA6909-ZW-XL?",
        "a": "The basic dynamic load rating C is 79 kN and the basic static load rating C0 is 127 kN; the fatigue load limit Cur is 21.8 kN."
      },
      {
        "q": "What is the maximum speed of the NA6909-ZW-XL?",
        "a": "The limiting speed is 8,600 r/min and the thermal reference speed is 4,750 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6909-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 45 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6909",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×68×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6909-ZW-XL",
      "NA6909-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS45-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS45-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 51,
    "static_load_kN": 74,
    "fatigue_load_limit_kN": 13,
    "limiting_speed_rpm": 8200,
    "max_rpm": 8200,
    "reference_speed_rpm": 4600,
    "weight_g": 336,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×72×22 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 13.5 mm radial section packed with small-diameter needle rollers C is 51 kN and C0 74 kN at the 45 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 13 kN, the limiting speed 8,200 r/min and the thermal reference speed 4,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 2.32 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 336 g, just 0.21 g per mm² of projected 72×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 45 mm bore marks the medium range: mounting forces and fits become critical, and the 336 g mass calls for proper induction or press tooling rather than hand fitting The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 74 kN C0 rating still assumes full rigid support under both rings The 13.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 13 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 72 mm outside diameter and 51 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 45 mm seat, and in two-stroke and compressor piston pins the 336 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 22 mm width and the published 74 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS45-XL?",
        "a": "The NKIS45-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 72 mm outside diameter, 45 mm bore and 22 mm width, envelope 45×72×22 mm. Mass is 336 g."
      },
      {
        "q": "What does the NKIS45-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS45-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×72×22 mm and the catalogue ratings are C 51 kN, C0 74 kN, Cur 13 kN."
      },
      {
        "q": "What is the load capacity of the NKIS45-XL?",
        "a": "The basic dynamic load rating C is 51 kN and the basic static load rating C0 is 74 kN; the fatigue load limit Cur is 13 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS45-XL?",
        "a": "The limiting speed is 8,200 r/min and the thermal reference speed is 4,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS45-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 45 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS45",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS45-XL",
      "NKIS45-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI50-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI50/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 68,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45.5,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 14.3,
    "limiting_speed_rpm": 8400,
    "max_rpm": 8400,
    "reference_speed_rpm": 4950,
    "weight_g": 270,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×68×25 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 45.5 kN and C0 82 kN at the 50 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 14.3 kN, the limiting speed 8,400 r/min and the thermal reference speed 4,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.91 kN/mm and per millimetre of width 1.82 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 270 g, just 0.16 g per mm² of projected 68×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 50 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 82 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 45.5 kN C rating and longer nominal life come without an envelope change. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 68 mm outside diameter and 45.5 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 50 mm seat, and in agricultural machine pivots and linkages the 270 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 25 mm width and the published 82 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI50/25-XL?",
        "a": "The NKI50/25-XL is a NKI machined-ring needle roller bearing with inner ring with 68 mm outside diameter, 50 mm bore and 25 mm width, envelope 50×68×25 mm. Mass is 270 g."
      },
      {
        "q": "What does the NKI50/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI50/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×68×25 mm and the catalogue ratings are C 45.5 kN, C0 82 kN, Cur 14.3 kN."
      },
      {
        "q": "What is the load capacity of the NKI50/25-XL?",
        "a": "The basic dynamic load rating C is 45.5 kN and the basic static load rating C0 is 82 kN; the fatigue load limit Cur is 14.3 kN."
      },
      {
        "q": "What is the maximum speed of the NKI50/25-XL?",
        "a": "The limiting speed is 8,400 r/min and the thermal reference speed is 4,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI50/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI50-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI50-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI50-25-XL",
      "NKI50/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI50-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI50/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 68,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 60,
    "static_load_kN": 118,
    "fatigue_load_limit_kN": 21.6,
    "limiting_speed_rpm": 8400,
    "max_rpm": 8400,
    "reference_speed_rpm": 4900,
    "weight_g": 379,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×68×35 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 60 kN and C0 118 kN at the 50 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.6 kN, the limiting speed 8,400 r/min and the thermal reference speed 4,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.20 kN/mm and per millimetre of width 1.71 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 379 g, just 0.16 g per mm² of projected 68×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 50 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons Cur 21.6 kN, limiting speed 8,400 r/min, reference speed 4,900 r/min — the inner ring adds a few grams (total 379 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 118 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 50×68×35 mm envelope. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 68 mm outside diameter and 60 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 50 mm seat, and in rocker arms and valve trains the 379 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 35 mm width and the published 118 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI50/35-XL?",
        "a": "The NKI50/35-XL is a NKI machined-ring needle roller bearing with inner ring with 68 mm outside diameter, 50 mm bore and 35 mm width, envelope 50×68×35 mm. Mass is 379 g."
      },
      {
        "q": "What does the NKI50/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI50/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×68×35 mm and the catalogue ratings are C 60 kN, C0 118 kN, Cur 21.6 kN."
      },
      {
        "q": "What is the load capacity of the NKI50/35-XL?",
        "a": "The basic dynamic load rating C is 60 kN and the basic static load rating C0 is 118 kN; the fatigue load limit Cur is 21.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKI50/35-XL?",
        "a": "The limiting speed is 8,400 r/min and the thermal reference speed is 4,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI50/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI50-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI50-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×68×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI50-35-XL",
      "NKI50/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4910-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4910-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 53,
    "static_load_kN": 80,
    "fatigue_load_limit_kN": 14.1,
    "limiting_speed_rpm": 7800,
    "max_rpm": 7800,
    "reference_speed_rpm": 4150,
    "weight_g": 274,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×72×22 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 80 kN at the 50 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 14.1 kN, the limiting speed 7,800 r/min and the thermal reference speed 4,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 2.41 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 274 g, just 0.17 g per mm² of projected 72×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 50 mm bore marks the medium range: mounting forces and fits become critical, and the 274 g mass calls for proper induction or press tooling rather than hand fitting This is the choice for OEM production on soft shafts: machine the 50 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,800 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 72 mm outside diameter and 53 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 50 mm seat, and in copying and printing machine mechanisms the 274 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 22 mm width and the published 80 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4910-XL?",
        "a": "The NA4910-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 72 mm outside diameter, 50 mm bore and 22 mm width, envelope 50×72×22 mm. Mass is 274 g."
      },
      {
        "q": "What does the NA4910-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4910-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×72×22 mm and the catalogue ratings are C 53 kN, C0 80 kN, Cur 14.1 kN."
      },
      {
        "q": "What is the load capacity of the NA4910-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 80 kN; the fatigue load limit Cur is 14.1 kN."
      },
      {
        "q": "What is the maximum speed of the NA4910-XL?",
        "a": "The limiting speed is 7,800 r/min and the thermal reference speed is 4,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4910-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4910",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4910-2RS",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4910-XL",
      "NA4910-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6910-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6910-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 82,
    "static_load_kN": 139,
    "fatigue_load_limit_kN": 23.8,
    "limiting_speed_rpm": 7800,
    "max_rpm": 7800,
    "reference_speed_rpm": 4200,
    "weight_g": 515,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×72×40 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 82 kN and C0 139 kN at the 50 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 23.8 kN, the limiting speed 7,800 r/min and the thermal reference speed 4,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.64 kN/mm and per millimetre of width 2.05 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 515 g, just 0.18 g per mm² of projected 72×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 50 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 40 mm width as a standard mounting space The 11.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 50×72×40 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 40 mm width while the outside diameter stays a compact 72 mm. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 72 mm outside diameter and 82 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 50 mm seat, and in rocker arms and valve trains the 515 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 40 mm width and the published 139 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6910-ZW-XL?",
        "a": "The NA6910-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 72 mm outside diameter, 50 mm bore and 40 mm width, envelope 50×72×40 mm. Mass is 515 g."
      },
      {
        "q": "What does the NA6910-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6910-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×72×40 mm and the catalogue ratings are C 82 kN, C0 139 kN, Cur 23.8 kN."
      },
      {
        "q": "What is the load capacity of the NA6910-ZW-XL?",
        "a": "The basic dynamic load rating C is 82 kN and the basic static load rating C0 is 139 kN; the fatigue load limit Cur is 23.8 kN."
      },
      {
        "q": "What is the maximum speed of the NA6910-ZW-XL?",
        "a": "The limiting speed is 7,800 r/min and the thermal reference speed is 4,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6910-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6910",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×72×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6910-ZW-XL",
      "NA6910-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS50-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS50-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 80,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 71,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 17.6,
    "limiting_speed_rpm": 7400,
    "max_rpm": 7400,
    "reference_speed_rpm": 4250,
    "weight_g": 518,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×80×28 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 71 kN and C0 98 kN at the 50 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 17.6 kN, the limiting speed 7,400 r/min and the thermal reference speed 4,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.42 kN/mm and per millimetre of width 2.54 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 518 g, just 0.23 g per mm² of projected 80×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 50 mm bore places this bearing in the medium band, where the 80 mm envelope already carries ratings in the tens of kilonewtons The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel NKIS50-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required X-life status (-XL) indicates the current Schaeffler premium execution at 50 mm bore; the 98 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 80 mm outside diameter and 71 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 50 mm seat, and in copying and printing machine mechanisms the 518 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 28 mm width and the published 98 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS50-XL?",
        "a": "The NKIS50-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 80 mm outside diameter, 50 mm bore and 28 mm width, envelope 50×80×28 mm. Mass is 518 g."
      },
      {
        "q": "What does the NKIS50-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS50-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×80×28 mm and the catalogue ratings are C 71 kN, C0 98 kN, Cur 17.6 kN."
      },
      {
        "q": "What is the load capacity of the NKIS50-XL?",
        "a": "The basic dynamic load rating C is 71 kN and the basic static load rating C0 is 98 kN; the fatigue load limit Cur is 17.6 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS50-XL?",
        "a": "The limiting speed is 7,400 r/min and the thermal reference speed is 4,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS50-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS50",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×80×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS50-XL",
      "NKIS50-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI55-25-TW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI55/25-TW-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 52,
    "static_load_kN": 92,
    "fatigue_load_limit_kN": 17.4,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4900,
    "weight_g": 255,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×72×25 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 52 kN and C0 92 kN at the 55 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 17.4 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 2.08 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 255 g, just 0.14 g per mm² of projected 72×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 255 g mass calls for proper induction or press tooling rather than hand fitting The 8.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 92 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 17.4 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 72 mm outside diameter and 52 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 55 mm seat, and in hydraulic and pneumatic pump eccentrics the 255 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 25 mm width and the published 92 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI55/25-TW-XL?",
        "a": "The NKI55/25-TW-XL is a NKI machined-ring needle roller bearing with inner ring with 72 mm outside diameter, 55 mm bore and 25 mm width, envelope 55×72×25 mm. Mass is 255 g."
      },
      {
        "q": "What does the NKI55/25-TW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI55/25-TW-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×72×25 mm and the catalogue ratings are C 52 kN, C0 92 kN, Cur 17.4 kN."
      },
      {
        "q": "What is the load capacity of the NKI55/25-TW-XL?",
        "a": "The basic dynamic load rating C is 52 kN and the basic static load rating C0 is 92 kN; the fatigue load limit Cur is 17.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKI55/25-TW-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI55/25-TW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI55-25-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI55-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI55-25-TW-XL",
      "NKI55/25-TW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI55-25-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI55/25-TV-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 53,
    "static_load_kN": 103,
    "fatigue_load_limit_kN": 17.8,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4400,
    "weight_g": 255,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×72×25 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 53 kN and C0 103 kN at the 55 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 17.8 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 2.12 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 255 g, just 0.14 g per mm² of projected 72×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 255 g mass calls for proper induction or press tooling rather than hand fitting Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 53 kN C Cur 17.8 kN, limiting speed 7,700 r/min, reference speed 4,400 r/min — the inner ring adds a few grams (total 255 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 17.8 kN Cur value. The -TV suffix specifies a glass-fibre reinforced polyamide 66 window-type cage; it spaces the rollers for low friction and is the reason the limiting speed can reach 7,700 r/min. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 72 mm outside diameter and 53 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 55 mm seat, and in planetary gear bearings the 255 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 25 mm width and the published 103 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI55/25-TV-XL?",
        "a": "The NKI55/25-TV-XL is a NKI machined-ring needle roller bearing with inner ring with 72 mm outside diameter, 55 mm bore and 25 mm width, envelope 55×72×25 mm. Mass is 255 g."
      },
      {
        "q": "What does the NKI55/25-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI55/25-TV-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×72×25 mm and the catalogue ratings are C 53 kN, C0 103 kN, Cur 17.8 kN."
      },
      {
        "q": "What is the load capacity of the NKI55/25-TV-XL?",
        "a": "The basic dynamic load rating C is 53 kN and the basic static load rating C0 is 103 kN; the fatigue load limit Cur is 17.8 kN."
      },
      {
        "q": "What is the maximum speed of the NKI55/25-TV-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI55/25-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI55-25-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI55-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI55-25-TV-XL",
      "NKI55/25-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI55-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI55/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 63,
    "static_load_kN": 130,
    "fatigue_load_limit_kN": 23.9,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4550,
    "weight_g": 379,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×72×35 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 63 kN and C0 130 kN at the 55 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 72 mm outside diameter the fatigue load limit Cur is 23.9 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.15 kN/mm and per millimetre of width 1.80 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 379 g, just 0.15 g per mm² of projected 72×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 55 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 35 mm width as a standard mounting space The 8.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel NKI55/35-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 63 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 72 mm outside diameter and 63 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 55 mm seat, and in rocker arms and valve trains the 379 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 35 mm width and the published 130 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI55/35-XL?",
        "a": "The NKI55/35-XL is a NKI machined-ring needle roller bearing with inner ring with 72 mm outside diameter, 55 mm bore and 35 mm width, envelope 55×72×35 mm. Mass is 379 g."
      },
      {
        "q": "What does the NKI55/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI55/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×72×35 mm and the catalogue ratings are C 63 kN, C0 130 kN, Cur 23.9 kN."
      },
      {
        "q": "What is the load capacity of the NKI55/35-XL?",
        "a": "The basic dynamic load rating C is 63 kN and the basic static load rating C0 is 130 kN; the fatigue load limit Cur is 23.9 kN."
      },
      {
        "q": "What is the maximum speed of the NKI55/35-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI55/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI55-25-TN",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI55-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×72×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI55-35-XL",
      "NKI55/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4911-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4911-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 65,
    "static_load_kN": 100,
    "fatigue_load_limit_kN": 17.6,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4000,
    "weight_g": 393,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×80×25 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 65 kN and C0 100 kN at the 55 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 17.6 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.18 kN/mm and per millimetre of width 2.60 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 393 g, just 0.20 g per mm² of projected 80×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 393 g mass calls for proper induction or press tooling rather than hand fitting The integral inner ring brings the bore to 55 mm inside the 80×25 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 100 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,200 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 80 mm outside diameter and 65 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 55 mm seat, and in textile machine heald and cam shafts the 393 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 25 mm width and the published 100 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4911-XL?",
        "a": "The NA4911-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 80 mm outside diameter, 55 mm bore and 25 mm width, envelope 55×80×25 mm. Mass is 393 g."
      },
      {
        "q": "What does the NA4911-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4911-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×80×25 mm and the catalogue ratings are C 65 kN, C0 100 kN, Cur 17.6 kN."
      },
      {
        "q": "What is the load capacity of the NA4911-XL?",
        "a": "The basic dynamic load rating C is 65 kN and the basic static load rating C0 is 100 kN; the fatigue load limit Cur is 17.6 kN."
      },
      {
        "q": "What is the maximum speed of the NA4911-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4911-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4911",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×80×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4911-XL",
      "NA4911-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6911-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6911-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 102,
    "static_load_kN": 176,
    "fatigue_load_limit_kN": 30.5,
    "limiting_speed_rpm": 7200,
    "max_rpm": 7200,
    "reference_speed_rpm": 4000,
    "weight_g": 780,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×80×45 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 102 kN and C0 176 kN at the 55 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 80 mm outside diameter the fatigue load limit Cur is 30.5 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.85 kN/mm and per millimetre of width 2.27 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 780 g, just 0.22 g per mm² of projected 80×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 55 mm bore places this bearing in the medium band, where the 80 mm envelope already carries ratings in the tens of kilonewtons Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 102 kN C This is the choice for OEM production on soft shafts: machine the 55 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 55×80×45 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 45 mm width while the outside diameter stays a compact 80 mm. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 80 mm outside diameter and 102 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 55 mm seat, and in motorcycle and light-vehicle transmissions the 780 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 45 mm width and the published 176 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6911-ZW-XL?",
        "a": "The NA6911-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 80 mm outside diameter, 55 mm bore and 45 mm width, envelope 55×80×45 mm. Mass is 780 g."
      },
      {
        "q": "What does the NA6911-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6911-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×80×45 mm and the catalogue ratings are C 102 kN, C0 176 kN, Cur 30.5 kN."
      },
      {
        "q": "What is the load capacity of the NA6911-ZW-XL?",
        "a": "The basic dynamic load rating C is 102 kN and the basic static load rating C0 is 176 kN; the fatigue load limit Cur is 30.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA6911-ZW-XL?",
        "a": "The limiting speed is 7,200 r/min and the thermal reference speed is 4,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6911-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6911",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×80×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6911-ZW-XL",
      "NA6911-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS55-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS55-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 85,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 75,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 19.4,
    "limiting_speed_rpm": 6900,
    "max_rpm": 6900,
    "reference_speed_rpm": 4000,
    "weight_g": 558,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×85×28 mm: 55 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 75 kN and C0 108 kN at the 55 mm seat; the C/C0 ratio of 0.69 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 19.4 kN, the limiting speed 6,900 r/min and the thermal reference speed 4,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.36 kN/mm and per millimetre of width 2.68 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 558 g, just 0.23 g per mm² of projected 85×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 55 mm bore marks the medium range: mounting forces and fits become critical, and the 558 g mass calls for proper induction or press tooling rather than hand fitting This is the choice for OEM production on soft shafts: machine the 55 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway NKIS55-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 75 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 85 mm outside diameter and 75 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 55 mm seat, and in copying and printing machine mechanisms the 558 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 28 mm width and the published 108 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS55-XL?",
        "a": "The NKIS55-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 85 mm outside diameter, 55 mm bore and 28 mm width, envelope 55×85×28 mm. Mass is 558 g."
      },
      {
        "q": "What does the NKIS55-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS55-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×85×28 mm and the catalogue ratings are C 75 kN, C0 108 kN, Cur 19.4 kN."
      },
      {
        "q": "What is the load capacity of the NKIS55-XL?",
        "a": "The basic dynamic load rating C is 75 kN and the basic static load rating C0 is 108 kN; the fatigue load limit Cur is 19.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS55-XL?",
        "a": "The limiting speed is 6,900 r/min and the thermal reference speed is 4,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS55-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 55 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS55",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 55×85×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS55-XL",
      "NKIS55-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI60-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI60/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 82,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 49.5,
    "static_load_kN": 89,
    "fatigue_load_limit_kN": 15.5,
    "limiting_speed_rpm": 6800,
    "max_rpm": 6800,
    "reference_speed_rpm": 4200,
    "weight_g": 394,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×82×25 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 49.5 kN and C0 89 kN at the 60 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 82 mm outside diameter the fatigue load limit Cur is 15.5 kN, the limiting speed 6,800 r/min and the thermal reference speed 4,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.82 kN/mm and per millimetre of width 1.98 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 394 g, just 0.19 g per mm² of projected 82×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 60 mm bore places this bearing in the medium band, where the 82 mm envelope already carries ratings in the tens of kilonewtons The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 89 kN C0 rating still assumes full rigid support under both rings The 11.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 60×82×25 mm envelope. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 82 mm outside diameter and 49.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 60 mm seat, and in motorcycle and light-vehicle transmissions the 394 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 25 mm width and the published 89 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI60/25-XL?",
        "a": "The NKI60/25-XL is a NKI machined-ring needle roller bearing with inner ring with 82 mm outside diameter, 60 mm bore and 25 mm width, envelope 60×82×25 mm. Mass is 394 g."
      },
      {
        "q": "What does the NKI60/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI60/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×82×25 mm and the catalogue ratings are C 49.5 kN, C0 89 kN, Cur 15.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI60/25-XL?",
        "a": "The basic dynamic load rating C is 49.5 kN and the basic static load rating C0 is 89 kN; the fatigue load limit Cur is 15.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI60/25-XL?",
        "a": "The limiting speed is 6,800 r/min and the thermal reference speed is 4,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI60/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 60 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI60-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×82×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI60-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI60-25-XL",
      "NKI60/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI60-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI60/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 82,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 70,
    "static_load_kN": 139,
    "fatigue_load_limit_kN": 26,
    "limiting_speed_rpm": 6800,
    "max_rpm": 6800,
    "reference_speed_rpm": 4050,
    "weight_g": 553,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×82×35 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 70 kN and C0 139 kN at the 60 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 82 mm outside diameter the fatigue load limit Cur is 26 kN, the limiting speed 6,800 r/min and the thermal reference speed 4,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.17 kN/mm and per millimetre of width 2.00 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 553 g, just 0.19 g per mm² of projected 82×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 60 mm bore places this bearing in the medium band, where the 82 mm envelope already carries ratings in the tens of kilonewtons Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 70 kN C Cur 26 kN, limiting speed 6,800 r/min, reference speed 4,050 r/min — the inner ring adds a few grams (total 553 g) but removes the hardening requirement The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,800 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 82 mm outside diameter and 70 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 60 mm seat, and in gearbox selector and change linkages the 553 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 35 mm width and the published 139 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI60/35-XL?",
        "a": "The NKI60/35-XL is a NKI machined-ring needle roller bearing with inner ring with 82 mm outside diameter, 60 mm bore and 35 mm width, envelope 60×82×35 mm. Mass is 553 g."
      },
      {
        "q": "What does the NKI60/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI60/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×82×35 mm and the catalogue ratings are C 70 kN, C0 139 kN, Cur 26 kN."
      },
      {
        "q": "What is the load capacity of the NKI60/35-XL?",
        "a": "The basic dynamic load rating C is 70 kN and the basic static load rating C0 is 139 kN; the fatigue load limit Cur is 26 kN."
      },
      {
        "q": "What is the maximum speed of the NKI60/35-XL?",
        "a": "The limiting speed is 6,800 r/min and the thermal reference speed is 4,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI60/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 60 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI60-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI60-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×82×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI60-35-XL",
      "NKI60/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4912-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4912-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 68,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 19.1,
    "limiting_speed_rpm": 6700,
    "max_rpm": 6700,
    "reference_speed_rpm": 3700,
    "weight_g": 426,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×85×25 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 68 kN and C0 108 kN at the 60 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 19.1 kN, the limiting speed 6,700 r/min and the thermal reference speed 3,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 2.72 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 426 g, just 0.20 g per mm² of projected 85×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 60 mm bore marks the medium range: mounting forces and fits become critical, and the 426 g mass calls for proper induction or press tooling rather than hand fitting The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 108 kN C0 rating still assumes full rigid support under both rings NA4912-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,700 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 85 mm outside diameter and 68 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 60 mm seat, and in two-stroke and compressor piston pins the 426 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 25 mm width and the published 108 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4912-XL?",
        "a": "The NA4912-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 85 mm outside diameter, 60 mm bore and 25 mm width, envelope 60×85×25 mm. Mass is 426 g."
      },
      {
        "q": "What does the NA4912-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4912-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×85×25 mm and the catalogue ratings are C 68 kN, C0 108 kN, Cur 19.1 kN."
      },
      {
        "q": "What is the load capacity of the NA4912-XL?",
        "a": "The basic dynamic load rating C is 68 kN and the basic static load rating C0 is 108 kN; the fatigue load limit Cur is 19.1 kN."
      },
      {
        "q": "What is the maximum speed of the NA4912-XL?",
        "a": "The limiting speed is 6,700 r/min and the thermal reference speed is 3,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4912-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 60 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4912",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4912-XL",
      "NA4912-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6912-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6912-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 106,
    "static_load_kN": 191,
    "fatigue_load_limit_kN": 33,
    "limiting_speed_rpm": 6700,
    "max_rpm": 6700,
    "reference_speed_rpm": 3700,
    "weight_g": 808,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×85×45 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 106 kN and C0 191 kN at the 60 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 33 kN, the limiting speed 6,700 r/min and the thermal reference speed 3,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.77 kN/mm and per millimetre of width 2.36 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 808 g, just 0.21 g per mm² of projected 85×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 60 mm bore places this bearing in the medium band, where the 85 mm envelope already carries ratings in the tens of kilonewtons Cur 33 kN, limiting speed 6,700 r/min, reference speed 3,700 r/min — the inner ring adds a few grams (total 808 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 191 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 60×85×45 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 45 mm width while the outside diameter stays a compact 85 mm. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 85 mm outside diameter and 106 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 60 mm seat, and in connecting-rod small ends the 808 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 45 mm width and the published 191 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6912-ZW-XL?",
        "a": "The NA6912-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 85 mm outside diameter, 60 mm bore and 45 mm width, envelope 60×85×45 mm. Mass is 808 g."
      },
      {
        "q": "What does the NA6912-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6912-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×85×45 mm and the catalogue ratings are C 106 kN, C0 191 kN, Cur 33 kN."
      },
      {
        "q": "What is the load capacity of the NA6912-ZW-XL?",
        "a": "The basic dynamic load rating C is 106 kN and the basic static load rating C0 is 191 kN; the fatigue load limit Cur is 33 kN."
      },
      {
        "q": "What is the maximum speed of the NA6912-ZW-XL?",
        "a": "The limiting speed is 6,700 r/min and the thermal reference speed is 3,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6912-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 60 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6912",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×85×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6912-ZW-XL",
      "NA6912-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS60-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS60-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 90,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 77,
    "static_load_kN": 113,
    "fatigue_load_limit_kN": 20.4,
    "limiting_speed_rpm": 6400,
    "max_rpm": 6400,
    "reference_speed_rpm": 3800,
    "weight_g": 560,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×90×28 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 77 kN and C0 113 kN at the 60 mm seat; the C/C0 ratio of 0.68 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 20.4 kN, the limiting speed 6,400 r/min and the thermal reference speed 3,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.28 kN/mm and per millimetre of width 2.75 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 560 g, just 0.22 g per mm² of projected 90×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 60 mm bore places this bearing in the medium band, where the 90 mm envelope already carries ratings in the tens of kilonewtons Reading the NKIS prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 77 kN C As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 20.4 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 90 mm outside diameter and 77 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 60 mm seat, and in motorcycle and light-vehicle transmissions the 560 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 28 mm width and the published 113 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS60-XL?",
        "a": "The NKIS60-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 90 mm outside diameter, 60 mm bore and 28 mm width, envelope 60×90×28 mm. Mass is 560 g."
      },
      {
        "q": "What does the NKIS60-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS60-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×90×28 mm and the catalogue ratings are C 77 kN, C0 113 kN, Cur 20.4 kN."
      },
      {
        "q": "What is the load capacity of the NKIS60-XL?",
        "a": "The basic dynamic load rating C is 77 kN and the basic static load rating C0 is 113 kN; the fatigue load limit Cur is 20.4 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS60-XL?",
        "a": "The limiting speed is 6,400 r/min and the thermal reference speed is 3,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS60-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 60 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS60",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 60×90×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=961",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS60-XL",
      "NKIS60-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI65-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI65/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 60,
    "static_load_kN": 100,
    "fatigue_load_limit_kN": 17.9,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3900,
    "weight_g": 467,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×90×25 mm: 65 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 60 kN and C0 100 kN at the 65 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 17.9 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 2.40 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 467 g, just 0.21 g per mm² of projected 90×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 65 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NKI65/25-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required This is the choice for OEM production on soft shafts: machine the 65 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 60 kN C rating and longer nominal life come without an envelope change. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 90 mm outside diameter and 60 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 65 mm seat, and in connecting-rod small ends the 467 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 25 mm width and the published 100 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI65/25-XL?",
        "a": "The NKI65/25-XL is a NKI machined-ring needle roller bearing with inner ring with 90 mm outside diameter, 65 mm bore and 25 mm width, envelope 65×90×25 mm. Mass is 467 g."
      },
      {
        "q": "What does the NKI65/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI65/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×90×25 mm and the catalogue ratings are C 60 kN, C0 100 kN, Cur 17.9 kN."
      },
      {
        "q": "What is the load capacity of the NKI65/25-XL?",
        "a": "The basic dynamic load rating C is 60 kN and the basic static load rating C0 is 100 kN; the fatigue load limit Cur is 17.9 kN."
      },
      {
        "q": "What is the maximum speed of the NKI65/25-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI65/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 65 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI65-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI65-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI65-25-XL",
      "NKI65/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI65-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI65/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 85,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 27.5,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3750,
    "weight_g": 659,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×90×35 mm: 65 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 85 kN and C0 156 kN at the 65 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 27.5 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,750 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.31 kN/mm and per millimetre of width 2.43 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 659 g, just 0.21 g per mm² of projected 90×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 65 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 156 kN C0 rating still assumes full rigid support under both rings NKI65/35-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 65×90×35 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 90 mm outside diameter and 85 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 65 mm seat, and in planetary gear bearings the 659 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 156 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI65/35-XL?",
        "a": "The NKI65/35-XL is a NKI machined-ring needle roller bearing with inner ring with 90 mm outside diameter, 65 mm bore and 35 mm width, envelope 65×90×35 mm. Mass is 659 g."
      },
      {
        "q": "What does the NKI65/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI65/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×90×35 mm and the catalogue ratings are C 85 kN, C0 156 kN, Cur 27.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI65/35-XL?",
        "a": "The basic dynamic load rating C is 85 kN and the basic static load rating C0 is 156 kN; the fatigue load limit Cur is 27.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI65/35-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,750 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI65/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 65 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI65-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI65-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI65-35-XL",
      "NKI65/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4913-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4913-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 69,
    "static_load_kN": 112,
    "fatigue_load_limit_kN": 19.9,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3500,
    "weight_g": 456,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×90×25 mm: 65 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 69 kN and C0 112 kN at the 65 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 19.9 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 2.76 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 456 g, just 0.20 g per mm² of projected 90×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 65 mm bore this is a heavy-industrial bearing: 456 g of stiff ring and roller set, specified where rigidity matters more than speed Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 69 kN C NA4913-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required X-life status (-XL) indicates the current Schaeffler premium execution at 65 mm bore; the 112 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 90 mm outside diameter and 69 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 65 mm seat, and in agricultural machine pivots and linkages the 456 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 25 mm width and the published 112 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4913-XL?",
        "a": "The NA4913-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 90 mm outside diameter, 65 mm bore and 25 mm width, envelope 65×90×25 mm. Mass is 456 g."
      },
      {
        "q": "What does the NA4913-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4913-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×90×25 mm and the catalogue ratings are C 69 kN, C0 112 kN, Cur 19.9 kN."
      },
      {
        "q": "What is the load capacity of the NA4913-XL?",
        "a": "The basic dynamic load rating C is 69 kN and the basic static load rating C0 is 112 kN; the fatigue load limit Cur is 19.9 kN."
      },
      {
        "q": "What is the maximum speed of the NA4913-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4913-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 65 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4913",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4913-XL",
      "NA4913-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6913-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6913-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 108,
    "static_load_kN": 198,
    "fatigue_load_limit_kN": 34.5,
    "limiting_speed_rpm": 6300,
    "max_rpm": 6300,
    "reference_speed_rpm": 3550,
    "weight_g": 833,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×90×45 mm: 65 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 108 kN and C0 198 kN at the 65 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 34.5 kN, the limiting speed 6,300 r/min and the thermal reference speed 3,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.66 kN/mm and per millimetre of width 2.40 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 833 g, just 0.21 g per mm² of projected 90×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 65 mm bore this is a heavy-industrial bearing: 833 g of stiff ring and roller set, specified where rigidity matters more than speed The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 198 kN C0 rating still assumes full rigid support under both rings This is the choice for OEM production on soft shafts: machine the 65 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 65×90×45 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 45 mm width while the outside diameter stays a compact 90 mm. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 90 mm outside diameter and 108 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 65 mm seat, and in agricultural machine pivots and linkages the 833 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 45 mm width and the published 198 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6913-ZW-XL?",
        "a": "The NA6913-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 90 mm outside diameter, 65 mm bore and 45 mm width, envelope 65×90×45 mm. Mass is 833 g."
      },
      {
        "q": "What does the NA6913-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6913-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×90×45 mm and the catalogue ratings are C 108 kN, C0 198 kN, Cur 34.5 kN."
      },
      {
        "q": "What is the load capacity of the NA6913-ZW-XL?",
        "a": "The basic dynamic load rating C is 108 kN and the basic static load rating C0 is 198 kN; the fatigue load limit Cur is 34.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA6913-ZW-XL?",
        "a": "The limiting speed is 6,300 r/min and the thermal reference speed is 3,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6913-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 65 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6913",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6913-ZW-XL",
      "NA6913-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS65-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKIS65-XL",
    "series": "nkis-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 95,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 81,
    "static_load_kN": 123,
    "fatigue_load_limit_kN": 22.2,
    "limiting_speed_rpm": 6000,
    "max_rpm": 6000,
    "reference_speed_rpm": 3600,
    "weight_g": 641,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×95×28 mm: 65 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 81 kN and C0 123 kN at the 65 mm seat; the C/C0 ratio of 0.66 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 22.2 kN, the limiting speed 6,000 r/min and the thermal reference speed 3,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 2.89 kN/mm — the reason 28 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 641 g, just 0.24 g per mm² of projected 95×28 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 65 mm bore this is a heavy-industrial bearing: 641 g of stiff ring and roller set, specified where rigidity matters more than speed Cur 22.2 kN, limiting speed 6,000 r/min, reference speed 3,600 r/min — the inner ring adds a few grams (total 641 g) but removes the hardening requirement The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 81 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 95 mm outside diameter and 81 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 65 mm seat, and in hydraulic and pneumatic pump eccentrics the 641 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 28 mm width and the published 123 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKIS65-XL?",
        "a": "The NKIS65-XL is a NKIS heavy-section machined-ring needle roller bearing with inner ring with 95 mm outside diameter, 65 mm bore and 28 mm width, envelope 65×95×28 mm. Mass is 641 g."
      },
      {
        "q": "What does the NKIS65-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKIS65-XL identifies this NKIS heavy-section machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×95×28 mm and the catalogue ratings are C 81 kN, C0 123 kN, Cur 22.2 kN."
      },
      {
        "q": "What is the load capacity of the NKIS65-XL?",
        "a": "The basic dynamic load rating C is 81 kN and the basic static load rating C0 is 123 kN; the fatigue load limit Cur is 22.2 kN."
      },
      {
        "q": "What is the maximum speed of the NKIS65-XL?",
        "a": "The limiting speed is 6,000 r/min and the thermal reference speed is 3,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKIS65-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 65 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS65",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×95×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS65-XL",
      "NKIS65-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI70-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI70/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 95,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 63,
    "static_load_kN": 119,
    "fatigue_load_limit_kN": 20,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3500,
    "weight_g": 521,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×95×25 mm: 70 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 63 kN and C0 119 kN at the 70 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 20 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.90 kN/mm and per millimetre of width 2.52 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 521 g, just 0.22 g per mm² of projected 95×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 70 mm bore this is a heavy-industrial bearing: 521 g of stiff ring and roller set, specified where rigidity matters more than speed Cur 20 kN, limiting speed 5,800 r/min, reference speed 3,500 r/min — the inner ring adds a few grams (total 521 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 119 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 5,800 r/min limit. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 95 mm outside diameter and 63 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 70 mm seat, and in rocker arms and valve trains the 521 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 25 mm width and the published 119 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI70/25-XL?",
        "a": "The NKI70/25-XL is a NKI machined-ring needle roller bearing with inner ring with 95 mm outside diameter, 70 mm bore and 25 mm width, envelope 70×95×25 mm. Mass is 521 g."
      },
      {
        "q": "What does the NKI70/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI70/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×95×25 mm and the catalogue ratings are C 63 kN, C0 119 kN, Cur 20 kN."
      },
      {
        "q": "What is the load capacity of the NKI70/25-XL?",
        "a": "The basic dynamic load rating C is 63 kN and the basic static load rating C0 is 119 kN; the fatigue load limit Cur is 20 kN."
      },
      {
        "q": "What is the maximum speed of the NKI70/25-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI70/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 70 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI70-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×95×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI70-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI70-25-XL",
      "NKI70/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI70-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI70/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 95,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 89,
    "static_load_kN": 184,
    "fatigue_load_limit_kN": 33,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3350,
    "weight_g": 737,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×95×35 mm: 70 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 89 kN and C0 184 kN at the 70 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 95 mm outside diameter the fatigue load limit Cur is 33 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,350 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.27 kN/mm and per millimetre of width 2.54 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 737 g, just 0.22 g per mm² of projected 95×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 70 mm bore this is a heavy-industrial bearing: 737 g of stiff ring and roller set, specified where rigidity matters more than speed Cur 33 kN, limiting speed 5,800 r/min, reference speed 3,350 r/min — the inner ring adds a few grams (total 737 g) but removes the hardening requirement Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 89 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 70 mm bore; the 184 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 95 mm outside diameter and 89 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 70 mm seat, and in hydraulic and pneumatic pump eccentrics the 737 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 35 mm width and the published 184 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI70/35-XL?",
        "a": "The NKI70/35-XL is a NKI machined-ring needle roller bearing with inner ring with 95 mm outside diameter, 70 mm bore and 35 mm width, envelope 70×95×35 mm. Mass is 737 g."
      },
      {
        "q": "What does the NKI70/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI70/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×95×35 mm and the catalogue ratings are C 89 kN, C0 184 kN, Cur 33 kN."
      },
      {
        "q": "What is the load capacity of the NKI70/35-XL?",
        "a": "The basic dynamic load rating C is 89 kN and the basic static load rating C0 is 184 kN; the fatigue load limit Cur is 33 kN."
      },
      {
        "q": "What is the maximum speed of the NKI70/35-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,350 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI70/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 70 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI70-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI70-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×95×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI70-35-XL",
      "NKI70/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4914-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4914-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 95,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 28,
    "limiting_speed_rpm": 5700,
    "max_rpm": 5700,
    "reference_speed_rpm": 3250,
    "weight_g": 728,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×100×30 mm: 70 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 95 kN and C0 156 kN at the 70 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 28 kN, the limiting speed 5,700 r/min and the thermal reference speed 3,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.36 kN/mm and per millimetre of width 3.17 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 728 g, just 0.24 g per mm² of projected 100×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 70 mm bore the 100 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,700 r/min The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 70 mm bore; the 156 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 100 mm outside diameter and 95 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 70 mm seat, and in connecting-rod small ends the 728 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 156 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4914-XL?",
        "a": "The NA4914-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 100 mm outside diameter, 70 mm bore and 30 mm width, envelope 70×100×30 mm. Mass is 728 g."
      },
      {
        "q": "What does the NA4914-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4914-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×100×30 mm and the catalogue ratings are C 95 kN, C0 156 kN, Cur 28 kN."
      },
      {
        "q": "What is the load capacity of the NA4914-XL?",
        "a": "The basic dynamic load rating C is 95 kN and the basic static load rating C0 is 156 kN; the fatigue load limit Cur is 28 kN."
      },
      {
        "q": "What is the maximum speed of the NA4914-XL?",
        "a": "The limiting speed is 5,700 r/min and the thermal reference speed is 3,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4914-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 70 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4914",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×100×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4914-XL",
      "NA4914-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6914-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6914-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 145,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 48,
    "limiting_speed_rpm": 5700,
    "max_rpm": 5700,
    "reference_speed_rpm": 3300,
    "weight_g": 1340,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×100×54 mm: 70 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 145 kN and C0 265 kN at the 70 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 48 kN, the limiting speed 5,700 r/min and the thermal reference speed 3,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.07 kN/mm and per millimetre of width 2.69 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.34 kg (1340 g), just 0.25 g per mm² of projected 100×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 70 mm bore this is a heavy-industrial bearing: 1.34 kg of stiff ring and roller set, specified where rigidity matters more than speed The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel This is the choice for OEM production on soft shafts: machine the 70 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 145 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 265 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 100 mm outside diameter and 145 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 70 mm seat, and in small electric motor accessory drives the 1.34 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 54 mm width and the published 265 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6914-ZW-XL?",
        "a": "The NA6914-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 100 mm outside diameter, 70 mm bore and 54 mm width, envelope 70×100×54 mm. Mass is 1.34 kg."
      },
      {
        "q": "What does the NA6914-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6914-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×100×54 mm and the catalogue ratings are C 145 kN, C0 265 kN, Cur 48 kN."
      },
      {
        "q": "What is the load capacity of the NA6914-ZW-XL?",
        "a": "The basic dynamic load rating C is 145 kN and the basic static load rating C0 is 265 kN; the fatigue load limit Cur is 48 kN."
      },
      {
        "q": "What is the maximum speed of the NA6914-ZW-XL?",
        "a": "The limiting speed is 5,700 r/min and the thermal reference speed is 3,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6914-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 70 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6914",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 70×100×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6914-ZW-XL",
      "NA6914-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI75-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI75/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 78,
    "static_load_kN": 123,
    "fatigue_load_limit_kN": 22.1,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3300,
    "weight_g": 641,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×105×25 mm: 75 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 78 kN and C0 123 kN at the 75 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 22.1 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 3.12 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 641 g, just 0.24 g per mm² of projected 105×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 75 mm bore this is a heavy-industrial bearing: 641 g of stiff ring and roller set, specified where rigidity matters more than speed This is the choice for OEM production on soft shafts: machine the 75 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 75×105×25 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 105 mm outside diameter and 78 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 75 mm seat, and in two-stroke and compressor piston pins the 641 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 25 mm width and the published 123 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI75/25-XL?",
        "a": "The NKI75/25-XL is a NKI machined-ring needle roller bearing with inner ring with 105 mm outside diameter, 75 mm bore and 25 mm width, envelope 75×105×25 mm. Mass is 641 g."
      },
      {
        "q": "What does the NKI75/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI75/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×105×25 mm and the catalogue ratings are C 78 kN, C0 123 kN, Cur 22.1 kN."
      },
      {
        "q": "What is the load capacity of the NKI75/25-XL?",
        "a": "The basic dynamic load rating C is 78 kN and the basic static load rating C0 is 123 kN; the fatigue load limit Cur is 22.1 kN."
      },
      {
        "q": "What is the maximum speed of the NKI75/25-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI75/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 75 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI75-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×105×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI75-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI75-25-XL",
      "NKI75/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI75-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI75/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 111,
    "static_load_kN": 193,
    "fatigue_load_limit_kN": 35,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3200,
    "weight_g": 908,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×105×35 mm: 75 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 111 kN and C0 193 kN at the 75 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 35 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.48 kN/mm and per millimetre of width 3.17 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 908 g, just 0.25 g per mm² of projected 105×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 75 mm bore this is a heavy-industrial bearing: 908 g of stiff ring and roller set, specified where rigidity matters more than speed Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 111 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 5,400 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 105 mm outside diameter and 111 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 75 mm seat, and in copying and printing machine mechanisms the 908 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 35 mm width and the published 193 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI75/35-XL?",
        "a": "The NKI75/35-XL is a NKI machined-ring needle roller bearing with inner ring with 105 mm outside diameter, 75 mm bore and 35 mm width, envelope 75×105×35 mm. Mass is 908 g."
      },
      {
        "q": "What does the NKI75/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI75/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×105×35 mm and the catalogue ratings are C 111 kN, C0 193 kN, Cur 35 kN."
      },
      {
        "q": "What is the load capacity of the NKI75/35-XL?",
        "a": "The basic dynamic load rating C is 111 kN and the basic static load rating C0 is 193 kN; the fatigue load limit Cur is 35 kN."
      },
      {
        "q": "What is the maximum speed of the NKI75/35-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI75/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 75 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI75-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI75-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×105×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI75-35-XL",
      "NKI75/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4915-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4915-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 97,
    "static_load_kN": 162,
    "fatigue_load_limit_kN": 29,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3100,
    "weight_g": 775,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×105×30 mm: 75 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 97 kN and C0 162 kN at the 75 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 29 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.29 kN/mm and per millimetre of width 3.23 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 775 g, just 0.25 g per mm² of projected 105×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 105 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,400 r/min Cur 29 kN, limiting speed 5,400 r/min, reference speed 3,100 r/min — the inner ring adds a few grams (total 775 g) but removes the hardening requirement The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 75 mm bore; the 162 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 105 mm outside diameter and 97 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 75 mm seat, and in rocker arms and valve trains the 775 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 30 mm width and the published 162 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4915-XL?",
        "a": "The NA4915-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 105 mm outside diameter, 75 mm bore and 30 mm width, envelope 75×105×30 mm. Mass is 775 g."
      },
      {
        "q": "What does the NA4915-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4915-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×105×30 mm and the catalogue ratings are C 97 kN, C0 162 kN, Cur 29 kN."
      },
      {
        "q": "What is the load capacity of the NA4915-XL?",
        "a": "The basic dynamic load rating C is 97 kN and the basic static load rating C0 is 162 kN; the fatigue load limit Cur is 29 kN."
      },
      {
        "q": "What is the maximum speed of the NA4915-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4915-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 75 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4915",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×105×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4915-XL",
      "NA4915-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6915-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6915-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 147,
    "static_load_kN": 275,
    "fatigue_load_limit_kN": 50,
    "limiting_speed_rpm": 5400,
    "max_rpm": 5400,
    "reference_speed_rpm": 3150,
    "weight_g": 1450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 75×105×54 mm: 75 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 147 kN and C0 275 kN at the 75 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 50 kN, the limiting speed 5,400 r/min and the thermal reference speed 3,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.96 kN/mm and per millimetre of width 2.72 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.45 kg (1450 g), just 0.26 g per mm² of projected 105×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 75 mm bore the 105 mm outside diameter and 54 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,400 r/min NA6915-ZW-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 147 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 147 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 275 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 105 mm outside diameter and 147 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 75 mm seat, and in two-stroke and compressor piston pins the 1.45 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 54 mm width and the published 275 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6915-ZW-XL?",
        "a": "The NA6915-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 105 mm outside diameter, 75 mm bore and 54 mm width, envelope 75×105×54 mm. Mass is 1.45 kg."
      },
      {
        "q": "What does the NA6915-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6915-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 75×105×54 mm and the catalogue ratings are C 147 kN, C0 275 kN, Cur 50 kN."
      },
      {
        "q": "What is the load capacity of the NA6915-ZW-XL?",
        "a": "The basic dynamic load rating C is 147 kN and the basic static load rating C0 is 275 kN; the fatigue load limit Cur is 50 kN."
      },
      {
        "q": "What is the maximum speed of the NA6915-ZW-XL?",
        "a": "The limiting speed is 5,400 r/min and the thermal reference speed is 3,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6915-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 75 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6915",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 75×105×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6915-ZW-XL",
      "NA6915-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI80-25-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI80/25-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 81,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 23.7,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3150,
    "weight_g": 677,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×110×25 mm: 80 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 81 kN and C0 132 kN at the 80 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 23.7 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 3.24 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 677 g, just 0.25 g per mm² of projected 110×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 80 mm bore the 110 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,100 r/min Cur 23.7 kN, limiting speed 5,100 r/min, reference speed 3,150 r/min — the inner ring adds a few grams (total 677 g) but removes the hardening requirement The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 80 mm bore; the 132 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 110 mm outside diameter and 81 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 80 mm seat, and in planetary gear bearings the 677 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 25 mm width and the published 132 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI80/25-XL?",
        "a": "The NKI80/25-XL is a NKI machined-ring needle roller bearing with inner ring with 110 mm outside diameter, 80 mm bore and 25 mm width, envelope 80×110×25 mm. Mass is 677 g."
      },
      {
        "q": "What does the NKI80/25-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI80/25-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×110×25 mm and the catalogue ratings are C 81 kN, C0 132 kN, Cur 23.7 kN."
      },
      {
        "q": "What is the load capacity of the NKI80/25-XL?",
        "a": "The basic dynamic load rating C is 81 kN and the basic static load rating C0 is 132 kN; the fatigue load limit Cur is 23.7 kN."
      },
      {
        "q": "What is the maximum speed of the NKI80/25-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI80/25-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 80 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI80-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×110×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI80-35",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI80-25-XL",
      "NKI80/25-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI80-35-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI80/35-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 116,
    "static_load_kN": 208,
    "fatigue_load_limit_kN": 38,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 3050,
    "weight_g": 959,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×110×35 mm: 80 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 116 kN and C0 208 kN at the 80 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 38 kN, the limiting speed 5,100 r/min and the thermal reference speed 3,050 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.45 kN/mm and per millimetre of width 3.31 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 959 g, just 0.25 g per mm² of projected 110×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 80 mm bore the 110 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,100 r/min Cur 38 kN, limiting speed 5,100 r/min, reference speed 3,050 r/min — the inner ring adds a few grams (total 959 g) but removes the hardening requirement This is the choice for OEM production on soft shafts: machine the 80 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 38 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 110 mm outside diameter and 116 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 80 mm seat, and in textile machine heald and cam shafts the 959 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 35 mm width and the published 208 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI80/35-XL?",
        "a": "The NKI80/35-XL is a NKI machined-ring needle roller bearing with inner ring with 110 mm outside diameter, 80 mm bore and 35 mm width, envelope 80×110×35 mm. Mass is 959 g."
      },
      {
        "q": "What does the NKI80/35-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI80/35-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×110×35 mm and the catalogue ratings are C 116 kN, C0 208 kN, Cur 38 kN."
      },
      {
        "q": "What is the load capacity of the NKI80/35-XL?",
        "a": "The basic dynamic load rating C is 116 kN and the basic static load rating C0 is 208 kN; the fatigue load limit Cur is 38 kN."
      },
      {
        "q": "What is the maximum speed of the NKI80/35-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 3,050 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI80/35-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 80 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI80-25",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI80-35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×110×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI80-35-XL",
      "NKI80/35-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4916-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4916-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 101,
    "static_load_kN": 174,
    "fatigue_load_limit_kN": 31,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 2900,
    "weight_g": 878,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×110×30 mm: 80 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 101 kN and C0 174 kN at the 80 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 31 kN, the limiting speed 5,100 r/min and the thermal reference speed 2,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.26 kN/mm and per millimetre of width 3.37 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 878 g, just 0.27 g per mm² of projected 110×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 80 mm bore the 110 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,100 r/min The integral inner ring brings the bore to 80 mm inside the 110×30 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Cur 31 kN, limiting speed 5,100 r/min, reference speed 2,900 r/min — the inner ring adds a few grams (total 878 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 31 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 110 mm outside diameter and 101 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 80 mm seat, and in textile machine heald and cam shafts the 878 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 174 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4916-XL?",
        "a": "The NA4916-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 110 mm outside diameter, 80 mm bore and 30 mm width, envelope 80×110×30 mm. Mass is 878 g."
      },
      {
        "q": "What does the NA4916-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4916-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×110×30 mm and the catalogue ratings are C 101 kN, C0 174 kN, Cur 31 kN."
      },
      {
        "q": "What is the load capacity of the NA4916-XL?",
        "a": "The basic dynamic load rating C is 101 kN and the basic static load rating C0 is 174 kN; the fatigue load limit Cur is 31 kN."
      },
      {
        "q": "What is the maximum speed of the NA4916-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 2,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4916-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 80 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4916",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×110×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4916-XL",
      "NA4916-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6916-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6916-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 153,
    "static_load_kN": 300,
    "fatigue_load_limit_kN": 54,
    "limiting_speed_rpm": 5100,
    "max_rpm": 5100,
    "reference_speed_rpm": 2900,
    "weight_g": 1522,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×110×54 mm: 80 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 153 kN and C0 300 kN at the 80 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 54 kN, the limiting speed 5,100 r/min and the thermal reference speed 2,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.91 kN/mm and per millimetre of width 2.83 kN/mm — the reason 54 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.522 kg (1522 g), just 0.26 g per mm² of projected 110×54 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 80 mm bore the 110 mm outside diameter and 54 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,100 r/min The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 300 kN C0 rating still assumes full rigid support under both rings The integral inner ring brings the bore to 80 mm inside the 110×54 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 153 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 300 kN in this thin-section bearing — two rows support the static peak that a single row could not. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 110 mm outside diameter and 153 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 80 mm seat, and in motorcycle and light-vehicle transmissions the 1.522 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 54 mm width and the published 300 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6916-ZW-XL?",
        "a": "The NA6916-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 110 mm outside diameter, 80 mm bore and 54 mm width, envelope 80×110×54 mm. Mass is 1.522 kg."
      },
      {
        "q": "What does the NA6916-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6916-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×110×54 mm and the catalogue ratings are C 153 kN, C0 300 kN, Cur 54 kN."
      },
      {
        "q": "What is the load capacity of the NA6916-ZW-XL?",
        "a": "The basic dynamic load rating C is 153 kN and the basic static load rating C0 is 300 kN; the fatigue load limit Cur is 54 kN."
      },
      {
        "q": "What is the maximum speed of the NA6916-ZW-XL?",
        "a": "The limiting speed is 5,100 r/min and the thermal reference speed is 2,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6916-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 80 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6916",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 80×110×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6916-ZW-XL",
      "NA6916-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI85-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI85/26-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 115,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 83,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 24.5,
    "limiting_speed_rpm": 4850,
    "max_rpm": 4850,
    "reference_speed_rpm": 3100,
    "weight_g": 743,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×115×26 mm: 85 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 83 kN and C0 137 kN at the 85 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 115 mm outside diameter the fatigue load limit Cur is 24.5 kN, the limiting speed 4,850 r/min and the thermal reference speed 3,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 3.19 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 743 g, just 0.25 g per mm² of projected 115×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 85 mm bore this is a heavy-industrial bearing: 743 g of stiff ring and roller set, specified where rigidity matters more than speed The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel This is the choice for OEM production on soft shafts: machine the 85 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,850 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 115 mm outside diameter and 83 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 85 mm seat, and in hydraulic and pneumatic pump eccentrics the 743 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 26 mm width and the published 137 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI85/26-XL?",
        "a": "The NKI85/26-XL is a NKI machined-ring needle roller bearing with inner ring with 115 mm outside diameter, 85 mm bore and 26 mm width, envelope 85×115×26 mm. Mass is 743 g."
      },
      {
        "q": "What does the NKI85/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI85/26-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×115×26 mm and the catalogue ratings are C 83 kN, C0 137 kN, Cur 24.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI85/26-XL?",
        "a": "The basic dynamic load rating C is 83 kN and the basic static load rating C0 is 137 kN; the fatigue load limit Cur is 24.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI85/26-XL?",
        "a": "The limiting speed is 4,850 r/min and the thermal reference speed is 3,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI85/26-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 85 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI85-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×115×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI85-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI85-26-XL",
      "NKI85/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI85-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI85/36-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 115,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 121,
    "static_load_kN": 223,
    "fatigue_load_limit_kN": 40.5,
    "limiting_speed_rpm": 4850,
    "max_rpm": 4850,
    "reference_speed_rpm": 2950,
    "weight_g": 1040,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×115×36 mm: 85 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 121 kN and C0 223 kN at the 85 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 115 mm outside diameter the fatigue load limit Cur is 40.5 kN, the limiting speed 4,850 r/min and the thermal reference speed 2,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.42 kN/mm and per millimetre of width 3.36 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.04 kg (1040 g), just 0.25 g per mm² of projected 115×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 85 mm bore this is a heavy-industrial bearing: 1.04 kg of stiff ring and roller set, specified where rigidity matters more than speed Cur 40.5 kN, limiting speed 4,850 r/min, reference speed 2,950 r/min — the inner ring adds a few grams (total 1040 g) but removes the hardening requirement Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 121 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 85 mm bore; the 223 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 115 mm outside diameter and 121 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 85 mm seat, and in two-stroke and compressor piston pins the 1.04 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 36 mm width and the published 223 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI85/36-XL?",
        "a": "The NKI85/36-XL is a NKI machined-ring needle roller bearing with inner ring with 115 mm outside diameter, 85 mm bore and 36 mm width, envelope 85×115×36 mm. Mass is 1.04 kg."
      },
      {
        "q": "What does the NKI85/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI85/36-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×115×36 mm and the catalogue ratings are C 121 kN, C0 223 kN, Cur 40.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI85/36-XL?",
        "a": "The basic dynamic load rating C is 121 kN and the basic static load rating C0 is 223 kN; the fatigue load limit Cur is 40.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI85/36-XL?",
        "a": "The limiting speed is 4,850 r/min and the thermal reference speed is 2,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI85/36-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 85 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI85-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI85-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×115×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI85-36-XL",
      "NKI85/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4917-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4917-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 120,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 125,
    "static_load_kN": 237,
    "fatigue_load_limit_kN": 42.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2650,
    "weight_g": 1250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×120×35 mm: 85 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 85 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.47 kN/mm and per millimetre of width 3.57 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.25 kg (1250 g), just 0.30 g per mm² of projected 120×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 85 mm bore the 120 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min The 17.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Cur 42.5 kN, limiting speed 4,600 r/min, reference speed 2,650 r/min — the inner ring adds a few grams (total 1250 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 42.5 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 85 mm seat, and in two-stroke and compressor piston pins the 1.25 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 35 mm width and the published 237 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4917-XL?",
        "a": "The NA4917-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 120 mm outside diameter, 85 mm bore and 35 mm width, envelope 85×120×35 mm. Mass is 1.25 kg."
      },
      {
        "q": "What does the NA4917-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4917-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×120×35 mm and the catalogue ratings are C 125 kN, C0 237 kN, Cur 42.5 kN."
      },
      {
        "q": "What is the load capacity of the NA4917-XL?",
        "a": "The basic dynamic load rating C is 125 kN and the basic static load rating C0 is 237 kN; the fatigue load limit Cur is 42.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA4917-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4917-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 85 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4917",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×120×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4917-XL",
      "NA4917-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6917-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6917-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 120,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 188,
    "static_load_kN": 400,
    "fatigue_load_limit_kN": 72,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2700,
    "weight_g": 2200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 85×120×63 mm: 85 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 188 kN and C0 400 kN at the 85 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 72 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.21 kN/mm and per millimetre of width 2.98 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.2 kg (2200 g), just 0.29 g per mm² of projected 120×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 85 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Cur 72 kN, limiting speed 4,600 r/min, reference speed 2,700 r/min — the inner ring adds a few grams (total 2200 g) but removes the hardening requirement The 17.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 72 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 120 mm outside diameter and 188 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 85 mm seat, and in gearbox selector and change linkages the 2.2 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 63 mm width and the published 400 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6917-ZW-XL?",
        "a": "The NA6917-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 120 mm outside diameter, 85 mm bore and 63 mm width, envelope 85×120×63 mm. Mass is 2.2 kg."
      },
      {
        "q": "What does the NA6917-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6917-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 85×120×63 mm and the catalogue ratings are C 188 kN, C0 400 kN, Cur 72 kN."
      },
      {
        "q": "What is the load capacity of the NA6917-ZW-XL?",
        "a": "The basic dynamic load rating C is 188 kN and the basic static load rating C0 is 400 kN; the fatigue load limit Cur is 72 kN."
      },
      {
        "q": "What is the maximum speed of the NA6917-ZW-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6917-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 85 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6917",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 85×120×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6917-ZW-XL",
      "NA6917-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI90-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI90/26-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 120,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 86,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 25.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2950,
    "weight_g": 778,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×120×26 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 86 kN and C0 146 kN at the 90 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 25.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 3.31 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 778 g, just 0.25 g per mm² of projected 120×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Cur 25.5 kN, limiting speed 4,600 r/min, reference speed 2,950 r/min — the inner ring adds a few grams (total 778 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 146 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 86 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 120 mm outside diameter and 86 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 90 mm seat, and in rocker arms and valve trains the 778 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 26 mm width and the published 146 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI90/26-XL?",
        "a": "The NKI90/26-XL is a NKI machined-ring needle roller bearing with inner ring with 120 mm outside diameter, 90 mm bore and 26 mm width, envelope 90×120×26 mm. Mass is 778 g."
      },
      {
        "q": "What does the NKI90/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI90/26-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×120×26 mm and the catalogue ratings are C 86 kN, C0 146 kN, Cur 25.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI90/26-XL?",
        "a": "The basic dynamic load rating C is 86 kN and the basic static load rating C0 is 146 kN; the fatigue load limit Cur is 25.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI90/26-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI90/26-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 90 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI90-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×120×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI90-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI90-26-XL",
      "NKI90/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI90-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI90/36-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 120,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 125,
    "static_load_kN": 237,
    "fatigue_load_limit_kN": 42.5,
    "limiting_speed_rpm": 4600,
    "max_rpm": 4600,
    "reference_speed_rpm": 2800,
    "weight_g": 1090,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×120×36 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 90 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.39 kN/mm and per millimetre of width 3.47 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.09 kg (1090 g), just 0.25 g per mm² of projected 120×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The 15.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel This is the choice for OEM production on soft shafts: machine the 90 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 125 kN C rating and longer nominal life come without an envelope change. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 90 mm seat, and in small electric motor accessory drives the 1.09 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 36 mm width and the published 237 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI90/36-XL?",
        "a": "The NKI90/36-XL is a NKI machined-ring needle roller bearing with inner ring with 120 mm outside diameter, 90 mm bore and 36 mm width, envelope 90×120×36 mm. Mass is 1.09 kg."
      },
      {
        "q": "What does the NKI90/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI90/36-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×120×36 mm and the catalogue ratings are C 125 kN, C0 237 kN, Cur 42.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI90/36-XL?",
        "a": "The basic dynamic load rating C is 125 kN and the basic static load rating C0 is 237 kN; the fatigue load limit Cur is 42.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI90/36-XL?",
        "a": "The limiting speed is 4,600 r/min and the thermal reference speed is 2,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI90/36-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 90 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI90-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI90-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×120×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI90-36-XL",
      "NKI90/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4918-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4918-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 125,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 129,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 44.5,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2500,
    "weight_g": 1312,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×125×35 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 129 kN and C0 250 kN at the 90 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 44.5 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.43 kN/mm and per millimetre of width 3.69 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.312 kg (1312 g), just 0.30 g per mm² of projected 125×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 90 mm bore the 125 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min Cur 44.5 kN, limiting speed 4,400 r/min, reference speed 2,500 r/min — the inner ring adds a few grams (total 1312 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 44.5 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 125 mm outside diameter and 129 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 90 mm seat, and in planetary gear bearings the 1.312 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 250 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4918-XL?",
        "a": "The NA4918-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 125 mm outside diameter, 90 mm bore and 35 mm width, envelope 90×125×35 mm. Mass is 1.312 kg."
      },
      {
        "q": "What does the NA4918-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4918-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×125×35 mm and the catalogue ratings are C 129 kN, C0 250 kN, Cur 44.5 kN."
      },
      {
        "q": "What is the load capacity of the NA4918-XL?",
        "a": "The basic dynamic load rating C is 129 kN and the basic static load rating C0 is 250 kN; the fatigue load limit Cur is 44.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA4918-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4918-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 90 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4918",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×125×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4918-XL",
      "NA4918-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6918-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6918-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 125,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 195,
    "static_load_kN": 425,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2550,
    "weight_g": 2310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×125×63 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 195 kN and C0 425 kN at the 90 mm seat; the C/C0 ratio of 0.46 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.17 kN/mm and per millimetre of width 3.10 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.31 kg (2310 g), just 0.29 g per mm² of projected 125×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery This is the choice for OEM production on soft shafts: machine the 90 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 425 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 76 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 125 mm outside diameter and 195 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 90 mm seat, and in planetary gear bearings the 2.31 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 63 mm width and the published 425 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6918-ZW-XL?",
        "a": "The NA6918-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 125 mm outside diameter, 90 mm bore and 63 mm width, envelope 90×125×63 mm. Mass is 2.31 kg."
      },
      {
        "q": "What does the NA6918-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6918-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×125×63 mm and the catalogue ratings are C 195 kN, C0 425 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the NA6918-ZW-XL?",
        "a": "The basic dynamic load rating C is 195 kN and the basic static load rating C0 is 425 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the NA6918-ZW-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6918-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 90 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6918",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 90×125×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6918-ZW-XL",
      "NA6918-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI95-26-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI95/26-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 125,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 89,
    "static_load_kN": 155,
    "fatigue_load_limit_kN": 27,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2850,
    "weight_g": 816,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×125×26 mm: 95 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 89 kN and C0 155 kN at the 95 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 27 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,850 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.94 kN/mm and per millimetre of width 3.42 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 816 g, just 0.25 g per mm² of projected 125×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 95 mm bore the 125 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min This is the choice for OEM production on soft shafts: machine the 95 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway NKI95/26-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required X-life status (-XL) indicates the current Schaeffler premium execution at 95 mm bore; the 155 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 125 mm outside diameter and 89 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 95 mm seat, and in textile machine heald and cam shafts the 816 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 26 mm width and the published 155 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI95/26-XL?",
        "a": "The NKI95/26-XL is a NKI machined-ring needle roller bearing with inner ring with 125 mm outside diameter, 95 mm bore and 26 mm width, envelope 95×125×26 mm. Mass is 816 g."
      },
      {
        "q": "What does the NKI95/26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI95/26-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×125×26 mm and the catalogue ratings are C 89 kN, C0 155 kN, Cur 27 kN."
      },
      {
        "q": "What is the load capacity of the NKI95/26-XL?",
        "a": "The basic dynamic load rating C is 89 kN and the basic static load rating C0 is 155 kN; the fatigue load limit Cur is 27 kN."
      },
      {
        "q": "What is the maximum speed of the NKI95/26-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,850 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI95/26-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 95 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI95-26",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×125×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI95-36",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI95-26-XL",
      "NKI95/26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI95-36-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI95/36-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 125,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 129,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 44.5,
    "limiting_speed_rpm": 4400,
    "max_rpm": 4400,
    "reference_speed_rpm": 2700,
    "weight_g": 1145,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×125×36 mm: 95 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 129 kN and C0 250 kN at the 95 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 44.5 kN, the limiting speed 4,400 r/min and the thermal reference speed 2,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.36 kN/mm and per millimetre of width 3.58 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.145 kg (1145 g), just 0.25 g per mm² of projected 125×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 95 mm bore the 125 mm outside diameter and 36 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 129 kN C The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 250 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 44.5 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 125 mm outside diameter and 129 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 95 mm seat, and in small electric motor accessory drives the 1.145 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 36 mm width and the published 250 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI95/36-XL?",
        "a": "The NKI95/36-XL is a NKI machined-ring needle roller bearing with inner ring with 125 mm outside diameter, 95 mm bore and 36 mm width, envelope 95×125×36 mm. Mass is 1.145 kg."
      },
      {
        "q": "What does the NKI95/36-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI95/36-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×125×36 mm and the catalogue ratings are C 129 kN, C0 250 kN, Cur 44.5 kN."
      },
      {
        "q": "What is the load capacity of the NKI95/36-XL?",
        "a": "The basic dynamic load rating C is 129 kN and the basic static load rating C0 is 250 kN; the fatigue load limit Cur is 44.5 kN."
      },
      {
        "q": "What is the maximum speed of the NKI95/36-XL?",
        "a": "The limiting speed is 4,400 r/min and the thermal reference speed is 2,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI95/36-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 95 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI95-26",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI95-36",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×125×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI95-36-XL",
      "NKI95/36-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4919-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4919-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 130,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 131,
    "static_load_kN": 260,
    "fatigue_load_limit_kN": 45,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2400,
    "weight_g": 1371,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×130×35 mm: 95 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 131 kN and C0 260 kN at the 95 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 45 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.38 kN/mm and per millimetre of width 3.74 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.371 kg (1371 g), just 0.30 g per mm² of projected 130×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 95 mm bore the 130 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,200 r/min The integral inner ring brings the bore to 95 mm inside the 130×35 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 131 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 131 kN C rating and longer nominal life come without an envelope change. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 130 mm outside diameter and 131 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 95 mm seat, and in motorcycle and light-vehicle transmissions the 1.371 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 35 mm width and the published 260 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4919-XL?",
        "a": "The NA4919-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 130 mm outside diameter, 95 mm bore and 35 mm width, envelope 95×130×35 mm. Mass is 1.371 kg."
      },
      {
        "q": "What does the NA4919-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4919-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×130×35 mm and the catalogue ratings are C 131 kN, C0 260 kN, Cur 45 kN."
      },
      {
        "q": "What is the load capacity of the NA4919-XL?",
        "a": "The basic dynamic load rating C is 131 kN and the basic static load rating C0 is 260 kN; the fatigue load limit Cur is 45 kN."
      },
      {
        "q": "What is the maximum speed of the NA4919-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4919-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 95 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4919",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×130×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4919-XL",
      "NA4919-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6919-ZW-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA6919-ZW-XL",
    "series": "na69-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 130,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 197,
    "static_load_kN": 440,
    "fatigue_load_limit_kN": 77,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2440,
    "weight_g": 2500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 95×130×63 mm: 95 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 197 kN and C0 440 kN at the 95 mm seat; the C/C0 ratio of 0.45 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 77 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,440 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.07 kN/mm and per millimetre of width 3.13 kN/mm — the reason 63 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.5 kg (2500 g), just 0.31 g per mm² of projected 130×63 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 95 mm bore this is a heavy-industrial bearing: 2.5 kg of stiff ring and roller set, specified where rigidity matters more than speed The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 440 kN C0 rating still assumes full rigid support under both rings Cur 77 kN, limiting speed 4,200 r/min, reference speed 2,440 r/min — the inner ring adds a few grams (total 2500 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 77 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 130 mm outside diameter and 197 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 95 mm seat, and in rocker arms and valve trains the 2.5 kg mass is part of the rotor inertia calculation. Designers also specify it for planetary gear bearings, relying on the 63 mm width and the published 440 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA6919-ZW-XL?",
        "a": "The NA6919-ZW-XL is a NA69 double-row dimension-series 69 needle roller bearing with inner ring with 130 mm outside diameter, 95 mm bore and 63 mm width, envelope 95×130×63 mm. Mass is 2.5 kg."
      },
      {
        "q": "What does the NA6919-ZW-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA6919-ZW-XL identifies this NA69 double-row dimension-series 69 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 95×130×63 mm and the catalogue ratings are C 197 kN, C0 440 kN, Cur 77 kN."
      },
      {
        "q": "What is the load capacity of the NA6919-ZW-XL?",
        "a": "The basic dynamic load rating C is 197 kN and the basic static load rating C0 is 440 kN; the fatigue load limit Cur is 77 kN."
      },
      {
        "q": "What is the maximum speed of the NA6919-ZW-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,440 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA6919-ZW-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 95 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6919",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 95×130×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=962",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6919-ZW-XL",
      "NA6919-ZW-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI100-30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI100/30-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 130,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 111,
    "static_load_kN": 210,
    "fatigue_load_limit_kN": 36,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2650,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×130×30 mm: 100 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 111 kN and C0 210 kN at the 100 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 36 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.11 kN/mm and per millimetre of width 3.70 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 990 g, just 0.25 g per mm² of projected 130×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 100 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NKI100/30-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 210 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 111 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 130 mm outside diameter and 111 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 100 mm seat, and in hydraulic and pneumatic pump eccentrics the 990 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 30 mm width and the published 210 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI100/30-XL?",
        "a": "The NKI100/30-XL is a NKI machined-ring needle roller bearing with inner ring with 130 mm outside diameter, 100 mm bore and 30 mm width, envelope 100×130×30 mm. Mass is 990 g."
      },
      {
        "q": "What does the NKI100/30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI100/30-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×130×30 mm and the catalogue ratings are C 111 kN, C0 210 kN, Cur 36 kN."
      },
      {
        "q": "What is the load capacity of the NKI100/30-XL?",
        "a": "The basic dynamic load rating C is 111 kN and the basic static load rating C0 is 210 kN; the fatigue load limit Cur is 36 kN."
      },
      {
        "q": "What is the maximum speed of the NKI100/30-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI100/30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 100 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI100-30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×130×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI100-40",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI100-30-XL",
      "NKI100/30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI100-40-XL",
    "brand": "FAG",
    "manufacturer_designation": "NKI100/40-XL",
    "series": "nki-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 130,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 143,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 51,
    "limiting_speed_rpm": 4200,
    "max_rpm": 4200,
    "reference_speed_rpm": 2600,
    "weight_g": 1330,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×130×40 mm: 100 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 143 kN and C0 290 kN at the 100 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 51 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.43 kN/mm and per millimetre of width 3.58 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.33 kg (1330 g), just 0.26 g per mm² of projected 130×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 100 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NKI100/40-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 143 kN C The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 100×130×40 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 130 mm outside diameter and 143 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 100 mm seat, and in two-stroke and compressor piston pins the 1.33 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 40 mm width and the published 290 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NKI100/40-XL?",
        "a": "The NKI100/40-XL is a NKI machined-ring needle roller bearing with inner ring with 130 mm outside diameter, 100 mm bore and 40 mm width, envelope 100×130×40 mm. Mass is 1.33 kg."
      },
      {
        "q": "What does the NKI100/40-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NKI100/40-XL identifies this NKI machined-ring needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×130×40 mm and the catalogue ratings are C 143 kN, C0 290 kN, Cur 51 kN."
      },
      {
        "q": "What is the load capacity of the NKI100/40-XL?",
        "a": "The basic dynamic load rating C is 143 kN and the basic static load rating C0 is 290 kN; the fatigue load limit Cur is 51 kN."
      },
      {
        "q": "What is the maximum speed of the NKI100/40-XL?",
        "a": "The limiting speed is 4,200 r/min and the thermal reference speed is 2,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NKI100/40-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 100 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI100-30",
        "equiv_brand": "SKF",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI100-40",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×130×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI100-40-XL",
      "NKI100/40-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4920-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4920-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 140,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 144,
    "static_load_kN": 270,
    "fatigue_load_limit_kN": 46,
    "limiting_speed_rpm": 4000,
    "max_rpm": 4000,
    "reference_speed_rpm": 2550,
    "weight_g": 1900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×140×40 mm: 100 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 20.0 mm radial section packed with small-diameter needle rollers C is 144 kN and C0 270 kN at the 100 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 140 mm outside diameter the fatigue load limit Cur is 46 kN, the limiting speed 4,000 r/min and the thermal reference speed 2,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.44 kN/mm and per millimetre of width 3.60 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.9 kg (1900 g), just 0.34 g per mm² of projected 140×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 100 mm bore this is a heavy-industrial bearing: 1.9 kg of stiff ring and roller set, specified where rigidity matters more than speed The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 270 kN C0 rating still assumes full rigid support under both rings The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 4,000 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 140 mm outside diameter and 144 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 100 mm seat, and in hydraulic and pneumatic pump eccentrics the 1.9 kg mass is part of the rotor inertia calculation. Designers also specify it for textile machine heald and cam shafts, relying on the 40 mm width and the published 270 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4920-XL?",
        "a": "The NA4920-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 140 mm outside diameter, 100 mm bore and 40 mm width, envelope 100×140×40 mm. Mass is 1.9 kg."
      },
      {
        "q": "What does the NA4920-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4920-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×140×40 mm and the catalogue ratings are C 144 kN, C0 270 kN, Cur 46 kN."
      },
      {
        "q": "What is the load capacity of the NA4920-XL?",
        "a": "The basic dynamic load rating C is 144 kN and the basic static load rating C0 is 270 kN; the fatigue load limit Cur is 46 kN."
      },
      {
        "q": "What is the maximum speed of the NA4920-XL?",
        "a": "The limiting speed is 4,000 r/min and the thermal reference speed is 2,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4920-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 100 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4920",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 100×140×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4920-XL",
      "NA4920-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4922-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4922-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 150,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 149,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 48,
    "limiting_speed_rpm": 3700,
    "max_rpm": 3700,
    "reference_speed_rpm": 2330,
    "weight_g": 2070,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×150×40 mm: 110 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 20.0 mm radial section packed with small-diameter needle rollers C is 149 kN and C0 290 kN at the 110 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 150 mm outside diameter the fatigue load limit Cur is 48 kN, the limiting speed 3,700 r/min and the thermal reference speed 2,330 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.35 kN/mm and per millimetre of width 3.73 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.07 kg (2070 g), just 0.34 g per mm² of projected 150×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 110 mm bore this is a heavy-industrial bearing: 2.07 kg of stiff ring and roller set, specified where rigidity matters more than speed The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 290 kN C0 rating still assumes full rigid support under both rings The 20.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel X-life status (-XL) indicates the current Schaeffler premium execution at 110 mm bore; the 290 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 150 mm outside diameter and 149 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 110 mm seat, and in copying and printing machine mechanisms the 2.07 kg mass is part of the rotor inertia calculation. Designers also specify it for agricultural machine pivots and linkages, relying on the 40 mm width and the published 290 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4922-XL?",
        "a": "The NA4922-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 150 mm outside diameter, 110 mm bore and 40 mm width, envelope 110×150×40 mm. Mass is 2.07 kg."
      },
      {
        "q": "What does the NA4922-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4922-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×150×40 mm and the catalogue ratings are C 149 kN, C0 290 kN, Cur 48 kN."
      },
      {
        "q": "What is the load capacity of the NA4922-XL?",
        "a": "The basic dynamic load rating C is 149 kN and the basic static load rating C0 is 290 kN; the fatigue load limit Cur is 48 kN."
      },
      {
        "q": "What is the maximum speed of the NA4922-XL?",
        "a": "The limiting speed is 3,700 r/min and the thermal reference speed is 2,330 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4922-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 110 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4922",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×150×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4922-XL",
      "NA4922-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4822-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4822-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 140,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 106,
    "static_load_kN": 216,
    "fatigue_load_limit_kN": 36.5,
    "limiting_speed_rpm": 3900,
    "max_rpm": 3900,
    "reference_speed_rpm": 2270,
    "weight_g": 1080,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 110×140×30 mm: 110 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 106 kN and C0 216 kN at the 110 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 140 mm outside diameter the fatigue load limit Cur is 36.5 kN, the limiting speed 3,900 r/min and the thermal reference speed 2,270 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.96 kN/mm and per millimetre of width 3.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.08 kg (1080 g), just 0.26 g per mm² of projected 140×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 110 mm bore the 140 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 3,900 r/min Cur 36.5 kN, limiting speed 3,900 r/min, reference speed 2,270 r/min — the inner ring adds a few grams (total 1080 g) but removes the hardening requirement Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 106 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 106 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 140 mm outside diameter and 106 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 110 mm seat, and in copying and printing machine mechanisms the 1.08 kg mass is part of the rotor inertia calculation. Designers also specify it for agricultural machine pivots and linkages, relying on the 30 mm width and the published 216 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4822-XL?",
        "a": "The NA4822-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 140 mm outside diameter, 110 mm bore and 30 mm width, envelope 110×140×30 mm. Mass is 1.08 kg."
      },
      {
        "q": "What does the NA4822-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4822-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 110×140×30 mm and the catalogue ratings are C 106 kN, C0 216 kN, Cur 36.5 kN."
      },
      {
        "q": "What is the load capacity of the NA4822-XL?",
        "a": "The basic dynamic load rating C is 106 kN and the basic static load rating C0 is 216 kN; the fatigue load limit Cur is 36.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA4822-XL?",
        "a": "The limiting speed is 3,900 r/min and the thermal reference speed is 2,270 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4822-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 110 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4822",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 110×140×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4822-XL",
      "NA4822-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4924-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4924-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 165,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 205,
    "static_load_kN": 390,
    "fatigue_load_limit_kN": 65,
    "limiting_speed_rpm": 3400,
    "max_rpm": 3400,
    "reference_speed_rpm": 2160,
    "weight_g": 2860,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 120×165×45 mm: 120 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 22.5 mm radial section packed with small-diameter needle rollers C is 205 kN and C0 390 kN at the 120 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 165 mm outside diameter the fatigue load limit Cur is 65 kN, the limiting speed 3,400 r/min and the thermal reference speed 2,160 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.71 kN/mm and per millimetre of width 4.56 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.86 kg (2860 g), just 0.39 g per mm² of projected 165×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 120 mm bore the 165 mm outside diameter and 45 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 3,400 r/min The 22.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel This is the choice for OEM production on soft shafts: machine the 120 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 65 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 165 mm outside diameter and 205 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 120 mm seat, and in planetary gear bearings the 2.86 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 45 mm width and the published 390 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4924-XL?",
        "a": "The NA4924-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 165 mm outside diameter, 120 mm bore and 45 mm width, envelope 120×165×45 mm. Mass is 2.86 kg."
      },
      {
        "q": "What does the NA4924-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4924-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 120×165×45 mm and the catalogue ratings are C 205 kN, C0 390 kN, Cur 65 kN."
      },
      {
        "q": "What is the load capacity of the NA4924-XL?",
        "a": "The basic dynamic load rating C is 205 kN and the basic static load rating C0 is 390 kN; the fatigue load limit Cur is 65 kN."
      },
      {
        "q": "What is the maximum speed of the NA4924-XL?",
        "a": "The limiting speed is 3,400 r/min and the thermal reference speed is 2,160 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4924-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 120 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4924",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 120×165×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4924-XL",
      "NA4924-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4824-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4824-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 150,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 112,
    "static_load_kN": 239,
    "fatigue_load_limit_kN": 39.5,
    "limiting_speed_rpm": 3600,
    "max_rpm": 3600,
    "reference_speed_rpm": 2070,
    "weight_g": 1170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 120×150×30 mm: 120 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 112 kN and C0 239 kN at the 120 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 150 mm outside diameter the fatigue load limit Cur is 39.5 kN, the limiting speed 3,600 r/min and the thermal reference speed 2,070 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 3.73 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.17 kg (1170 g), just 0.26 g per mm² of projected 150×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 120 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 239 kN C0 rating still assumes full rigid support under both rings Cur 39.5 kN, limiting speed 3,600 r/min, reference speed 2,070 r/min — the inner ring adds a few grams (total 1170 g) but removes the hardening requirement The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 120×150×30 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 150 mm outside diameter and 112 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 120 mm seat, and in planetary gear bearings the 1.17 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 30 mm width and the published 239 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4824-XL?",
        "a": "The NA4824-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 150 mm outside diameter, 120 mm bore and 30 mm width, envelope 120×150×30 mm. Mass is 1.17 kg."
      },
      {
        "q": "What does the NA4824-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4824-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 120×150×30 mm and the catalogue ratings are C 112 kN, C0 239 kN, Cur 39.5 kN."
      },
      {
        "q": "What is the load capacity of the NA4824-XL?",
        "a": "The basic dynamic load rating C is 112 kN and the basic static load rating C0 is 239 kN; the fatigue load limit Cur is 39.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA4824-XL?",
        "a": "The limiting speed is 3,600 r/min and the thermal reference speed is 2,070 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4824-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 120 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4824",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 120×150×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4824-XL",
      "NA4824-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4926-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4926-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 180,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 229,
    "static_load_kN": 470,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 3100,
    "max_rpm": 3100,
    "reference_speed_rpm": 2000,
    "weight_g": 3900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 130×180×50 mm: 130 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 229 kN and C0 470 kN at the 130 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 180 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 3,100 r/min and the thermal reference speed 2,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.76 kN/mm and per millimetre of width 4.58 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.9 kg (3900 g), just 0.43 g per mm² of projected 180×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 130 mm bore this is among the largest catalogue sizes; the 3,100 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The integral inner ring brings the bore to 130 mm inside the 180×50 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Cur 76 kN, limiting speed 3,100 r/min, reference speed 2,000 r/min — the inner ring adds a few grams (total 3900 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 76 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 180 mm outside diameter and 229 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 130 mm seat, and in connecting-rod small ends the 3.9 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 50 mm width and the published 470 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4926-XL?",
        "a": "The NA4926-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 180 mm outside diameter, 130 mm bore and 50 mm width, envelope 130×180×50 mm. Mass is 3.9 kg."
      },
      {
        "q": "What does the NA4926-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4926-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 130×180×50 mm and the catalogue ratings are C 229 kN, C0 470 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the NA4926-XL?",
        "a": "The basic dynamic load rating C is 229 kN and the basic static load rating C0 is 470 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the NA4926-XL?",
        "a": "The limiting speed is 3,100 r/min and the thermal reference speed is 2,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4926-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 130 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4926",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 130×180×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4926-XL",
      "NA4926-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4826-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4826-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 165,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 134,
    "static_load_kN": 310,
    "fatigue_load_limit_kN": 49.5,
    "limiting_speed_rpm": 3250,
    "max_rpm": 3250,
    "reference_speed_rpm": 1930,
    "weight_g": 1810,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 130×165×35 mm: 130 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 134 kN and C0 310 kN at the 130 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 165 mm outside diameter the fatigue load limit Cur is 49.5 kN, the limiting speed 3,250 r/min and the thermal reference speed 1,930 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 3.83 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.81 kg (1810 g), just 0.31 g per mm² of projected 165×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 130 mm bore puts this execution at the top of the HR1 range — the 165 mm outside diameter, 35 mm width and 1.81 kg mass are built for primary-industry load cases The 17.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Cur 49.5 kN, limiting speed 3,250 r/min, reference speed 1,930 r/min — the inner ring adds a few grams (total 1810 g) but removes the hardening requirement The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 130×165×35 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 165 mm outside diameter and 134 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 130 mm seat, and in connecting-rod small ends the 1.81 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 35 mm width and the published 310 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4826-XL?",
        "a": "The NA4826-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 165 mm outside diameter, 130 mm bore and 35 mm width, envelope 130×165×35 mm. Mass is 1.81 kg."
      },
      {
        "q": "What does the NA4826-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4826-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 130×165×35 mm and the catalogue ratings are C 134 kN, C0 310 kN, Cur 49.5 kN."
      },
      {
        "q": "What is the load capacity of the NA4826-XL?",
        "a": "The basic dynamic load rating C is 134 kN and the basic static load rating C0 is 310 kN; the fatigue load limit Cur is 49.5 kN."
      },
      {
        "q": "What is the maximum speed of the NA4826-XL?",
        "a": "The limiting speed is 3,250 r/min and the thermal reference speed is 1,930 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4826-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 130 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4826",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 130×165×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4826-XL",
      "NA4826-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4928-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4928-XL",
    "series": "na49-series",
    "type": "needle",
    "d_mm": 140,
    "D_mm": 190,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 237,
    "static_load_kN": 500,
    "fatigue_load_limit_kN": 79,
    "limiting_speed_rpm": 2900,
    "max_rpm": 2900,
    "reference_speed_rpm": 1860,
    "weight_g": 4150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 140×190×50 mm: 140 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 237 kN and C0 500 kN at the 140 mm seat; the C/C0 ratio of 0.47 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 190 mm outside diameter the fatigue load limit Cur is 79 kN, the limiting speed 2,900 r/min and the thermal reference speed 1,860 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.69 kN/mm and per millimetre of width 4.74 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 4.15 kg (4150 g), just 0.44 g per mm² of projected 190×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 140 mm bore this is among the largest catalogue sizes; the 2,900 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 500 kN C0 rating still assumes full rigid support under both rings Reading the NA49 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 237 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 237 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 190 mm outside diameter and 237 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 140 mm seat, and in textile machine heald and cam shafts the 4.15 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 50 mm width and the published 500 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4928-XL?",
        "a": "The NA4928-XL is a NA49 dimension-series 49 needle roller bearing with inner ring with 190 mm outside diameter, 140 mm bore and 50 mm width, envelope 140×190×50 mm. Mass is 4.15 kg."
      },
      {
        "q": "What does the NA4928-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4928-XL identifies this NA49 dimension-series 49 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 140×190×50 mm and the catalogue ratings are C 237 kN, C0 500 kN, Cur 79 kN."
      },
      {
        "q": "What is the load capacity of the NA4928-XL?",
        "a": "The basic dynamic load rating C is 237 kN and the basic static load rating C0 is 500 kN; the fatigue load limit Cur is 79 kN."
      },
      {
        "q": "What is the maximum speed of the NA4928-XL?",
        "a": "The limiting speed is 2,900 r/min and the thermal reference speed is 1,860 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4928-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 140 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4928",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 140×190×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4928-XL",
      "NA4928-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4828-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4828-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 140,
    "D_mm": 175,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 136,
    "static_load_kN": 325,
    "fatigue_load_limit_kN": 51,
    "limiting_speed_rpm": 3050,
    "max_rpm": 3050,
    "reference_speed_rpm": 1810,
    "weight_g": 1920,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 140×175×35 mm: 140 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 136 kN and C0 325 kN at the 140 mm seat; the C/C0 ratio of 0.42 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 175 mm outside diameter the fatigue load limit Cur is 51 kN, the limiting speed 3,050 r/min and the thermal reference speed 1,810 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.97 kN/mm and per millimetre of width 3.89 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.92 kg (1920 g), just 0.31 g per mm² of projected 175×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 140 mm bore puts this execution at the top of the HR1 range — the 175 mm outside diameter, 35 mm width and 1.92 kg mass are built for primary-industry load cases The integral inner ring brings the bore to 140 mm inside the 175×35 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 136 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 3,050 r/min limit. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 175 mm outside diameter and 136 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 140 mm seat, and in textile machine heald and cam shafts the 1.92 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 35 mm width and the published 325 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4828-XL?",
        "a": "The NA4828-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 175 mm outside diameter, 140 mm bore and 35 mm width, envelope 140×175×35 mm. Mass is 1.92 kg."
      },
      {
        "q": "What does the NA4828-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4828-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 140×175×35 mm and the catalogue ratings are C 136 kN, C0 325 kN, Cur 51 kN."
      },
      {
        "q": "What is the load capacity of the NA4828-XL?",
        "a": "The basic dynamic load rating C is 136 kN and the basic static load rating C0 is 325 kN; the fatigue load limit Cur is 51 kN."
      },
      {
        "q": "What is the maximum speed of the NA4828-XL?",
        "a": "The limiting speed is 3,050 r/min and the thermal reference speed is 1,810 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4828-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 140 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4828",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 140×175×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4828-XL",
      "NA4828-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4830-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4830-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 150,
    "D_mm": 190,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 172,
    "static_load_kN": 400,
    "fatigue_load_limit_kN": 63,
    "limiting_speed_rpm": 2850,
    "max_rpm": 2850,
    "reference_speed_rpm": 1780,
    "weight_g": 2720,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 150×190×40 mm: 150 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 20.0 mm radial section packed with small-diameter needle rollers C is 172 kN and C0 400 kN at the 150 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 190 mm outside diameter the fatigue load limit Cur is 63 kN, the limiting speed 2,850 r/min and the thermal reference speed 1,780 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.15 kN/mm and per millimetre of width 4.30 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.72 kg (2720 g), just 0.36 g per mm² of projected 190×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 150 mm bore this is among the largest catalogue sizes; the 2,850 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The integral inner ring brings the bore to 150 mm inside the 190×40 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 172 kN C -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 172 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 190 mm outside diameter and 172 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 150 mm seat, and in two-stroke and compressor piston pins the 2.72 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 40 mm width and the published 400 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4830-XL?",
        "a": "The NA4830-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 190 mm outside diameter, 150 mm bore and 40 mm width, envelope 150×190×40 mm. Mass is 2.72 kg."
      },
      {
        "q": "What does the NA4830-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4830-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 150×190×40 mm and the catalogue ratings are C 172 kN, C0 400 kN, Cur 63 kN."
      },
      {
        "q": "What is the load capacity of the NA4830-XL?",
        "a": "The basic dynamic load rating C is 172 kN and the basic static load rating C0 is 400 kN; the fatigue load limit Cur is 63 kN."
      },
      {
        "q": "What is the maximum speed of the NA4830-XL?",
        "a": "The limiting speed is 2,850 r/min and the thermal reference speed is 1,780 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4830-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 150 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4830",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 150×190×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4830-XL",
      "NA4830-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4832-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4832-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 160,
    "D_mm": 200,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 181,
    "static_load_kN": 435,
    "fatigue_load_limit_kN": 67,
    "limiting_speed_rpm": 2700,
    "max_rpm": 2700,
    "reference_speed_rpm": 1650,
    "weight_g": 2890,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 160×200×40 mm: 160 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 20.0 mm radial section packed with small-diameter needle rollers C is 181 kN and C0 435 kN at the 160 mm seat; the C/C0 ratio of 0.42 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 200 mm outside diameter the fatigue load limit Cur is 67 kN, the limiting speed 2,700 r/min and the thermal reference speed 1,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.13 kN/mm and per millimetre of width 4.53 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.89 kg (2890 g), just 0.36 g per mm² of projected 200×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 160 mm bore this is among the largest catalogue sizes; the 2,700 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The integral inner ring brings the bore to 160 mm inside the 200×40 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing This is the choice for OEM production on soft shafts: machine the 160 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 160×200×40 mm envelope. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 200 mm outside diameter and 181 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 160 mm seat, and in motorcycle and light-vehicle transmissions the 2.89 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 40 mm width and the published 435 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4832-XL?",
        "a": "The NA4832-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 200 mm outside diameter, 160 mm bore and 40 mm width, envelope 160×200×40 mm. Mass is 2.89 kg."
      },
      {
        "q": "What does the NA4832-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4832-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 160×200×40 mm and the catalogue ratings are C 181 kN, C0 435 kN, Cur 67 kN."
      },
      {
        "q": "What is the load capacity of the NA4832-XL?",
        "a": "The basic dynamic load rating C is 181 kN and the basic static load rating C0 is 435 kN; the fatigue load limit Cur is 67 kN."
      },
      {
        "q": "What is the maximum speed of the NA4832-XL?",
        "a": "The limiting speed is 2,700 r/min and the thermal reference speed is 1,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4832-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 160 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4832",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 160×200×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4832-XL",
      "NA4832-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4834-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4834-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 170,
    "D_mm": 215,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 209,
    "static_load_kN": 510,
    "fatigue_load_limit_kN": 76,
    "limiting_speed_rpm": 2550,
    "max_rpm": 2550,
    "reference_speed_rpm": 1610,
    "weight_g": 3960,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 170×215×45 mm: 170 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 22.5 mm radial section packed with small-diameter needle rollers C is 209 kN and C0 510 kN at the 170 mm seat; the C/C0 ratio of 0.41 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 215 mm outside diameter the fatigue load limit Cur is 76 kN, the limiting speed 2,550 r/min and the thermal reference speed 1,610 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.23 kN/mm and per millimetre of width 4.64 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3.96 kg (3960 g), just 0.41 g per mm² of projected 215×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 170 mm bore puts this execution at the top of the HR1 range — the 215 mm outside diameter, 45 mm width and 3.96 kg mass are built for primary-industry load cases This is the choice for OEM production on soft shafts: machine the 170 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway The 22.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 170×215×45 mm envelope. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 215 mm outside diameter and 209 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 170 mm seat, and in gearbox selector and change linkages the 3.96 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 45 mm width and the published 510 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4834-XL?",
        "a": "The NA4834-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 215 mm outside diameter, 170 mm bore and 45 mm width, envelope 170×215×45 mm. Mass is 3.96 kg."
      },
      {
        "q": "What does the NA4834-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4834-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 170×215×45 mm and the catalogue ratings are C 209 kN, C0 510 kN, Cur 76 kN."
      },
      {
        "q": "What is the load capacity of the NA4834-XL?",
        "a": "The basic dynamic load rating C is 209 kN and the basic static load rating C0 is 510 kN; the fatigue load limit Cur is 76 kN."
      },
      {
        "q": "What is the maximum speed of the NA4834-XL?",
        "a": "The limiting speed is 2,550 r/min and the thermal reference speed is 1,610 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4834-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 170 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4834",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 170×215×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4834-XL",
      "NA4834-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4836-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4836-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 180,
    "D_mm": 225,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 219,
    "static_load_kN": 550,
    "fatigue_load_limit_kN": 81,
    "limiting_speed_rpm": 2420,
    "max_rpm": 2420,
    "reference_speed_rpm": 1490,
    "weight_g": 4200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 180×225×45 mm: 180 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 22.5 mm radial section packed with small-diameter needle rollers C is 219 kN and C0 550 kN at the 180 mm seat; the C/C0 ratio of 0.40 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 225 mm outside diameter the fatigue load limit Cur is 81 kN, the limiting speed 2,420 r/min and the thermal reference speed 1,490 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.22 kN/mm and per millimetre of width 4.87 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 4.2 kg (4200 g), just 0.41 g per mm² of projected 225×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 180 mm bore puts this execution at the top of the HR1 range — the 225 mm outside diameter, 45 mm width and 4.2 kg mass are built for primary-industry load cases Cur 81 kN, limiting speed 2,420 r/min, reference speed 1,490 r/min — the inner ring adds a few grams (total 4200 g) but removes the hardening requirement The integral inner ring brings the bore to 180 mm inside the 225×45 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 2,420 r/min limit. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 225 mm outside diameter and 219 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 180 mm seat, and in planetary gear bearings the 4.2 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 45 mm width and the published 550 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4836-XL?",
        "a": "The NA4836-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 225 mm outside diameter, 180 mm bore and 45 mm width, envelope 180×225×45 mm. Mass is 4.2 kg."
      },
      {
        "q": "What does the NA4836-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4836-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 180×225×45 mm and the catalogue ratings are C 219 kN, C0 550 kN, Cur 81 kN."
      },
      {
        "q": "What is the load capacity of the NA4836-XL?",
        "a": "The basic dynamic load rating C is 219 kN and the basic static load rating C0 is 550 kN; the fatigue load limit Cur is 81 kN."
      },
      {
        "q": "What is the maximum speed of the NA4836-XL?",
        "a": "The limiting speed is 2,420 r/min and the thermal reference speed is 1,490 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4836-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 180 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4836",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 180×225×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4836-XL",
      "NA4836-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4838-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4838-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 190,
    "D_mm": 240,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 255,
    "static_load_kN": 690,
    "fatigue_load_limit_kN": 102,
    "limiting_speed_rpm": 2250,
    "max_rpm": 2250,
    "reference_speed_rpm": 1330,
    "weight_g": 5610,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 190×240×50 mm: 190 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 255 kN and C0 690 kN at the 190 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 240 mm outside diameter the fatigue load limit Cur is 102 kN, the limiting speed 2,250 r/min and the thermal reference speed 1,330 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.34 kN/mm and per millimetre of width 5.10 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.61 kg (5610 g), just 0.47 g per mm² of projected 240×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 190 mm bore puts this execution at the top of the HR1 range — the 240 mm outside diameter, 50 mm width and 5.61 kg mass are built for primary-industry load cases This is the choice for OEM production on soft shafts: machine the 190 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway X-life status (-XL) indicates the current Schaeffler premium execution at 190 mm bore; the 690 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 240 mm outside diameter and 255 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 190 mm seat, and in small electric motor accessory drives the 5.61 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 50 mm width and the published 690 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4838-XL?",
        "a": "The NA4838-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 240 mm outside diameter, 190 mm bore and 50 mm width, envelope 190×240×50 mm. Mass is 5.61 kg."
      },
      {
        "q": "What does the NA4838-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4838-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 190×240×50 mm and the catalogue ratings are C 255 kN, C0 690 kN, Cur 102 kN."
      },
      {
        "q": "What is the load capacity of the NA4838-XL?",
        "a": "The basic dynamic load rating C is 255 kN and the basic static load rating C0 is 690 kN; the fatigue load limit Cur is 102 kN."
      },
      {
        "q": "What is the maximum speed of the NA4838-XL?",
        "a": "The limiting speed is 2,250 r/min and the thermal reference speed is 1,330 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4838-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 190 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4838",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 190×240×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4838-XL",
      "NA4838-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4840-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4840-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 200,
    "D_mm": 250,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 260,
    "static_load_kN": 720,
    "fatigue_load_limit_kN": 104,
    "limiting_speed_rpm": 2150,
    "max_rpm": 2150,
    "reference_speed_rpm": 1250,
    "weight_g": 5840,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 200×250×50 mm: 200 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 260 kN and C0 720 kN at the 200 mm seat; the C/C0 ratio of 0.36 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 250 mm outside diameter the fatigue load limit Cur is 104 kN, the limiting speed 2,150 r/min and the thermal reference speed 1,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.30 kN/mm and per millimetre of width 5.20 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 5.84 kg (5840 g), just 0.47 g per mm² of projected 250×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 200 mm bore this is among the largest catalogue sizes; the 2,150 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 720 kN C0 rating still assumes full rigid support under both rings The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 200×250×50 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 250 mm outside diameter and 260 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 200 mm seat, and in copying and printing machine mechanisms the 5.84 kg mass is part of the rotor inertia calculation. Designers also specify it for agricultural machine pivots and linkages, relying on the 50 mm width and the published 720 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4840-XL?",
        "a": "The NA4840-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 250 mm outside diameter, 200 mm bore and 50 mm width, envelope 200×250×50 mm. Mass is 5.84 kg."
      },
      {
        "q": "What does the NA4840-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4840-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 200×250×50 mm and the catalogue ratings are C 260 kN, C0 720 kN, Cur 104 kN."
      },
      {
        "q": "What is the load capacity of the NA4840-XL?",
        "a": "The basic dynamic load rating C is 260 kN and the basic static load rating C0 is 720 kN; the fatigue load limit Cur is 104 kN."
      },
      {
        "q": "What is the maximum speed of the NA4840-XL?",
        "a": "The limiting speed is 2,150 r/min and the thermal reference speed is 1,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4840-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 200 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4840",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 200×250×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4840-XL",
      "NA4840-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4844-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4844-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 220,
    "D_mm": 270,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 275,
    "static_load_kN": 790,
    "fatigue_load_limit_kN": 112,
    "limiting_speed_rpm": 1980,
    "max_rpm": 1980,
    "reference_speed_rpm": 1110,
    "weight_g": 6380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 220×270×50 mm: 220 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 25.0 mm radial section packed with small-diameter needle rollers C is 275 kN and C0 790 kN at the 220 mm seat; the C/C0 ratio of 0.35 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 270 mm outside diameter the fatigue load limit Cur is 112 kN, the limiting speed 1,980 r/min and the thermal reference speed 1,110 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.25 kN/mm and per millimetre of width 5.50 kN/mm — the reason 50 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 6.38 kg (6380 g), just 0.47 g per mm² of projected 270×50 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 220 mm bore this is among the largest catalogue sizes; the 1,980 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position Cur 112 kN, limiting speed 1,980 r/min, reference speed 1,110 r/min — the inner ring adds a few grams (total 6380 g) but removes the hardening requirement The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 1,980 r/min limit. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 270 mm outside diameter and 275 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 220 mm seat, and in motorcycle and light-vehicle transmissions the 6.38 kg mass is part of the rotor inertia calculation. Designers also specify it for rocker arms and valve trains, relying on the 50 mm width and the published 790 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4844-XL?",
        "a": "The NA4844-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 270 mm outside diameter, 220 mm bore and 50 mm width, envelope 220×270×50 mm. Mass is 6.38 kg."
      },
      {
        "q": "What does the NA4844-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4844-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 220×270×50 mm and the catalogue ratings are C 275 kN, C0 790 kN, Cur 112 kN."
      },
      {
        "q": "What is the load capacity of the NA4844-XL?",
        "a": "The basic dynamic load rating C is 275 kN and the basic static load rating C0 is 790 kN; the fatigue load limit Cur is 112 kN."
      },
      {
        "q": "What is the maximum speed of the NA4844-XL?",
        "a": "The limiting speed is 1,980 r/min and the thermal reference speed is 1,110 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4844-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 220 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4844",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 220×270×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4844-XL",
      "NA4844-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4848-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4848-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 240,
    "D_mm": 300,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 400,
    "static_load_kN": 1080,
    "fatigue_load_limit_kN": 153,
    "limiting_speed_rpm": 1780,
    "max_rpm": 1780,
    "reference_speed_rpm": 960,
    "weight_g": 10000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 240×300×60 mm: 240 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 30.0 mm radial section packed with small-diameter needle rollers C is 400 kN and C0 1080 kN at the 240 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 300 mm outside diameter the fatigue load limit Cur is 153 kN, the limiting speed 1,780 r/min and the thermal reference speed 960 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.67 kN/mm and per millimetre of width 6.67 kN/mm — the reason 60 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 10 kg (10000 g), just 0.56 g per mm² of projected 300×60 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 240 mm bore puts this execution at the top of the HR1 range — the 300 mm outside diameter, 60 mm width and 10 kg mass are built for primary-industry load cases Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 400 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 240 mm bore; the 1080 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 300 mm outside diameter and 400 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 240 mm seat, and in planetary gear bearings the 10 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 60 mm width and the published 1080 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4848-XL?",
        "a": "The NA4848-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 300 mm outside diameter, 240 mm bore and 60 mm width, envelope 240×300×60 mm. Mass is 10 kg."
      },
      {
        "q": "What does the NA4848-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4848-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 240×300×60 mm and the catalogue ratings are C 400 kN, C0 1080 kN, Cur 153 kN."
      },
      {
        "q": "What is the load capacity of the NA4848-XL?",
        "a": "The basic dynamic load rating C is 400 kN and the basic static load rating C0 is 1080 kN; the fatigue load limit Cur is 153 kN."
      },
      {
        "q": "What is the maximum speed of the NA4848-XL?",
        "a": "The limiting speed is 1,780 r/min and the thermal reference speed is 960 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4848-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 240 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4848",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 240×300×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4848-XL",
      "NA4848-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4852-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4852-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 260,
    "D_mm": 320,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 415,
    "static_load_kN": 1160,
    "fatigue_load_limit_kN": 161,
    "limiting_speed_rpm": 1660,
    "max_rpm": 1660,
    "reference_speed_rpm": 870,
    "weight_g": 10600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 260×320×60 mm: 260 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 30.0 mm radial section packed with small-diameter needle rollers C is 415 kN and C0 1160 kN at the 260 mm seat; the C/C0 ratio of 0.36 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 320 mm outside diameter the fatigue load limit Cur is 161 kN, the limiting speed 1,660 r/min and the thermal reference speed 870 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.60 kN/mm and per millimetre of width 6.92 kN/mm — the reason 60 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 10.6 kg (10600 g), just 0.55 g per mm² of projected 320×60 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 260 mm bore this is among the largest catalogue sizes; the 1,660 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position Cur 161 kN, limiting speed 1,660 r/min, reference speed 870 r/min — the inner ring adds a few grams (total 10600 g) but removes the hardening requirement NA4852-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 1,660 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 320 mm outside diameter and 415 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 260 mm seat, and in copying and printing machine mechanisms the 10.6 kg mass is part of the rotor inertia calculation. Designers also specify it for agricultural machine pivots and linkages, relying on the 60 mm width and the published 1160 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4852-XL?",
        "a": "The NA4852-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 320 mm outside diameter, 260 mm bore and 60 mm width, envelope 260×320×60 mm. Mass is 10.6 kg."
      },
      {
        "q": "What does the NA4852-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4852-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 260×320×60 mm and the catalogue ratings are C 415 kN, C0 1160 kN, Cur 161 kN."
      },
      {
        "q": "What is the load capacity of the NA4852-XL?",
        "a": "The basic dynamic load rating C is 415 kN and the basic static load rating C0 is 1160 kN; the fatigue load limit Cur is 161 kN."
      },
      {
        "q": "What is the maximum speed of the NA4852-XL?",
        "a": "The limiting speed is 1,660 r/min and the thermal reference speed is 870 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4852-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 260 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4852",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 260×320×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4852-XL",
      "NA4852-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4856-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4856-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 280,
    "D_mm": 350,
    "B_mm": 69,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 510,
    "static_load_kN": 1300,
    "fatigue_load_limit_kN": 178,
    "limiting_speed_rpm": 1540,
    "max_rpm": 1540,
    "reference_speed_rpm": 840,
    "weight_g": 15300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 280×350×69 mm: 280 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 35.0 mm radial section packed with small-diameter needle rollers C is 510 kN and C0 1300 kN at the 280 mm seat; the C/C0 ratio of 0.39 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 350 mm outside diameter the fatigue load limit Cur is 178 kN, the limiting speed 1,540 r/min and the thermal reference speed 840 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.82 kN/mm and per millimetre of width 7.39 kN/mm — the reason 69 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 15.3 kg (15300 g), just 0.63 g per mm² of projected 350×69 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 280 mm bore puts this execution at the top of the HR1 range — the 350 mm outside diameter, 69 mm width and 15.3 kg mass are built for primary-industry load cases The 35.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 510 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 280 mm bore; the 1300 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 350 mm outside diameter and 510 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 280 mm seat, and in connecting-rod small ends the 15.3 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 69 mm width and the published 1300 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4856-XL?",
        "a": "The NA4856-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 350 mm outside diameter, 280 mm bore and 69 mm width, envelope 280×350×69 mm. Mass is 15.3 kg."
      },
      {
        "q": "What does the NA4856-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4856-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 280×350×69 mm and the catalogue ratings are C 510 kN, C0 1300 kN, Cur 178 kN."
      },
      {
        "q": "What is the load capacity of the NA4856-XL?",
        "a": "The basic dynamic load rating C is 510 kN and the basic static load rating C0 is 1300 kN; the fatigue load limit Cur is 178 kN."
      },
      {
        "q": "What is the maximum speed of the NA4856-XL?",
        "a": "The limiting speed is 1,540 r/min and the thermal reference speed is 840 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4856-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 280 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4856",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 280×350×69 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4856-XL",
      "NA4856-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4860-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4860-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 300,
    "D_mm": 380,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 700,
    "static_load_kN": 1770,
    "fatigue_load_limit_kN": 239,
    "limiting_speed_rpm": 1420,
    "max_rpm": 1420,
    "reference_speed_rpm": 720,
    "weight_g": 21800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 300×380×80 mm: 300 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 40.0 mm radial section packed with small-diameter needle rollers C is 700 kN and C0 1770 kN at the 300 mm seat; the C/C0 ratio of 0.40 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 380 mm outside diameter the fatigue load limit Cur is 239 kN, the limiting speed 1,420 r/min and the thermal reference speed 720 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.33 kN/mm and per millimetre of width 8.75 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21.8 kg (21800 g), just 0.72 g per mm² of projected 380×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 300 mm bore this is among the largest catalogue sizes; the 1,420 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 1770 kN C0 rating still assumes full rigid support under both rings Reading the NA48 prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 700 kN C The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 1,420 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 380 mm outside diameter and 700 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 300 mm seat, and in two-stroke and compressor piston pins the 21.8 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 80 mm width and the published 1770 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4860-XL?",
        "a": "The NA4860-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 380 mm outside diameter, 300 mm bore and 80 mm width, envelope 300×380×80 mm. Mass is 21.8 kg."
      },
      {
        "q": "What does the NA4860-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4860-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 300×380×80 mm and the catalogue ratings are C 700 kN, C0 1770 kN, Cur 239 kN."
      },
      {
        "q": "What is the load capacity of the NA4860-XL?",
        "a": "The basic dynamic load rating C is 700 kN and the basic static load rating C0 is 1770 kN; the fatigue load limit Cur is 239 kN."
      },
      {
        "q": "What is the maximum speed of the NA4860-XL?",
        "a": "The limiting speed is 1,420 r/min and the thermal reference speed is 720 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4860-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 300 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4860",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 300×380×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4860-XL",
      "NA4860-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4864-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4864-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 320,
    "D_mm": 400,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 710,
    "static_load_kN": 1850,
    "fatigue_load_limit_kN": 246,
    "limiting_speed_rpm": 1340,
    "max_rpm": 1340,
    "reference_speed_rpm": 670,
    "weight_g": 23000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 320×400×80 mm: 320 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 40.0 mm radial section packed with small-diameter needle rollers C is 710 kN and C0 1850 kN at the 320 mm seat; the C/C0 ratio of 0.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 400 mm outside diameter the fatigue load limit Cur is 246 kN, the limiting speed 1,340 r/min and the thermal reference speed 670 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.22 kN/mm and per millimetre of width 8.88 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 23 kg (23000 g), just 0.72 g per mm² of projected 400×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 320 mm bore this is among the largest catalogue sizes; the 1,340 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 1850 kN C0 rating still assumes full rigid support under both rings The integral inner ring brings the bore to 320 mm inside the 400×80 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 246 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 400 mm outside diameter and 710 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 320 mm seat, and in connecting-rod small ends the 23 kg mass is part of the rotor inertia calculation. Designers also specify it for two-stroke and compressor piston pins, relying on the 80 mm width and the published 1850 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4864-XL?",
        "a": "The NA4864-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 400 mm outside diameter, 320 mm bore and 80 mm width, envelope 320×400×80 mm. Mass is 23 kg."
      },
      {
        "q": "What does the NA4864-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4864-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 320×400×80 mm and the catalogue ratings are C 710 kN, C0 1850 kN, Cur 246 kN."
      },
      {
        "q": "What is the load capacity of the NA4864-XL?",
        "a": "The basic dynamic load rating C is 710 kN and the basic static load rating C0 is 1850 kN; the fatigue load limit Cur is 246 kN."
      },
      {
        "q": "What is the maximum speed of the NA4864-XL?",
        "a": "The limiting speed is 1,340 r/min and the thermal reference speed is 670 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4864-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 320 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4864",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 320×400×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4864-XL",
      "NA4864-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4868-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4868-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 340,
    "D_mm": 420,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 730,
    "static_load_kN": 1940,
    "fatigue_load_limit_kN": 255,
    "limiting_speed_rpm": 1270,
    "max_rpm": 1270,
    "reference_speed_rpm": 620,
    "weight_g": 24200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 340×420×80 mm: 340 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 40.0 mm radial section packed with small-diameter needle rollers C is 730 kN and C0 1940 kN at the 340 mm seat; the C/C0 ratio of 0.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 420 mm outside diameter the fatigue load limit Cur is 255 kN, the limiting speed 1,270 r/min and the thermal reference speed 620 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.15 kN/mm and per millimetre of width 9.13 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 24.2 kg (24200 g), just 0.72 g per mm² of projected 420×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 340 mm bore puts this execution at the top of the HR1 range — the 420 mm outside diameter, 80 mm width and 24.2 kg mass are built for primary-industry load cases The integral inner ring brings the bore to 340 mm inside the 420×80 mm envelope; removing that ring gives the corresponding RNA/NK execution and a larger shaft for the same housing The 40.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 730 kN C rating and longer nominal life come without an envelope change. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 420 mm outside diameter and 730 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 340 mm seat, and in small electric motor accessory drives the 24.2 kg mass is part of the rotor inertia calculation. Designers also specify it for gearbox selector and change linkages, relying on the 80 mm width and the published 1940 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4868-XL?",
        "a": "The NA4868-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 420 mm outside diameter, 340 mm bore and 80 mm width, envelope 340×420×80 mm. Mass is 24.2 kg."
      },
      {
        "q": "What does the NA4868-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4868-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 340×420×80 mm and the catalogue ratings are C 730 kN, C0 1940 kN, Cur 255 kN."
      },
      {
        "q": "What is the load capacity of the NA4868-XL?",
        "a": "The basic dynamic load rating C is 730 kN and the basic static load rating C0 is 1940 kN; the fatigue load limit Cur is 255 kN."
      },
      {
        "q": "What is the maximum speed of the NA4868-XL?",
        "a": "The limiting speed is 1,270 r/min and the thermal reference speed is 620 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4868-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 340 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4868",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 340×420×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4868-XL",
      "NA4868-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4872-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4872-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 360,
    "D_mm": 440,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 740,
    "static_load_kN": 2020,
    "fatigue_load_limit_kN": 260,
    "limiting_speed_rpm": 1210,
    "max_rpm": 1210,
    "reference_speed_rpm": 590,
    "weight_g": 25600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 360×440×80 mm: 360 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 40.0 mm radial section packed with small-diameter needle rollers C is 740 kN and C0 2020 kN at the 360 mm seat; the C/C0 ratio of 0.37 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 440 mm outside diameter the fatigue load limit Cur is 260 kN, the limiting speed 1,210 r/min and the thermal reference speed 590 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.06 kN/mm and per millimetre of width 9.25 kN/mm — the reason 80 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 25.6 kg (25600 g), just 0.73 g per mm² of projected 440×80 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 360 mm bore this is among the largest catalogue sizes; the 1,210 r/min limiting speed confirms a slow-speed, extreme-load application such as a slewing or rolling-mill position The 40.0 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel NA4872-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 260 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 440 mm outside diameter and 740 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 360 mm seat, and in gearbox selector and change linkages the 25.6 kg mass is part of the rotor inertia calculation. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 80 mm width and the published 2020 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4872-XL?",
        "a": "The NA4872-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 440 mm outside diameter, 360 mm bore and 80 mm width, envelope 360×440×80 mm. Mass is 25.6 kg."
      },
      {
        "q": "What does the NA4872-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4872-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 360×440×80 mm and the catalogue ratings are C 740 kN, C0 2020 kN, Cur 260 kN."
      },
      {
        "q": "What is the load capacity of the NA4872-XL?",
        "a": "The basic dynamic load rating C is 740 kN and the basic static load rating C0 is 2020 kN; the fatigue load limit Cur is 260 kN."
      },
      {
        "q": "What is the maximum speed of the NA4872-XL?",
        "a": "The limiting speed is 1,210 r/min and the thermal reference speed is 590 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4872-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 360 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4872",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 360×440×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4872-XL",
      "NA4872-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4876-XL",
    "brand": "FAG",
    "manufacturer_designation": "NA4876-XL",
    "series": "na48-series",
    "type": "needle",
    "d_mm": 380,
    "D_mm": 480,
    "B_mm": 100,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 1130,
    "static_load_kN": 2900,
    "fatigue_load_limit_kN": 375,
    "limiting_speed_rpm": 1130,
    "max_rpm": 1130,
    "reference_speed_rpm": 510,
    "weight_g": 42600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 380×480×100 mm: 380 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 50.0 mm radial section packed with small-diameter needle rollers C is 1130 kN and C0 2900 kN at the 380 mm seat; the C/C0 ratio of 0.39 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 480 mm outside diameter the fatigue load limit Cur is 375 kN, the limiting speed 1,130 r/min and the thermal reference speed 510 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 2.97 kN/mm and per millimetre of width 11.30 kN/mm — the reason 100 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42.6 kg (42600 g), just 0.89 g per mm² of projected 480×100 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 380 mm bore puts this execution at the top of the HR1 range — the 480 mm outside diameter, 100 mm width and 42.6 kg mass are built for primary-industry load cases The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 2900 kN C0 rating still assumes full rigid support under both rings Cur 375 kN, limiting speed 1,130 r/min, reference speed 510 r/min — the inner ring adds a few grams (total 42600 g) but removes the hardening requirement -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 1130 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 480 mm outside diameter and 1130 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 380 mm seat, and in textile machine heald and cam shafts the 42.6 kg mass is part of the rotor inertia calculation. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 100 mm width and the published 2900 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NA4876-XL?",
        "a": "The NA4876-XL is a NA48 dimension-series 48 needle roller bearing with inner ring with 480 mm outside diameter, 380 mm bore and 100 mm width, envelope 380×480×100 mm. Mass is 42.6 kg."
      },
      {
        "q": "What does the NA4876-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NA4876-XL identifies this NA48 dimension-series 48 needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 380×480×100 mm and the catalogue ratings are C 1130 kN, C0 2900 kN, Cur 375 kN."
      },
      {
        "q": "What is the load capacity of the NA4876-XL?",
        "a": "The basic dynamic load rating C is 1130 kN and the basic static load rating C0 is 2900 kN; the fatigue load limit Cur is 375 kN."
      },
      {
        "q": "What is the maximum speed of the NA4876-XL?",
        "a": "The limiting speed is 1,130 r/min and the thermal reference speed is 510 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NA4876-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 380 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4876",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 380×480×100 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=963",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4876-XL",
      "NA4876-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO5X10X8-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO5×10×8-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 10,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.65,
    "static_load_kN": 1.92,
    "fatigue_load_limit_kN": 0.3,
    "limiting_speed_rpm": 39000,
    "max_rpm": 39000,
    "reference_speed_rpm": 53000,
    "weight_g": 3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 5×10×8 mm: 5 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 2.5 mm radial section packed with small-diameter needle rollers C is 2.65 kN and C0 1.92 kN at the 5 mm seat; the C/C0 ratio of 1.38 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 10 mm outside diameter the fatigue load limit Cur is 0.3 kN, the limiting speed 39,000 r/min and the thermal reference speed 53,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.53 kN/mm and per millimetre of width 0.33 kN/mm — the reason 8 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 3 g, just 0.04 g per mm² of projected 10×8 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 5 mm bore sits in the miniature band; at 8 mm wide the RNAO5×10×8-TV-XL is built into compact cam drives, indexing pawls and light linkages Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 5 mm hardened shaft journal and the housing faces provide all axial guidance As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.3 kN Cur value. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 10 mm outside diameter and 2.65 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 5 mm seat, and in two-stroke and compressor piston pins the 3 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 8 mm width and the published 1.92 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO5×10×8-TV-XL?",
        "a": "The RNAO5×10×8-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 10 mm outside diameter, 5 mm bore and 8 mm width, envelope 5×10×8 mm. Mass is 3 g."
      },
      {
        "q": "What does the RNAO5×10×8-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO5×10×8-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 5×10×8 mm and the catalogue ratings are C 2.65 kN, C0 1.92 kN, Cur 0.3 kN."
      },
      {
        "q": "What is the load capacity of the RNAO5×10×8-TV-XL?",
        "a": "The basic dynamic load rating C is 2.65 kN and the basic static load rating C0 is 1.92 kN; the fatigue load limit Cur is 0.3 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO5×10×8-TV-XL?",
        "a": "The limiting speed is 39,000 r/min and the thermal reference speed is 53,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO5×10×8-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO5×10×8-TV-XL has no inner ring, so the 5 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO5X10X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO5X10X8-TV-XL",
      "RNAO5×10×8-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO6X13X8-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO6×13×8-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 13,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.95,
    "static_load_kN": 2.28,
    "fatigue_load_limit_kN": 0.36,
    "limiting_speed_rpm": 36500,
    "max_rpm": 36500,
    "reference_speed_rpm": 48500,
    "weight_g": 6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×13×8 mm: 6 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 2.95 kN and C0 2.28 kN at the 6 mm seat; the C/C0 ratio of 1.29 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 13 mm outside diameter the fatigue load limit Cur is 0.36 kN, the limiting speed 36,500 r/min and the thermal reference speed 48,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.49 kN/mm and per millimetre of width 0.37 kN/mm — the reason 8 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 6 g, just 0.06 g per mm² of projected 13×8 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 6 mm bore this is one of the smallest HR1 executions — chosen where a 13 mm envelope must carry line-contact loads that no miniature ball bearing could take With no ribs the rollers can be arranged very freely in the 8 mm width, giving C 2.95 kN at only 13 mm outside diameter — the most compact radial unit in the HR1 needle section Cur 0.36 kN and speeds up to 36,500 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.36 kN Cur value. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 6 g in the 13 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 13 mm outside diameter and 2.95 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 6 mm seat, and in copying and printing machine mechanisms the 6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 8 mm width and the published 2.28 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO6×13×8-TV-XL?",
        "a": "The RNAO6×13×8-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 13 mm outside diameter, 6 mm bore and 8 mm width, envelope 6×13×8 mm. Mass is 6 g."
      },
      {
        "q": "What does the RNAO6×13×8-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO6×13×8-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×13×8 mm and the catalogue ratings are C 2.95 kN, C0 2.28 kN, Cur 0.36 kN."
      },
      {
        "q": "What is the load capacity of the RNAO6×13×8-TV-XL?",
        "a": "The basic dynamic load rating C is 2.95 kN and the basic static load rating C0 is 2.28 kN; the fatigue load limit Cur is 0.36 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO6×13×8-TV-XL?",
        "a": "The limiting speed is 36,500 r/min and the thermal reference speed is 48,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO6×13×8-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO6×13×8-TV-XL has no inner ring, so the 6 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO6X13X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO6X13X8-TV-XL",
      "RNAO6×13×8-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO7X14X8-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO7×14×8-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.25,
    "static_load_kN": 2.65,
    "fatigue_load_limit_kN": 0.42,
    "limiting_speed_rpm": 34500,
    "max_rpm": 34500,
    "reference_speed_rpm": 41500,
    "weight_g": 6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 7×14×8 mm: 7 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 3.25 kN and C0 2.65 kN at the 7 mm seat; the C/C0 ratio of 1.23 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 14 mm outside diameter the fatigue load limit Cur is 0.42 kN, the limiting speed 34,500 r/min and the thermal reference speed 41,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.46 kN/mm and per millimetre of width 0.41 kN/mm — the reason 8 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 6 g, just 0.05 g per mm² of projected 14×8 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 7 mm bore and only 6 g: the smallest sizes demand accurate shaft geometry, because the 3.5 mm section leaves no tolerance for a soft or tapered seat Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 0.42 kN Cur value. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 34,500 r/min limiting speed without roller-to-roller sliding. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 14 mm outside diameter and 3.25 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 7 mm seat, and in textile machine heald and cam shafts the 6 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 8 mm width and the published 2.65 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO7×14×8-TV-XL?",
        "a": "The RNAO7×14×8-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 14 mm outside diameter, 7 mm bore and 8 mm width, envelope 7×14×8 mm. Mass is 6 g."
      },
      {
        "q": "What does the RNAO7×14×8-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO7×14×8-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 7×14×8 mm and the catalogue ratings are C 3.25 kN, C0 2.65 kN, Cur 0.42 kN."
      },
      {
        "q": "What is the load capacity of the RNAO7×14×8-TV-XL?",
        "a": "The basic dynamic load rating C is 3.25 kN and the basic static load rating C0 is 2.65 kN; the fatigue load limit Cur is 0.42 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO7×14×8-TV-XL?",
        "a": "The limiting speed is 34,500 r/min and the thermal reference speed is 41,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO7×14×8-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO7×14×8-TV-XL has no inner ring, so the 7 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO7X14X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO7X14X8-TV-XL",
      "RNAO7×14×8-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO8X15X10-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO8×15×10-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 15,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.45,
    "static_load_kN": 4.1,
    "fatigue_load_limit_kN": 0.7,
    "limiting_speed_rpm": 32500,
    "max_rpm": 32500,
    "reference_speed_rpm": 35500,
    "weight_g": 8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 8×15×10 mm: 8 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 4.45 kN and C0 4.1 kN at the 8 mm seat; the C/C0 ratio of 1.09 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 15 mm outside diameter the fatigue load limit Cur is 0.7 kN, the limiting speed 32,500 r/min and the thermal reference speed 35,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.56 kN/mm and per millimetre of width 0.45 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 8 g, just 0.05 g per mm² of projected 15×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 8 mm bore and only 8 g: the smallest sizes demand accurate shaft geometry, because the 3.5 mm section leaves no tolerance for a soft or tapered seat The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 4.1 kN static rating cannot be used RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 8 mm hardened shaft journal and the housing faces provide all axial guidance The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 8×15×10 mm envelope. With the -TV polyamide cage the rollers are positively separated, so the 8 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 15 mm outside diameter and 4.45 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 8 mm seat, and in textile machine heald and cam shafts the 8 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 10 mm width and the published 4.1 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO8×15×10-TV-XL?",
        "a": "The RNAO8×15×10-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 15 mm outside diameter, 8 mm bore and 10 mm width, envelope 8×15×10 mm. Mass is 8 g."
      },
      {
        "q": "What does the RNAO8×15×10-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO8×15×10-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 8×15×10 mm and the catalogue ratings are C 4.45 kN, C0 4.1 kN, Cur 0.7 kN."
      },
      {
        "q": "What is the load capacity of the RNAO8×15×10-TV-XL?",
        "a": "The basic dynamic load rating C is 4.45 kN and the basic static load rating C0 is 4.1 kN; the fatigue load limit Cur is 0.7 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO8×15×10-TV-XL?",
        "a": "The limiting speed is 32,500 r/min and the thermal reference speed is 35,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO8×15×10-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO8×15×10-TV-XL has no inner ring, so the 8 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO8X15X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO8X15X10-TV-XL",
      "RNAO8×15×10-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO10X17X10-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO10×17×10-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 17,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.3,
    "static_load_kN": 5.5,
    "fatigue_load_limit_kN": 0.94,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 28000,
    "weight_g": 10,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 10×17×10 mm: 10 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 3.5 mm radial section packed with small-diameter needle rollers C is 5.3 kN and C0 5.5 kN at the 10 mm seat; the C/C0 ratio of 0.96 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 0.94 kN, the limiting speed 29,500 r/min and the thermal reference speed 28,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.53 kN/mm and per millimetre of width 0.53 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 10 g, just 0.06 g per mm² of projected 17×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 10 mm bore sits in the miniature band; at 10 mm wide the RNAO10×17×10-TV-XL is built into compact cam drives, indexing pawls and light linkages With no ribs the rollers can be arranged very freely in the 10 mm width, giving C 5.3 kN at only 17 mm outside diameter — the most compact radial unit in the HR1 needle section At 10 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 10×17×10 mm envelope. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 17 mm outside diameter and 5.3 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 10 mm seat, and in two-stroke and compressor piston pins the 10 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 10 mm width and the published 5.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO10×17×10-TV-XL?",
        "a": "The RNAO10×17×10-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 17 mm outside diameter, 10 mm bore and 10 mm width, envelope 10×17×10 mm. Mass is 10 g."
      },
      {
        "q": "What does the RNAO10×17×10-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO10×17×10-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 10×17×10 mm and the catalogue ratings are C 5.3 kN, C0 5.5 kN, Cur 0.94 kN."
      },
      {
        "q": "What is the load capacity of the RNAO10×17×10-TV-XL?",
        "a": "The basic dynamic load rating C is 5.3 kN and the basic static load rating C0 is 5.5 kN; the fatigue load limit Cur is 0.94 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO10×17×10-TV-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 28,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO10×17×10-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO10×17×10-TV-XL has no inner ring, so the 10 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO10X17X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO10X17X10-TV-XL",
      "RNAO10×17×10-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO12X22X12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO12×22×12-TV-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 22,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 11.3,
    "static_load_kN": 9.9,
    "fatigue_load_limit_kN": 1.77,
    "limiting_speed_rpm": 26000,
    "max_rpm": 26000,
    "reference_speed_rpm": 19700,
    "weight_g": 19,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×22×12 mm: 12 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 11.3 kN and C0 9.9 kN at the 12 mm seat; the C/C0 ratio of 1.14 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 1.77 kN, the limiting speed 26,000 r/min and the thermal reference speed 19,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.94 kN/mm and per millimetre of width 0.94 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 19 g, just 0.07 g per mm² of projected 22×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 12 mm bore this is one of the smallest HR1 executions — chosen where a 22 mm envelope must carry line-contact loads that no miniature ball bearing could take The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 9.9 kN static rating cannot be used With no ribs the rollers can be arranged very freely in the 12 mm width, giving C 11.3 kN at only 22 mm outside diameter — the most compact radial unit in the HR1 needle section The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 26,000 r/min limit. Reading -TV: an injection-moulded polyamide cage guides the rolling elements — the lightweight choice that keeps the mass at 19 g in the 22 mm envelope. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 22 mm outside diameter and 11.3 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 12 mm seat, and in agricultural machine pivots and linkages the 19 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 12 mm width and the published 9.9 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO12×22×12-TV-XL?",
        "a": "The RNAO12×22×12-TV-XL is a RNAO flangeless needle roller bearing without inner ring with 22 mm outside diameter, 12 mm bore and 12 mm width, envelope 12×22×12 mm. Mass is 19 g."
      },
      {
        "q": "What does the RNAO12×22×12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO12×22×12-TV-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×22×12 mm and the catalogue ratings are C 11.3 kN, C0 9.9 kN, Cur 1.77 kN."
      },
      {
        "q": "What is the load capacity of the RNAO12×22×12-TV-XL?",
        "a": "The basic dynamic load rating C is 11.3 kN and the basic static load rating C0 is 9.9 kN; the fatigue load limit Cur is 1.77 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO12×22×12-TV-XL?",
        "a": "The limiting speed is 26,000 r/min and the thermal reference speed is 19,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO12×22×12-TV-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO12×22×12-TV-XL has no inner ring, so the 12 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO12X22X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO12X22X12-TV-XL",
      "RNAO12×22×12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO15X23X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO15×23×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 23,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 9.7,
    "static_load_kN": 10.9,
    "fatigue_load_limit_kN": 1.79,
    "limiting_speed_rpm": 24300,
    "max_rpm": 24300,
    "reference_speed_rpm": 17900,
    "weight_g": 20,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×23×13 mm: 15 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 9.7 kN and C0 10.9 kN at the 15 mm seat; the C/C0 ratio of 0.89 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 23 mm outside diameter the fatigue load limit Cur is 1.79 kN, the limiting speed 24,300 r/min and the thermal reference speed 17,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.65 kN/mm and per millimetre of width 0.75 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 20 g, just 0.07 g per mm² of projected 23×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 15 mm bore the 13 mm width and 9.7 kN C rating suit high-cycle industrial machinery rather than instrument duty Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore Cur 1.79 kN and speeds up to 24,300 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 15×23×13 mm envelope. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 23 mm outside diameter and 9.7 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 15 mm seat, and in connecting-rod small ends the 20 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 13 mm width and the published 10.9 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO15×23×13-XL?",
        "a": "The RNAO15×23×13-XL is a RNAO flangeless needle roller bearing without inner ring with 23 mm outside diameter, 15 mm bore and 13 mm width, envelope 15×23×13 mm. Mass is 20 g."
      },
      {
        "q": "What does the RNAO15×23×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO15×23×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×23×13 mm and the catalogue ratings are C 9.7 kN, C0 10.9 kN, Cur 1.79 kN."
      },
      {
        "q": "What is the load capacity of the RNAO15×23×13-XL?",
        "a": "The basic dynamic load rating C is 9.7 kN and the basic static load rating C0 is 10.9 kN; the fatigue load limit Cur is 1.79 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO15×23×13-XL?",
        "a": "The limiting speed is 24,300 r/min and the thermal reference speed is 17,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO15×23×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO15×23×13-XL has no inner ring, so the 15 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO15X23X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO15X23X13-XL",
      "RNAO15×23×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO16X24X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO16×24×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.1,
    "static_load_kN": 11.8,
    "fatigue_load_limit_kN": 1.93,
    "limiting_speed_rpm": 23600,
    "max_rpm": 23600,
    "reference_speed_rpm": 16800,
    "weight_g": 21,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×24×13 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 10.1 kN and C0 11.8 kN at the 16 mm seat; the C/C0 ratio of 0.86 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 1.93 kN, the limiting speed 23,600 r/min and the thermal reference speed 16,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.63 kN/mm and per millimetre of width 0.78 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 21 g, just 0.07 g per mm² of projected 24×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 16 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With no ribs the rollers can be arranged very freely in the 13 mm width, giving C 10.1 kN at only 24 mm outside diameter — the most compact radial unit in the HR1 needle section Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 10.1 kN C rating and longer nominal life come without an envelope change. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 24 mm outside diameter and 10.1 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 16 mm seat, and in planetary gear bearings the 21 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 13 mm width and the published 11.8 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO16×24×13-XL?",
        "a": "The RNAO16×24×13-XL is a RNAO flangeless needle roller bearing without inner ring with 24 mm outside diameter, 16 mm bore and 13 mm width, envelope 16×24×13 mm. Mass is 21 g."
      },
      {
        "q": "What does the RNAO16×24×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO16×24×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×24×13 mm and the catalogue ratings are C 10.1 kN, C0 11.8 kN, Cur 1.93 kN."
      },
      {
        "q": "What is the load capacity of the RNAO16×24×13-XL?",
        "a": "The basic dynamic load rating C is 10.1 kN and the basic static load rating C0 is 11.8 kN; the fatigue load limit Cur is 1.93 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO16×24×13-XL?",
        "a": "The limiting speed is 23,600 r/min and the thermal reference speed is 16,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO16×24×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO16×24×13-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO16X24X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO16X24X13-XL",
      "RNAO16×24×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO16X28X12-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO16×28×12-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 28,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 13,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 2.25,
    "limiting_speed_rpm": 22900,
    "max_rpm": 22900,
    "reference_speed_rpm": 15900,
    "weight_g": 32,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 16×28×12 mm: 16 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 13 kN and C0 12.5 kN at the 16 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.25 kN, the limiting speed 22,900 r/min and the thermal reference speed 15,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 1.08 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 32 g, just 0.10 g per mm² of projected 28×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 16 mm bore this size balances the 28 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore Cur 2.25 kN and speeds up to 22,900 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter X-life status (-XL) indicates the current Schaeffler premium execution at 16 mm bore; the 12.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 28 mm outside diameter and 13 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 16 mm seat, and in textile machine heald and cam shafts the 32 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 12 mm width and the published 12.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO16×28×12-XL?",
        "a": "The RNAO16×28×12-XL is a RNAO flangeless needle roller bearing without inner ring with 28 mm outside diameter, 16 mm bore and 12 mm width, envelope 16×28×12 mm. Mass is 32 g."
      },
      {
        "q": "What does the RNAO16×28×12-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO16×28×12-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 16×28×12 mm and the catalogue ratings are C 13 kN, C0 12.5 kN, Cur 2.25 kN."
      },
      {
        "q": "What is the load capacity of the RNAO16×28×12-XL?",
        "a": "The basic dynamic load rating C is 13 kN and the basic static load rating C0 is 12.5 kN; the fatigue load limit Cur is 2.25 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO16×28×12-XL?",
        "a": "The limiting speed is 22,900 r/min and the thermal reference speed is 15,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO16×28×12-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO16×28×12-XL has no inner ring, so the 16 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO16X28X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO16X28X12-XL",
      "RNAO16×28×12-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO17X25X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO17×25×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 25,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.7,
    "static_load_kN": 14.6,
    "fatigue_load_limit_kN": 2.28,
    "limiting_speed_rpm": 22900,
    "max_rpm": 22900,
    "reference_speed_rpm": 15200,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×25×13 mm: 17 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 11.7 kN and C0 14.6 kN at the 17 mm seat; the C/C0 ratio of 0.80 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 25 mm outside diameter the fatigue load limit Cur is 2.28 kN, the limiting speed 22,900 r/min and the thermal reference speed 15,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.69 kN/mm and per millimetre of width 0.90 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 22 g, just 0.07 g per mm² of projected 25×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 17 mm bore this size balances the 25 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 14.6 kN static rating cannot be used X-life status (-XL) indicates the current Schaeffler premium execution at 17 mm bore; the 14.6 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 25 mm outside diameter and 11.7 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 17 mm seat, and in gearbox selector and change linkages the 22 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 13 mm width and the published 14.6 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO17×25×13-XL?",
        "a": "The RNAO17×25×13-XL is a RNAO flangeless needle roller bearing without inner ring with 25 mm outside diameter, 17 mm bore and 13 mm width, envelope 17×25×13 mm. Mass is 22 g."
      },
      {
        "q": "What does the RNAO17×25×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO17×25×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×25×13 mm and the catalogue ratings are C 11.7 kN, C0 14.6 kN, Cur 2.28 kN."
      },
      {
        "q": "What is the load capacity of the RNAO17×25×13-XL?",
        "a": "The basic dynamic load rating C is 11.7 kN and the basic static load rating C0 is 14.6 kN; the fatigue load limit Cur is 2.28 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO17×25×13-XL?",
        "a": "The limiting speed is 22,900 r/min and the thermal reference speed is 15,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO17×25×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO17×25×13-XL has no inner ring, so the 17 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO17X25X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO17X25X13-XL",
      "RNAO17×25×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO18X30X24-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO18×30×24-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 30,
    "B_mm": 24,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 24.8,
    "static_load_kN": 30,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 21800,
    "max_rpm": 21800,
    "reference_speed_rpm": 14000,
    "weight_g": 69,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 18×30×24 mm: 18 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 24.8 kN and C0 30 kN at the 18 mm seat; the C/C0 ratio of 0.83 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 21,800 r/min and the thermal reference speed 14,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.38 kN/mm and per millimetre of width 1.03 kN/mm — the reason 24 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 69 g, just 0.10 g per mm² of projected 30×24 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 18 mm bore the 24 mm width and 24.8 kN C rating suit high-cycle industrial machinery rather than instrument duty RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 18 mm hardened shaft journal and the housing faces provide all axial guidance X-life status (-XL) indicates the current Schaeffler premium execution at 18 mm bore; the 30 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 24 mm-wide envelope for higher capacity at the same bore. The ASR groove is particularly useful on double-row -ZW executions, feeding both rows evenly across the 30 mm outer ring. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 30 mm outside diameter and 24.8 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 18 mm seat, and in planetary gear bearings the 69 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 24 mm width and the published 30 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO18×30×24-ZW-ASR1-XL?",
        "a": "The RNAO18×30×24-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 30 mm outside diameter, 18 mm bore and 24 mm width, envelope 18×30×24 mm. Mass is 69 g."
      },
      {
        "q": "What does the RNAO18×30×24-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO18×30×24-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 18×30×24 mm and the catalogue ratings are C 24.8 kN, C0 30 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the RNAO18×30×24-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 24.8 kN and the basic static load rating C0 is 30 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO18×30×24-ZW-ASR1-XL?",
        "a": "The limiting speed is 21,800 r/min and the thermal reference speed is 14,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO18×30×24-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO18×30×24-ZW-ASR1-XL has no inner ring, so the 18 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO18X30X24",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO18X30X24-ZW-ASR1-XL",
      "RNAO18×30×24-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO20X28X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO20×28×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.1,
    "static_load_kN": 14.3,
    "fatigue_load_limit_kN": 2.35,
    "limiting_speed_rpm": 21300,
    "max_rpm": 21300,
    "reference_speed_rpm": 13700,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×13 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 11.1 kN and C0 14.3 kN at the 20 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.35 kN, the limiting speed 21,300 r/min and the thermal reference speed 13,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.55 kN/mm and per millimetre of width 0.85 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 25 g, just 0.07 g per mm² of projected 28×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 13 mm width and 11.1 kN C rating suit high-cycle industrial machinery rather than instrument duty Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal At 25 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts X-life status (-XL) indicates the current Schaeffler premium execution at 20 mm bore; the 14.3 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 28 mm outside diameter and 11.1 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 20 mm seat, and in gearbox selector and change linkages the 25 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 13 mm width and the published 14.3 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO20×28×13-XL?",
        "a": "The RNAO20×28×13-XL is a RNAO flangeless needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 13 mm width, envelope 20×28×13 mm. Mass is 25 g."
      },
      {
        "q": "What does the RNAO20×28×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO20×28×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×13 mm and the catalogue ratings are C 11.1 kN, C0 14.3 kN, Cur 2.35 kN."
      },
      {
        "q": "What is the load capacity of the RNAO20×28×13-XL?",
        "a": "The basic dynamic load rating C is 11.1 kN and the basic static load rating C0 is 14.3 kN; the fatigue load limit Cur is 2.35 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO20×28×13-XL?",
        "a": "The limiting speed is 21,300 r/min and the thermal reference speed is 13,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO20×28×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO20×28×13-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO20X28X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO20X28X13-XL",
      "RNAO20×28×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO20X28X26-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO20×28×26-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 19,
    "static_load_kN": 28.5,
    "fatigue_load_limit_kN": 4.7,
    "limiting_speed_rpm": 21300,
    "max_rpm": 21300,
    "reference_speed_rpm": 13700,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×28×26 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 19 kN and C0 28.5 kN at the 20 mm seat; the C/C0 ratio of 0.67 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 4.7 kN, the limiting speed 21,300 r/min and the thermal reference speed 13,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 0.73 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 50 g, just 0.07 g per mm² of projected 28×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 20 mm bore this size balances the 28 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range Reading RNAO: O denotes the ribless (open-sided) race design; ZW means two roller rows in the one envelope Cur 4.7 kN and speeds up to 21,300 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 21,300 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 20×28 mm ring pair, giving the 19 kN C rating in a housing space sized for a wide single bearing. -ASR1 leaves the envelope unchanged but requires a registering groove or port in the housing bore around the 20 mm seat. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 28 mm outside diameter and 19 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 20 mm seat, and in two-stroke and compressor piston pins the 50 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 26 mm width and the published 28.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO20×28×26-ZW-ASR1-XL?",
        "a": "The RNAO20×28×26-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 28 mm outside diameter, 20 mm bore and 26 mm width, envelope 20×28×26 mm. Mass is 50 g."
      },
      {
        "q": "What does the RNAO20×28×26-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO20×28×26-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×28×26 mm and the catalogue ratings are C 19 kN, C0 28.5 kN, Cur 4.7 kN."
      },
      {
        "q": "What is the load capacity of the RNAO20×28×26-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 19 kN and the basic static load rating C0 is 28.5 kN; the fatigue load limit Cur is 4.7 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO20×28×26-ZW-ASR1-XL?",
        "a": "The limiting speed is 21,300 r/min and the thermal reference speed is 13,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO20×28×26-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO20×28×26-ZW-ASR1-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO20X28X26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO20X28X26-ZW-ASR1-XL",
      "RNAO20×28×26-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO20X32X12-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO20×32×12-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 16.2,
    "fatigue_load_limit_kN": 2.9,
    "limiting_speed_rpm": 20900,
    "max_rpm": 20900,
    "reference_speed_rpm": 12700,
    "weight_g": 38,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×32×12 mm: 20 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 15.1 kN and C0 16.2 kN at the 20 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 2.9 kN, the limiting speed 20,900 r/min and the thermal reference speed 12,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.76 kN/mm and per millimetre of width 1.26 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 38 g, just 0.10 g per mm² of projected 32×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 12 mm width and 15.1 kN C rating suit high-cycle industrial machinery rather than instrument duty Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 15.1 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 32 mm outside diameter and 15.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 20 mm seat, and in hydraulic and pneumatic pump eccentrics the 38 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 12 mm width and the published 16.2 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO20×32×12-XL?",
        "a": "The RNAO20×32×12-XL is a RNAO flangeless needle roller bearing without inner ring with 32 mm outside diameter, 20 mm bore and 12 mm width, envelope 20×32×12 mm. Mass is 38 g."
      },
      {
        "q": "What does the RNAO20×32×12-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO20×32×12-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×32×12 mm and the catalogue ratings are C 15.1 kN, C0 16.2 kN, Cur 2.9 kN."
      },
      {
        "q": "What is the load capacity of the RNAO20×32×12-XL?",
        "a": "The basic dynamic load rating C is 15.1 kN and the basic static load rating C0 is 16.2 kN; the fatigue load limit Cur is 2.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO20×32×12-XL?",
        "a": "The limiting speed is 20,900 r/min and the thermal reference speed is 12,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO20×32×12-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO20×32×12-XL has no inner ring, so the 20 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO20X32X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO20X32X12-XL",
      "RNAO20×32×12-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO22X30X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO22×30×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.8,
    "static_load_kN": 15.9,
    "fatigue_load_limit_kN": 2.6,
    "limiting_speed_rpm": 20400,
    "max_rpm": 20400,
    "reference_speed_rpm": 12400,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×30×13 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 11.8 kN and C0 15.9 kN at the 22 mm seat; the C/C0 ratio of 0.74 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 2.6 kN, the limiting speed 20,400 r/min and the thermal reference speed 12,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.54 kN/mm and per millimetre of width 0.91 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 27 g, just 0.07 g per mm² of projected 30×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 22 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore X-life status (-XL) indicates the current Schaeffler premium execution at 22 mm bore; the 15.9 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 30 mm outside diameter and 11.8 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 22 mm seat, and in planetary gear bearings the 27 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 13 mm width and the published 15.9 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO22×30×13-XL?",
        "a": "The RNAO22×30×13-XL is a RNAO flangeless needle roller bearing without inner ring with 30 mm outside diameter, 22 mm bore and 13 mm width, envelope 22×30×13 mm. Mass is 27 g."
      },
      {
        "q": "What does the RNAO22×30×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO22×30×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×30×13 mm and the catalogue ratings are C 11.8 kN, C0 15.9 kN, Cur 2.6 kN."
      },
      {
        "q": "What is the load capacity of the RNAO22×30×13-XL?",
        "a": "The basic dynamic load rating C is 11.8 kN and the basic static load rating C0 is 15.9 kN; the fatigue load limit Cur is 2.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO22×30×13-XL?",
        "a": "The limiting speed is 20,400 r/min and the thermal reference speed is 12,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO22×30×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO22×30×13-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO22X30X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO22X30X13-XL",
      "RNAO22×30×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO22X35X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO22×35×16-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 35,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22.6,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.25,
    "limiting_speed_rpm": 19200,
    "max_rpm": 19200,
    "reference_speed_rpm": 11200,
    "weight_g": 59,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 22×35×16 mm: 22 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 22.6 kN and C0 25.5 kN at the 22 mm seat; the C/C0 ratio of 0.89 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 4.25 kN, the limiting speed 19,200 r/min and the thermal reference speed 11,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 1.41 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 59 g, just 0.11 g per mm² of projected 35×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 22 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty At 59 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts X-life status (-XL) indicates the current Schaeffler premium execution at 22 mm bore; the 25.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 35 mm outside diameter and 22.6 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 22 mm seat, and in gearbox selector and change linkages the 59 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 16 mm width and the published 25.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO22×35×16-XL?",
        "a": "The RNAO22×35×16-XL is a RNAO flangeless needle roller bearing without inner ring with 35 mm outside diameter, 22 mm bore and 16 mm width, envelope 22×35×16 mm. Mass is 59 g."
      },
      {
        "q": "What does the RNAO22×35×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO22×35×16-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 22×35×16 mm and the catalogue ratings are C 22.6 kN, C0 25.5 kN, Cur 4.25 kN."
      },
      {
        "q": "What is the load capacity of the RNAO22×35×16-XL?",
        "a": "The basic dynamic load rating C is 22.6 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.25 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO22×35×16-XL?",
        "a": "The limiting speed is 19,200 r/min and the thermal reference speed is 11,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO22×35×16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO22×35×16-XL has no inner ring, so the 22 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO22X35X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO22X35X16-XL",
      "RNAO22×35×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO25X35X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO25×35×17-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 35,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.8,
    "static_load_kN": 26,
    "fatigue_load_limit_kN": 4.3,
    "limiting_speed_rpm": 18100,
    "max_rpm": 18100,
    "reference_speed_rpm": 11000,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×35×17 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 16.8 kN and C0 26 kN at the 25 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 4.3 kN, the limiting speed 18,100 r/min and the thermal reference speed 11,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.67 kN/mm and per millimetre of width 0.99 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 53 g, just 0.09 g per mm² of projected 35×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 25 mm bore this size balances the 35 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range At 53 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 4.3 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 35 mm outside diameter and 16.8 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 25 mm seat, and in two-stroke and compressor piston pins the 53 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 17 mm width and the published 26 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO25×35×17-XL?",
        "a": "The RNAO25×35×17-XL is a RNAO flangeless needle roller bearing without inner ring with 35 mm outside diameter, 25 mm bore and 17 mm width, envelope 25×35×17 mm. Mass is 53 g."
      },
      {
        "q": "What does the RNAO25×35×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO25×35×17-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×35×17 mm and the catalogue ratings are C 16.8 kN, C0 26 kN, Cur 4.3 kN."
      },
      {
        "q": "What is the load capacity of the RNAO25×35×17-XL?",
        "a": "The basic dynamic load rating C is 16.8 kN and the basic static load rating C0 is 26 kN; the fatigue load limit Cur is 4.3 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO25×35×17-XL?",
        "a": "The limiting speed is 18,100 r/min and the thermal reference speed is 11,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO25×35×17-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO25×35×17-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO25X35X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO25X35X17-XL",
      "RNAO25×35×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO25X35X26-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO25×35×26-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 35,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 21.9,
    "static_load_kN": 37,
    "fatigue_load_limit_kN": 6.1,
    "limiting_speed_rpm": 18100,
    "max_rpm": 18100,
    "reference_speed_rpm": 11200,
    "weight_g": 76,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×35×26 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 21.9 kN and C0 37 kN at the 25 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 6.1 kN, the limiting speed 18,100 r/min and the thermal reference speed 11,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 0.84 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 76 g, just 0.08 g per mm² of projected 35×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty At 76 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 37 kN static rating cannot be used -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 21.9 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 37 kN in this thin-section bearing — two rows support the static peak that a single row could not. -ASR1 marks the outer-ring lubrication feature: the annular groove distributes grease to both needle rows of the 26 mm-wide pack. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 35 mm outside diameter and 21.9 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 25 mm seat, and in textile machine heald and cam shafts the 76 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 26 mm width and the published 37 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO25×35×26-ZW-ASR1-XL?",
        "a": "The RNAO25×35×26-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 35 mm outside diameter, 25 mm bore and 26 mm width, envelope 25×35×26 mm. Mass is 76 g."
      },
      {
        "q": "What does the RNAO25×35×26-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO25×35×26-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×35×26 mm and the catalogue ratings are C 21.9 kN, C0 37 kN, Cur 6.1 kN."
      },
      {
        "q": "What is the load capacity of the RNAO25×35×26-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 21.9 kN and the basic static load rating C0 is 37 kN; the fatigue load limit Cur is 6.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO25×35×26-ZW-ASR1-XL?",
        "a": "The limiting speed is 18,100 r/min and the thermal reference speed is 11,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO25×35×26-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO25×35×26-ZW-ASR1-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO25X35X26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO25X35X26-ZW-ASR1-XL",
      "RNAO25×35×26-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO25X37X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO25×37×16-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.5,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 4.65,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 10000,
    "weight_g": 60,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×37×16 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 23.5 kN and C0 27.5 kN at the 25 mm seat; the C/C0 ratio of 0.85 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 4.65 kN, the limiting speed 17,200 r/min and the thermal reference speed 10,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.94 kN/mm and per millimetre of width 1.47 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 60 g, just 0.10 g per mm² of projected 37×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 25 mm bore this size balances the 37 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range With no ribs the rollers can be arranged very freely in the 16 mm width, giving C 23.5 kN at only 37 mm outside diameter — the most compact radial unit in the HR1 needle section At 60 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 27.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 37 mm outside diameter and 23.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 25 mm seat, and in small electric motor accessory drives the 60 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 16 mm width and the published 27.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO25×37×16-XL?",
        "a": "The RNAO25×37×16-XL is a RNAO flangeless needle roller bearing without inner ring with 37 mm outside diameter, 25 mm bore and 16 mm width, envelope 25×37×16 mm. Mass is 60 g."
      },
      {
        "q": "What does the RNAO25×37×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO25×37×16-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×37×16 mm and the catalogue ratings are C 23.5 kN, C0 27.5 kN, Cur 4.65 kN."
      },
      {
        "q": "What is the load capacity of the RNAO25×37×16-XL?",
        "a": "The basic dynamic load rating C is 23.5 kN and the basic static load rating C0 is 27.5 kN; the fatigue load limit Cur is 4.65 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO25×37×16-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 10,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO25×37×16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO25×37×16-XL has no inner ring, so the 25 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO25X37X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO25X37X16-XL",
      "RNAO25×37×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO30X40X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO30×40×17-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22.1,
    "static_load_kN": 34,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 15100,
    "max_rpm": 15100,
    "reference_speed_rpm": 8800,
    "weight_g": 60,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×40×17 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 22.1 kN and C0 34 kN at the 30 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 40 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 15,100 r/min and the thermal reference speed 8,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.74 kN/mm and per millimetre of width 1.30 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 60 g, just 0.09 g per mm² of projected 40×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Cur 5.4 kN and speeds up to 15,100 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter At 60 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 5.4 kN Cur value. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 40 mm outside diameter and 22.1 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 30 mm seat, and in motorcycle and light-vehicle transmissions the 60 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 17 mm width and the published 34 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO30×40×17-XL?",
        "a": "The RNAO30×40×17-XL is a RNAO flangeless needle roller bearing without inner ring with 40 mm outside diameter, 30 mm bore and 17 mm width, envelope 30×40×17 mm. Mass is 60 g."
      },
      {
        "q": "What does the RNAO30×40×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO30×40×17-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×40×17 mm and the catalogue ratings are C 22.1 kN, C0 34 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the RNAO30×40×17-XL?",
        "a": "The basic dynamic load rating C is 22.1 kN and the basic static load rating C0 is 34 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO30×40×17-XL?",
        "a": "The limiting speed is 15,100 r/min and the thermal reference speed is 8,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO30×40×17-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO30×40×17-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO30X40X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO30X40X17-XL",
      "RNAO30×40×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO30X42X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO30×42×16-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 5.6,
    "limiting_speed_rpm": 14600,
    "max_rpm": 14600,
    "reference_speed_rpm": 8500,
    "weight_g": 59,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×42×16 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 33.5 kN at the 30 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 5.6 kN, the limiting speed 14,600 r/min and the thermal reference speed 8,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.87 kN/mm and per millimetre of width 1.63 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 59 g, just 0.09 g per mm² of projected 42×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 16 mm width and 26 kN C rating suit high-cycle industrial machinery rather than instrument duty RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 30 mm hardened shaft journal and the housing faces provide all axial guidance At 59 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 33.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 42 mm outside diameter and 26 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 30 mm seat, and in two-stroke and compressor piston pins the 59 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 16 mm width and the published 33.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO30×42×16-XL?",
        "a": "The RNAO30×42×16-XL is a RNAO flangeless needle roller bearing without inner ring with 42 mm outside diameter, 30 mm bore and 16 mm width, envelope 30×42×16 mm. Mass is 59 g."
      },
      {
        "q": "What does the RNAO30×42×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO30×42×16-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×42×16 mm and the catalogue ratings are C 26 kN, C0 33.5 kN, Cur 5.6 kN."
      },
      {
        "q": "What is the load capacity of the RNAO30×42×16-XL?",
        "a": "The basic dynamic load rating C is 26 kN and the basic static load rating C0 is 33.5 kN; the fatigue load limit Cur is 5.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO30×42×16-XL?",
        "a": "The limiting speed is 14,600 r/min and the thermal reference speed is 8,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO30×42×16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO30×42×16-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO30X42X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO30X42X16-XL",
      "RNAO30×42×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO30X42X32-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO30×42×32-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.3,
    "limiting_speed_rpm": 14600,
    "max_rpm": 14600,
    "reference_speed_rpm": 8500,
    "weight_g": 137,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×42×32 mm: 30 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 45 kN and C0 67 kN at the 30 mm seat; the C/C0 ratio of 0.67 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 11.3 kN, the limiting speed 14,600 r/min and the thermal reference speed 8,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.50 kN/mm and per millimetre of width 1.41 kN/mm — the reason 32 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 137 g, just 0.10 g per mm² of projected 42×32 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 30 mm bore this size balances the 42 mm outside diameter against machineability of the adjacent parts — the most frequently specified band in the HR1 range The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 67 kN static rating cannot be used At 137 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 67 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 32 mm-wide envelope for higher capacity at the same bore. The ASR groove is particularly useful on double-row -ZW executions, feeding both rows evenly across the 42 mm outer ring. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 42 mm outside diameter and 45 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 30 mm seat, and in hydraulic and pneumatic pump eccentrics the 137 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 32 mm width and the published 67 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO30×42×32-ZW-ASR1-XL?",
        "a": "The RNAO30×42×32-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 42 mm outside diameter, 30 mm bore and 32 mm width, envelope 30×42×32 mm. Mass is 137 g."
      },
      {
        "q": "What does the RNAO30×42×32-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO30×42×32-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×42×32 mm and the catalogue ratings are C 45 kN, C0 67 kN, Cur 11.3 kN."
      },
      {
        "q": "What is the load capacity of the RNAO30×42×32-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 45 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.3 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO30×42×32-ZW-ASR1-XL?",
        "a": "The limiting speed is 14,600 r/min and the thermal reference speed is 8,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO30×42×32-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO30×42×32-ZW-ASR1-XL has no inner ring, so the 30 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO30X42X32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO30X42X32-ZW-ASR1-XL",
      "RNAO30×42×32-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X45X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×45×13-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 18.3,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 4.55,
    "limiting_speed_rpm": 13100,
    "max_rpm": 13100,
    "reference_speed_rpm": 7800,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×45×13 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 18.3 kN and C0 28 kN at the 35 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 4.55 kN, the limiting speed 13,100 r/min and the thermal reference speed 7,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.52 kN/mm and per millimetre of width 1.41 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 53 g, just 0.09 g per mm² of projected 45×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 45 mm envelope already carries ratings in the tens of kilonewtons With no ribs the rollers can be arranged very freely in the 13 mm width, giving C 18.3 kN at only 45 mm outside diameter — the most compact radial unit in the HR1 needle section The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 28 kN static rating cannot be used As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 4.55 kN Cur value. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 45 mm outside diameter and 18.3 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 35 mm seat, and in gearbox selector and change linkages the 53 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 13 mm width and the published 28 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×45×13-XL?",
        "a": "The RNAO35×45×13-XL is a RNAO flangeless needle roller bearing without inner ring with 45 mm outside diameter, 35 mm bore and 13 mm width, envelope 35×45×13 mm. Mass is 53 g."
      },
      {
        "q": "What does the RNAO35×45×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×45×13-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×45×13 mm and the catalogue ratings are C 18.3 kN, C0 28 kN, Cur 4.55 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×45×13-XL?",
        "a": "The basic dynamic load rating C is 18.3 kN and the basic static load rating C0 is 28 kN; the fatigue load limit Cur is 4.55 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×45×13-XL?",
        "a": "The limiting speed is 13,100 r/min and the thermal reference speed is 7,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×45×13-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×45×13-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X45X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X45X13-XL",
      "RNAO35×45×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X45X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×45×17-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.5,
    "static_load_kN": 38.5,
    "fatigue_load_limit_kN": 6.2,
    "limiting_speed_rpm": 13100,
    "max_rpm": 13100,
    "reference_speed_rpm": 7700,
    "weight_g": 69,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×45×17 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 23.5 kN and C0 38.5 kN at the 35 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 6.2 kN, the limiting speed 13,100 r/min and the thermal reference speed 7,700 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.67 kN/mm and per millimetre of width 1.38 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 69 g, just 0.09 g per mm² of projected 45×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 35 mm bore marks the medium range: mounting forces and fits become critical, and the 69 g mass calls for proper induction or press tooling rather than hand fitting RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 35 mm hardened shaft journal and the housing faces provide all axial guidance With no ribs the rollers can be arranged very freely in the 17 mm width, giving C 23.5 kN at only 45 mm outside diameter — the most compact radial unit in the HR1 needle section -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 23.5 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 45 mm outside diameter and 23.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 35 mm seat, and in textile machine heald and cam shafts the 69 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 17 mm width and the published 38.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×45×17-XL?",
        "a": "The RNAO35×45×17-XL is a RNAO flangeless needle roller bearing without inner ring with 45 mm outside diameter, 35 mm bore and 17 mm width, envelope 35×45×17 mm. Mass is 69 g."
      },
      {
        "q": "What does the RNAO35×45×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×45×17-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×45×17 mm and the catalogue ratings are C 23.5 kN, C0 38.5 kN, Cur 6.2 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×45×17-XL?",
        "a": "The basic dynamic load rating C is 23.5 kN and the basic static load rating C0 is 38.5 kN; the fatigue load limit Cur is 6.2 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×45×17-XL?",
        "a": "The limiting speed is 13,100 r/min and the thermal reference speed is 7,700 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×45×17-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×45×17-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X45X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X45X17-XL",
      "RNAO35×45×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X45X26-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×45×26-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 31.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 13100,
    "max_rpm": 13100,
    "reference_speed_rpm": 7800,
    "weight_g": 91,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×45×26 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 31.5 kN and C0 56 kN at the 35 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 13,100 r/min and the thermal reference speed 7,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.90 kN/mm and per millimetre of width 1.21 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 91 g, just 0.08 g per mm² of projected 45×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 45 mm envelope already carries ratings in the tens of kilonewtons At 91 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 56 kN static rating cannot be used The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 13,100 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 35×45 mm ring pair, giving the 31.5 kN C rating in a housing space sized for a wide single bearing. -ASR1 leaves the envelope unchanged but requires a registering groove or port in the housing bore around the 35 mm seat. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 45 mm outside diameter and 31.5 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 35 mm seat, and in rocker arms and valve trains the 91 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 26 mm width and the published 56 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×45×26-ZW-ASR1-XL?",
        "a": "The RNAO35×45×26-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 45 mm outside diameter, 35 mm bore and 26 mm width, envelope 35×45×26 mm. Mass is 91 g."
      },
      {
        "q": "What does the RNAO35×45×26-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×45×26-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×45×26 mm and the catalogue ratings are C 31.5 kN, C0 56 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×45×26-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 31.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×45×26-ZW-ASR1-XL?",
        "a": "The limiting speed is 13,100 r/min and the thermal reference speed is 7,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×45×26-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×45×26-ZW-ASR1-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X45X26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X45X26-ZW-ASR1-XL",
      "RNAO35×45×26-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X47X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×47×16-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 37.5,
    "fatigue_load_limit_kN": 6.3,
    "limiting_speed_rpm": 12700,
    "max_rpm": 12700,
    "reference_speed_rpm": 7500,
    "weight_g": 78,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×47×16 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 37.5 kN at the 35 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 6.3 kN, the limiting speed 12,700 r/min and the thermal reference speed 7,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.79 kN/mm and per millimetre of width 1.72 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 78 g, just 0.10 g per mm² of projected 47×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 16 mm width as a standard mounting space The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 37.5 kN static rating cannot be used With no ribs the rollers can be arranged very freely in the 16 mm width, giving C 27.5 kN at only 47 mm outside diameter — the most compact radial unit in the HR1 needle section As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 6.3 kN Cur value. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 47 mm outside diameter and 27.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 35 mm seat, and in connecting-rod small ends the 78 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 16 mm width and the published 37.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×47×16-XL?",
        "a": "The RNAO35×47×16-XL is a RNAO flangeless needle roller bearing without inner ring with 47 mm outside diameter, 35 mm bore and 16 mm width, envelope 35×47×16 mm. Mass is 78 g."
      },
      {
        "q": "What does the RNAO35×47×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×47×16-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×47×16 mm and the catalogue ratings are C 27.5 kN, C0 37.5 kN, Cur 6.3 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×47×16-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 37.5 kN; the fatigue load limit Cur is 6.3 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×47×16-XL?",
        "a": "The limiting speed is 12,700 r/min and the thermal reference speed is 7,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×47×16-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×47×16-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X47X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X47X16-XL",
      "RNAO35×47×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X47X18-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×47×18-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 31,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 7.5,
    "limiting_speed_rpm": 12700,
    "max_rpm": 12700,
    "reference_speed_rpm": 7400,
    "weight_g": 89,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×47×18 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 31 kN and C0 43 kN at the 35 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.5 kN, the limiting speed 12,700 r/min and the thermal reference speed 7,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 1.72 kN/mm — the reason 18 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 89 g, just 0.11 g per mm² of projected 47×18 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 18 mm width as a standard mounting space Cur 7.5 kN and speeds up to 12,700 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 35 mm hardened shaft journal and the housing faces provide all axial guidance -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 31 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 47 mm outside diameter and 31 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 35 mm seat, and in textile machine heald and cam shafts the 89 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 18 mm width and the published 43 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×47×18-XL?",
        "a": "The RNAO35×47×18-XL is a RNAO flangeless needle roller bearing without inner ring with 47 mm outside diameter, 35 mm bore and 18 mm width, envelope 35×47×18 mm. Mass is 89 g."
      },
      {
        "q": "What does the RNAO35×47×18-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×47×18-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×47×18 mm and the catalogue ratings are C 31 kN, C0 43 kN, Cur 7.5 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×47×18-XL?",
        "a": "The basic dynamic load rating C is 31 kN and the basic static load rating C0 is 43 kN; the fatigue load limit Cur is 7.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×47×18-XL?",
        "a": "The limiting speed is 12,700 r/min and the thermal reference speed is 7,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×47×18-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×47×18-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X47X18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X47X18-XL",
      "RNAO35×47×18-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO35X47X32-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO35×47×32-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 47.5,
    "static_load_kN": 75,
    "fatigue_load_limit_kN": 12.6,
    "limiting_speed_rpm": 12700,
    "max_rpm": 12700,
    "reference_speed_rpm": 7500,
    "weight_g": 156,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×47×32 mm: 35 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 47.5 kN and C0 75 kN at the 35 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 12.6 kN, the limiting speed 12,700 r/min and the thermal reference speed 7,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.36 kN/mm and per millimetre of width 1.48 kN/mm — the reason 32 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 156 g, just 0.10 g per mm² of projected 47×32 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 35 mm bore places this bearing in the medium band, where the 47 mm envelope already carries ratings in the tens of kilonewtons Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal Reading RNAO: O denotes the ribless (open-sided) race design; ZW means two roller rows in the one envelope -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 47.5 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 75 kN in this thin-section bearing — two rows support the static peak that a single row could not. -ASR1 marks the outer-ring lubrication feature: the annular groove distributes grease to both needle rows of the 32 mm-wide pack. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 47 mm outside diameter and 47.5 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 35 mm seat, and in gearbox selector and change linkages the 156 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 32 mm width and the published 75 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO35×47×32-ZW-ASR1-XL?",
        "a": "The RNAO35×47×32-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 47 mm outside diameter, 35 mm bore and 32 mm width, envelope 35×47×32 mm. Mass is 156 g."
      },
      {
        "q": "What does the RNAO35×47×32-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO35×47×32-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×47×32 mm and the catalogue ratings are C 47.5 kN, C0 75 kN, Cur 12.6 kN."
      },
      {
        "q": "What is the load capacity of the RNAO35×47×32-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 47.5 kN and the basic static load rating C0 is 75 kN; the fatigue load limit Cur is 12.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO35×47×32-ZW-ASR1-XL?",
        "a": "The limiting speed is 12,700 r/min and the thermal reference speed is 7,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO35×47×32-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO35×47×32-ZW-ASR1-XL has no inner ring, so the 35 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO35X47X32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=967",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO35X47X32-ZW-ASR1-XL",
      "RNAO35×47×32-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO40X50X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO40×50×17-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 41.5,
    "fatigue_load_limit_kN": 6.6,
    "limiting_speed_rpm": 11500,
    "max_rpm": 11500,
    "reference_speed_rpm": 7000,
    "weight_g": 74,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×50×17 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 24.2 kN and C0 41.5 kN at the 40 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 6.6 kN, the limiting speed 11,500 r/min and the thermal reference speed 7,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.60 kN/mm and per millimetre of width 1.42 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 74 g, just 0.09 g per mm² of projected 50×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 40 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 17 mm width as a standard mounting space Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 40×50×17 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 50 mm outside diameter and 24.2 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 40 mm seat, and in two-stroke and compressor piston pins the 74 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 17 mm width and the published 41.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO40×50×17-XL?",
        "a": "The RNAO40×50×17-XL is a RNAO flangeless needle roller bearing without inner ring with 50 mm outside diameter, 40 mm bore and 17 mm width, envelope 40×50×17 mm. Mass is 74 g."
      },
      {
        "q": "What does the RNAO40×50×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO40×50×17-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×50×17 mm and the catalogue ratings are C 24.2 kN, C0 41.5 kN, Cur 6.6 kN."
      },
      {
        "q": "What is the load capacity of the RNAO40×50×17-XL?",
        "a": "The basic dynamic load rating C is 24.2 kN and the basic static load rating C0 is 41.5 kN; the fatigue load limit Cur is 6.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO40×50×17-XL?",
        "a": "The limiting speed is 11,500 r/min and the thermal reference speed is 7,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO40×50×17-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO40×50×17-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO40X50X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO40X50X17-XL",
      "RNAO40×50×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO40X50X34-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO40×50×34-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 41.5,
    "static_load_kN": 83,
    "fatigue_load_limit_kN": 13.1,
    "limiting_speed_rpm": 11500,
    "max_rpm": 11500,
    "reference_speed_rpm": 7000,
    "weight_g": 152,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×50×34 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 41.5 kN and C0 83 kN at the 40 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 13.1 kN, the limiting speed 11,500 r/min and the thermal reference speed 7,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 1.22 kN/mm — the reason 34 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 152 g, just 0.09 g per mm² of projected 50×34 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 50 mm envelope already carries ratings in the tens of kilonewtons RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 40 mm hardened shaft journal and the housing faces provide all axial guidance With no ribs the rollers can be arranged very freely in the 34 mm width, giving C 41.5 kN at only 50 mm outside diameter — the most compact radial unit in the HR1 needle section The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 40×50×34 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 34 mm width while the outside diameter stays a compact 50 mm. The -ASR1 suffix provides an annular groove with lubrication holes in the outer ring, fed directly from the housing side. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 50 mm outside diameter and 41.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 40 mm seat, and in motorcycle and light-vehicle transmissions the 152 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 34 mm width and the published 83 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO40×50×34-ZW-ASR1-XL?",
        "a": "The RNAO40×50×34-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 50 mm outside diameter, 40 mm bore and 34 mm width, envelope 40×50×34 mm. Mass is 152 g."
      },
      {
        "q": "What does the RNAO40×50×34-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO40×50×34-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×50×34 mm and the catalogue ratings are C 41.5 kN, C0 83 kN, Cur 13.1 kN."
      },
      {
        "q": "What is the load capacity of the RNAO40×50×34-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 41.5 kN and the basic static load rating C0 is 83 kN; the fatigue load limit Cur is 13.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO40×50×34-ZW-ASR1-XL?",
        "a": "The limiting speed is 11,500 r/min and the thermal reference speed is 7,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO40×50×34-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO40×50×34-ZW-ASR1-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO40X50X34",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO40X50X34-ZW-ASR1-XL",
      "RNAO40×50×34-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO40X55X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO40×55×20-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 37,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 11300,
    "max_rpm": 11300,
    "reference_speed_rpm": 6600,
    "weight_g": 145,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×20 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 40 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 11,300 r/min and the thermal reference speed 6,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.93 kN/mm and per millimetre of width 1.85 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 145 g, just 0.13 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 145 g mass calls for proper induction or press tooling rather than hand fitting Cur 9.1 kN and speeds up to 11,300 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 57 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 55 mm outside diameter and 37 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 40 mm seat, and in copying and printing machine mechanisms the 145 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 57 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO40×55×20-XL?",
        "a": "The RNAO40×55×20-XL is a RNAO flangeless needle roller bearing without inner ring with 55 mm outside diameter, 40 mm bore and 20 mm width, envelope 40×55×20 mm. Mass is 145 g."
      },
      {
        "q": "What does the RNAO40×55×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO40×55×20-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×20 mm and the catalogue ratings are C 37 kN, C0 57 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the RNAO40×55×20-XL?",
        "a": "The basic dynamic load rating C is 37 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO40×55×20-XL?",
        "a": "The limiting speed is 11,300 r/min and the thermal reference speed is 6,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO40×55×20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO40×55×20-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO40X55X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO40X55X20-XL",
      "RNAO40×55×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO40X55X40-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO40×55×40-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 70,
    "static_load_kN": 118,
    "fatigue_load_limit_kN": 19,
    "limiting_speed_rpm": 11100,
    "max_rpm": 11100,
    "reference_speed_rpm": 6500,
    "weight_g": 275,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×40 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 70 kN and C0 118 kN at the 40 mm seat; the C/C0 ratio of 0.59 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 19 kN, the limiting speed 11,100 r/min and the thermal reference speed 6,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.75 kN/mm and per millimetre of width 1.75 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 275 g, just 0.13 g per mm² of projected 55×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 275 g mass calls for proper induction or press tooling rather than hand fitting At 275 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts With no ribs the rollers can be arranged very freely in the 40 mm width, giving C 70 kN at only 55 mm outside diameter — the most compact radial unit in the HR1 needle section -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 70 kN C rating and longer nominal life come without an envelope change. The -ZW double-row pack explains the high C0 of 118 kN in this thin-section bearing — two rows support the static peak that a single row could not. -ASR1 marks the outer-ring lubrication feature: the annular groove distributes grease to both needle rows of the 40 mm-wide pack. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 55 mm outside diameter and 70 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 40 mm seat, and in planetary gear bearings the 275 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 40 mm width and the published 118 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO40×55×40-ZW-ASR1-XL?",
        "a": "The RNAO40×55×40-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 55 mm outside diameter, 40 mm bore and 40 mm width, envelope 40×55×40 mm. Mass is 275 g."
      },
      {
        "q": "What does the RNAO40×55×40-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO40×55×40-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×40 mm and the catalogue ratings are C 70 kN, C0 118 kN, Cur 19 kN."
      },
      {
        "q": "What is the load capacity of the RNAO40×55×40-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 70 kN and the basic static load rating C0 is 118 kN; the fatigue load limit Cur is 19 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO40×55×40-ZW-ASR1-XL?",
        "a": "The limiting speed is 11,100 r/min and the thermal reference speed is 6,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO40×55×40-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO40×55×40-ZW-ASR1-XL has no inner ring, so the 40 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO40X55X40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO40X55X40-ZW-ASR1-XL",
      "RNAO40×55×40-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO45X55X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO45×55×17-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 55,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 46,
    "fatigue_load_limit_kN": 7.3,
    "limiting_speed_rpm": 10300,
    "max_rpm": 10300,
    "reference_speed_rpm": 6300,
    "weight_g": 83,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×55×17 mm: 45 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 25.5 kN and C0 46 kN at the 45 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 7.3 kN, the limiting speed 10,300 r/min and the thermal reference speed 6,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.57 kN/mm and per millimetre of width 1.50 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 83 g, just 0.09 g per mm² of projected 55×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons With no ribs the rollers can be arranged very freely in the 17 mm width, giving C 25.5 kN at only 55 mm outside diameter — the most compact radial unit in the HR1 needle section The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 46 kN static rating cannot be used The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 10,300 r/min limit. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 55 mm outside diameter and 25.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 45 mm seat, and in connecting-rod small ends the 83 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 17 mm width and the published 46 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO45×55×17-XL?",
        "a": "The RNAO45×55×17-XL is a RNAO flangeless needle roller bearing without inner ring with 55 mm outside diameter, 45 mm bore and 17 mm width, envelope 45×55×17 mm. Mass is 83 g."
      },
      {
        "q": "What does the RNAO45×55×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO45×55×17-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×55×17 mm and the catalogue ratings are C 25.5 kN, C0 46 kN, Cur 7.3 kN."
      },
      {
        "q": "What is the load capacity of the RNAO45×55×17-XL?",
        "a": "The basic dynamic load rating C is 25.5 kN and the basic static load rating C0 is 46 kN; the fatigue load limit Cur is 7.3 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO45×55×17-XL?",
        "a": "The limiting speed is 10,300 r/min and the thermal reference speed is 6,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO45×55×17-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO45×55×17-XL has no inner ring, so the 45 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO45X55X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO45X55X17-XL",
      "RNAO45×55×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO45X62X40-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO45×62×40-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 76,
    "static_load_kN": 135,
    "fatigue_load_limit_kN": 21.9,
    "limiting_speed_rpm": 10000,
    "max_rpm": 10000,
    "reference_speed_rpm": 5900,
    "weight_g": 377,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 45×62×40 mm: 45 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 76 kN and C0 135 kN at the 45 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 21.9 kN, the limiting speed 10,000 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.69 kN/mm and per millimetre of width 1.90 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 377 g, just 0.15 g per mm² of projected 62×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 45 mm bore marks the medium range: mounting forces and fits become critical, and the 377 g mass calls for proper induction or press tooling rather than hand fitting Reading RNAO: O denotes the ribless (open-sided) race design; ZW means two roller rows in the one envelope With no ribs the rollers can be arranged very freely in the 40 mm width, giving C 76 kN at only 62 mm outside diameter — the most compact radial unit in the HR1 needle section X-life status (-XL) indicates the current Schaeffler premium execution at 45 mm bore; the 135 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 40 mm-wide envelope for higher capacity at the same bore. The ASR groove is particularly useful on double-row -ZW executions, feeding both rows evenly across the 62 mm outer ring. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 62 mm outside diameter and 76 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 45 mm seat, and in rocker arms and valve trains the 377 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 40 mm width and the published 135 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO45×62×40-ZW-ASR1-XL?",
        "a": "The RNAO45×62×40-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 62 mm outside diameter, 45 mm bore and 40 mm width, envelope 45×62×40 mm. Mass is 377 g."
      },
      {
        "q": "What does the RNAO45×62×40-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO45×62×40-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 45×62×40 mm and the catalogue ratings are C 76 kN, C0 135 kN, Cur 21.9 kN."
      },
      {
        "q": "What is the load capacity of the RNAO45×62×40-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 76 kN and the basic static load rating C0 is 135 kN; the fatigue load limit Cur is 21.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO45×62×40-ZW-ASR1-XL?",
        "a": "The limiting speed is 10,000 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO45×62×40-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO45×62×40-ZW-ASR1-XL has no inner ring, so the 45 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO45X62X40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO45X62X40-ZW-ASR1-XL",
      "RNAO45×62×40-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO50X62X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO50×62×20-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 62,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 30,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 9.7,
    "limiting_speed_rpm": 9300,
    "max_rpm": 9300,
    "reference_speed_rpm": 5800,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×62×20 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 30 kN and C0 60 kN at the 50 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 9.7 kN, the limiting speed 9,300 r/min and the thermal reference speed 5,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.60 kN/mm and per millimetre of width 1.50 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 140 g, just 0.11 g per mm² of projected 62×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 50 mm bore marks the medium range: mounting forces and fits become critical, and the 140 g mass calls for proper induction or press tooling rather than hand fitting Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 50 mm hardened shaft journal and the housing faces provide all axial guidance -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 30 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 62 mm outside diameter and 30 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 50 mm seat, and in two-stroke and compressor piston pins the 140 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 20 mm width and the published 60 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO50×62×20-XL?",
        "a": "The RNAO50×62×20-XL is a RNAO flangeless needle roller bearing without inner ring with 62 mm outside diameter, 50 mm bore and 20 mm width, envelope 50×62×20 mm. Mass is 140 g."
      },
      {
        "q": "What does the RNAO50×62×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO50×62×20-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×62×20 mm and the catalogue ratings are C 30 kN, C0 60 kN, Cur 9.7 kN."
      },
      {
        "q": "What is the load capacity of the RNAO50×62×20-XL?",
        "a": "The basic dynamic load rating C is 30 kN and the basic static load rating C0 is 60 kN; the fatigue load limit Cur is 9.7 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO50×62×20-XL?",
        "a": "The limiting speed is 9,300 r/min and the thermal reference speed is 5,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO50×62×20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO50×62×20-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO50X62X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO50X62X20-XL",
      "RNAO50×62×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO50X65X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO50×65×20-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 65,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 40.5,
    "static_load_kN": 62,
    "fatigue_load_limit_kN": 11,
    "limiting_speed_rpm": 9100,
    "max_rpm": 9100,
    "reference_speed_rpm": 5600,
    "weight_g": 168,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×65×20 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 40.5 kN and C0 62 kN at the 50 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 65 mm outside diameter the fatigue load limit Cur is 11 kN, the limiting speed 9,100 r/min and the thermal reference speed 5,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.81 kN/mm and per millimetre of width 2.02 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 168 g, just 0.13 g per mm² of projected 65×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 50 mm bore places this bearing in the medium band, where the 65 mm envelope already carries ratings in the tens of kilonewtons At 168 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts Cur 11 kN and speeds up to 9,100 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 65 mm outside diameter and 40.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 50 mm seat, and in small electric motor accessory drives the 168 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 20 mm width and the published 62 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO50×65×20-XL?",
        "a": "The RNAO50×65×20-XL is a RNAO flangeless needle roller bearing without inner ring with 65 mm outside diameter, 50 mm bore and 20 mm width, envelope 50×65×20 mm. Mass is 168 g."
      },
      {
        "q": "What does the RNAO50×65×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO50×65×20-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×65×20 mm and the catalogue ratings are C 40.5 kN, C0 62 kN, Cur 11 kN."
      },
      {
        "q": "What is the load capacity of the RNAO50×65×20-XL?",
        "a": "The basic dynamic load rating C is 40.5 kN and the basic static load rating C0 is 62 kN; the fatigue load limit Cur is 11 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO50×65×20-XL?",
        "a": "The limiting speed is 9,100 r/min and the thermal reference speed is 5,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO50×65×20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO50×65×20-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO50X65X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO50X65X20-XL",
      "RNAO50×65×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO50X65X40-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO50×65×40-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 65,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 69,
    "static_load_kN": 124,
    "fatigue_load_limit_kN": 22.1,
    "limiting_speed_rpm": 9100,
    "max_rpm": 9100,
    "reference_speed_rpm": 5600,
    "weight_g": 355,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×65×40 mm: 50 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 69 kN and C0 124 kN at the 50 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 65 mm outside diameter the fatigue load limit Cur is 22.1 kN, the limiting speed 9,100 r/min and the thermal reference speed 5,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.38 kN/mm and per millimetre of width 1.73 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 355 g, just 0.14 g per mm² of projected 65×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 50 mm bore marks the medium range: mounting forces and fits become critical, and the 355 g mass calls for proper induction or press tooling rather than hand fitting Cur 22.1 kN and speeds up to 9,100 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 50 mm hardened shaft journal and the housing faces provide all axial guidance The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 9,100 r/min limit. -ZW marks the double-row execution — two offset needle rows in one 50×65 mm ring pair, giving the 69 kN C rating in a housing space sized for a wide single bearing. -ASR1 leaves the envelope unchanged but requires a registering groove or port in the housing bore around the 50 mm seat. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 65 mm outside diameter and 69 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 50 mm seat, and in agricultural machine pivots and linkages the 355 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 40 mm width and the published 124 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO50×65×40-ZW-ASR1-XL?",
        "a": "The RNAO50×65×40-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 65 mm outside diameter, 50 mm bore and 40 mm width, envelope 50×65×40 mm. Mass is 355 g."
      },
      {
        "q": "What does the RNAO50×65×40-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO50×65×40-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×65×40 mm and the catalogue ratings are C 69 kN, C0 124 kN, Cur 22.1 kN."
      },
      {
        "q": "What is the load capacity of the RNAO50×65×40-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 69 kN and the basic static load rating C0 is 124 kN; the fatigue load limit Cur is 22.1 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO50×65×40-ZW-ASR1-XL?",
        "a": "The limiting speed is 9,100 r/min and the thermal reference speed is 5,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO50×65×40-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO50×65×40-ZW-ASR1-XL has no inner ring, so the 50 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO50X65X40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO50X65X40-ZW-ASR1-XL",
      "RNAO50×65×40-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO55X68X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO55×68×20-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32,
    "static_load_kN": 66,
    "fatigue_load_limit_kN": 10.9,
    "limiting_speed_rpm": 8500,
    "max_rpm": 8500,
    "reference_speed_rpm": 5400,
    "weight_g": 166,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 55×68×20 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 32 kN and C0 66 kN at the 55 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 10.9 kN, the limiting speed 8,500 r/min and the thermal reference speed 5,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.58 kN/mm and per millimetre of width 1.60 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 166 g, just 0.12 g per mm² of projected 68×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 55 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 55×68×20 mm envelope. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 68 mm outside diameter and 32 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 55 mm seat, and in agricultural machine pivots and linkages the 166 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 66 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO55×68×20-XL?",
        "a": "The RNAO55×68×20-XL is a RNAO flangeless needle roller bearing without inner ring with 68 mm outside diameter, 55 mm bore and 20 mm width, envelope 55×68×20 mm. Mass is 166 g."
      },
      {
        "q": "What does the RNAO55×68×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO55×68×20-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 55×68×20 mm and the catalogue ratings are C 32 kN, C0 66 kN, Cur 10.9 kN."
      },
      {
        "q": "What is the load capacity of the RNAO55×68×20-XL?",
        "a": "The basic dynamic load rating C is 32 kN and the basic static load rating C0 is 66 kN; the fatigue load limit Cur is 10.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO55×68×20-XL?",
        "a": "The limiting speed is 8,500 r/min and the thermal reference speed is 5,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO55×68×20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO55×68×20-XL has no inner ring, so the 55 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO55X68X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO55X68X20-XL",
      "RNAO55×68×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO60X78X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO60×78×20-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 78,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 49.5,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 13.9,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4650,
    "weight_g": 255,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×78×20 mm: 60 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 49.5 kN and C0 85 kN at the 60 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 78 mm outside diameter the fatigue load limit Cur is 13.9 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.82 kN/mm and per millimetre of width 2.48 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 255 g, just 0.16 g per mm² of projected 78×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 60 mm bore marks the medium range: mounting forces and fits become critical, and the 255 g mass calls for proper induction or press tooling rather than hand fitting At 255 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts With no ribs the rollers can be arranged very freely in the 20 mm width, giving C 49.5 kN at only 78 mm outside diameter — the most compact radial unit in the HR1 needle section -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 49.5 kN C rating and longer nominal life come without an envelope change. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 78 mm outside diameter and 49.5 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 60 mm seat, and in copying and printing machine mechanisms the 255 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 85 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO60×78×20-XL?",
        "a": "The RNAO60×78×20-XL is a RNAO flangeless needle roller bearing without inner ring with 78 mm outside diameter, 60 mm bore and 20 mm width, envelope 60×78×20 mm. Mass is 255 g."
      },
      {
        "q": "What does the RNAO60×78×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO60×78×20-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×78×20 mm and the catalogue ratings are C 49.5 kN, C0 85 kN, Cur 13.9 kN."
      },
      {
        "q": "What is the load capacity of the RNAO60×78×20-XL?",
        "a": "The basic dynamic load rating C is 49.5 kN and the basic static load rating C0 is 85 kN; the fatigue load limit Cur is 13.9 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO60×78×20-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO60×78×20-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO60×78×20-XL has no inner ring, so the 60 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO60X78X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO60X78X20-XL",
      "RNAO60×78×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO60X78X40-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO60×78×40-ZW-ASR1-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 78,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 85,
    "static_load_kN": 171,
    "fatigue_load_limit_kN": 28,
    "limiting_speed_rpm": 7700,
    "max_rpm": 7700,
    "reference_speed_rpm": 4650,
    "weight_g": 435,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 60×78×40 mm: 60 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 85 kN and C0 171 kN at the 60 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 78 mm outside diameter the fatigue load limit Cur is 28 kN, the limiting speed 7,700 r/min and the thermal reference speed 4,650 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.42 kN/mm and per millimetre of width 2.13 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 435 g, just 0.14 g per mm² of projected 78×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 60 mm bore marks the medium range: mounting forces and fits become critical, and the 435 g mass calls for proper induction or press tooling rather than hand fitting The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 171 kN static rating cannot be used At 435 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 60×78×40 mm envelope. Reading -ZW: two needle rows instead of one; the load is spread over the 40 mm width while the outside diameter stays a compact 78 mm. The -ASR1 suffix provides an annular groove with lubrication holes in the outer ring, fed directly from the housing side. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 78 mm outside diameter and 85 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 60 mm seat, and in hydraulic and pneumatic pump eccentrics the 435 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 40 mm width and the published 171 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO60×78×40-ZW-ASR1-XL?",
        "a": "The RNAO60×78×40-ZW-ASR1-XL is a RNAO flangeless needle roller bearing without inner ring with 78 mm outside diameter, 60 mm bore and 40 mm width, envelope 60×78×40 mm. Mass is 435 g."
      },
      {
        "q": "What does the RNAO60×78×40-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO60×78×40-ZW-ASR1-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 60×78×40 mm and the catalogue ratings are C 85 kN, C0 171 kN, Cur 28 kN."
      },
      {
        "q": "What is the load capacity of the RNAO60×78×40-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 85 kN and the basic static load rating C0 is 171 kN; the fatigue load limit Cur is 28 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO60×78×40-ZW-ASR1-XL?",
        "a": "The limiting speed is 7,700 r/min and the thermal reference speed is 4,650 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO60×78×40-ZW-ASR1-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO60×78×40-ZW-ASR1-XL has no inner ring, so the 60 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO60X78X40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO60X78X40-ZW-ASR1-XL",
      "RNAO60×78×40-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO65X85X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO65×85×30-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 85,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 64,
    "static_load_kN": 123,
    "fatigue_load_limit_kN": 21.5,
    "limiting_speed_rpm": 7100,
    "max_rpm": 7100,
    "reference_speed_rpm": 4550,
    "weight_g": 464,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 65×85×30 mm: 65 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 64 kN and C0 123 kN at the 65 mm seat; the C/C0 ratio of 0.52 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 21.5 kN, the limiting speed 7,100 r/min and the thermal reference speed 4,550 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.98 kN/mm and per millimetre of width 2.13 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 464 g, just 0.18 g per mm² of projected 85×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 65 mm bore this is a heavy-industrial bearing: 464 g of stiff ring and roller set, specified where rigidity matters more than speed With no ribs the rollers can be arranged very freely in the 30 mm width, giving C 64 kN at only 85 mm outside diameter — the most compact radial unit in the HR1 needle section RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 65 mm hardened shaft journal and the housing faces provide all axial guidance -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 64 kN C rating and longer nominal life come without an envelope change. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 85 mm outside diameter and 64 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 65 mm seat, and in connecting-rod small ends the 464 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 123 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO65×85×30-XL?",
        "a": "The RNAO65×85×30-XL is a RNAO flangeless needle roller bearing without inner ring with 85 mm outside diameter, 65 mm bore and 30 mm width, envelope 65×85×30 mm. Mass is 464 g."
      },
      {
        "q": "What does the RNAO65×85×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO65×85×30-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 65×85×30 mm and the catalogue ratings are C 64 kN, C0 123 kN, Cur 21.5 kN."
      },
      {
        "q": "What is the load capacity of the RNAO65×85×30-XL?",
        "a": "The basic dynamic load rating C is 64 kN and the basic static load rating C0 is 123 kN; the fatigue load limit Cur is 21.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO65×85×30-XL?",
        "a": "The limiting speed is 7,100 r/min and the thermal reference speed is 4,550 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO65×85×30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO65×85×30-XL has no inner ring, so the 65 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO65X85X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO65X85X30-XL",
      "RNAO65×85×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO70X90X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO70×90×30-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 90,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 68,
    "static_load_kN": 135,
    "fatigue_load_limit_kN": 23.6,
    "limiting_speed_rpm": 6600,
    "max_rpm": 6600,
    "reference_speed_rpm": 4250,
    "weight_g": 499,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×90×30 mm: 70 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 68 kN and C0 135 kN at the 70 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 23.6 kN, the limiting speed 6,600 r/min and the thermal reference speed 4,250 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.97 kN/mm and per millimetre of width 2.27 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 499 g, just 0.18 g per mm² of projected 90×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 70 mm bore the 90 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 6,600 r/min With no ribs the rollers can be arranged very freely in the 30 mm width, giving C 68 kN at only 90 mm outside diameter — the most compact radial unit in the HR1 needle section -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 68 kN C rating and longer nominal life come without an envelope change. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 90 mm outside diameter and 68 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 70 mm seat, and in textile machine heald and cam shafts the 499 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 135 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO70×90×30-XL?",
        "a": "The RNAO70×90×30-XL is a RNAO flangeless needle roller bearing without inner ring with 90 mm outside diameter, 70 mm bore and 30 mm width, envelope 70×90×30 mm. Mass is 499 g."
      },
      {
        "q": "What does the RNAO70×90×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO70×90×30-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×90×30 mm and the catalogue ratings are C 68 kN, C0 135 kN, Cur 23.6 kN."
      },
      {
        "q": "What is the load capacity of the RNAO70×90×30-XL?",
        "a": "The basic dynamic load rating C is 68 kN and the basic static load rating C0 is 135 kN; the fatigue load limit Cur is 23.6 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO70×90×30-XL?",
        "a": "The limiting speed is 6,600 r/min and the thermal reference speed is 4,250 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO70×90×30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO70×90×30-XL has no inner ring, so the 70 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO70X90X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO70X90X30-XL",
      "RNAO70×90×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO80X100X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO80×100×30-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 80,
    "static_load_kN": 176,
    "fatigue_load_limit_kN": 31.5,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3600,
    "weight_g": 580,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×100×30 mm: 80 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 80 kN and C0 176 kN at the 80 mm seat; the C/C0 ratio of 0.45 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 31.5 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.00 kN/mm and per millimetre of width 2.67 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 580 g, just 0.19 g per mm² of projected 100×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 80 mm bore the 100 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,800 r/min With no ribs the rollers can be arranged very freely in the 30 mm width, giving C 80 kN at only 100 mm outside diameter — the most compact radial unit in the HR1 needle section Cur 31.5 kN and speeds up to 5,800 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter X-life status (-XL) indicates the current Schaeffler premium execution at 80 mm bore; the 176 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 100 mm outside diameter and 80 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 80 mm seat, and in connecting-rod small ends the 580 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 30 mm width and the published 176 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO80×100×30-XL?",
        "a": "The RNAO80×100×30-XL is a RNAO flangeless needle roller bearing without inner ring with 100 mm outside diameter, 80 mm bore and 30 mm width, envelope 80×100×30 mm. Mass is 580 g."
      },
      {
        "q": "What does the RNAO80×100×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO80×100×30-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×100×30 mm and the catalogue ratings are C 80 kN, C0 176 kN, Cur 31.5 kN."
      },
      {
        "q": "What is the load capacity of the RNAO80×100×30-XL?",
        "a": "The basic dynamic load rating C is 80 kN and the basic static load rating C0 is 176 kN; the fatigue load limit Cur is 31.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO80×100×30-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,600 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO80×100×30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO80×100×30-XL has no inner ring, so the 80 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO80X100X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO80X100X30-XL",
      "RNAO80×100×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO90X105X26-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO90×105×26-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 105,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 69,
    "static_load_kN": 150,
    "fatigue_load_limit_kN": 25.5,
    "limiting_speed_rpm": 5200,
    "max_rpm": 5200,
    "reference_speed_rpm": 3350,
    "weight_g": 373,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×105×26 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 69 kN and C0 150 kN at the 90 mm seat; the C/C0 ratio of 0.46 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 105 mm outside diameter the fatigue load limit Cur is 25.5 kN, the limiting speed 5,200 r/min and the thermal reference speed 3,350 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.77 kN/mm and per millimetre of width 2.65 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 373 g, just 0.14 g per mm² of projected 105×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 90 mm bore the 105 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,200 r/min With no ribs the rollers can be arranged very freely in the 26 mm width, giving C 69 kN at only 105 mm outside diameter — the most compact radial unit in the HR1 needle section At 373 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 25.5 kN Cur value. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 105 mm outside diameter and 69 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 90 mm seat, and in agricultural machine pivots and linkages the 373 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 26 mm width and the published 150 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO90×105×26-XL?",
        "a": "The RNAO90×105×26-XL is a RNAO flangeless needle roller bearing without inner ring with 105 mm outside diameter, 90 mm bore and 26 mm width, envelope 90×105×26 mm. Mass is 373 g."
      },
      {
        "q": "What does the RNAO90×105×26-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO90×105×26-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×105×26 mm and the catalogue ratings are C 69 kN, C0 150 kN, Cur 25.5 kN."
      },
      {
        "q": "What is the load capacity of the RNAO90×105×26-XL?",
        "a": "The basic dynamic load rating C is 69 kN and the basic static load rating C0 is 150 kN; the fatigue load limit Cur is 25.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO90×105×26-XL?",
        "a": "The limiting speed is 5,200 r/min and the thermal reference speed is 3,350 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO90×105×26-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO90×105×26-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO90X105X26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO90X105X26-XL",
      "RNAO90×105×26-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO90X110X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO90×110×30-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 76,
    "static_load_kN": 172,
    "fatigue_load_limit_kN": 30,
    "limiting_speed_rpm": 5200,
    "max_rpm": 5200,
    "reference_speed_rpm": 3450,
    "weight_g": 610,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×110×30 mm: 90 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 76 kN and C0 172 kN at the 90 mm seat; the C/C0 ratio of 0.44 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 30 kN, the limiting speed 5,200 r/min and the thermal reference speed 3,450 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 2.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 610 g, just 0.18 g per mm² of projected 110×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 90 mm bore the 110 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 5,200 r/min The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 172 kN static rating cannot be used Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 76 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 110 mm outside diameter and 76 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 90 mm seat, and in rocker arms and valve trains the 610 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 30 mm width and the published 172 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO90×110×30-XL?",
        "a": "The RNAO90×110×30-XL is a RNAO flangeless needle roller bearing without inner ring with 110 mm outside diameter, 90 mm bore and 30 mm width, envelope 90×110×30 mm. Mass is 610 g."
      },
      {
        "q": "What does the RNAO90×110×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO90×110×30-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×110×30 mm and the catalogue ratings are C 76 kN, C0 172 kN, Cur 30 kN."
      },
      {
        "q": "What is the load capacity of the RNAO90×110×30-XL?",
        "a": "The basic dynamic load rating C is 76 kN and the basic static load rating C0 is 172 kN; the fatigue load limit Cur is 30 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO90×110×30-XL?",
        "a": "The limiting speed is 5,200 r/min and the thermal reference speed is 3,450 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO90×110×30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO90×110×30-XL has no inner ring, so the 90 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO90X110X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO90X110X30-XL",
      "RNAO90×110×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNAO100X120X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "RNAO100×120×30-XL",
    "series": "rnao-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 80,
    "static_load_kN": 188,
    "fatigue_load_limit_kN": 32.5,
    "limiting_speed_rpm": 4700,
    "max_rpm": 4700,
    "reference_speed_rpm": 3150,
    "weight_g": 694,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 100×120×30 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 80 kN and C0 188 kN at the 100 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 32.5 kN, the limiting speed 4,700 r/min and the thermal reference speed 3,150 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.80 kN/mm and per millimetre of width 2.67 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 694 g, just 0.19 g per mm² of projected 120×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 100 mm bore the 120 mm outside diameter and 30 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,700 r/min At 694 g the assembly is easy to drop into a connecting-rod eye, but without ribs even a small axial offset skews the needles — end float must be controlled by the surrounding parts RNAO marks the flangeless needle bearing without inner ring: neither race carries ribs, so the 100 mm hardened shaft journal and the housing faces provide all axial guidance X-life status (-XL) indicates the current Schaeffler premium execution at 100 mm bore; the 188 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 120 mm outside diameter and 80 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 100 mm seat, and in gearbox selector and change linkages the 694 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 30 mm width and the published 188 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the RNAO100×120×30-XL?",
        "a": "The RNAO100×120×30-XL is a RNAO flangeless needle roller bearing without inner ring with 120 mm outside diameter, 100 mm bore and 30 mm width, envelope 100×120×30 mm. Mass is 694 g."
      },
      {
        "q": "What does the RNAO100×120×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "RNAO100×120×30-XL identifies this RNAO flangeless needle roller bearing without inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 100×120×30 mm and the catalogue ratings are C 80 kN, C0 188 kN, Cur 32.5 kN."
      },
      {
        "q": "What is the load capacity of the RNAO100×120×30-XL?",
        "a": "The basic dynamic load rating C is 80 kN and the basic static load rating C0 is 188 kN; the fatigue load limit Cur is 32.5 kN."
      },
      {
        "q": "What is the maximum speed of the RNAO100×120×30-XL?",
        "a": "The limiting speed is 4,700 r/min and the thermal reference speed is 3,150 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "Can the RNAO100×120×30-XL run directly on an ordinary shaft?",
        "a": "Not on a soft shaft. The RNAO100×120×30-XL has no inner ring, so the 100 mm journal itself is the raceway: harden it to 58–64 HRC and finish-grind to the catalogue journal tolerance. Where the shaft cannot be hardened, use the corresponding with-inner-ring execution instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNAO100X120X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=969",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNAO100X120X30-XL",
      "RNAO100×120×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO6X17X10-TV-IS1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO6×17×10-TV-IS1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 17,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.3,
    "static_load_kN": 5.5,
    "fatigue_load_limit_kN": 0.94,
    "limiting_speed_rpm": 29500,
    "max_rpm": 29500,
    "reference_speed_rpm": 23800,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 6×17×10 mm: 6 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 5.5 mm radial section packed with small-diameter needle rollers C is 5.3 kN and C0 5.5 kN at the 6 mm seat; the C/C0 ratio of 0.96 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 17 mm outside diameter the fatigue load limit Cur is 0.94 kN, the limiting speed 29,500 r/min and the thermal reference speed 23,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 0.53 kN/mm — the reason 10 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 14 g, just 0.08 g per mm² of projected 17×10 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 6 mm bore this is one of the smallest HR1 executions — chosen where a 17 mm envelope must carry line-contact loads that no miniature ball bearing could take The single needle row fills the thin section, with limiting speed 29,500 r/min and reference speed 23,800 r/min With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 5.5 kN and Cur 0.94 kN for the 14 g unit The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 6×17×10 mm envelope. The -TV cage is part of the speed story here: cage-guided kinematics permit the published 29,500 r/min limiting speed without roller-to-roller sliding. The IS1 groove keeps the flangeless races lubricable from the shaft side despite the compact 5.5 mm section. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 17 mm outside diameter and 5.3 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 6 mm seat, and in gearbox selector and change linkages the 14 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 10 mm width and the published 5.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO6×17×10-TV-IS1-XL?",
        "a": "The NAO6×17×10-TV-IS1-XL is a NAO flangeless needle roller bearing with inner ring with 17 mm outside diameter, 6 mm bore and 10 mm width, envelope 6×17×10 mm. Mass is 14 g."
      },
      {
        "q": "What does the NAO6×17×10-TV-IS1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO6×17×10-TV-IS1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 6×17×10 mm and the catalogue ratings are C 5.3 kN, C0 5.5 kN, Cur 0.94 kN."
      },
      {
        "q": "What is the load capacity of the NAO6×17×10-TV-IS1-XL?",
        "a": "The basic dynamic load rating C is 5.3 kN and the basic static load rating C0 is 5.5 kN; the fatigue load limit Cur is 0.94 kN."
      },
      {
        "q": "What is the maximum speed of the NAO6×17×10-TV-IS1-XL?",
        "a": "The limiting speed is 29,500 r/min and the thermal reference speed is 23,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO6×17×10-TV-IS1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 6 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO6X17X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO6X17X10-TV-IS1-XL",
      "NAO6×17×10-TV-IS1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO9X22X12-TV-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO9×22×12-TV-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 22,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 11.3,
    "static_load_kN": 9.9,
    "fatigue_load_limit_kN": 1.77,
    "limiting_speed_rpm": 26000,
    "max_rpm": 26000,
    "reference_speed_rpm": 17900,
    "weight_g": 23.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 9×22×12 mm: 9 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 11.3 kN and C0 9.9 kN at the 9 mm seat; the C/C0 ratio of 1.14 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 22 mm outside diameter the fatigue load limit Cur is 1.77 kN, the limiting speed 26,000 r/min and the thermal reference speed 17,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.26 kN/mm and per millimetre of width 0.94 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 23.5 g, just 0.09 g per mm² of projected 22×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 9 mm bore this is one of the smallest HR1 executions — chosen where a 22 mm envelope must carry line-contact loads that no miniature ball bearing could take Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges The inner ring gives a 9 mm plain bore inside the 22×12 mm envelope and the flangeless pack delivers C 11.3 kN — a frequent choice in gear change linkages and pumps The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 26,000 r/min limit. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 22 mm outside diameter and 11.3 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 9 mm seat, and in agricultural machine pivots and linkages the 23.5 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 12 mm width and the published 9.9 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO9×22×12-TV-XL?",
        "a": "The NAO9×22×12-TV-XL is a NAO flangeless needle roller bearing with inner ring with 22 mm outside diameter, 9 mm bore and 12 mm width, envelope 9×22×12 mm. Mass is 23.5 g."
      },
      {
        "q": "What does the NAO9×22×12-TV-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO9×22×12-TV-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 9×22×12 mm and the catalogue ratings are C 11.3 kN, C0 9.9 kN, Cur 1.77 kN."
      },
      {
        "q": "What is the load capacity of the NAO9×22×12-TV-XL?",
        "a": "The basic dynamic load rating C is 11.3 kN and the basic static load rating C0 is 9.9 kN; the fatigue load limit Cur is 1.77 kN."
      },
      {
        "q": "What is the maximum speed of the NAO9×22×12-TV-XL?",
        "a": "The limiting speed is 26,000 r/min and the thermal reference speed is 17,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO9×22×12-TV-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 9 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO9X22X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO9X22X12-TV-XL",
      "NAO9×22×12-TV-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO12X24X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO12×24×13-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 10.1,
    "static_load_kN": 11.8,
    "fatigue_load_limit_kN": 1.93,
    "limiting_speed_rpm": 23600,
    "max_rpm": 23600,
    "reference_speed_rpm": 15000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×24×13 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 10.1 kN and C0 11.8 kN at the 12 mm seat; the C/C0 ratio of 0.86 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 24 mm outside diameter the fatigue load limit Cur is 1.93 kN, the limiting speed 23,600 r/min and the thermal reference speed 15,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 0.78 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 30 g, just 0.10 g per mm² of projected 24×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 12 mm bore this is one of the smallest HR1 executions — chosen where a 24 mm envelope must carry line-contact loads that no miniature ball bearing could take Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 6.0 mm section is too thin to compensate for tilted seats With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 11.8 kN and Cur 1.93 kN for the 30 g unit The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 23,600 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 24 mm outside diameter and 10.1 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 12 mm seat, and in two-stroke and compressor piston pins the 30 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 13 mm width and the published 11.8 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO12×24×13-XL?",
        "a": "The NAO12×24×13-XL is a NAO flangeless needle roller bearing with inner ring with 24 mm outside diameter, 12 mm bore and 13 mm width, envelope 12×24×13 mm. Mass is 30 g."
      },
      {
        "q": "What does the NAO12×24×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO12×24×13-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×24×13 mm and the catalogue ratings are C 10.1 kN, C0 11.8 kN, Cur 1.93 kN."
      },
      {
        "q": "What is the load capacity of the NAO12×24×13-XL?",
        "a": "The basic dynamic load rating C is 10.1 kN and the basic static load rating C0 is 11.8 kN; the fatigue load limit Cur is 1.93 kN."
      },
      {
        "q": "What is the maximum speed of the NAO12×24×13-XL?",
        "a": "The limiting speed is 23,600 r/min and the thermal reference speed is 15,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO12×24×13-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO12X24X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO12X24X13-XL",
      "NAO12×24×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO12X28X12-IS1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO12×28×12-IS1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 28,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 13,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 2.25,
    "limiting_speed_rpm": 22900,
    "max_rpm": 22900,
    "reference_speed_rpm": 14300,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 12×28×12 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.0 mm radial section packed with small-diameter needle rollers C is 13 kN and C0 12.5 kN at the 12 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.25 kN, the limiting speed 22,900 r/min and the thermal reference speed 14,300 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.08 kN/mm and per millimetre of width 1.08 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 40 g, just 0.12 g per mm² of projected 28×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 12 mm bore and only 40 g: the smallest sizes demand accurate shaft geometry, because the 8.0 mm section leaves no tolerance for a soft or tapered seat The single needle row fills the thin section, with limiting speed 22,900 r/min and reference speed 14,300 r/min X-life status (-XL) indicates the current Schaeffler premium execution at 12 mm bore; the 12.5 kN C0 rating reflects the improved rolling-contact geometry. -IS1 is the inner-ring lube option; it changes nothing in the 12×28×12 mm envelope but requires a matching oilway in the shaft. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 28 mm outside diameter and 13 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 12 mm seat, and in two-stroke and compressor piston pins the 40 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 12 mm width and the published 12.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "copying and printing machine mechanisms",
      "rocker arms and valve trains",
      "hydraulic and pneumatic pump eccentrics",
      "agricultural machine pivots and linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO12×28×12-IS1-XL?",
        "a": "The NAO12×28×12-IS1-XL is a NAO flangeless needle roller bearing with inner ring with 28 mm outside diameter, 12 mm bore and 12 mm width, envelope 12×28×12 mm. Mass is 40 g."
      },
      {
        "q": "What does the NAO12×28×12-IS1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO12×28×12-IS1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 12×28×12 mm and the catalogue ratings are C 13 kN, C0 12.5 kN, Cur 2.25 kN."
      },
      {
        "q": "What is the load capacity of the NAO12×28×12-IS1-XL?",
        "a": "The basic dynamic load rating C is 13 kN and the basic static load rating C0 is 12.5 kN; the fatigue load limit Cur is 2.25 kN."
      },
      {
        "q": "What is the maximum speed of the NAO12×28×12-IS1-XL?",
        "a": "The limiting speed is 22,900 r/min and the thermal reference speed is 14,300 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO12×28×12-IS1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 12 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO12X28X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO12X28X12-IS1-XL",
      "NAO12×28×12-IS1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO15X28X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO15×28×13-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.1,
    "static_load_kN": 14.3,
    "fatigue_load_limit_kN": 2.35,
    "limiting_speed_rpm": 21300,
    "max_rpm": 21300,
    "reference_speed_rpm": 12100,
    "weight_g": 29,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×28×13 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 11.1 kN and C0 14.3 kN at the 15 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.35 kN, the limiting speed 21,300 r/min and the thermal reference speed 12,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.74 kN/mm and per millimetre of width 0.85 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 29 g, just 0.08 g per mm² of projected 28×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 15 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Reading NAO: the O-suffix race design has no integral ribs on either ring, so the bearing can be separated and the outer assembly swivelled into split housings during mounting With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 14.3 kN and Cur 2.35 kN for the 29 g unit The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 21,300 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 28 mm outside diameter and 11.1 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 15 mm seat, and in hydraulic and pneumatic pump eccentrics the 29 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 13 mm width and the published 14.3 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO15×28×13-XL?",
        "a": "The NAO15×28×13-XL is a NAO flangeless needle roller bearing with inner ring with 28 mm outside diameter, 15 mm bore and 13 mm width, envelope 15×28×13 mm. Mass is 29 g."
      },
      {
        "q": "What does the NAO15×28×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO15×28×13-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×28×13 mm and the catalogue ratings are C 11.1 kN, C0 14.3 kN, Cur 2.35 kN."
      },
      {
        "q": "What is the load capacity of the NAO15×28×13-XL?",
        "a": "The basic dynamic load rating C is 11.1 kN and the basic static load rating C0 is 14.3 kN; the fatigue load limit Cur is 2.35 kN."
      },
      {
        "q": "What is the maximum speed of the NAO15×28×13-XL?",
        "a": "The limiting speed is 21,300 r/min and the thermal reference speed is 12,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO15×28×13-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO15X28X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO15X28X13-XL",
      "NAO15×28×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO15X32X12-IS1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO15×32×12-IS1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 32,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 16.2,
    "fatigue_load_limit_kN": 2.9,
    "limiting_speed_rpm": 20900,
    "max_rpm": 20900,
    "reference_speed_rpm": 11400,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 15×32×12 mm: 15 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 15.1 kN and C0 16.2 kN at the 15 mm seat; the C/C0 ratio of 0.93 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 32 mm outside diameter the fatigue load limit Cur is 2.9 kN, the limiting speed 20,900 r/min and the thermal reference speed 11,400 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.01 kN/mm and per millimetre of width 1.26 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 50 g, just 0.13 g per mm² of projected 32×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 15 mm bore the 12 mm width and 15.1 kN C rating suit high-cycle industrial machinery rather than instrument duty With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 16.2 kN and Cur 2.9 kN for the 50 g unit As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 2.9 kN Cur value. -IS1 marks the inner-ring lubrication feature: grease reaches the needle pack via the groove machined around the inner ring of the NAO15×32×12-IS1-XL. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 32 mm outside diameter and 15.1 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 15 mm seat, and in small electric motor accessory drives the 50 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 12 mm width and the published 16.2 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO15×32×12-IS1-XL?",
        "a": "The NAO15×32×12-IS1-XL is a NAO flangeless needle roller bearing with inner ring with 32 mm outside diameter, 15 mm bore and 12 mm width, envelope 15×32×12 mm. Mass is 50 g."
      },
      {
        "q": "What does the NAO15×32×12-IS1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO15×32×12-IS1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 15×32×12 mm and the catalogue ratings are C 15.1 kN, C0 16.2 kN, Cur 2.9 kN."
      },
      {
        "q": "What is the load capacity of the NAO15×32×12-IS1-XL?",
        "a": "The basic dynamic load rating C is 15.1 kN and the basic static load rating C0 is 16.2 kN; the fatigue load limit Cur is 2.9 kN."
      },
      {
        "q": "What is the maximum speed of the NAO15×32×12-IS1-XL?",
        "a": "The limiting speed is 20,900 r/min and the thermal reference speed is 11,400 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO15×32×12-IS1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 15 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO15X32X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO15X32X12-IS1-XL",
      "NAO15×32×12-IS1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO17X30X13-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO17×30×13-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 11.8,
    "static_load_kN": 15.9,
    "fatigue_load_limit_kN": 2.6,
    "limiting_speed_rpm": 20400,
    "max_rpm": 20400,
    "reference_speed_rpm": 11100,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×30×13 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 11.8 kN and C0 15.9 kN at the 17 mm seat; the C/C0 ratio of 0.74 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 30 mm outside diameter the fatigue load limit Cur is 2.6 kN, the limiting speed 20,400 r/min and the thermal reference speed 11,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.69 kN/mm and per millimetre of width 0.91 kN/mm — the reason 13 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 42 g, just 0.11 g per mm² of projected 30×13 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 17 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The inner ring gives a 17 mm plain bore inside the 30×13 mm envelope and the flangeless pack delivers C 11.8 kN — a frequent choice in gear change linkages and pumps Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 6.5 mm section is too thin to compensate for tilted seats The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 20,400 r/min limit. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 30 mm outside diameter and 11.8 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 17 mm seat, and in gearbox selector and change linkages the 42 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 13 mm width and the published 15.9 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO17×30×13-XL?",
        "a": "The NAO17×30×13-XL is a NAO flangeless needle roller bearing with inner ring with 30 mm outside diameter, 17 mm bore and 13 mm width, envelope 17×30×13 mm. Mass is 42 g."
      },
      {
        "q": "What does the NAO17×30×13-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO17×30×13-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×30×13 mm and the catalogue ratings are C 11.8 kN, C0 15.9 kN, Cur 2.6 kN."
      },
      {
        "q": "What is the load capacity of the NAO17×30×13-XL?",
        "a": "The basic dynamic load rating C is 11.8 kN and the basic static load rating C0 is 15.9 kN; the fatigue load limit Cur is 2.6 kN."
      },
      {
        "q": "What is the maximum speed of the NAO17×30×13-XL?",
        "a": "The limiting speed is 20,400 r/min and the thermal reference speed is 11,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO17×30×13-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO17X30X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO17X30X13-XL",
      "NAO17×30×13-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO17X35X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO17×35×16-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 35,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22.6,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 4.25,
    "limiting_speed_rpm": 19200,
    "max_rpm": 19200,
    "reference_speed_rpm": 10100,
    "weight_g": 78,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 17×35×16 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 22.6 kN and C0 25.5 kN at the 17 mm seat; the C/C0 ratio of 0.89 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 4.25 kN, the limiting speed 19,200 r/min and the thermal reference speed 10,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.33 kN/mm and per millimetre of width 1.41 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 78 g, just 0.14 g per mm² of projected 35×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 17 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 9.0 mm section is too thin to compensate for tilted seats The single needle row fills the thin section, with limiting speed 19,200 r/min and reference speed 10,100 r/min The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 19,200 r/min limit. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 35 mm outside diameter and 22.6 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 17 mm seat, and in copying and printing machine mechanisms the 78 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 16 mm width and the published 25.5 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "textile machine heald and cam shafts",
      "gearbox selector and change linkages",
      "connecting-rod small ends",
      "motorcycle and light-vehicle transmissions"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO17×35×16-XL?",
        "a": "The NAO17×35×16-XL is a NAO flangeless needle roller bearing with inner ring with 35 mm outside diameter, 17 mm bore and 16 mm width, envelope 17×35×16 mm. Mass is 78 g."
      },
      {
        "q": "What does the NAO17×35×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO17×35×16-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 17×35×16 mm and the catalogue ratings are C 22.6 kN, C0 25.5 kN, Cur 4.25 kN."
      },
      {
        "q": "What is the load capacity of the NAO17×35×16-XL?",
        "a": "The basic dynamic load rating C is 22.6 kN and the basic static load rating C0 is 25.5 kN; the fatigue load limit Cur is 4.25 kN."
      },
      {
        "q": "What is the maximum speed of the NAO17×35×16-XL?",
        "a": "The limiting speed is 19,200 r/min and the thermal reference speed is 10,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO17×35×16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 17 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO17X35X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO17X35X16-XL",
      "NAO17×35×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO20X35X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO20×35×17-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 35,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 16.8,
    "static_load_kN": 26,
    "fatigue_load_limit_kN": 4.3,
    "limiting_speed_rpm": 18100,
    "max_rpm": 18100,
    "reference_speed_rpm": 10000,
    "weight_g": 76,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×35×17 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 16.8 kN and C0 26 kN at the 20 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 35 mm outside diameter the fatigue load limit Cur is 4.3 kN, the limiting speed 18,100 r/min and the thermal reference speed 10,000 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.84 kN/mm and per millimetre of width 0.99 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 76 g, just 0.13 g per mm² of projected 35×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 17 mm width and 16.8 kN C rating suit high-cycle industrial machinery rather than instrument duty Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 7.5 mm section is too thin to compensate for tilted seats X-life status (-XL) indicates the current Schaeffler premium execution at 20 mm bore; the 26 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 35 mm outside diameter and 16.8 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 20 mm seat, and in copying and printing machine mechanisms the 76 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 17 mm width and the published 26 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO20×35×17-XL?",
        "a": "The NAO20×35×17-XL is a NAO flangeless needle roller bearing with inner ring with 35 mm outside diameter, 20 mm bore and 17 mm width, envelope 20×35×17 mm. Mass is 76 g."
      },
      {
        "q": "What does the NAO20×35×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO20×35×17-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×35×17 mm and the catalogue ratings are C 16.8 kN, C0 26 kN, Cur 4.3 kN."
      },
      {
        "q": "What is the load capacity of the NAO20×35×17-XL?",
        "a": "The basic dynamic load rating C is 16.8 kN and the basic static load rating C0 is 26 kN; the fatigue load limit Cur is 4.3 kN."
      },
      {
        "q": "What is the maximum speed of the NAO20×35×17-XL?",
        "a": "The limiting speed is 18,100 r/min and the thermal reference speed is 10,000 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO20×35×17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO20X35X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO20X35X17-XL",
      "NAO20×35×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO20X37X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO20×37×16-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.5,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 4.65,
    "limiting_speed_rpm": 17200,
    "max_rpm": 17200,
    "reference_speed_rpm": 9100,
    "weight_g": 82,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 20×37×16 mm: 20 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 23.5 kN and C0 27.5 kN at the 20 mm seat; the C/C0 ratio of 0.85 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 4.65 kN, the limiting speed 17,200 r/min and the thermal reference speed 9,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.18 kN/mm and per millimetre of width 1.47 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 82 g, just 0.14 g per mm² of projected 37×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 20 mm bore the 16 mm width and 23.5 kN C rating suit high-cycle industrial machinery rather than instrument duty The single needle row fills the thin section, with limiting speed 17,200 r/min and reference speed 9,100 r/min With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 27.5 kN and Cur 4.65 kN for the 82 g unit The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 17,200 r/min limit. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 37 mm outside diameter and 23.5 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 20 mm seat, and in agricultural machine pivots and linkages the 82 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 16 mm width and the published 27.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "small electric motor accessory drives",
      "connecting-rod small ends",
      "planetary gear bearings",
      "gearbox selector and change linkages"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO20×37×16-XL?",
        "a": "The NAO20×37×16-XL is a NAO flangeless needle roller bearing with inner ring with 37 mm outside diameter, 20 mm bore and 16 mm width, envelope 20×37×16 mm. Mass is 82 g."
      },
      {
        "q": "What does the NAO20×37×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO20×37×16-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 20×37×16 mm and the catalogue ratings are C 23.5 kN, C0 27.5 kN, Cur 4.65 kN."
      },
      {
        "q": "What is the load capacity of the NAO20×37×16-XL?",
        "a": "The basic dynamic load rating C is 23.5 kN and the basic static load rating C0 is 27.5 kN; the fatigue load limit Cur is 4.65 kN."
      },
      {
        "q": "What is the maximum speed of the NAO20×37×16-XL?",
        "a": "The limiting speed is 17,200 r/min and the thermal reference speed is 9,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO20×37×16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 20 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO20X37X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO20X37X16-XL",
      "NAO20×37×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO25X40X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO25×40×17-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 40,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 22.1,
    "static_load_kN": 34,
    "fatigue_load_limit_kN": 5.4,
    "limiting_speed_rpm": 15100,
    "max_rpm": 15100,
    "reference_speed_rpm": 8100,
    "weight_g": 88,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×40×17 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 22.1 kN and C0 34 kN at the 25 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 40 mm outside diameter the fatigue load limit Cur is 5.4 kN, the limiting speed 15,100 r/min and the thermal reference speed 8,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.88 kN/mm and per millimetre of width 1.30 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 88 g, just 0.13 g per mm² of projected 40×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges The single needle row fills the thin section, with limiting speed 15,100 r/min and reference speed 8,100 r/min X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 34 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 40 mm outside diameter and 22.1 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 25 mm seat, and in two-stroke and compressor piston pins the 88 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 17 mm width and the published 34 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "agricultural machine pivots and linkages",
      "planetary gear bearings",
      "textile machine heald and cam shafts",
      "connecting-rod small ends"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO25×40×17-XL?",
        "a": "The NAO25×40×17-XL is a NAO flangeless needle roller bearing with inner ring with 40 mm outside diameter, 25 mm bore and 17 mm width, envelope 25×40×17 mm. Mass is 88 g."
      },
      {
        "q": "What does the NAO25×40×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO25×40×17-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×40×17 mm and the catalogue ratings are C 22.1 kN, C0 34 kN, Cur 5.4 kN."
      },
      {
        "q": "What is the load capacity of the NAO25×40×17-XL?",
        "a": "The basic dynamic load rating C is 22.1 kN and the basic static load rating C0 is 34 kN; the fatigue load limit Cur is 5.4 kN."
      },
      {
        "q": "What is the maximum speed of the NAO25×40×17-XL?",
        "a": "The limiting speed is 15,100 r/min and the thermal reference speed is 8,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO25×40×17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO25X40X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO25X40X17-XL",
      "NAO25×40×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO25X42X16-IS1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO25×42×16-IS1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 26,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 5.6,
    "limiting_speed_rpm": 14600,
    "max_rpm": 14600,
    "reference_speed_rpm": 7800,
    "weight_g": 86,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×42×16 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 26 kN and C0 33.5 kN at the 25 mm seat; the C/C0 ratio of 0.78 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 5.6 kN, the limiting speed 14,600 r/min and the thermal reference speed 7,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.04 kN/mm and per millimetre of width 1.63 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 86 g, just 0.13 g per mm² of projected 42×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The single needle row fills the thin section, with limiting speed 14,600 r/min and reference speed 7,800 r/min Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 8.5 mm section is too thin to compensate for tilted seats -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 26 kN C rating and longer nominal life come without an envelope change. The IS1 groove keeps the flangeless races lubricable from the shaft side despite the compact 8.5 mm section. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 42 mm outside diameter and 26 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 25 mm seat, and in copying and printing machine mechanisms the 86 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 16 mm width and the published 33.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO25×42×16-IS1-XL?",
        "a": "The NAO25×42×16-IS1-XL is a NAO flangeless needle roller bearing with inner ring with 42 mm outside diameter, 25 mm bore and 16 mm width, envelope 25×42×16 mm. Mass is 86 g."
      },
      {
        "q": "What does the NAO25×42×16-IS1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO25×42×16-IS1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×42×16 mm and the catalogue ratings are C 26 kN, C0 33.5 kN, Cur 5.6 kN."
      },
      {
        "q": "What is the load capacity of the NAO25×42×16-IS1-XL?",
        "a": "The basic dynamic load rating C is 26 kN and the basic static load rating C0 is 33.5 kN; the fatigue load limit Cur is 5.6 kN."
      },
      {
        "q": "What is the maximum speed of the NAO25×42×16-IS1-XL?",
        "a": "The limiting speed is 14,600 r/min and the thermal reference speed is 7,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO25×42×16-IS1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO25X42X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO25X42X16-IS1-XL",
      "NAO25×42×16-IS1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO25X42X32-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO25×42×32-ZW-ASR1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 45,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 11.3,
    "limiting_speed_rpm": 14600,
    "max_rpm": 14600,
    "reference_speed_rpm": 7800,
    "weight_g": 190,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 25×42×32 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 45 kN and C0 67 kN at the 25 mm seat; the C/C0 ratio of 0.67 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 11.3 kN, the limiting speed 14,600 r/min and the thermal reference speed 7,800 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.80 kN/mm and per millimetre of width 1.41 kN/mm — the reason 32 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 190 g, just 0.14 g per mm² of projected 42×32 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The inner ring gives a 25 mm plain bore inside the 42×32 mm envelope and the flangeless pack delivers C 45 kN — a frequent choice in gear change linkages and pumps With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 67 kN and Cur 11.3 kN for the 190 g unit X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 67 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 32 mm-wide envelope for higher capacity at the same bore. The ASR groove is particularly useful on double-row -ZW executions, feeding both rows evenly across the 42 mm outer ring. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 42 mm outside diameter and 45 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 25 mm seat, and in motorcycle and light-vehicle transmissions the 190 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 32 mm width and the published 67 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "two-stroke and compressor piston pins",
      "agricultural machine pivots and linkages",
      "rocker arms and valve trains",
      "small electric motor accessory drives"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO25×42×32-ZW-ASR1-XL?",
        "a": "The NAO25×42×32-ZW-ASR1-XL is a NAO flangeless needle roller bearing with inner ring with 42 mm outside diameter, 25 mm bore and 32 mm width, envelope 25×42×32 mm. Mass is 190 g."
      },
      {
        "q": "What does the NAO25×42×32-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO25×42×32-ZW-ASR1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 25×42×32 mm and the catalogue ratings are C 45 kN, C0 67 kN, Cur 11.3 kN."
      },
      {
        "q": "What is the load capacity of the NAO25×42×32-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 45 kN and the basic static load rating C0 is 67 kN; the fatigue load limit Cur is 11.3 kN."
      },
      {
        "q": "What is the maximum speed of the NAO25×42×32-ZW-ASR1-XL?",
        "a": "The limiting speed is 14,600 r/min and the thermal reference speed is 7,800 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO25×42×32-ZW-ASR1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 25 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO25X42X32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO25X42X32-ZW-ASR1-XL",
      "NAO25×42×32-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO30X45X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO30×45×17-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 23.5,
    "static_load_kN": 38.5,
    "fatigue_load_limit_kN": 6.2,
    "limiting_speed_rpm": 13100,
    "max_rpm": 13100,
    "reference_speed_rpm": 7100,
    "weight_g": 102,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×45×17 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 23.5 kN and C0 38.5 kN at the 30 mm seat; the C/C0 ratio of 0.61 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 6.2 kN, the limiting speed 13,100 r/min and the thermal reference speed 7,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.78 kN/mm and per millimetre of width 1.38 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 102 g, just 0.13 g per mm² of projected 45×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 30 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 38.5 kN and Cur 6.2 kN for the 102 g unit Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 6.2 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 45 mm outside diameter and 23.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 30 mm seat, and in small electric motor accessory drives the 102 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 17 mm width and the published 38.5 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "gearbox selector and change linkages",
      "two-stroke and compressor piston pins",
      "copying and printing machine mechanisms",
      "hydraulic and pneumatic pump eccentrics"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO30×45×17-XL?",
        "a": "The NAO30×45×17-XL is a NAO flangeless needle roller bearing with inner ring with 45 mm outside diameter, 30 mm bore and 17 mm width, envelope 30×45×17 mm. Mass is 102 g."
      },
      {
        "q": "What does the NAO30×45×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO30×45×17-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×45×17 mm and the catalogue ratings are C 23.5 kN, C0 38.5 kN, Cur 6.2 kN."
      },
      {
        "q": "What is the load capacity of the NAO30×45×17-XL?",
        "a": "The basic dynamic load rating C is 23.5 kN and the basic static load rating C0 is 38.5 kN; the fatigue load limit Cur is 6.2 kN."
      },
      {
        "q": "What is the maximum speed of the NAO30×45×17-XL?",
        "a": "The limiting speed is 13,100 r/min and the thermal reference speed is 7,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO30×45×17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO30X45X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO30X45X17-XL",
      "NAO30×45×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO30X45X26-ZW-ASR1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO30×45×26-ZW-ASR1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 31.5,
    "static_load_kN": 56,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 13100,
    "max_rpm": 13100,
    "reference_speed_rpm": 7200,
    "weight_g": 157,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×45×26 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 31.5 kN and C0 56 kN at the 30 mm seat; the C/C0 ratio of 0.56 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 45 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 13,100 r/min and the thermal reference speed 7,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.05 kN/mm and per millimetre of width 1.21 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 157 g, just 0.13 g per mm² of projected 45×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 26 mm width and 31.5 kN C rating suit high-cycle industrial machinery rather than instrument duty With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 56 kN and Cur 9.1 kN for the 157 g unit Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 7.5 mm section is too thin to compensate for tilted seats As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 9.1 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Reading -ASR1: outer-ring groove plus lube holes — housing-fed relubrication for the 31.5 kN C bearing without dismounting. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 45 mm outside diameter and 31.5 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 30 mm seat, and in motorcycle and light-vehicle transmissions the 157 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 26 mm width and the published 56 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO30×45×26-ZW-ASR1-XL?",
        "a": "The NAO30×45×26-ZW-ASR1-XL is a NAO flangeless needle roller bearing with inner ring with 45 mm outside diameter, 30 mm bore and 26 mm width, envelope 30×45×26 mm. Mass is 157 g."
      },
      {
        "q": "What does the NAO30×45×26-ZW-ASR1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO30×45×26-ZW-ASR1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×45×26 mm and the catalogue ratings are C 31.5 kN, C0 56 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the NAO30×45×26-ZW-ASR1-XL?",
        "a": "The basic dynamic load rating C is 31.5 kN and the basic static load rating C0 is 56 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the NAO30×45×26-ZW-ASR1-XL?",
        "a": "The limiting speed is 13,100 r/min and the thermal reference speed is 7,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO30×45×26-ZW-ASR1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO30X45X26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO30X45X26-ZW-ASR1-XL",
      "NAO30×45×26-ZW-ASR1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO30X47X16-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO30×47×16-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 37.5,
    "fatigue_load_limit_kN": 6.3,
    "limiting_speed_rpm": 12700,
    "max_rpm": 12700,
    "reference_speed_rpm": 6900,
    "weight_g": 109,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×47×16 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 27.5 kN and C0 37.5 kN at the 30 mm seat; the C/C0 ratio of 0.73 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 6.3 kN, the limiting speed 12,700 r/min and the thermal reference speed 6,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.92 kN/mm and per millimetre of width 1.72 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 109 g, just 0.14 g per mm² of projected 47×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 16 mm width and 27.5 kN C rating suit high-cycle industrial machinery rather than instrument duty With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 37.5 kN and Cur 6.3 kN for the 109 g unit X-life status (-XL) indicates the current Schaeffler premium execution at 30 mm bore; the 37.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 47 mm outside diameter and 27.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 30 mm seat, and in planetary gear bearings the 109 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 16 mm width and the published 37.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO30×47×16-XL?",
        "a": "The NAO30×47×16-XL is a NAO flangeless needle roller bearing with inner ring with 47 mm outside diameter, 30 mm bore and 16 mm width, envelope 30×47×16 mm. Mass is 109 g."
      },
      {
        "q": "What does the NAO30×47×16-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO30×47×16-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×47×16 mm and the catalogue ratings are C 27.5 kN, C0 37.5 kN, Cur 6.3 kN."
      },
      {
        "q": "What is the load capacity of the NAO30×47×16-XL?",
        "a": "The basic dynamic load rating C is 27.5 kN and the basic static load rating C0 is 37.5 kN; the fatigue load limit Cur is 6.3 kN."
      },
      {
        "q": "What is the maximum speed of the NAO30×47×16-XL?",
        "a": "The limiting speed is 12,700 r/min and the thermal reference speed is 6,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO30×47×16-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO30X47X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO30X47X16-XL",
      "NAO30×47×16-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO30X47X18-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO30×47×18-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 31,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 7.5,
    "limiting_speed_rpm": 12700,
    "max_rpm": 12700,
    "reference_speed_rpm": 6900,
    "weight_g": 119,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 30×47×18 mm: 30 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 31 kN and C0 43 kN at the 30 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 47 mm outside diameter the fatigue load limit Cur is 7.5 kN, the limiting speed 12,700 r/min and the thermal reference speed 6,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.03 kN/mm and per millimetre of width 1.72 kN/mm — the reason 18 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 119 g, just 0.14 g per mm² of projected 47×18 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 30 mm bore the 18 mm width and 31 kN C rating suit high-cycle industrial machinery rather than instrument duty Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges The inner ring gives a 30 mm plain bore inside the 47×18 mm envelope and the flangeless pack delivers C 31 kN — a frequent choice in gear change linkages and pumps As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 7.5 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 47 mm outside diameter and 31 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 30 mm seat, and in small electric motor accessory drives the 119 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 18 mm width and the published 43 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO30×47×18-XL?",
        "a": "The NAO30×47×18-XL is a NAO flangeless needle roller bearing with inner ring with 47 mm outside diameter, 30 mm bore and 18 mm width, envelope 30×47×18 mm. Mass is 119 g."
      },
      {
        "q": "What does the NAO30×47×18-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO30×47×18-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 30×47×18 mm and the catalogue ratings are C 31 kN, C0 43 kN, Cur 7.5 kN."
      },
      {
        "q": "What is the load capacity of the NAO30×47×18-XL?",
        "a": "The basic dynamic load rating C is 31 kN and the basic static load rating C0 is 43 kN; the fatigue load limit Cur is 7.5 kN."
      },
      {
        "q": "What is the maximum speed of the NAO30×47×18-XL?",
        "a": "The limiting speed is 12,700 r/min and the thermal reference speed is 6,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO30×47×18-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 30 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO30X47X18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO30X47X18-XL",
      "NAO30×47×18-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO35X50X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO35×50×17-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 41.5,
    "fatigue_load_limit_kN": 6.6,
    "limiting_speed_rpm": 11500,
    "max_rpm": 11500,
    "reference_speed_rpm": 6500,
    "weight_g": 113,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×50×17 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 24.2 kN and C0 41.5 kN at the 35 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 6.6 kN, the limiting speed 11,500 r/min and the thermal reference speed 6,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.69 kN/mm and per millimetre of width 1.42 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 113 g, just 0.13 g per mm² of projected 50×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 17 mm width as a standard mounting space NAO marks the flangeless needle bearing with an inner ring: the separable ribless races accept pure radial load while adjacent parts handle axial location, and the shaft needs no hardening As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 6.6 kN Cur value. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 50 mm outside diameter and 24.2 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 35 mm seat, and in textile machine heald and cam shafts the 113 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 17 mm width and the published 41.5 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO35×50×17-XL?",
        "a": "The NAO35×50×17-XL is a NAO flangeless needle roller bearing with inner ring with 50 mm outside diameter, 35 mm bore and 17 mm width, envelope 35×50×17 mm. Mass is 113 g."
      },
      {
        "q": "What does the NAO35×50×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO35×50×17-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×50×17 mm and the catalogue ratings are C 24.2 kN, C0 41.5 kN, Cur 6.6 kN."
      },
      {
        "q": "What is the load capacity of the NAO35×50×17-XL?",
        "a": "The basic dynamic load rating C is 24.2 kN and the basic static load rating C0 is 41.5 kN; the fatigue load limit Cur is 6.6 kN."
      },
      {
        "q": "What is the maximum speed of the NAO35×50×17-XL?",
        "a": "The limiting speed is 11,500 r/min and the thermal reference speed is 6,500 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO35×50×17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO35X50X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO35X50X17-XL",
      "NAO35×50×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO35X55X20-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO35×55×20-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 37,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 9.1,
    "limiting_speed_rpm": 11300,
    "max_rpm": 11300,
    "reference_speed_rpm": 6200,
    "weight_g": 190,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 35×55×20 mm: 35 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 35 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 11,300 r/min and the thermal reference speed 6,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.06 kN/mm and per millimetre of width 1.85 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 190 g, just 0.17 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 35 mm bore marks the medium range: mounting forces and fits become critical, and the 190 g mass calls for proper induction or press tooling rather than hand fitting With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 57 kN and Cur 9.1 kN for the 190 g unit NAO marks the flangeless needle bearing with an inner ring: the separable ribless races accept pure radial load while adjacent parts handle axial location, and the shaft needs no hardening The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 35×55×20 mm envelope. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 55 mm outside diameter and 37 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 35 mm seat, and in small electric motor accessory drives the 190 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 20 mm width and the published 57 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO35×55×20-XL?",
        "a": "The NAO35×55×20-XL is a NAO flangeless needle roller bearing with inner ring with 55 mm outside diameter, 35 mm bore and 20 mm width, envelope 35×55×20 mm. Mass is 190 g."
      },
      {
        "q": "What does the NAO35×55×20-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO35×55×20-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 35×55×20 mm and the catalogue ratings are C 37 kN, C0 57 kN, Cur 9.1 kN."
      },
      {
        "q": "What is the load capacity of the NAO35×55×20-XL?",
        "a": "The basic dynamic load rating C is 37 kN and the basic static load rating C0 is 57 kN; the fatigue load limit Cur is 9.1 kN."
      },
      {
        "q": "What is the maximum speed of the NAO35×55×20-XL?",
        "a": "The limiting speed is 11,300 r/min and the thermal reference speed is 6,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO35×55×20-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 35 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO35X55X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO35X55X20-XL",
      "NAO35×55×20-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO40X55X17-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO40×55×17-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 46,
    "fatigue_load_limit_kN": 7.3,
    "limiting_speed_rpm": 10300,
    "max_rpm": 10300,
    "reference_speed_rpm": 5900,
    "weight_g": 127,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 40×55×17 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 25.5 kN and C0 46 kN at the 40 mm seat; the C/C0 ratio of 0.55 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 7.3 kN, the limiting speed 10,300 r/min and the thermal reference speed 5,900 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.64 kN/mm and per millimetre of width 1.50 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 127 g, just 0.14 g per mm² of projected 55×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 40 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 17 mm width as a standard mounting space The single needle row fills the thin section, with limiting speed 10,300 r/min and reference speed 5,900 r/min Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 7.5 mm section is too thin to compensate for tilted seats The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 40×55×17 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 55 mm outside diameter and 25.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 40 mm seat, and in planetary gear bearings the 127 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 17 mm width and the published 46 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
    "applications": [
      "planetary gear bearings",
      "motorcycle and light-vehicle transmissions",
      "gearbox selector and change linkages",
      "copying and printing machine mechanisms"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO40×55×17-XL?",
        "a": "The NAO40×55×17-XL is a NAO flangeless needle roller bearing with inner ring with 55 mm outside diameter, 40 mm bore and 17 mm width, envelope 40×55×17 mm. Mass is 127 g."
      },
      {
        "q": "What does the NAO40×55×17-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO40×55×17-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 40×55×17 mm and the catalogue ratings are C 25.5 kN, C0 46 kN, Cur 7.3 kN."
      },
      {
        "q": "What is the load capacity of the NAO40×55×17-XL?",
        "a": "The basic dynamic load rating C is 25.5 kN and the basic static load rating C0 is 46 kN; the fatigue load limit Cur is 7.3 kN."
      },
      {
        "q": "What is the maximum speed of the NAO40×55×17-XL?",
        "a": "The limiting speed is 10,300 r/min and the thermal reference speed is 5,900 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO40×55×17-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 40 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO40X55X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO40X55X17-XL",
      "NAO40×55×17-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO50X68X20-IS1-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO50×68×20-IS1-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 68,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 32,
    "static_load_kN": 66,
    "fatigue_load_limit_kN": 10.9,
    "limiting_speed_rpm": 8500,
    "max_rpm": 8500,
    "reference_speed_rpm": 5100,
    "weight_g": 230,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 50×68×20 mm: 50 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 9.0 mm radial section packed with small-diameter needle rollers C is 32 kN and C0 66 kN at the 50 mm seat; the C/C0 ratio of 0.48 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 10.9 kN, the limiting speed 8,500 r/min and the thermal reference speed 5,100 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.64 kN/mm and per millimetre of width 1.60 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 230 g, just 0.17 g per mm² of projected 68×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 50 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons The inner ring gives a 50 mm plain bore inside the 68×20 mm envelope and the flangeless pack delivers C 32 kN — a frequent choice in gear change linkages and pumps NAO marks the flangeless needle bearing with an inner ring: the separable ribless races accept pure radial load while adjacent parts handle axial location, and the shaft needs no hardening X-life status (-XL) indicates the current Schaeffler premium execution at 50 mm bore; the 66 kN C0 rating reflects the improved rolling-contact geometry. -IS1 marks the inner-ring lubrication feature: grease reaches the needle pack via the groove machined around the inner ring of the NAO50×68×20-IS1-XL. Typical applications include copying and printing machine mechanisms, gearbox selector and change linkages and hydraulic and pneumatic pump eccentrics, where the 68 mm outside diameter and 32 kN dynamic rating match the duty. In copying and printing machine mechanisms the unit fits a compact 50 mm seat, and in gearbox selector and change linkages the 230 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for hydraulic and pneumatic pump eccentrics, relying on the 20 mm width and the published 66 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
    "applications": [
      "rocker arms and valve trains",
      "textile machine heald and cam shafts",
      "small electric motor accessory drives",
      "planetary gear bearings"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.",
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO50×68×20-IS1-XL?",
        "a": "The NAO50×68×20-IS1-XL is a NAO flangeless needle roller bearing with inner ring with 68 mm outside diameter, 50 mm bore and 20 mm width, envelope 50×68×20 mm. Mass is 230 g."
      },
      {
        "q": "What does the NAO50×68×20-IS1-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO50×68×20-IS1-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 50×68×20 mm and the catalogue ratings are C 32 kN, C0 66 kN, Cur 10.9 kN."
      },
      {
        "q": "What is the load capacity of the NAO50×68×20-IS1-XL?",
        "a": "The basic dynamic load rating C is 32 kN and the basic static load rating C0 is 66 kN; the fatigue load limit Cur is 10.9 kN."
      },
      {
        "q": "What is the maximum speed of the NAO50×68×20-IS1-XL?",
        "a": "The limiting speed is 8,500 r/min and the thermal reference speed is 5,100 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO50×68×20-IS1-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 50 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO50X68X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO50X68X20-IS1-XL",
      "NAO50×68×20-IS1-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO70X100X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO70×100×30-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 80,
    "static_load_kN": 176,
    "fatigue_load_limit_kN": 31.5,
    "limiting_speed_rpm": 5800,
    "max_rpm": 5800,
    "reference_speed_rpm": 3350,
    "weight_g": 850,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 70×100×30 mm: 70 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 80 kN and C0 176 kN at the 70 mm seat; the C/C0 ratio of 0.45 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 100 mm outside diameter the fatigue load limit Cur is 31.5 kN, the limiting speed 5,800 r/min and the thermal reference speed 3,350 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.14 kN/mm and per millimetre of width 2.67 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 850 g, just 0.28 g per mm² of projected 100×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 70 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery The inner ring gives a 70 mm plain bore inside the 100×30 mm envelope and the flangeless pack delivers C 80 kN — a frequent choice in gear change linkages and pumps Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 70×100×30 mm envelope. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 100 mm outside diameter and 80 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 70 mm seat, and in copying and printing machine mechanisms the 850 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 30 mm width and the published 176 kN static rating. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "hydraulic and pneumatic pump eccentrics",
      "small electric motor accessory drives",
      "agricultural machine pivots and linkages",
      "textile machine heald and cam shafts"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO70×100×30-XL?",
        "a": "The NAO70×100×30-XL is a NAO flangeless needle roller bearing with inner ring with 100 mm outside diameter, 70 mm bore and 30 mm width, envelope 70×100×30 mm. Mass is 850 g."
      },
      {
        "q": "What does the NAO70×100×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO70×100×30-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 70×100×30 mm and the catalogue ratings are C 80 kN, C0 176 kN, Cur 31.5 kN."
      },
      {
        "q": "What is the load capacity of the NAO70×100×30-XL?",
        "a": "The basic dynamic load rating C is 80 kN and the basic static load rating C0 is 176 kN; the fatigue load limit Cur is 31.5 kN."
      },
      {
        "q": "What is the maximum speed of the NAO70×100×30-XL?",
        "a": "The limiting speed is 5,800 r/min and the thermal reference speed is 3,350 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO70×100×30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 70 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO70X100X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO70X100X30-XL",
      "NAO70×100×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO80X110X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO80×110×30-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 76,
    "static_load_kN": 172,
    "fatigue_load_limit_kN": 30,
    "limiting_speed_rpm": 5200,
    "max_rpm": 5200,
    "reference_speed_rpm": 3200,
    "weight_g": 920,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 80×110×30 mm: 80 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 76 kN and C0 172 kN at the 80 mm seat; the C/C0 ratio of 0.44 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 110 mm outside diameter the fatigue load limit Cur is 30 kN, the limiting speed 5,200 r/min and the thermal reference speed 3,200 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.95 kN/mm and per millimetre of width 2.53 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 920 g, just 0.28 g per mm² of projected 110×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 80 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Because neither ring guides axially, housing and shaft shoulders position the races; uncontrolled end float lets the rollers run off the raceway edges NAO marks the flangeless needle bearing with an inner ring: the separable ribless races accept pure radial load while adjacent parts handle axial location, and the shaft needs no hardening X-life status (-XL) indicates the current Schaeffler premium execution at 80 mm bore; the 172 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 110 mm outside diameter and 76 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 80 mm seat, and in textile machine heald and cam shafts the 920 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 172 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
    "applications": [
      "connecting-rod small ends",
      "copying and printing machine mechanisms",
      "motorcycle and light-vehicle transmissions",
      "two-stroke and compressor piston pins"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.",
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO80×110×30-XL?",
        "a": "The NAO80×110×30-XL is a NAO flangeless needle roller bearing with inner ring with 110 mm outside diameter, 80 mm bore and 30 mm width, envelope 80×110×30 mm. Mass is 920 g."
      },
      {
        "q": "What does the NAO80×110×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO80×110×30-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 80×110×30 mm and the catalogue ratings are C 76 kN, C0 172 kN, Cur 30 kN."
      },
      {
        "q": "What is the load capacity of the NAO80×110×30-XL?",
        "a": "The basic dynamic load rating C is 76 kN and the basic static load rating C0 is 172 kN; the fatigue load limit Cur is 30 kN."
      },
      {
        "q": "What is the maximum speed of the NAO80×110×30-XL?",
        "a": "The limiting speed is 5,200 r/min and the thermal reference speed is 3,200 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO80×110×30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 80 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO80X110X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO80X110X30-XL",
      "NAO80×110×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NAO90X120X30-XL",
    "brand": "FAG",
    "manufacturer_designation": "NAO90×120×30-XL",
    "series": "nao-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 120,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "steel",
    "dynamic_load_kN": 80,
    "static_load_kN": 188,
    "fatigue_load_limit_kN": 32.5,
    "limiting_speed_rpm": 4700,
    "max_rpm": 4700,
    "reference_speed_rpm": 2950,
    "weight_g": 1044,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 15",
    "naming_rule_text": "envelope 90×120×30 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 80 kN and C0 188 kN at the 90 mm seat; the C/C0 ratio of 0.43 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 32.5 kN, the limiting speed 4,700 r/min and the thermal reference speed 2,950 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 0.89 kN/mm and per millimetre of width 2.67 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.044 kg (1044 g), just 0.29 g per mm² of projected 120×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Reading NAO: the O-suffix race design has no integral ribs on either ring, so the bearing can be separated and the outer assembly swivelled into split housings during mounting With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 188 kN and Cur 32.5 kN for the 1044 g unit As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 32.5 kN Cur value. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 120 mm outside diameter and 80 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 90 mm seat, and in agricultural machine pivots and linkages the 1.044 kg mass is part of the rotor inertia calculation. Designers also specify it for connecting-rod small ends, relying on the 30 mm width and the published 188 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
    "applications": [
      "motorcycle and light-vehicle transmissions",
      "hydraulic and pneumatic pump eccentrics",
      "two-stroke and compressor piston pins",
      "rocker arms and valve trains"
    ],
    "failure_modes": [
      "journal brinelling when a no-inner-ring bearing runs on a shaft hardened below 58 HRC or finished too rough",
      "needle skewing and jamming after momentary unloading of a flangeless (RNAO/NAO) pack",
      "raceway pitting from contamination drawn through the open ends of an unsealed bearing",
      "edge loading at the roller ends from a tapered or lobed shaft seat",
      "cage damage from shock loading or from pressing the bearing through the wrong ring",
      "lubricant starvation on fast reciprocating strokes that never fully rotate the needles",
      "false brinelling during stationary transport vibration",
      "spalling from excessive interference that removes the radial clearance",
      "roller wear from misaligned connecting-rod eyes and rocker bores"
    ],
    "pitfalls": [
      "Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.",
      "Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.",
      "On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions."
    ],
    "faq": [
      {
        "q": "What are the dimensions of the NAO90×120×30-XL?",
        "a": "The NAO90×120×30-XL is a NAO flangeless needle roller bearing with inner ring with 120 mm outside diameter, 90 mm bore and 30 mm width, envelope 90×120×30 mm. Mass is 1.044 kg."
      },
      {
        "q": "What does the NAO90×120×30-XL designation mean in the FAG/INA HR1 catalogue?",
        "a": "NAO90×120×30-XL identifies this NAO flangeless needle roller bearing with inner ring in the Schaeffler HR1 rolling bearings catalogue; the -XL suffix marks the X-life execution. The envelope is 90×120×30 mm and the catalogue ratings are C 80 kN, C0 188 kN, Cur 32.5 kN."
      },
      {
        "q": "What is the load capacity of the NAO90×120×30-XL?",
        "a": "The basic dynamic load rating C is 80 kN and the basic static load rating C0 is 188 kN; the fatigue load limit Cur is 32.5 kN."
      },
      {
        "q": "What is the maximum speed of the NAO90×120×30-XL?",
        "a": "The limiting speed is 4,700 r/min and the thermal reference speed is 2,950 r/min. In the Schaeffler catalogue the reference speed is the thermally permissible running speed under defined load; the lower of the two values governs each application."
      },
      {
        "q": "How is the NAO90×120×30-XL mounted on the shaft?",
        "a": "The integral inner ring accepts an ordinary ground shaft at the 90 mm nominal bore with the recommended normal bearing-seat tolerance; no hardening is required. The ring is separable, so the outer assembly can be pressed into the housing first and the inner ring fitted with the shaft."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NAO90X120X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/catalogue_1/downloads_6/hr1_de_en.pdf#pdfpage=971",
    "catalog_ver": "HR1 2026-09-25",
    "extracted_at": "2026-09-30",
    "last_verified": "2026-09-30",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NAO90X120X30-XL",
      "NAO90×120×30-XL"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0306FT2",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 3,
    "D_mm": 6.5,
    "B_mm": 6,
    "seal_type": "open",
    "dynamic_load_kN": 0.925,
    "static_load_kN": 0.565,
    "fatigue_load_limit_kN": 0.069,
    "limiting_speed_rpm": 33000,
    "speed_oil_rpm": 50000,
    "weight_g": 1,
    "manufacturer_designation": "HK0306FT2",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0306FT2"
    ],
    "naming_rule_text": "HK0306FT2 is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 3 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 6.5 mm and the width is 6 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. At this miniature shaft size the cup wall is fractions of a millimetre thick, so handling cleanliness and housing-bore accuracy matter more than the paper load rating. Automotive steering-column and pedal-box pivots use this size, where the cup is pressed into a sheet-metal bracket and the shaft sees only slow, heavily loaded oscillation. Never re-grease through a drilled hole in the housing wall without a vent path: pressure builds behind the cup, blows grease past the rollers, and starves the bearing while the housing looks full.",
    "applications": [
      "small appliance gear drives",
      "instrument and meter linkages",
      "model and hobby drive trains",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "At a 3 mm shaft diameter the cup wall of HK0306FT2 is extremely thin; inspect for transportation dents before pressing in, and deburr the housing bore edge or the cup will score and split on entry.",
      "The cage in HK0306FT2 spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 3 mm.",
      "The 6 mm narrow section of HK0306FT2 is the compact option at 3 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 3×6.5 mm envelope.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0306FT2 needle roller bearing?",
        "a": "A HK0306FT2 drawn-cup needle roller bearing has a 3 mm shaft diameter (Fw, under-roller diameter), 6.5 mm outside diameter and 6 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0306FT2 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0306FT2, Fw = 3 mm, so the shaft must be machined to 3 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0306FT2 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0306FT2 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK0306FT2 retained in the housing?",
        "a": "The thin-walled drawn cup of HK0306FT2 is press-fitted into a 6.5 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0306FT2",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0408FT2",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 4,
    "D_mm": 8,
    "B_mm": 8,
    "seal_type": "open",
    "dynamic_load_kN": 1.77,
    "static_load_kN": 1.27,
    "fatigue_load_limit_kN": 0.155,
    "limiting_speed_rpm": 30000,
    "speed_oil_rpm": 45000,
    "weight_g": 2,
    "manufacturer_designation": "HK0408FT2",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0408FT2"
    ],
    "naming_rule_text": "NTN HK0408FT2 belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 4 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 8 mm outside and 8 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. At this miniature shaft size the cup wall is fractions of a millimetre thick, so handling cleanliness and housing-bore accuracy matter more than the paper load rating. Small compressor crankshafts and refrigeration equipment fit this size on the eccentric pin, where the housing bore is finish-bored in the same setup as the main bearing seats. Where the housing is a welded fabrication, finish-bore the seat after all welding and stress-relief is complete — pressing the cup into a distorted, as-welded bore guarantees early spalling.",
    "applications": [
      "small appliance gear drives",
      "instrument and meter linkages",
      "model and hobby drive trains",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "At a 4 mm shaft diameter the cup wall of HK0408FT2 is extremely thin; inspect for transportation dents before pressing in, and deburr the housing bore edge or the cup will score and split on entry.",
      "The cage in HK0408FT2 spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 4 mm.",
      "The 8 mm narrow section of HK0408FT2 is the compact option at 4 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 4×8 mm envelope.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0408FT2 needle roller bearing?",
        "a": "A HK0408FT2 drawn-cup needle roller bearing has a 4 mm shaft diameter (Fw, under-roller diameter), 8 mm outside diameter and 8 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0408FT2 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0408FT2, Fw = 4 mm, so the shaft must be machined to 4 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0408FT2 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0408FT2 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK0408FT2 retained in the housing?",
        "a": "The thin-walled drawn cup of HK0408FT2 is press-fitted into a 8 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0408FT2",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0509FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 9,
    "B_mm": 9,
    "seal_type": "open",
    "dynamic_load_kN": 2.45,
    "static_load_kN": 1.99,
    "fatigue_load_limit_kN": 0.243,
    "limiting_speed_rpm": 27000,
    "speed_oil_rpm": 40000,
    "weight_g": 2,
    "manufacturer_designation": "HK0509FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0509FM"
    ],
    "naming_rule_text": "HK0509FM is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 5 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 9 mm and the width is 9 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. At this miniature shaft size the cup wall is fractions of a millimetre thick, so handling cleanliness and housing-bore accuracy matter more than the paper load rating. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "office machine and printer mechanisms",
      "small appliance gear drives",
      "instrument and meter linkages",
      "heavily loaded slow pivots where static rating, not dynamic life, governs the choice"
    ],
    "failure_modes": [
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path"
    ],
    "pitfalls": [
      "At a 5 mm shaft diameter the cup wall of HK0509FM is extremely thin; inspect for transportation dents before pressing in, and deburr the housing bore edge or the cup will score and split on entry.",
      "The cage in HK0509FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 5 mm.",
      "The 9 mm narrow section of HK0509FM is the compact option at 5 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 5×9 mm envelope.",
      "HK0509FM runs directly on the shaft: the 5 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK0509FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0509FM needle roller bearing?",
        "a": "A HK0509FM drawn-cup needle roller bearing has a 5 mm shaft diameter (Fw, under-roller diameter), 9 mm outside diameter and 9 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0509FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0509FM, Fw = 5 mm, so the shaft must be machined to 5 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0509FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0509FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK0509FM retained in the housing?",
        "a": "The thin-walled drawn cup of HK0509FM is press-fitted into a 9 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What duty conditions suit a HK0509FM drawn-cup bearing?",
        "a": "HK0509FM is typically specified for reciprocating or oscillating motion where the rollers never complete a full revolution; match the grease/oil speed limits (27000/40000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0509FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0609FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 10,
    "B_mm": 9,
    "seal_type": "open",
    "dynamic_load_kN": 2.92,
    "static_load_kN": 2.59,
    "fatigue_load_limit_kN": 0.315,
    "limiting_speed_rpm": 25000,
    "speed_oil_rpm": 37000,
    "weight_g": 2,
    "manufacturer_designation": "HK0609FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0609FM"
    ],
    "naming_rule_text": "HK0609FM is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 6 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 10 mm and the width is 9 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. At this miniature shaft size the cup wall is fractions of a millimetre thick, so handling cleanliness and housing-bore accuracy matter more than the paper load rating. Garden machinery and small outboard engines fit this size in the crankcase web: the thin cup keeps the crank web narrow while still carrying the combustion pulses through the connecting-rod small end. Use a mandrel with a lead chamfer that matches the cup bore when pressing this size home; a flat-faced drift can catch the roller cage and distort the shell before it is fully seated.",
    "applications": [
      "micro gearbox and servo output shafts",
      "office machine and printer mechanisms",
      "small appliance gear drives",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "At a 6 mm shaft diameter the cup wall of HK0609FM is extremely thin; inspect for transportation dents before pressing in, and deburr the housing bore edge or the cup will score and split on entry.",
      "The cage in HK0609FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 6 mm.",
      "The 9 mm narrow section of HK0609FM is the compact option at 6 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 6×10 mm envelope.",
      "The HK0609FM drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0609FM needle roller bearing?",
        "a": "A HK0609FM drawn-cup needle roller bearing has a 6 mm shaft diameter (Fw, under-roller diameter), 10 mm outside diameter and 9 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0609FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0609FM, Fw = 6 mm, so the shaft must be machined to 6 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0609FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0609FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK0609FM retained in the housing?",
        "a": "The thin-walled drawn cup of HK0609FM is press-fitted into a 10 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0609FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0709FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 11,
    "B_mm": 9,
    "seal_type": "open",
    "dynamic_load_kN": 3.15,
    "static_load_kN": 2.93,
    "fatigue_load_limit_kN": 0.355,
    "limiting_speed_rpm": 23000,
    "speed_oil_rpm": 34000,
    "weight_g": 2,
    "manufacturer_designation": "HK0709FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0709FM"
    ],
    "naming_rule_text": "NTN HK0709FM belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 7 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 11 mm outside and 9 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this size range the drawn cup gives a far smaller radial section than any machined-ring needle bearing of the same shaft, which is why it dominates in compact transmissions. Small compressor crankshafts and refrigeration equipment fit this size on the eccentric pin, where the housing bore is finish-bored in the same setup as the main bearing seats. Where the housing is a welded fabrication, finish-bore the seat after all welding and stress-relief is complete — pressing the cup into a distorted, as-welded bore guarantees early spalling.",
    "applications": [
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "motorcycle and scooter transmissions",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "At a 7 mm shaft diameter, shaft surface finish is critical for HK0709FM: grinding marks, corrosion pits or chrome flaking on the journal will fluke the rollers within hours — polish or replace a suspect shaft.",
      "The cage in HK0709FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 7 mm.",
      "The 9 mm narrow section of HK0709FM is the compact option at 7 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 7×11 mm envelope.",
      "The open ends of HK0709FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0709FM needle roller bearing?",
        "a": "A HK0709FM drawn-cup needle roller bearing has a 7 mm shaft diameter (Fw, under-roller diameter), 11 mm outside diameter and 9 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0709FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0709FM, Fw = 7 mm, so the shaft must be machined to 7 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0709FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0709FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK0709FM retained in the housing?",
        "a": "The thin-walled drawn cup of HK0709FM is press-fitted into a 11 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0709FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0810FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 12,
    "B_mm": 10,
    "seal_type": "open",
    "dynamic_load_kN": 3.85,
    "static_load_kN": 3.95,
    "fatigue_load_limit_kN": 0.48,
    "limiting_speed_rpm": 20000,
    "speed_oil_rpm": 30000,
    "weight_g": 3,
    "manufacturer_designation": "HK0810FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0810FM",
      "HK0810FM+IR5x8x12"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK0810FM is built around a thin hardened steel cup.Its printed envelope — 8 mm under-roller diameter, 12 mm outside diameter, 10 mm width — is fixed by ISO 3245; the 8 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this size range the drawn cup gives a far smaller radial section than any machined-ring needle bearing of the same shaft, which is why it dominates in compact transmissions. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "lawn and garden equipment spindles",
      "motorcycle and scooter transmissions",
      "two-stroke engine crank and piston pins",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "Needle rollers tolerate almost no misalignment; if the 12 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "At a 8 mm shaft diameter, shaft surface finish is critical for HK0810FM: grinding marks, corrosion pits or chrome flaking on the journal will fluke the rollers within hours — polish or replace a suspect shaft.",
      "The cage in HK0810FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 8 mm.",
      "The 10 mm narrow section of HK0810FM is the compact option at 8 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 8×12 mm envelope."
    ],
    "faq": [
      {
        "q": "Does HK0810FM need a hardened shaft?",
        "a": "Either the 8 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR5x8x12) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK0810FM drawn-cup bearing?",
        "a": "HK0810FM is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (20000/30000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK0810FM needle roller bearing?",
        "a": "A HK0810FM drawn-cup needle roller bearing has a 8 mm shaft diameter (Fw, under-roller diameter), 12 mm outside diameter and 10 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0810FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0810FM, Fw = 8 mm, so the shaft must be machined to 8 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0810FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0810FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0810FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0910FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 13,
    "B_mm": 10,
    "seal_type": "open",
    "dynamic_load_kN": 4.3,
    "static_load_kN": 4.65,
    "fatigue_load_limit_kN": 0.57,
    "limiting_speed_rpm": 18000,
    "speed_oil_rpm": 27000,
    "weight_g": 4,
    "manufacturer_designation": "HK0910FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0910FM",
      "HK0910FM+IR6x9x12"
    ],
    "naming_rule_text": "HK0910FM is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 9 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 13 mm and the width is 10 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this size range the drawn cup gives a far smaller radial section than any machined-ring needle bearing of the same shaft, which is why it dominates in compact transmissions. Garden machinery and small outboard engines fit this size in the crankcase web: the thin cup keeps the crank web narrow while still carrying the combustion pulses through the connecting-rod small end. Use a mandrel with a lead chamfer that matches the cup bore when pressing this size home; a flat-faced drift can catch the roller cage and distort the shell before it is fully seated.",
    "applications": [
      "small hydraulic pump drives",
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "At a 9 mm shaft diameter, shaft surface finish is critical for HK0910FM: grinding marks, corrosion pits or chrome flaking on the journal will fluke the rollers within hours — polish or replace a suspect shaft.",
      "The cage in HK0910FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 9 mm.",
      "The 10 mm narrow section of HK0910FM is the compact option at 9 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 9×13 mm envelope.",
      "Drawn-cup needle bearings carry radial load only: HK0910FM provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces.",
      "The HK0910FM drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK0910FM needle roller bearing?",
        "a": "A HK0910FM drawn-cup needle roller bearing has a 9 mm shaft diameter (Fw, under-roller diameter), 13 mm outside diameter and 10 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0910FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0910FM, Fw = 9 mm, so the shaft must be machined to 9 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0910FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0910FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK0910FM need a hardened shaft?",
        "a": "Either the 9 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR6x9x12) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK0910FM drawn-cup bearing?",
        "a": "HK0910FM is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (18000/27000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0910FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK0912F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 13,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 5.4,
    "static_load_kN": 6.25,
    "fatigue_load_limit_kN": 0.765,
    "limiting_speed_rpm": 18000,
    "speed_oil_rpm": 27000,
    "weight_g": 4,
    "manufacturer_designation": "HK0912F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK0912F",
      "HK0912F+IR6x9x12"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK0912F is built around a thin hardened steel cup.Its printed envelope — 9 mm under-roller diameter, 13 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 9 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "power tool gear reduction stages",
      "small hydraulic pump drives",
      "automotive accessory drives",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "The open ends of HK0912F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "With no inner ring, HK0912F reads the 9 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK0912F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 9 mm.",
      "The 12 mm standard width of HK0912F is the general-purpose section at 9 mm shaft; wider HK variants in the same 9×13 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "HK0912F runs directly on the shaft: the 9 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead."
    ],
    "faq": [
      {
        "q": "What duty conditions suit a HK0912F drawn-cup bearing?",
        "a": "HK0912F is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (18000/27000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK0912F needle roller bearing?",
        "a": "A HK0912F drawn-cup needle roller bearing has a 9 mm shaft diameter (Fw, under-roller diameter), 13 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK0912F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0912F, Fw = 9 mm, so the shaft must be machined to 9 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK0912F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK0912F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK0912F need a hardened shaft?",
        "a": "Either the 9 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR6x9x12) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK0912F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1010FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 10,
    "seal_type": "open",
    "dynamic_load_kN": 4.5,
    "static_load_kN": 5.1,
    "fatigue_load_limit_kN": 0.62,
    "limiting_speed_rpm": 16000,
    "speed_oil_rpm": 24000,
    "weight_g": 4,
    "manufacturer_designation": "HK1010FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1010FM",
      "HK1010FM+IR7x10x10.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK1010FM is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 10 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 14 mm cup outside diameter and 10 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. Garden machinery and small outboard engines fit this size in the crankcase web: the thin cup keeps the crank web narrow while still carrying the combustion pulses through the connecting-rod small end. Use a mandrel with a lead chamfer that matches the cup bore when pressing this size home; a flat-faced drift can catch the roller cage and distort the shell before it is fully seated.",
    "applications": [
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "motorcycle and scooter transmissions",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The 10 mm narrow section of HK1010FM is the compact option at 10 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 10×14 mm envelope.",
      "The open ends of HK1010FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "With no inner ring, HK1010FM reads the 10 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1010FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 10 mm."
    ],
    "faq": [
      {
        "q": "Can a HK1010FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1010FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1010FM need a hardened shaft?",
        "a": "Either the 10 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR7x10x10.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1010FM needle roller bearing?",
        "a": "A HK1010FM drawn-cup needle roller bearing has a 10 mm shaft diameter (Fw, under-roller diameter), 14 mm outside diameter and 10 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1010FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1010FM, Fw = 10 mm, so the shaft must be machined to 10 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1010FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1012F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 5.65,
    "static_load_kN": 6.8,
    "fatigue_load_limit_kN": 0.83,
    "limiting_speed_rpm": 16000,
    "speed_oil_rpm": 24000,
    "weight_g": 4,
    "manufacturer_designation": "HK1012F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1012F",
      "HK1012F+IR7x10x16"
    ],
    "naming_rule_text": "HK1012F is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 10 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 14 mm and the width is 12 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. Office automation equipment — printers, copiers, paper feeders — uses this size in the transport rollers, where the open ends are enclosed by the chassis and relubrication is never planned. For vertical shafts, arrange the housing so the open end of the cup faces up or provides a grease reservoir below — gravity drains lubricant away from the roller set otherwise.",
    "applications": [
      "two-stroke engine crank and piston pins",
      "power tool gear reduction stages",
      "small hydraulic pump drives",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The HK1012F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "With no inner ring, HK1012F reads the 10 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1012F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 10 mm.",
      "The 12 mm standard width of HK1012F is the general-purpose section at 10 mm shaft; wider HK variants in the same 10×14 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1012F need a hardened shaft?",
        "a": "Either the 10 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR7x10x16) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1012F needle roller bearing?",
        "a": "A HK1012F drawn-cup needle roller bearing has a 10 mm shaft diameter (Fw, under-roller diameter), 14 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1012F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1012F, Fw = 10 mm, so the shaft must be machined to 10 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1012F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1012F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1012F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1015F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 15,
    "seal_type": "open",
    "dynamic_load_kN": 7.25,
    "static_load_kN": 9.4,
    "fatigue_load_limit_kN": 1.14,
    "limiting_speed_rpm": 16000,
    "speed_oil_rpm": 24000,
    "weight_g": 6,
    "manufacturer_designation": "HK1015F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1015F",
      "HK1015F+IR7x10x16"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK1015F is built around a thin hardened steel cup.Its printed envelope — 10 mm under-roller diameter, 14 mm outside diameter, 15 mm width — is fixed by ISO 3245; the 10 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. Industrial sewing machines and textile equipment run this size on their shuttle and needle-bar drive shafts, where the compact radial section keeps the arm profile slim. Shaft tolerance for this size is h5 or j5: the roller complement needs a controlled radial clearance, and a shaft ground to general-purpose tolerances can leave the bearing either slack or pinched.",
    "applications": [
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "motorcycle and scooter transmissions",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "The HK1015F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "With no inner ring, HK1015F reads the 10 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1015F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 10 mm.",
      "The 15 mm standard width of HK1015F is the general-purpose section at 10 mm shaft; wider HK variants in the same 10×14 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Drawn-cup needle bearings carry radial load only: HK1015F provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces."
    ],
    "faq": [
      {
        "q": "What duty conditions suit a HK1015F drawn-cup bearing?",
        "a": "HK1015F is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (16000/24000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK1015F needle roller bearing?",
        "a": "A HK1015F drawn-cup needle roller bearing has a 10 mm shaft diameter (Fw, under-roller diameter), 14 mm outside diameter and 15 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1015F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1015F, Fw = 10 mm, so the shaft must be machined to 10 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1015F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1015F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1015F need a hardened shaft?",
        "a": "Either the 10 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR7x10x16) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1015F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1210FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 16,
    "B_mm": 10,
    "seal_type": "open",
    "dynamic_load_kN": 5.05,
    "static_load_kN": 6.25,
    "fatigue_load_limit_kN": 0.76,
    "limiting_speed_rpm": 13000,
    "speed_oil_rpm": 20000,
    "weight_g": 5,
    "manufacturer_designation": "HK1210FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1210FM",
      "HK1210FM+IR8x12x10.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK1210FM is built around a thin hardened steel cup.Its printed envelope — 12 mm under-roller diameter, 16 mm outside diameter, 10 mm width — is fixed by ISO 3245; the 12 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. Industrial sewing machines and textile equipment run this size on their shuttle and needle-bar drive shafts, where the compact radial section keeps the arm profile slim. Shaft tolerance for this size is h5 or j5: the roller complement needs a controlled radial clearance, and a shaft ground to general-purpose tolerances can leave the bearing either slack or pinched.",
    "applications": [
      "two-stroke engine crank and piston pins",
      "power tool gear reduction stages",
      "small hydraulic pump drives",
      "heavily loaded slow pivots where static rating, not dynamic life, governs the choice"
    ],
    "failure_modes": [
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path"
    ],
    "pitfalls": [
      "HK1210FM runs directly on the shaft: the 12 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK1210FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "With no inner ring, HK1210FM reads the 12 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1210FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 12 mm.",
      "The 10 mm narrow section of HK1210FM is the compact option at 12 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 12×16 mm envelope."
    ],
    "faq": [
      {
        "q": "Does HK1210FM need a hardened shaft?",
        "a": "Either the 12 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR8x12x10.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK1210FM drawn-cup bearing?",
        "a": "HK1210FM is typically specified for reciprocating or oscillating motion where the rollers never complete a full revolution; match the grease/oil speed limits (13000/20000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK1210FM needle roller bearing?",
        "a": "A HK1210FM drawn-cup needle roller bearing has a 12 mm shaft diameter (Fw, under-roller diameter), 16 mm outside diameter and 10 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1210FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1210FM, Fw = 12 mm, so the shaft must be machined to 12 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1210FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1210FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1210FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1212FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 18,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 6.6,
    "static_load_kN": 7.3,
    "fatigue_load_limit_kN": 0.89,
    "limiting_speed_rpm": 13000,
    "speed_oil_rpm": 20000,
    "weight_g": 9,
    "manufacturer_designation": "HK1212FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1212FM",
      "HK1212FM+IR8x12x12.5"
    ],
    "naming_rule_text": "NTN HK1212FM belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 12 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 18 mm outside and 12 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "small hydraulic pump drives",
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "The cage in HK1212FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 12 mm.",
      "The 12 mm standard width of HK1212FM is the general-purpose section at 12 mm shaft; wider HK variants in the same 12×18 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "With no inner ring, HK1212FM reads the 12 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations."
    ],
    "faq": [
      {
        "q": "What does Fw mean on a HK1212FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1212FM, Fw = 12 mm, so the shaft must be machined to 12 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1212FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1212FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1212FM need a hardened shaft?",
        "a": "Either the 12 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR8x12x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1212FM needle roller bearing?",
        "a": "A HK1212FM drawn-cup needle roller bearing has a 12 mm shaft diameter (Fw, under-roller diameter), 18 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1212FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1312FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 13,
    "D_mm": 19,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 6.95,
    "static_load_kN": 7.9,
    "fatigue_load_limit_kN": 0.965,
    "limiting_speed_rpm": 12000,
    "speed_oil_rpm": 18000,
    "weight_g": 10,
    "manufacturer_designation": "HK1312FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1312FM",
      "HK1312FM+IR10x13x12.5"
    ],
    "naming_rule_text": "NTN HK1312FM belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 13 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 19 mm outside and 12 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. This cup size is common in power-tool intermediate shafts — drills, saws, grinders — where the gearbox casing is magnesium or aluminium and the cup is pressed into a steel insert. If the shaft sees axial float, allow for it in the housing width — the cup cannot guide the shaft axially, and a shaft that walks will eventually hammer the open end of the shell.",
    "applications": [
      "power tool gear reduction stages",
      "small hydraulic pump drives",
      "automotive accessory drives",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "HK1312FM runs directly on the shaft: the 13 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK1312FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "With no inner ring, HK1312FM reads the 13 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1312FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 13 mm.",
      "The 12 mm standard width of HK1312FM is the general-purpose section at 13 mm shaft; wider HK variants in the same 13×19 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1312FM need a hardened shaft?",
        "a": "Either the 13 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR10x13x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK1312FM drawn-cup bearing?",
        "a": "HK1312FM is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (12000/18000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK1312FM needle roller bearing?",
        "a": "A HK1312FM drawn-cup needle roller bearing has a 13 mm shaft diameter (Fw, under-roller diameter), 19 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1312FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1312FM, Fw = 13 mm, so the shaft must be machined to 13 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1312FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1312FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1312FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1412FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 20,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 7.2,
    "static_load_kN": 8.5,
    "fatigue_load_limit_kN": 1.04,
    "limiting_speed_rpm": 11000,
    "speed_oil_rpm": 17000,
    "weight_g": 11,
    "manufacturer_designation": "HK1412FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1412FM",
      "HK1412FM+IR10x14x13"
    ],
    "naming_rule_text": "The NTN HK1412FM — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 14 mm is Fw, the under-roller (shaft journal) diameter; 20 mm and 12 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. Compact hydraulic gear pumps use this size on their drive shafts: the pump housing is machined once, the cup is pressed home, and the shaft runs directly on the rollers for the life of the unit. For oscillating service, pack this size with a high-tackiness grease and re-lubricate at short intervals: the rollers do not complete a full revolution, so the same contact patch carries the load cycle after cycle.",
    "applications": [
      "motorcycle and scooter transmissions",
      "two-stroke engine crank and piston pins",
      "power tool gear reduction stages",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "With no inner ring, HK1412FM reads the 14 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.",
      "The cage in HK1412FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 14 mm.",
      "The 12 mm standard width of HK1412FM is the general-purpose section at 14 mm shaft; wider HK variants in the same 14×20 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Needle rollers tolerate almost no misalignment; if the 20 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK1412FM needle roller bearing?",
        "a": "A HK1412FM drawn-cup needle roller bearing has a 14 mm shaft diameter (Fw, under-roller diameter), 20 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1412FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1412FM, Fw = 14 mm, so the shaft must be machined to 14 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1412FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1412FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1412FM need a hardened shaft?",
        "a": "Either the 14 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR10x14x13) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK1412FM drawn-cup bearing?",
        "a": "HK1412FM is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (11000/17000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1412FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1416F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 20,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 10.3,
    "static_load_kN": 13.4,
    "fatigue_load_limit_kN": 1.64,
    "limiting_speed_rpm": 11000,
    "speed_oil_rpm": 17000,
    "weight_g": 15,
    "manufacturer_designation": "HK1416F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1416F"
    ],
    "naming_rule_text": "NTN HK1416F belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 14 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 20 mm outside and 16 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Drawn cups in this class are the default compact radial bearing in motorcycle and power-tool gearboxes, where housing space is the binding constraint. Office automation equipment — printers, copiers, paper feeders — uses this size in the transport rollers, where the open ends are enclosed by the chassis and relubrication is never planned. For vertical shafts, arrange the housing so the open end of the cup faces up or provides a grease reservoir below — gravity drains lubricant away from the roller set otherwise.",
    "applications": [
      "small hydraulic pump drives",
      "automotive accessory drives",
      "lawn and garden equipment spindles",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "The rollers of HK1416F run directly on the 14 mm journal: any score mark, rust pit or plating flake on that surface becomes a raceway defect — dress or replace a marginal shaft.",
      "The cage in HK1416F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 14 mm.",
      "The 16 mm standard width of HK1416F is the general-purpose section at 14 mm shaft; wider HK variants in the same 14×20 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "How is a HK1416F retained in the housing?",
        "a": "The thin-walled drawn cup of HK1416F is press-fitted into a 20 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What are the dimensions of a HK1416F needle roller bearing?",
        "a": "A HK1416F drawn-cup needle roller bearing has a 14 mm shaft diameter (Fw, under-roller diameter), 20 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1416F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1416F, Fw = 14 mm, so the shaft must be machined to 14 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1416F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1416F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1416F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1512FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 7.5,
    "static_load_kN": 9.1,
    "fatigue_load_limit_kN": 1.11,
    "limiting_speed_rpm": 11000,
    "speed_oil_rpm": 16000,
    "weight_g": 11,
    "manufacturer_designation": "HK1512FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1512FM",
      "HK1512FM+IR12x15x12.5"
    ],
    "naming_rule_text": "The NTN HK1512FM — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 15 mm is Fw, the under-roller (shaft journal) diameter; 21 mm and 12 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The open ends of HK1512FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "Mid-size cups like HK1512FM (15 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK1512FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 15 mm.",
      "The 12 mm standard width of HK1512FM is the general-purpose section at 15 mm shaft; wider HK variants in the same 15×21 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1512FM need a hardened shaft?",
        "a": "Either the 15 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR12x15x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1512FM needle roller bearing?",
        "a": "A HK1512FM drawn-cup needle roller bearing has a 15 mm shaft diameter (Fw, under-roller diameter), 21 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1512FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1512FM, Fw = 15 mm, so the shaft must be machined to 15 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1512FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1512FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1512FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1516F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 10.7,
    "static_load_kN": 14.4,
    "fatigue_load_limit_kN": 1.75,
    "limiting_speed_rpm": 11000,
    "speed_oil_rpm": 16000,
    "weight_g": 15,
    "manufacturer_designation": "HK1516F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1516F",
      "HK1516F+IR12x15x16.5"
    ],
    "naming_rule_text": "The NTN HK1516F — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 15 mm is Fw, the under-roller (shaft journal) diameter; 21 mm and 16 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Automotive gearbox designers default to this class when the radial envelope is fixed: the cup keeps the casing compact without giving up the required rating. You will find this cup size inside small two-stroke crankcases, supporting the small-end of the connecting rod where the housing is split and the bearing is pressed in before the case halves close. If the shaft cannot be hardened, press the matching IR inner ring onto it first; the ring gives the rollers a hardened, ground raceway and lets you keep a soft shaft for assembly reasons.",
    "applications": [
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The HK1516F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Before pressing HK1516F in, verify the 15 mm housing seat is still round — extracting the old cup often pulls the bore, and the new thin shell will conform to any distortion.",
      "The cage in HK1516F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 15 mm.",
      "The 16 mm standard width of HK1516F is the general-purpose section at 15 mm shaft; wider HK variants in the same 15×21 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1516F need a hardened shaft?",
        "a": "Either the 15 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR12x15x16.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1516F needle roller bearing?",
        "a": "A HK1516F drawn-cup needle roller bearing has a 15 mm shaft diameter (Fw, under-roller diameter), 21 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1516F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1516F, Fw = 15 mm, so the shaft must be machined to 15 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1516F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1516F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1516F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1522ZWFD",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 22,
    "seal_type": "open",
    "dynamic_load_kN": 12.9,
    "static_load_kN": 18.2,
    "fatigue_load_limit_kN": 2.22,
    "limiting_speed_rpm": 11000,
    "speed_oil_rpm": 16000,
    "weight_g": 20,
    "manufacturer_designation": "HK1522ZWFD",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1522ZWFD",
      "HK1522ZWFD+IR12x15x22.5"
    ],
    "naming_rule_text": "NTN HK1522ZWFD belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 15 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 21 mm outside and 22 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. In this mid size range the HK cup is the standard compact radial bearing choice across automotive and industrial gearboxes. Automotive steering-column and pedal-box pivots use this size, where the cup is pressed into a sheet-metal bracket and the shaft sees only slow, heavily loaded oscillation. Never re-grease through a drilled hole in the housing wall without a vent path: pressure builds behind the cup, blows grease past the rollers, and starves the bearing while the housing looks full.",
    "applications": [
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "The 22 mm wide section of HK1522ZWFD gains rating through longer rollers at 15 mm shaft; confirm the housing width accepts 22 mm — it will not drop into a seat machined for the 15×21 mm narrow variant.",
      "The open ends of HK1522ZWFD retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "At a 15 mm shaft diameter, check housing bore roundness after previous bearing removal for HK1522ZWFD; a pulled or scored seat must be re-machined or sleeved before the new cup goes in.",
      "The two roller rows in HK1522ZWFD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 21 mm seat straight over the full 22 mm width and keep shaft deflection minimal."
    ],
    "faq": [
      {
        "q": "Can a HK1522ZWFD needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1522ZWFD carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1522ZWFD need a hardened shaft?",
        "a": "Either the 15 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR12x15x22.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1522ZWFD needle roller bearing?",
        "a": "A HK1522ZWFD drawn-cup needle roller bearing has a 15 mm shaft diameter (Fw, under-roller diameter), 21 mm outside diameter and 22 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1522ZWFD drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1522ZWFD, Fw = 15 mm, so the shaft must be machined to 15 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1522ZWFD",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1612FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 7.75,
    "static_load_kN": 9.7,
    "fatigue_load_limit_kN": 1.18,
    "limiting_speed_rpm": 10000,
    "speed_oil_rpm": 15000,
    "weight_g": 12,
    "manufacturer_designation": "HK1612FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1612FM",
      "HK1612FM+IR12x16x13"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK1612FM is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 16 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 22 mm cup outside diameter and 12 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Garden machinery and small outboard engines fit this size in the crankcase web: the thin cup keeps the crank web narrow while still carrying the combustion pulses through the connecting-rod small end. Use a mandrel with a lead chamfer that matches the cup bore when pressing this size home; a flat-faced drift can catch the roller cage and distort the shell before it is fully seated.",
    "applications": [
      "compressor crankshaft supports",
      "agricultural machinery PTO drives",
      "universal joint and steering pivots",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Mid-size cups like HK1612FM (16 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK1612FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 16 mm.",
      "The 12 mm standard width of HK1612FM is the general-purpose section at 16 mm shaft; wider HK variants in the same 16×22 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1612FM need a hardened shaft?",
        "a": "Either the 16 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR12x16x13) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1612FM needle roller bearing?",
        "a": "A HK1612FM drawn-cup needle roller bearing has a 16 mm shaft diameter (Fw, under-roller diameter), 22 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1612FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1612FM, Fw = 16 mm, so the shaft must be machined to 16 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1612FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1612FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1612FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1616F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 11.1,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.87,
    "limiting_speed_rpm": 10000,
    "speed_oil_rpm": 15000,
    "weight_g": 16,
    "manufacturer_designation": "HK1616F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1616F",
      "HK1616F+IR12x16x20"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK1616F is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 16 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 22 mm cup outside diameter and 16 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. In this mid size range the HK cup is the standard compact radial bearing choice across automotive and industrial gearboxes. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The open ends of HK1616F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "At a 16 mm shaft diameter, check housing bore roundness after previous bearing removal for HK1616F; a pulled or scored seat must be re-machined or sleeved before the new cup goes in.",
      "The cage in HK1616F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 16 mm.",
      "The 16 mm standard width of HK1616F is the general-purpose section at 16 mm shaft; wider HK variants in the same 16×22 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1616F need a hardened shaft?",
        "a": "Either the 16 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR12x16x20) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1616F needle roller bearing?",
        "a": "A HK1616F drawn-cup needle roller bearing has a 16 mm shaft diameter (Fw, under-roller diameter), 22 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1616F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1616F, Fw = 16 mm, so the shaft must be machined to 16 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1616F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1616F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1616F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1622ZWFD",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 22,
    "seal_type": "open",
    "dynamic_load_kN": 13.3,
    "static_load_kN": 19.4,
    "fatigue_load_limit_kN": 2.37,
    "limiting_speed_rpm": 10000,
    "speed_oil_rpm": 15000,
    "weight_g": 22,
    "manufacturer_designation": "HK1622ZWFD",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1622ZWFD"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK1622ZWFD is built around a thin hardened steel cup.Its printed envelope — 16 mm under-roller diameter, 22 mm outside diameter, 22 mm width — is fixed by ISO 3245; the 16 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Small electric actuators and valve gear specify this size on the output shaft, where the gearmotor pinion needs support but the casting leaves no room for a machined ring. In dusty environments, place an external lip seal or felt washer immediately adjacent to the open cup end; the rollers have no defence against grit that migrates through the housing.",
    "applications": [
      "compressor crankshaft supports",
      "agricultural machinery PTO drives",
      "universal joint and steering pivots",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "Mid-size cups like HK1622ZWFD (16 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The two roller rows in HK1622ZWFD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 22 mm seat straight over the full 22 mm width and keep shaft deflection minimal.",
      "The 22 mm wide section of HK1622ZWFD gains rating through longer rollers at 16 mm shaft; confirm the housing width accepts 22 mm — it will not drop into a seat machined for the 16×22 mm narrow variant.",
      "HK1622ZWFD runs directly on the shaft: the 16 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK1622ZWFD retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK1622ZWFD needle roller bearing?",
        "a": "A HK1622ZWFD drawn-cup needle roller bearing has a 16 mm shaft diameter (Fw, under-roller diameter), 22 mm outside diameter and 22 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1622ZWFD drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1622ZWFD, Fw = 16 mm, so the shaft must be machined to 16 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1622ZWFD needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1622ZWFD carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK1622ZWFD retained in the housing?",
        "a": "The thin-walled drawn cup of HK1622ZWFD is press-fitted into a 22 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What duty conditions suit a HK1622ZWFD drawn-cup bearing?",
        "a": "HK1622ZWFD is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (10000/15000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1622ZWFD",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1712FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 23,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 8.05,
    "static_load_kN": 10.3,
    "fatigue_load_limit_kN": 1.26,
    "limiting_speed_rpm": 9500,
    "speed_oil_rpm": 14000,
    "weight_g": 12,
    "manufacturer_designation": "HK1712FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1712FM"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK1712FM is built around a thin hardened steel cup.Its printed envelope — 17 mm under-roller diameter, 23 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 17 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Small compressor crankshafts and refrigeration equipment fit this size on the eccentric pin, where the housing bore is finish-bored in the same setup as the main bearing seats. Where the housing is a welded fabrication, finish-bore the seat after all welding and stress-relief is complete — pressing the cup into a distorted, as-welded bore guarantees early spalling.",
    "applications": [
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The HK1712FM drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK1712FM (17 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK1712FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 17 mm.",
      "The 12 mm standard width of HK1712FM is the general-purpose section at 17 mm shaft; wider HK variants in the same 17×23 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "How is a HK1712FM retained in the housing?",
        "a": "The thin-walled drawn cup of HK1712FM is press-fitted into a 23 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What are the dimensions of a HK1712FM needle roller bearing?",
        "a": "A HK1712FM drawn-cup needle roller bearing has a 17 mm shaft diameter (Fw, under-roller diameter), 23 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1712FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1712FM, Fw = 17 mm, so the shaft must be machined to 17 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1712FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1712FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1712FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1812FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 24,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 8.3,
    "static_load_kN": 10.9,
    "fatigue_load_limit_kN": 1.33,
    "limiting_speed_rpm": 8500,
    "speed_oil_rpm": 13000,
    "weight_g": 13,
    "manufacturer_designation": "HK1812FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1812FM",
      "HK1812FM+IR15x18x12.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK1812FM is built around a thin hardened steel cup.Its printed envelope — 18 mm under-roller diameter, 24 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 18 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Agricultural PTO shafts and small tractor linkages use this size at the pivot points: the cup is pressed into a welded eye and forgotten until the implement is overhauled. Mounting this size in a split housing needs the cup pressed into one half only, with the joint face relieved so the shell is not pinched when the case bolts come up to torque.",
    "applications": [
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Mid-size cups like HK1812FM (18 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK1812FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 18 mm.",
      "The 12 mm standard width of HK1812FM is the general-purpose section at 18 mm shaft; wider HK variants in the same 18×24 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Needle rollers tolerate almost no misalignment; if the 24 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling."
    ],
    "faq": [
      {
        "q": "What duty conditions suit a HK1812FM drawn-cup bearing?",
        "a": "HK1812FM is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (8500/13000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK1812FM needle roller bearing?",
        "a": "A HK1812FM drawn-cup needle roller bearing has a 18 mm shaft diameter (Fw, under-roller diameter), 24 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1812FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1812FM, Fw = 18 mm, so the shaft must be machined to 18 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1812FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1812FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK1812FM need a hardened shaft?",
        "a": "Either the 18 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR15x18x12.5) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1812FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK1816F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 24,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 11.8,
    "static_load_kN": 17.3,
    "fatigue_load_limit_kN": 2.11,
    "limiting_speed_rpm": 8500,
    "speed_oil_rpm": 13000,
    "weight_g": 18,
    "manufacturer_designation": "HK1816F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK1816F",
      "HK1816F+IR15x18x16.5"
    ],
    "naming_rule_text": "HK1816F is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 18 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 24 mm and the width is 16 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.",
    "applications": [
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The HK1816F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK1816F (18 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK1816F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 18 mm.",
      "The 16 mm standard width of HK1816F is the general-purpose section at 18 mm shaft; wider HK variants in the same 18×24 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK1816F need a hardened shaft?",
        "a": "Either the 18 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR15x18x16.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK1816F needle roller bearing?",
        "a": "A HK1816F drawn-cup needle roller bearing has a 18 mm shaft diameter (Fw, under-roller diameter), 24 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK1816F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK1816F, Fw = 18 mm, so the shaft must be machined to 18 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK1816F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK1816F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK1816F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2012FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 8.75,
    "static_load_kN": 12.1,
    "fatigue_load_limit_kN": 1.48,
    "limiting_speed_rpm": 8000,
    "speed_oil_rpm": 12000,
    "weight_g": 14,
    "manufacturer_designation": "HK2012FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2012FM",
      "HK2012FM+IR15x20x13"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2012FM is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 20 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 26 mm cup outside diameter and 12 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this mid size range the HK cup is the standard compact radial bearing choice across automotive and industrial gearboxes. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "The cage in HK2012FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 20 mm.",
      "The 12 mm standard width of HK2012FM is the general-purpose section at 20 mm shaft; wider HK variants in the same 20×26 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "The open ends of HK2012FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "At a 20 mm shaft diameter, check housing bore roundness after previous bearing removal for HK2012FM; a pulled or scored seat must be re-machined or sleeved before the new cup goes in."
    ],
    "faq": [
      {
        "q": "What does Fw mean on a HK2012FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2012FM, Fw = 20 mm, so the shaft must be machined to 20 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2012FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2012FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2012FM need a hardened shaft?",
        "a": "Either the 20 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR15x20x13) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2012FM needle roller bearing?",
        "a": "A HK2012FM drawn-cup needle roller bearing has a 20 mm shaft diameter (Fw, under-roller diameter), 26 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2012FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2016F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 12.5,
    "static_load_kN": 19.2,
    "fatigue_load_limit_kN": 2.34,
    "limiting_speed_rpm": 8000,
    "speed_oil_rpm": 12000,
    "weight_g": 19,
    "manufacturer_designation": "HK2016F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2016F",
      "HK2016F+IR17x20x16.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2016F is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 20 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 26 mm cup outside diameter and 16 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Automotive gearbox designers default to this class when the radial envelope is fixed: the cup keeps the casing compact without giving up the required rating. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "compressor crankshaft supports",
      "agricultural machinery PTO drives",
      "universal joint and steering pivots",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Before pressing HK2016F in, verify the 20 mm housing seat is still round — extracting the old cup often pulls the bore, and the new thin shell will conform to any distortion.",
      "The cage in HK2016F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 20 mm.",
      "The 16 mm standard width of HK2016F is the general-purpose section at 20 mm shaft; wider HK variants in the same 20×26 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK2016F need a hardened shaft?",
        "a": "Either the 20 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x20x16.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2016F needle roller bearing?",
        "a": "A HK2016F drawn-cup needle roller bearing has a 20 mm shaft diameter (Fw, under-roller diameter), 26 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2016F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2016F, Fw = 20 mm, so the shaft must be machined to 20 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2016F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2016F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2016F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2020F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 16,
    "static_load_kN": 26.2,
    "fatigue_load_limit_kN": 3.2,
    "limiting_speed_rpm": 8000,
    "speed_oil_rpm": 12000,
    "weight_g": 24,
    "manufacturer_designation": "HK2020F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2020F",
      "HK2020F+IR17x20x20.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2020F is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 20 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 26 mm cup outside diameter and 20 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Marine outboard and small diesel linkage points use this size: the pressed-in cup tolerates the corrosion-prone environment better than a machined ring with a separate inner race. In high-speed applications, switch from grease to a circulating oil supply: the open ends let oil through, but grease at high speed channels and overheats the roller set.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "Drawn-cup needle bearings carry radial load only: HK2020F provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces.",
      "The HK2020F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK2020F (20 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK2020F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 20 mm.",
      "The 20 mm wide section of HK2020F gains rating through longer rollers at 20 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 20×26 mm narrow variant."
    ],
    "faq": [
      {
        "q": "Does HK2020F need a hardened shaft?",
        "a": "Either the 20 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x20x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK2020F drawn-cup bearing?",
        "a": "HK2020F is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (8000/12000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2020F needle roller bearing?",
        "a": "A HK2020F drawn-cup needle roller bearing has a 20 mm shaft diameter (Fw, under-roller diameter), 26 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2020F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2020F, Fw = 20 mm, so the shaft must be machined to 20 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2020F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2020F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2020F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2030ZWFD",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 30,
    "seal_type": "open",
    "dynamic_load_kN": 21.5,
    "static_load_kN": 38.5,
    "fatigue_load_limit_kN": 4.7,
    "limiting_speed_rpm": 8000,
    "speed_oil_rpm": 12000,
    "weight_g": 35,
    "manufacturer_designation": "HK2030ZWFD",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2030ZWFD",
      "HK2030ZWFD+IR17x20x30.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2030ZWFD is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 20 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 26 mm cup outside diameter and 30 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. Automotive gearbox designers default to this class when the radial envelope is fixed: the cup keeps the casing compact without giving up the required rating. Marine outboard and small diesel linkage points use this size: the pressed-in cup tolerates the corrosion-prone environment better than a machined ring with a separate inner race. In high-speed applications, switch from grease to a circulating oil supply: the open ends let oil through, but grease at high speed channels and overheats the roller set.",
    "applications": [
      "agricultural machinery PTO drives",
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "The open ends of HK2030ZWFD retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "Before pressing HK2030ZWFD in, verify the 20 mm housing seat is still round — extracting the old cup often pulls the bore, and the new thin shell will conform to any distortion.",
      "The two roller rows in HK2030ZWFD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 26 mm seat straight over the full 30 mm width and keep shaft deflection minimal.",
      "The 30 mm extra-wide section of HK2030ZWFD (double-row or extended roller set) is the high-capacity option at 20 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 30 mm width.",
      "HK2030ZWFD runs directly on the shaft: the 20 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead."
    ],
    "faq": [
      {
        "q": "What duty conditions suit a HK2030ZWFD drawn-cup bearing?",
        "a": "HK2030ZWFD is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (8000/12000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2030ZWFD needle roller bearing?",
        "a": "A HK2030ZWFD drawn-cup needle roller bearing has a 20 mm shaft diameter (Fw, under-roller diameter), 26 mm outside diameter and 30 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2030ZWFD drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2030ZWFD, Fw = 20 mm, so the shaft must be machined to 20 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2030ZWFD needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2030ZWFD carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2030ZWFD need a hardened shaft?",
        "a": "Either the 20 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x20x30.5) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2030ZWFD",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2212FM",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 9.2,
    "static_load_kN": 13.4,
    "fatigue_load_limit_kN": 1.63,
    "limiting_speed_rpm": 7500,
    "speed_oil_rpm": 11000,
    "weight_g": 13,
    "manufacturer_designation": "HK2212FM",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2212FM",
      "HK2212FM+IR17x22x13"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK2212FM is built around a thin hardened steel cup.Its printed envelope — 22 mm under-roller diameter, 28 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 22 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this mid size range the HK cup is the standard compact radial bearing choice across automotive and industrial gearboxes. Compact hydraulic gear pumps use this size on their drive shafts: the pump housing is machined once, the cup is pressed home, and the shaft runs directly on the rollers for the life of the unit. For oscillating service, pack this size with a high-tackiness grease and re-lubricate at short intervals: the rollers do not complete a full revolution, so the same contact patch carries the load cycle after cycle.",
    "applications": [
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "agricultural machinery PTO drives",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "The open ends of HK2212FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "At a 22 mm shaft diameter, check housing bore roundness after previous bearing removal for HK2212FM; a pulled or scored seat must be re-machined or sleeved before the new cup goes in.",
      "The cage in HK2212FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 22 mm.",
      "The 12 mm standard width of HK2212FM is the general-purpose section at 22 mm shaft; wider HK variants in the same 22×28 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "HK2212FM runs directly on the shaft: the 22 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead."
    ],
    "faq": [
      {
        "q": "What duty conditions suit a HK2212FM drawn-cup bearing?",
        "a": "HK2212FM is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (7500/11000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2212FM needle roller bearing?",
        "a": "A HK2212FM drawn-cup needle roller bearing has a 22 mm shaft diameter (Fw, under-roller diameter), 28 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2212FM drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2212FM, Fw = 22 mm, so the shaft must be machined to 22 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2212FM needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2212FM carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2212FM need a hardened shaft?",
        "a": "Either the 22 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x22x13) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2212FM",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2216F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 21.1,
    "fatigue_load_limit_kN": 2.57,
    "limiting_speed_rpm": 7500,
    "speed_oil_rpm": 11000,
    "weight_g": 21,
    "manufacturer_designation": "HK2216F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2216F",
      "HK2216F+IR17x22x18"
    ],
    "naming_rule_text": "HK2216F is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 22 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 28 mm and the width is 16 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The open ends of HK2216F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "Mid-size cups like HK2216F (22 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK2216F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 22 mm.",
      "The 16 mm standard width of HK2216F is the general-purpose section at 22 mm shaft; wider HK variants in the same 22×28 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK2216F need a hardened shaft?",
        "a": "Either the 22 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x22x18) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2216F needle roller bearing?",
        "a": "A HK2216F drawn-cup needle roller bearing has a 22 mm shaft diameter (Fw, under-roller diameter), 28 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2216F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2216F, Fw = 22 mm, so the shaft must be machined to 22 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2216F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2216F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2216F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2220F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 16.8,
    "static_load_kN": 28.8,
    "fatigue_load_limit_kN": 3.5,
    "limiting_speed_rpm": 7500,
    "speed_oil_rpm": 11000,
    "weight_g": 26,
    "manufacturer_designation": "HK2220F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2220F",
      "HK2220F+IR17x22x20.5"
    ],
    "naming_rule_text": "HK2220F is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 22 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 28 mm and the width is 20 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Automotive gearbox designers default to this class when the radial envelope is fixed: the cup keeps the casing compact without giving up the required rating. Small compressor crankshafts and refrigeration equipment fit this size on the eccentric pin, where the housing bore is finish-bored in the same setup as the main bearing seats. Where the housing is a welded fabrication, finish-bore the seat after all welding and stress-relief is complete — pressing the cup into a distorted, as-welded bore guarantees early spalling.",
    "applications": [
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "The 20 mm wide section of HK2220F gains rating through longer rollers at 22 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 22×28 mm narrow variant.",
      "Needle rollers tolerate almost no misalignment; if the 28 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Before pressing HK2220F in, verify the 22 mm housing seat is still round — extracting the old cup often pulls the bore, and the new thin shell will conform to any distortion.",
      "The cage in HK2220F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 22 mm."
    ],
    "faq": [
      {
        "q": "Can a HK2220F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2220F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2220F need a hardened shaft?",
        "a": "Either the 22 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR17x22x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK2220F drawn-cup bearing?",
        "a": "HK2220F is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (7500/11000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2220F needle roller bearing?",
        "a": "A HK2220F drawn-cup needle roller bearing has a 22 mm shaft diameter (Fw, under-roller diameter), 28 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2220F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2220F, Fw = 22 mm, so the shaft must be machined to 22 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2220F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2512F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 11.1,
    "static_load_kN": 15.2,
    "fatigue_load_limit_kN": 1.85,
    "limiting_speed_rpm": 6500,
    "speed_oil_rpm": 9500,
    "weight_g": 21,
    "manufacturer_designation": "HK2512F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2512F",
      "HK2512F+IR20x25x12.5"
    ],
    "naming_rule_text": "NTN HK2512F belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 25 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 32 mm outside and 12 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Agricultural PTO shafts and small tractor linkages use this size at the pivot points: the cup is pressed into a welded eye and forgotten until the implement is overhauled. Mounting this size in a split housing needs the cup pressed into one half only, with the joint face relieved so the shell is not pinched when the case bolts come up to torque.",
    "applications": [
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "compressor crankshaft supports",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The HK2512F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK2512F (25 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "The cage in HK2512F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 25 mm.",
      "The 12 mm standard width of HK2512F is the general-purpose section at 25 mm shaft; wider HK variants in the same 25×32 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK2512F need a hardened shaft?",
        "a": "Either the 25 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR20x25x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2512F needle roller bearing?",
        "a": "A HK2512F drawn-cup needle roller bearing has a 25 mm shaft diameter (Fw, under-roller diameter), 32 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2512F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2512F, Fw = 25 mm, so the shaft must be machined to 25 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2512F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2512F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2512F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2516F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 15.9,
    "static_load_kN": 24,
    "fatigue_load_limit_kN": 2.92,
    "limiting_speed_rpm": 6500,
    "speed_oil_rpm": 9500,
    "weight_g": 27,
    "manufacturer_designation": "HK2516F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2516F",
      "HK2516F+IR20x25x17"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2516F is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 25 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 32 mm cup outside diameter and 16 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Automotive gearbox designers default to this class when the radial envelope is fixed: the cup keeps the casing compact without giving up the required rating. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "intermittent duty with long standstill periods that invite false brinelling"
    ],
    "failure_modes": [
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness"
    ],
    "pitfalls": [
      "The open ends of HK2516F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "Before pressing HK2516F in, verify the 25 mm housing seat is still round — extracting the old cup often pulls the bore, and the new thin shell will conform to any distortion.",
      "The cage in HK2516F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 25 mm.",
      "The 16 mm standard width of HK2516F is the general-purpose section at 25 mm shaft; wider HK variants in the same 25×32 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK2516F need a hardened shaft?",
        "a": "Either the 25 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR20x25x17) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2516F needle roller bearing?",
        "a": "A HK2516F drawn-cup needle roller bearing has a 25 mm shaft diameter (Fw, under-roller diameter), 32 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2516F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2516F, Fw = 25 mm, so the shaft must be machined to 25 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2516F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2516F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2516F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2520",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 20.3,
    "static_load_kN": 33,
    "fatigue_load_limit_kN": 4,
    "limiting_speed_rpm": 6500,
    "speed_oil_rpm": 9500,
    "weight_g": 34,
    "manufacturer_designation": "HK2520",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2520",
      "HK2520+IR20x25x20.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK2520 is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 25 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 32 mm cup outside diameter and 20 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "Drawn-cup needle bearings carry radial load only: HK2520 provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces.",
      "The HK2520 drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK2520 (25 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "With no suffix letters, HK2520 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 25×32×20 mm match exactly — suffix conventions for cage and shell variants differ between makers.",
      "The 20 mm wide section of HK2520 gains rating through longer rollers at 25 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 25×32 mm narrow variant."
    ],
    "faq": [
      {
        "q": "Does HK2520 need a hardened shaft?",
        "a": "Either the 25 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR20x25x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK2520 drawn-cup bearing?",
        "a": "HK2520 is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (6500/9500 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2520 needle roller bearing?",
        "a": "A HK2520 drawn-cup needle roller bearing has a 25 mm shaft diameter (Fw, under-roller diameter), 32 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2520 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2520, Fw = 25 mm, so the shaft must be machined to 25 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2520 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2520 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2520-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×32×20 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ]
  },
  {
    "sku": "HK2526C",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 26,
    "seal_type": "open",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 46,
    "fatigue_load_limit_kN": 5.6,
    "limiting_speed_rpm": 6500,
    "speed_oil_rpm": 9500,
    "weight_g": 45,
    "manufacturer_designation": "HK2526C",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2526C",
      "HK2526C+IR20x25x26.5"
    ],
    "naming_rule_text": "The NTN HK2526C — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 25 mm is Fw, the under-roller (shaft journal) diameter; 32 mm and 26 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. Small electric actuators and valve gear specify this size on the output shaft, where the gearmotor pinion needs support but the casting leaves no room for a machined ring. In dusty environments, place an external lip seal or felt washer immediately adjacent to the open cup end; the rollers have no defence against grit that migrates through the housing.",
    "applications": [
      "universal joint and steering pivots",
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Mid-size cups like HK2526C (25 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short.",
      "HK2526C carries a maker-specific variant code after the size: when substituting another brand, match the printed 25×32×26 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 26 mm extra-wide section of HK2526C (double-row or extended roller set) is the high-capacity option at 25 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 26 mm width."
    ],
    "faq": [
      {
        "q": "Does HK2526C need a hardened shaft?",
        "a": "Either the 25 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR20x25x26.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2526C needle roller bearing?",
        "a": "A HK2526C drawn-cup needle roller bearing has a 25 mm shaft diameter (Fw, under-roller diameter), 32 mm outside diameter and 26 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2526C drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2526C, Fw = 25 mm, so the shaft must be machined to 25 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2526C needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2526C carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2526C",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2538ZWD",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 38,
    "seal_type": "open",
    "dynamic_load_kN": 35,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8,
    "limiting_speed_rpm": 6500,
    "speed_oil_rpm": 9500,
    "weight_g": 65,
    "manufacturer_designation": "HK2538ZWD",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2538ZWD",
      "HK2538ZWD+IR20x25x38.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK2538ZWD is built around a thin hardened steel cup.Its printed envelope — 25 mm under-roller diameter, 32 mm outside diameter, 38 mm width — is fixed by ISO 3245; the 25 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. Mid-size drawn cups like this appear throughout passenger-car and light-truck transmissions, pressed into cast housings where a machined ring would not fit. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.",
    "applications": [
      "automotive manual transmission gear sets",
      "industrial gearbox lay shafts",
      "hydraulic pump and motor shafts",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "The two roller rows in HK2538ZWD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 32 mm seat straight over the full 38 mm width and keep shaft deflection minimal.",
      "The 38 mm extra-wide section of HK2538ZWD (double-row or extended roller set) is the high-capacity option at 25 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 38 mm width.",
      "Drawn-cup needle bearings carry radial load only: HK2538ZWD provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces.",
      "The HK2538ZWD drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Mid-size cups like HK2538ZWD (25 mm shaft) inherit the shape of their seat: a scored or oval housing bore from the previous bearing will cut the new bearing's life short."
    ],
    "faq": [
      {
        "q": "What does Fw mean on a HK2538ZWD drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2538ZWD, Fw = 25 mm, so the shaft must be machined to 25 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2538ZWD needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2538ZWD carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2538ZWD need a hardened shaft?",
        "a": "Either the 25 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR20x25x38.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK2538ZWD drawn-cup bearing?",
        "a": "HK2538ZWD is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (6500/9500 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK2538ZWD needle roller bearing?",
        "a": "A HK2538ZWD drawn-cup needle roller bearing has a 25 mm shaft diameter (Fw, under-roller diameter), 32 mm outside diameter and 38 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2538ZWD",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2816CT",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 35,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 16.7,
    "static_load_kN": 26.4,
    "fatigue_load_limit_kN": 3.2,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8500,
    "weight_g": 30,
    "manufacturer_designation": "HK2816CT",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2816CT",
      "HK2816CT+IR22x28x17"
    ],
    "naming_rule_text": "The NTN HK2816CT — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 28 mm is Fw, the under-roller (shaft journal) diameter; 35 mm and 16 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. Garden machinery and small outboard engines fit this size in the crankcase web: the thin cup keeps the crank web narrow while still carrying the combustion pulses through the connecting-rod small end. Use a mandrel with a lead chamfer that matches the cup bore when pressing this size home; a flat-faced drift can catch the roller cage and distort the shell before it is fully seated.",
    "applications": [
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "The press-fit of HK2816CT at 28 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "HK2816CT carries a maker-specific variant code after the size: when substituting another brand, match the printed 28×35×16 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 16 mm standard width of HK2816CT is the general-purpose section at 28 mm shaft; wider HK variants in the same 28×35 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Needle rollers tolerate almost no misalignment; if the 35 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK2816CT needle roller bearing?",
        "a": "A HK2816CT drawn-cup needle roller bearing has a 28 mm shaft diameter (Fw, under-roller diameter), 35 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2816CT drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2816CT, Fw = 28 mm, so the shaft must be machined to 28 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK2816CT needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2816CT carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2816CT need a hardened shaft?",
        "a": "Either the 28 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR22x28x17) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK2816CT drawn-cup bearing?",
        "a": "HK2816CT is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (5500/8500 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2816CT",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK2820",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 35,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 21.3,
    "static_load_kN": 36,
    "fatigue_load_limit_kN": 4.4,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8500,
    "weight_g": 38,
    "manufacturer_designation": "HK2820",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK2820",
      "HK2820+IR22x28x20.5"
    ],
    "naming_rule_text": "The NTN HK2820 — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 28 mm is Fw, the under-roller (shaft journal) diameter; 35 mm and 20 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. This cup size is common in power-tool intermediate shafts — drills, saws, grinders — where the gearbox casing is magnesium or aluminium and the cup is pressed into a steel insert. If the shaft sees axial float, allow for it in the housing width — the cup cannot guide the shaft axially, and a shaft that walks will eventually hammer the open end of the shell.",
    "applications": [
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "The 20 mm wide section of HK2820 gains rating through longer rollers at 28 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 28×35 mm narrow variant.",
      "The HK2820 drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Pressing HK2820 (28 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.",
      "With no suffix letters, HK2820 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 28×35×20 mm match exactly — suffix conventions for cage and shell variants differ between makers."
    ],
    "faq": [
      {
        "q": "Can a HK2820 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK2820 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK2820 need a hardened shaft?",
        "a": "Either the 28 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR22x28x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK2820 needle roller bearing?",
        "a": "A HK2820 drawn-cup needle roller bearing has a 28 mm shaft diameter (Fw, under-roller diameter), 35 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK2820 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2820, Fw = 28 mm, so the shaft must be machined to 28 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK2820-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×35×20 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ]
  },
  {
    "sku": "HK3012CT",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 12.3,
    "static_load_kN": 18.2,
    "fatigue_load_limit_kN": 2.22,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8000,
    "weight_g": 24,
    "manufacturer_designation": "HK3012CT",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3012CT",
      "HK3012CT+IR25x30x12.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3012CT is built around a thin hardened steel cup.Its printed envelope — 30 mm under-roller diameter, 37 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 30 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. Model and hobby drivetrains, from RC cars to small robotics, use this size because the thin cup lets designers shrink the gearbox around the gears rather than around the bearing. For low-temperature service, verify the grease is rated for the minimum ambient — a standard lithium grease in this cup will stiffen and starve the rollers on a cold start.",
    "applications": [
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The HK3012CT drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.",
      "Pressing HK3012CT (30 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.",
      "HK3012CT carries a maker-specific variant code after the size: when substituting another brand, match the printed 30×37×12 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 12 mm standard width of HK3012CT is the general-purpose section at 30 mm shaft; wider HK variants in the same 30×37 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK3012CT need a hardened shaft?",
        "a": "Either the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR25x30x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK3012CT needle roller bearing?",
        "a": "A HK3012CT drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3012CT drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3012CT, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3012CT needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3012CT carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3012CT",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "7E-HK3016C",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 18.1,
    "static_load_kN": 30,
    "fatigue_load_limit_kN": 3.65,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8000,
    "weight_g": 32,
    "manufacturer_designation": "7E-HK3016C",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "7E-HK3016C",
      "7E-HK3016C+IR25x30x17"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), 7E-HK3016C is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 30 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 37 mm cup outside diameter and 16 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. You will find this cup size inside small two-stroke crankcases, supporting the small-end of the connecting rod where the housing is split and the bearing is pressed in before the case halves close. If the shaft cannot be hardened, press the matching IR inner ring onto it first; the ring gives the rollers a hardened, ground raceway and lets you keep a soft shaft for assembly reasons.",
    "applications": [
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "heavily loaded slow pivots where static rating, not dynamic life, governs the choice"
    ],
    "failure_modes": [
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting",
      "grease starvation in the open-end arrangement with no relubrication path"
    ],
    "pitfalls": [
      "The 16 mm standard width of 7E-HK3016C is the general-purpose section at 30 mm shaft; wider HK variants in the same 30×37 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "7E-HK3016C runs directly on the shaft: the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of 7E-HK3016C retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "The press-fit of 7E-HK3016C at 30 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "7E-HK3016C carries a maker-specific variant code after the size: when substituting another brand, match the printed 30×37×16 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers."
    ],
    "faq": [
      {
        "q": "Can a 7E-HK3016C needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like 7E-HK3016C carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does 7E-HK3016C need a hardened shaft?",
        "a": "Either the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR25x30x17) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a 7E-HK3016C drawn-cup bearing?",
        "a": "7E-HK3016C is typically specified for reciprocating or oscillating motion where the rollers never complete a full revolution; match the grease/oil speed limits (5500/8000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a 7E-HK3016C needle roller bearing?",
        "a": "A 7E-HK3016C drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a 7E-HK3016C drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For 7E-HK3016C, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "7E",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3020F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 22.3,
    "static_load_kN": 39.5,
    "fatigue_load_limit_kN": 4.8,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8000,
    "weight_g": 40,
    "manufacturer_designation": "HK3020F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3020F",
      "HK3020F+IR25x30x20.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3020F is built around a thin hardened steel cup.Its printed envelope — 30 mm under-roller diameter, 37 mm outside diameter, 20 mm width — is fixed by ISO 3245; the 30 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. Small electric actuators and valve gear specify this size on the output shaft, where the gearmotor pinion needs support but the casting leaves no room for a machined ring. In dusty environments, place an external lip seal or felt washer immediately adjacent to the open cup end; the rollers have no defence against grit that migrates through the housing.",
    "applications": [
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "rolling mill auxiliary drives",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "The press-fit of HK3020F at 30 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "The cage in HK3020F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 30 mm.",
      "The 20 mm wide section of HK3020F gains rating through longer rollers at 30 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 30×37 mm narrow variant.",
      "HK3020F runs directly on the shaft: the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK3020F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK3020F needle roller bearing?",
        "a": "A HK3020F drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3020F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3020F, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3020F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3020F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK3020F need a hardened shaft?",
        "a": "Either the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR25x30x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK3020F drawn-cup bearing?",
        "a": "HK3020F is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (5500/8000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3020F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3026F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 26,
    "seal_type": "open",
    "dynamic_load_kN": 28.5,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.55,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8000,
    "weight_g": 53,
    "manufacturer_designation": "HK3026F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3026F",
      "HK3026F+IR25x30x26.5"
    ],
    "naming_rule_text": "The NTN HK3026F — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 30 mm is Fw, the under-roller (shaft journal) diameter; 37 mm and 26 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.",
    "applications": [
      "marine steering and linkage shafts",
      "rolling mill auxiliary drives",
      "heavy gearbox and final drive shafts",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "The 26 mm extra-wide section of HK3026F (double-row or extended roller set) is the high-capacity option at 30 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 26 mm width.",
      "HK3026F runs directly on the shaft: the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK3026F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "The press-fit of HK3026F at 30 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "The cage in HK3026F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 30 mm."
    ],
    "faq": [
      {
        "q": "Can a HK3026F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3026F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK3026F need a hardened shaft?",
        "a": "Either the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR25x30x26.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK3026F drawn-cup bearing?",
        "a": "HK3026F is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (5500/8000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK3026F needle roller bearing?",
        "a": "A HK3026F drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 26 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3026F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3026F, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3026F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3038ZWD",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 38,
    "seal_type": "open",
    "dynamic_load_kN": 38.5,
    "static_load_kN": 78.5,
    "fatigue_load_limit_kN": 9.6,
    "limiting_speed_rpm": 5500,
    "speed_oil_rpm": 8000,
    "weight_g": 76,
    "manufacturer_designation": "HK3038ZWD",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3038ZWD",
      "HK3038ZWD+IR25x30x38.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3038ZWD is built around a thin hardened steel cup.Its printed envelope — 30 mm under-roller diameter, 37 mm outside diameter, 38 mm width — is fixed by ISO 3245; the 30 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. At this shaft size the cup carries substantial radial load, but correct press-fit practice and housing rigidity become decisive for reaching the calculated life. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.",
    "applications": [
      "rolling mill auxiliary drives",
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "At a 30 mm shaft diameter the press-in force for HK3038ZWD is substantial; use a press with a guided mandrel and confirm the cup seats against the housing shoulder — a cocked cup concentrates load on the outermost roller row.",
      "The two roller rows in HK3038ZWD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 37 mm seat straight over the full 38 mm width and keep shaft deflection minimal.",
      "The 38 mm extra-wide section of HK3038ZWD (double-row or extended roller set) is the high-capacity option at 30 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 38 mm width."
    ],
    "faq": [
      {
        "q": "Does HK3038ZWD need a hardened shaft?",
        "a": "Either the 30 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR25x30x38.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK3038ZWD needle roller bearing?",
        "a": "A HK3038ZWD drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 38 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3038ZWD drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3038ZWD, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3038ZWD needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3038ZWD carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3038ZWD",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3512CV2",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 13.3,
    "static_load_kN": 21.3,
    "fatigue_load_limit_kN": 2.6,
    "limiting_speed_rpm": 4700,
    "speed_oil_rpm": 7000,
    "weight_g": 28,
    "manufacturer_designation": "HK3512CV2",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3512CV2"
    ],
    "naming_rule_text": "The NTN HK3512CV2 — an open-end drawn-cup needle roller bearing — sits in the HK-series under ISO 3245 boundary dimensions.Reading the size code: 35 mm is Fw, the under-roller (shaft journal) diameter; 42 mm and 12 mm are the cup outside diameter and width respectively. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. Agricultural PTO shafts and small tractor linkages use this size at the pivot points: the cup is pressed into a welded eye and forgotten until the implement is overhauled. Mounting this size in a split housing needs the cup pressed into one half only, with the joint face relieved so the shell is not pinched when the case bolts come up to torque.",
    "applications": [
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "shock-loaded start-stop service such as clutch and kick-starter mechanisms"
    ],
    "failure_modes": [
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell"
    ],
    "pitfalls": [
      "Pressing HK3512CV2 (35 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.",
      "HK3512CV2 carries a maker-specific variant code after the size: when substituting another brand, match the printed 35×42×12 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 12 mm standard width of HK3512CV2 is the general-purpose section at 35 mm shaft; wider HK variants in the same 35×42 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Needle rollers tolerate almost no misalignment; if the 42 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK3512CV2 needle roller bearing?",
        "a": "A HK3512CV2 drawn-cup needle roller bearing has a 35 mm shaft diameter (Fw, under-roller diameter), 42 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3512CV2 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3512CV2, Fw = 35 mm, so the shaft must be machined to 35 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3512CV2 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3512CV2 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK3512CV2 retained in the housing?",
        "a": "The thin-walled drawn cup of HK3512CV2 is press-fitted into a 42 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What duty conditions suit a HK3512CV2 drawn-cup bearing?",
        "a": "HK3512CV2 is typically specified for dirty environments where the open ends rely entirely on the housing seals; match the grease/oil speed limits (4700/7000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3512CV2",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3516CT",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 19,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 4.1,
    "limiting_speed_rpm": 4700,
    "speed_oil_rpm": 7000,
    "weight_g": 37,
    "manufacturer_designation": "HK3516CT",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3516CT"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3516CT is built around a thin hardened steel cup.Its printed envelope — 35 mm under-roller diameter, 42 mm outside diameter, 16 mm width — is fixed by ISO 3245; the 35 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. Conveyor and packaging-machinery builders choose this size for idler and tensioner rollers: the open ends accept a grease fill at assembly and the cup survives the life of the roller shell. When the housing is aluminium or magnesium, press this cup into a steel insert rather than the bare casting — differential thermal expansion will walk the cup out of a soft bore at operating temperature.",
    "applications": [
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "rolling mill auxiliary drives",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "HK3516CT carries a maker-specific variant code after the size: when substituting another brand, match the printed 35×42×16 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 16 mm standard width of HK3516CT is the general-purpose section at 35 mm shaft; wider HK variants in the same 35×42 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Pressing HK3516CT (35 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder."
    ],
    "faq": [
      {
        "q": "What does Fw mean on a HK3516CT drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3516CT, Fw = 35 mm, so the shaft must be machined to 35 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3516CT needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3516CT carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK3516CT retained in the housing?",
        "a": "The thin-walled drawn cup of HK3516CT is press-fitted into a 42 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What are the dimensions of a HK3516CT needle roller bearing?",
        "a": "A HK3516CT drawn-cup needle roller bearing has a 35 mm shaft diameter (Fw, under-roller diameter), 42 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3516CT",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK3520",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 24.8,
    "static_load_kN": 47.5,
    "fatigue_load_limit_kN": 5.8,
    "limiting_speed_rpm": 4700,
    "speed_oil_rpm": 7000,
    "weight_g": 46,
    "manufacturer_designation": "HK3520",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK3520"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3520 is built around a thin hardened steel cup.Its printed envelope — 35 mm under-roller diameter, 42 mm outside diameter, 20 mm width — is fixed by ISO 3245; the 35 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. Model and hobby drivetrains, from RC cars to small robotics, use this size because the thin cup lets designers shrink the gearbox around the gears rather than around the bearing. For low-temperature service, verify the grease is rated for the minimum ambient — a standard lithium grease in this cup will stiffen and starve the rollers on a cold start.",
    "applications": [
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "rolling mill auxiliary drives",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "Pressing HK3520 (35 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.",
      "With no suffix letters, HK3520 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 35×42×20 mm match exactly — suffix conventions for cage and shell variants differ between makers.",
      "The 20 mm wide section of HK3520 gains rating through longer rollers at 35 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 35×42 mm narrow variant.",
      "HK3520 runs directly on the shaft: the 35 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK3520 retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK3520 needle roller bearing?",
        "a": "A HK3520 drawn-cup needle roller bearing has a 35 mm shaft diameter (Fw, under-roller diameter), 42 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK3520 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3520, Fw = 35 mm, so the shaft must be machined to 35 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK3520 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK3520 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "How is a HK3520 retained in the housing?",
        "a": "The thin-walled drawn cup of HK3520 is press-fitted into a 42 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid."
      },
      {
        "q": "What duty conditions suit a HK3520 drawn-cup bearing?",
        "a": "HK3520 is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (4700/7000 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK3520-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×42×20 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ]
  },
  {
    "sku": "HK4012V2",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 12,
    "seal_type": "open",
    "dynamic_load_kN": 12.1,
    "static_load_kN": 19.5,
    "fatigue_load_limit_kN": 2.38,
    "limiting_speed_rpm": 4000,
    "speed_oil_rpm": 6000,
    "weight_g": 31,
    "manufacturer_designation": "HK4012V2",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK4012V2",
      "HK4012V2+IR35x40x12.5"
    ],
    "naming_rule_text": "In the HK-series (ISO 3245), HK4012V2 is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 40 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 47 mm cup outside diameter and 12 mm width. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. Industrial sewing machines and textile equipment run this size on their shuttle and needle-bar drive shafts, where the compact radial section keeps the arm profile slim. Shaft tolerance for this size is h5 or j5: the roller complement needs a controlled radial clearance, and a shaft ground to general-purpose tolerances can leave the bearing either slack or pinched.",
    "applications": [
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "compact linkages where the cup doubles as both bearing and structural spacer"
    ],
    "failure_modes": [
      "grease starvation in the open-end arrangement with no relubrication path",
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection"
    ],
    "pitfalls": [
      "The 12 mm standard width of HK4012V2 is the general-purpose section at 40 mm shaft; wider HK variants in the same 40×47 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "HK4012V2 runs directly on the shaft: the 40 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.",
      "The open ends of HK4012V2 retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "The press-fit of HK4012V2 at 40 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "HK4012V2 carries a maker-specific variant code after the size: when substituting another brand, match the printed 40×47×12 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers."
    ],
    "faq": [
      {
        "q": "Can a HK4012V2 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK4012V2 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK4012V2 need a hardened shaft?",
        "a": "Either the 40 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR35x40x12.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK4012V2 drawn-cup bearing?",
        "a": "HK4012V2 is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (4000/6000 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK4012V2 needle roller bearing?",
        "a": "A HK4012V2 drawn-cup needle roller bearing has a 40 mm shaft diameter (Fw, under-roller diameter), 47 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK4012V2 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4012V2, Fw = 40 mm, so the shaft must be machined to 40 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK4012V2",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK4016CT",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 20.3,
    "static_load_kN": 38.5,
    "fatigue_load_limit_kN": 4.7,
    "limiting_speed_rpm": 4000,
    "speed_oil_rpm": 6000,
    "weight_g": 41,
    "manufacturer_designation": "HK4016CT",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK4016CT",
      "HK4016CT+IR35x40x17"
    ],
    "naming_rule_text": "HK4016CT is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 40 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 47 mm and the width is 16 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "rolling mill auxiliary drives",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "The press-fit of HK4016CT at 40 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "HK4016CT carries a maker-specific variant code after the size: when substituting another brand, match the printed 40×47×16 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.",
      "The 16 mm standard width of HK4016CT is the general-purpose section at 40 mm shaft; wider HK variants in the same 40×47 mm envelope carry more load and are not interchangeable if the housing width is fixed."
    ],
    "faq": [
      {
        "q": "Does HK4016CT need a hardened shaft?",
        "a": "Either the 40 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR35x40x17) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK4016CT needle roller bearing?",
        "a": "A HK4016CT drawn-cup needle roller bearing has a 40 mm shaft diameter (Fw, under-roller diameter), 47 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK4016CT drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4016CT, Fw = 40 mm, so the shaft must be machined to 40 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK4016CT needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK4016CT carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK4016CT",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK4020F",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 25.9,
    "static_load_kN": 52.5,
    "fatigue_load_limit_kN": 6.4,
    "limiting_speed_rpm": 4000,
    "speed_oil_rpm": 6000,
    "weight_g": 52,
    "manufacturer_designation": "HK4020F",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK4020F",
      "HK4020F+IR35x40x20.5"
    ],
    "naming_rule_text": "As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK4020F is built around a thin hardened steel cup.Its printed envelope — 40 mm under-roller diameter, 47 mm outside diameter, 20 mm width — is fixed by ISO 3245; the 40 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. You will find this cup size inside small two-stroke crankcases, supporting the small-end of the connecting rod where the housing is split and the bearing is pressed in before the case halves close. If the shaft cannot be hardened, press the matching IR inner ring onto it first; the ring gives the rollers a hardened, ground raceway and lets you keep a soft shaft for assembly reasons.",
    "applications": [
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "marine steering and linkage shafts",
      "lightly loaded high-speed idler positions where roller skidding must be watched"
    ],
    "failure_modes": [
      "cage wear or fracture from sustained operation near the limiting speed",
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat"
    ],
    "pitfalls": [
      "The press-fit of HK4020F at 40 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "The cage in HK4020F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 40 mm.",
      "The 20 mm wide section of HK4020F gains rating through longer rollers at 40 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 40×47 mm narrow variant.",
      "The HK4020F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK4020F needle roller bearing?",
        "a": "A HK4020F drawn-cup needle roller bearing has a 40 mm shaft diameter (Fw, under-roller diameter), 47 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK4020F drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4020F, Fw = 40 mm, so the shaft must be machined to 40 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK4020F needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK4020F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK4020F need a hardened shaft?",
        "a": "Either the 40 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR35x40x20.5) so a standard unhardened shaft can be used."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK4020F",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK4516",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 52,
    "B_mm": 16,
    "seal_type": "open",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.25,
    "limiting_speed_rpm": 3700,
    "speed_oil_rpm": 5500,
    "weight_g": 46,
    "manufacturer_designation": "HK4516",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK4516",
      "HK4516+IR40x45x17"
    ],
    "naming_rule_text": "HK4516 is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 45 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 52 mm and the width is 16 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. Industrial sewing machines and textile equipment run this size on their shuttle and needle-bar drive shafts, where the compact radial section keeps the arm profile slim. Shaft tolerance for this size is h5 or j5: the roller complement needs a controlled radial clearance, and a shaft ground to general-purpose tolerances can leave the bearing either slack or pinched.",
    "applications": [
      "rolling mill auxiliary drives",
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "reciprocating or oscillating motion where the rollers never complete a full revolution"
    ],
    "failure_modes": [
      "raceway spalling on a shaft that was below the required 58–64 HRC hardness",
      "edge loading and needle skewing under shaft misalignment or deflection",
      "cage wear or fracture from sustained operation near the limiting speed"
    ],
    "pitfalls": [
      "With no suffix letters, HK4516 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 45×52×16 mm match exactly — suffix conventions for cage and shell variants differ between makers.",
      "The 16 mm standard width of HK4516 is the general-purpose section at 45 mm shaft; wider HK variants in the same 45×52 mm envelope carry more load and are not interchangeable if the housing width is fixed.",
      "The open ends of HK4516 retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "The press-fit of HK4516 at 45 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row."
    ],
    "faq": [
      {
        "q": "What does Fw mean on a HK4516 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4516, Fw = 45 mm, so the shaft must be machined to 45 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK4516 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK4516 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK4516 need a hardened shaft?",
        "a": "Either the 45 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR40x45x17) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK4516 needle roller bearing?",
        "a": "A HK4516 drawn-cup needle roller bearing has a 45 mm shaft diameter (Fw, under-roller diameter), 52 mm outside diameter and 16 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK4516",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK4520",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 52,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 27.6,
    "static_load_kN": 59,
    "fatigue_load_limit_kN": 7.2,
    "limiting_speed_rpm": 3700,
    "speed_oil_rpm": 5500,
    "weight_g": 58,
    "manufacturer_designation": "HK4520",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK4520",
      "HK4520+IR40x45x20.5"
    ],
    "naming_rule_text": "HK4520 is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 45 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 52 mm and the width is 20 mm. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. This cup size is common in power-tool intermediate shafts — drills, saws, grinders — where the gearbox casing is magnesium or aluminium and the cup is pressed into a steel insert. If the shaft sees axial float, allow for it in the housing width — the cup cannot guide the shaft axially, and a shaft that walks will eventually hammer the open end of the shell.",
    "applications": [
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "machine tool feed drive supports",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "The 20 mm wide section of HK4520 gains rating through longer rollers at 45 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 45×52 mm narrow variant.",
      "Needle rollers tolerate almost no misalignment; if the 52 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.",
      "Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.",
      "Pressing HK4520 (45 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.",
      "With no suffix letters, HK4520 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 45×52×20 mm match exactly — suffix conventions for cage and shell variants differ between makers."
    ],
    "faq": [
      {
        "q": "Can a HK4520 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK4520 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK4520 need a hardened shaft?",
        "a": "Either the 45 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR40x45x20.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK4520 drawn-cup bearing?",
        "a": "HK4520 is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (3700/5500 rpm) and radial load against the actual duty before finalizing."
      },
      {
        "q": "What are the dimensions of a HK4520 needle roller bearing?",
        "a": "A HK4520 drawn-cup needle roller bearing has a 45 mm shaft diameter (Fw, under-roller diameter), 52 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK4520 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4520, Fw = 45 mm, so the shaft must be machined to 45 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK4520-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 45×52×20 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting."
      }
    ]
  },
  {
    "sku": "HK5020",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 58,
    "B_mm": 20,
    "seal_type": "open",
    "dynamic_load_kN": 31.5,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 7.7,
    "limiting_speed_rpm": 3200,
    "speed_oil_rpm": 4800,
    "weight_g": 72,
    "manufacturer_designation": "HK5020",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK5020",
      "HK5020+IR40x50x22"
    ],
    "naming_rule_text": "NTN HK5020 belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 50 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 58 mm outside and 20 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.",
    "applications": [
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "dirty environments where the open ends rely entirely on the housing seals"
    ],
    "failure_modes": [
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends",
      "brinelling of the drawn cup from hammer blows during press-in mounting"
    ],
    "pitfalls": [
      "The 20 mm wide section of HK5020 gains rating through longer rollers at 50 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 50×58 mm narrow variant.",
      "The open ends of HK5020 retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.",
      "The press-fit of HK5020 at 50 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.",
      "With no suffix letters, HK5020 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 50×58×20 mm match exactly — suffix conventions for cage and shell variants differ between makers."
    ],
    "faq": [
      {
        "q": "Can a HK5020 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK5020 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK5020 need a hardened shaft?",
        "a": "Either the 50 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR40x50x22) so a standard unhardened shaft can be used."
      },
      {
        "q": "What are the dimensions of a HK5020 needle roller bearing?",
        "a": "A HK5020 drawn-cup needle roller bearing has a 50 mm shaft diameter (Fw, under-roller diameter), 58 mm outside diameter and 20 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK5020 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK5020, Fw = 50 mm, so the shaft must be machined to 50 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK5020",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "HK5025",
    "brand": "NTN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 58,
    "B_mm": 25,
    "seal_type": "open",
    "dynamic_load_kN": 38.5,
    "static_load_kN": 82,
    "fatigue_load_limit_kN": 10,
    "limiting_speed_rpm": 3200,
    "speed_oil_rpm": 4800,
    "weight_g": 90,
    "manufacturer_designation": "HK5025",
    "standard": "ISO 3245",
    "source_ref": "https://www.ntnglobal.com/",
    "catalog_ver": "CAT. No. 2203-3/E 2024",
    "extracted_at": "2026-09-25",
    "aliases": [
      "HK5025",
      "HK5025+IR45x50x25.5"
    ],
    "naming_rule_text": "NTN HK5025 belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 50 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 58 mm outside and 25 mm across. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. At this shaft size the cup carries substantial radial load, but correct press-fit practice and housing rigidity become decisive for reaching the calculated life. You will find this cup size inside small two-stroke crankcases, supporting the small-end of the connecting rod where the housing is split and the bearing is pressed in before the case halves close. If the shaft cannot be hardened, press the matching IR inner ring onto it first; the ring gives the rollers a hardened, ground raceway and lets you keep a soft shaft for assembly reasons.",
    "applications": [
      "heavy gearbox and final drive shafts",
      "construction equipment swing pivots",
      "printing press cylinder journals",
      "continuous high-speed rotation where grease redistribution is the limiting factor"
    ],
    "failure_modes": [
      "cup cracking from an oval or tapered housing bore distorting the thin shell",
      "fretting of the cup outer surface in a soft or worn housing seat",
      "scoring of the needle rollers from abrasive contamination past the open ends"
    ],
    "pitfalls": [
      "At a 50 mm shaft diameter the press-in force for HK5025 is substantial; use a press with a guided mandrel and confirm the cup seats against the housing shoulder — a cocked cup concentrates load on the outermost roller row.",
      "With no suffix letters, HK5025 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 50×58×25 mm match exactly — suffix conventions for cage and shell variants differ between makers.",
      "The 25 mm extra-wide section of HK5025 (double-row or extended roller set) is the high-capacity option at 50 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 25 mm width.",
      "Drawn-cup needle bearings carry radial load only: HK5025 provides no axial shaft location — use separate thrust washers or a locating bearing for axial forces.",
      "The HK5025 drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life."
    ],
    "faq": [
      {
        "q": "What are the dimensions of a HK5025 needle roller bearing?",
        "a": "A HK5025 drawn-cup needle roller bearing has a 50 mm shaft diameter (Fw, under-roller diameter), 58 mm outside diameter and 25 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway."
      },
      {
        "q": "What does Fw mean on a HK5025 drawn-cup bearing?",
        "a": "Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK5025, Fw = 50 mm, so the shaft must be machined to 50 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted."
      },
      {
        "q": "Can a HK5025 needle roller bearing carry axial load?",
        "a": "No. Drawn-cup needle roller bearings like HK5025 carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement."
      },
      {
        "q": "Does HK5025 need a hardened shaft?",
        "a": "Either the 50 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR45x50x25.5) so a standard unhardened shaft can be used."
      },
      {
        "q": "What duty conditions suit a HK5025 drawn-cup bearing?",
        "a": "HK5025 is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (3200/4800 rpm) and radial load against the actual duty before finalizing."
      }
    ],
    "confidence_score": 0.7,
    "status": "published",
    "last_verified": "2026-09-25",
    "cross_ref": [
      {
        "equiv_sku": "HK5025",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ]
  },
  {
    "sku": "K3X5X7-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 3x5x7 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 3,
    "D_mm": 5,
    "B_mm": 7,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 1.51,
    "static_load_kN": 1.34,
    "fatigue_load_limit_kN": 0.134,
    "max_rpm": 45000,
    "reference_speed_rpm": 40000,
    "limiting_speed_rpm": 45000,
    "weight_g": 0.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 3x5x7 TN in the K series of needle roller and cage assemblies: needle rollers caged at 3×5×7 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 3×5×7 is a boundary plan, not an envelope: the assembly has no rings, so E 5 mm is the needle set diameter the housing bore must match, and the 3 mm journal must be ground and hardened. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 45,000 r/min limiting speed assumes a precision ground journal and bore. Speed planning separates the two ceilings: 40,000 r/min thermal reference and 45,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 3 mm seat. Mounting: grind the 3 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 5 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 3 mm the rolling elements are under two millimetres long — handle the K 3x5x7 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Reference and limiting speeds are different limits: the 40,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 3 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 1.51/1.34 kN ratings and 0.3 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 3x5x7 TN?",
        "a": "Slide the assembly over the ground 3 mm journal with a mounting sleeve, bore the housing to E 5 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 3x5x7 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 3x5x7 TN have?",
        "a": "A K 3x5x7 TN measures 3 mm bore/Fw × 5 mm outside diameter × 7 mm width (0.118 × 0.197 × 0.276 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.51 kN, static C0 1.34 kN, fatigue limit Pu 0.134 kN, limiting speed 45,000 r/min, reference speed 40,000 r/min, mass about 0.3 g."
      },
      {
        "q": "What does K 3x5x7 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 3 mm (shaft journal), E 5 mm (complement outside diameter, matched by the housing bore) and B 7 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K3X5X7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K3X5X7-TN",
      "K 3x5x7 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K3X5X9-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 3x5x9 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 3,
    "D_mm": 5,
    "B_mm": 9,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 1.68,
    "static_load_kN": 1.53,
    "fatigue_load_limit_kN": 0.153,
    "max_rpm": 45000,
    "reference_speed_rpm": 40000,
    "limiting_speed_rpm": 45000,
    "weight_g": 0.4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 3x5x9 TN denotes a needle roller and cage assembly for a 3 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 9 mm width is all the radial room it needs. The designation numbers of K 3x5x9 TN state the three machine-seat dimensions — 3 mm journal, 5 mm bore-side complement diameter, 9 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Selection arithmetic: C 1.68 kN against C0 1.53 kN gives a C0/C ratio of 0.91, and the 0.153 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: grind the 3 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 5 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 3 mm the rolling elements are under two millimetres long — handle the K 3x5x9 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 1.68/1.53 kN ratings and 0.4 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the K 3x5x9 TN be mounted?",
        "a": "Slide the assembly over the ground 3 mm journal with a mounting sleeve, bore the housing to E 5 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 3x5x9 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 3 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 3x5x9 TN?",
        "a": "A K 3x5x9 TN measures 3 mm bore/Fw × 5 mm outside diameter × 9 mm width (0.118 × 0.197 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.68 kN, static C0 1.53 kN, fatigue limit Pu 0.153 kN, limiting speed 45,000 r/min, reference speed 40,000 r/min, mass about 0.4 g."
      },
      {
        "q": "How is the K 3x5x9 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 3 mm (shaft journal), E 5 mm (complement outside diameter, matched by the housing bore) and B 9 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K3X5X9",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K3X5X9-TN",
      "K 3x5x9 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K4X7X7-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 4x7x7 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 4,
    "D_mm": 7,
    "B_mm": 7,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 1.72,
    "static_load_kN": 1.32,
    "fatigue_load_limit_kN": 0.137,
    "max_rpm": 43000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 43000,
    "weight_g": 0.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "The K assembly K 4x7x7 TN is the lowest-radial-section rolling bearing available for a 4 mm shaft: only the 7 mm wide cage-and-roller set sits between journal and bore, giving extreme compactness where even a drawn cup is too heavy a section. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 4 (shaft journal), E 7 (assembly outside diameter) and B 7 (width) in millimetres — the machine parts complete the bearing. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Speed planning separates the two ceilings: 36,000 r/min thermal reference and 43,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 4 mm seat. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 4 mm the rolling elements are under two millimetres long — handle the K 4x7x7 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 4x7x7 TN shares its 4×7×7 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 1.72/1.32 kN ratings and 0.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 4x7x7 TN?",
        "a": "Slide the assembly over the ground 4 mm journal with a mounting sleeve, bore the housing to E 7 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 4x7x7 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 4x7x7 TN have?",
        "a": "A K 4x7x7 TN measures 4 mm bore/Fw × 7 mm outside diameter × 7 mm width (0.157 × 0.276 × 0.276 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.72 kN, static C0 1.32 kN, fatigue limit Pu 0.137 kN, limiting speed 43,000 r/min, reference speed 36,000 r/min, mass about 0.5 g."
      },
      {
        "q": "What does K 4x7x7 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 4 mm (shaft journal), E 7 mm (complement outside diameter, matched by the housing bore) and B 7 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K4X7X7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K4X7X7-TN",
      "K 4x7x7 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K4X7X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 4x7x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 4,
    "D_mm": 7,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.29,
    "static_load_kN": 1.9,
    "fatigue_load_limit_kN": 0.204,
    "max_rpm": 43000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 43000,
    "weight_g": 0.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 4x7x10 TN is a caged needle roller set, not a complete bearing: paired with a 58–64 HRC ground journal of 4 mm and a housing bore of 7 mm, it forms a full rolling bearing with the smallest possible radial space demand. In the K code K 4x7x10 TN, Fw×E×B reads directly as journal 4 mm, complement diameter 7 mm and cage width 10 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Catalogue mass 0.7 g at 4×7×10 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 4 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 7 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 4 mm the rolling elements are under two millimetres long — handle the K 4x7x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Hardness is load capacity: in families without an inner ring the 4 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 2.29/1.9 kN ratings are SKF catalogue values for this exact execution (K 4x7x10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 2.29/1.9 kN ratings and 0.7 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a K 4x7x10 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 4 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 4x7x10 TN?",
        "a": "A K 4x7x10 TN measures 4 mm bore/Fw × 7 mm outside diameter × 10 mm width (0.157 × 0.276 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.29 kN, static C0 1.9 kN, fatigue limit Pu 0.204 kN, limiting speed 43,000 r/min, reference speed 36,000 r/min, mass about 0.7 g."
      },
      {
        "q": "How is the K 4x7x10 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 4 mm (shaft journal), E 7 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 4x7x10 TN run on an unhardened shaft?",
        "a": "No. In this execution the 4 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K4X7X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K4X7X10-TN",
      "K 4x7x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K5X8X8-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 5x8x8 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 8,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.29,
    "static_load_kN": 2,
    "fatigue_load_limit_kN": 0.212,
    "max_rpm": 40000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 40000,
    "weight_g": 0.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 5x8x8 TN in the K series of needle roller and cage assemblies: needle rollers caged at 5×8×8 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. The designation numbers of K 5x8x8 TN state the three machine-seat dimensions — 5 mm journal, 8 mm bore-side complement diameter, 8 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. The 0.7 g catalogue mass and 1.5 mm radial section ((8−5)/2) frame a rating of about 0.46 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: grind the 5 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 8 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the K 5x8x8 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Hardness is load capacity: in families without an inner ring the 5 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 2.29/2 kN ratings are SKF catalogue values for this exact execution (K 5x8x8 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 2.29/2 kN ratings and 0.7 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 5x8x8 TN?",
        "a": "A K 5x8x8 TN measures 5 mm bore/Fw × 8 mm outside diameter × 8 mm width (0.197 × 0.315 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.29 kN, static C0 2 kN, fatigue limit Pu 0.212 kN, limiting speed 40,000 r/min, reference speed 36,000 r/min, mass about 0.7 g."
      },
      {
        "q": "How is the K 5x8x8 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 5 mm (shaft journal), E 8 mm (complement outside diameter, matched by the housing bore) and B 8 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 5x8x8 TN run on an unhardened shaft?",
        "a": "No. In this execution the 5 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 5x8x8 TN be mounted?",
        "a": "Slide the assembly over the ground 5 mm journal with a mounting sleeve, bore the housing to E 8 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K5X8X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K5X8X8-TN",
      "K 5x8x8 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K5X8X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 5x8x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 8,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.92,
    "static_load_kN": 2.7,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 40000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 40000,
    "weight_g": 0.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 5x8x10 TN denotes a needle roller and cage assembly for a 5 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 10 mm width is all the radial room it needs. K 5×8×10 is a boundary plan, not an envelope: the assembly has no rings, so E 8 mm is the needle set diameter the housing bore must match, and the 5 mm journal must be ground and hardened. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 10 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the K 5x8x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 2.92/2.7 kN ratings are SKF catalogue values for this exact execution (K 5x8x10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 2.92/2.7 kN ratings and 0.9 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 5x8x10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 5x8x10 TN have?",
        "a": "A K 5x8x10 TN measures 5 mm bore/Fw × 8 mm outside diameter × 10 mm width (0.197 × 0.315 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.92 kN, static C0 2.7 kN, fatigue limit Pu 0.29 kN, limiting speed 40,000 r/min, reference speed 36,000 r/min, mass about 0.9 g."
      },
      {
        "q": "What does K 5x8x10 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 5 mm (shaft journal), E 8 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 5x8x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 5 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K5X8X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K5X8X10-TN",
      "K 5x8x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K6X9X8-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 6x9x8 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 9,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.55,
    "static_load_kN": 2.36,
    "fatigue_load_limit_kN": 0.25,
    "max_rpm": 38000,
    "reference_speed_rpm": 34000,
    "limiting_speed_rpm": 38000,
    "weight_g": 0.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 6x9x8 TN: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 6 × E 9 × B 8 mm. In the K code K 6x9x8 TN, Fw×E×B reads directly as journal 6 mm, complement diameter 9 mm and cage width 8 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 8 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the K 6x9x8 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 2.55/2.36 kN ratings and 0.8 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 6x9x8 TN run on an unhardened shaft?",
        "a": "No. In this execution the 6 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 6x9x8 TN be mounted?",
        "a": "Slide the assembly over the ground 6 mm journal with a mounting sleeve, bore the housing to E 9 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 6x9x8 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 6 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 6x9x8 TN?",
        "a": "A K 6x9x8 TN measures 6 mm bore/Fw × 9 mm outside diameter × 8 mm width (0.236 × 0.354 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.55 kN, static C0 2.36 kN, fatigue limit Pu 0.25 kN, limiting speed 38,000 r/min, reference speed 34,000 r/min, mass about 0.8 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K6X9X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K6X9X8-TN",
      "K 6x9x8 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K6X9X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 6x9x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 9,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.3,
    "static_load_kN": 3.2,
    "fatigue_load_limit_kN": 0.345,
    "max_rpm": 38000,
    "reference_speed_rpm": 34000,
    "limiting_speed_rpm": 38000,
    "weight_g": 1.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 6x9x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 6×9×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 6×9×10 is a boundary plan, not an envelope: the assembly has no rings, so E 9 mm is the needle set diameter the housing bore must match, and the 6 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the K 6x9x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 6x9x10 TN shares its 6×9×10 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 3.3/3.2 kN ratings and 1.1 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 6x9x10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 6x9x10 TN have?",
        "a": "A K 6x9x10 TN measures 6 mm bore/Fw × 9 mm outside diameter × 10 mm width (0.236 × 0.354 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.3 kN, static C0 3.2 kN, fatigue limit Pu 0.345 kN, limiting speed 38,000 r/min, reference speed 34,000 r/min, mass about 1.1 g."
      },
      {
        "q": "What does K 6x9x10 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 6 mm (shaft journal), E 9 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 6x9x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 6 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K6X9X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K6X9X10-TN",
      "K 6x9x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K7X10X8-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 7x10x8 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 10,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.81,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 0.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 7x10x8 TN denotes a needle roller and cage assembly for a 7 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 8 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 7 (shaft journal), E 10 (assembly outside diameter) and B 8 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 36,000 r/min limiting speed assumes a precision ground journal and bore. Selection arithmetic: C 2.81 kN against C0 2.75 kN gives a C0/C ratio of 0.98, and the 0.29 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: grind the 7 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 10 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the K 7x10x8 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 2.81/2.75 kN ratings are SKF catalogue values for this exact execution (K 7x10x8 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 2.81/2.75 kN ratings and 0.9 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 7x10x8 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 7 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 7x10x8 TN?",
        "a": "Slide the assembly over the ground 7 mm journal with a mounting sleeve, bore the housing to E 10 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 7x10x8 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 7x10x8 TN have?",
        "a": "A K 7x10x8 TN measures 7 mm bore/Fw × 10 mm outside diameter × 8 mm width (0.276 × 0.394 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.81 kN, static C0 2.75 kN, fatigue limit Pu 0.29 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 0.9 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K7X10X8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K7X10X8-TN",
      "K 7x10x8 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K7X10X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 7x10x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 10,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.58,
    "static_load_kN": 3.75,
    "fatigue_load_limit_kN": 0.415,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 7x10x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 7×10×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 7×10×10 is a boundary plan, not an envelope: the assembly has no rings, so E 10 mm is the needle set diameter the housing bore must match, and the 7 mm journal must be ground and hardened. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 36,000 r/min limiting speed assumes a precision ground journal and bore. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 7 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 10 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the K 7x10x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Reference and limiting speeds are different limits: the 32,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 7 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 3.58/3.75 kN ratings and 1 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 7x10x10 TN have?",
        "a": "A K 7x10x10 TN measures 7 mm bore/Fw × 10 mm outside diameter × 10 mm width (0.276 × 0.394 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.58 kN, static C0 3.75 kN, fatigue limit Pu 0.415 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 1 g."
      },
      {
        "q": "What does K 7x10x10 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 7 mm (shaft journal), E 10 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 7x10x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 7 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 7x10x10 TN?",
        "a": "Slide the assembly over the ground 7 mm journal with a mounting sleeve, bore the housing to E 10 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K7X10X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K7X10X10-TN",
      "K 7x10x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K8X11X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 8x11x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 11,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.8,
    "static_load_kN": 4.25,
    "fatigue_load_limit_kN": 0.465,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 1.2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 8x11x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 8×11×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. The designation numbers of K 8x11x10 TN state the three machine-seat dimensions — 8 mm journal, 11 mm bore-side complement diameter, 10 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. For life calculation, the 3.8/4.25 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 10 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the K 8x11x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: K 8x11x10 TN shares its 8×11×10 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 32,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 3.8/4.25 kN ratings and 1.2 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the K 8x11x10 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 8 mm (shaft journal), E 11 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 8x11x10 TN run on an unhardened shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 8x11x10 TN be mounted?",
        "a": "Slide the assembly over the ground 8 mm journal with a mounting sleeve, bore the housing to E 11 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 8x11x10 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 8 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K8X11X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K8X11X10-TN",
      "K 8x11x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K8X11X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 8x11x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 11,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.01,
    "static_load_kN": 5.85,
    "fatigue_load_limit_kN": 0.67,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 1.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 8x11x13 TN denotes a needle roller and cage assembly for a 8 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 13 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 8 (shaft journal), E 11 (assembly outside diameter) and B 13 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Speed planning separates the two ceilings: 32,000 r/min thermal reference and 36,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 8 mm seat. Mounting: grind the 8 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 11 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the K 8x11x13 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 8x11x13 TN shares its 8×11×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 5.01/5.85 kN ratings and 1.7 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 8x11x13 TN have?",
        "a": "A K 8x11x13 TN measures 8 mm bore/Fw × 11 mm outside diameter × 13 mm width (0.315 × 0.433 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.01 kN, static C0 5.85 kN, fatigue limit Pu 0.67 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 1.7 g."
      },
      {
        "q": "What does K 8x11x13 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 8 mm (shaft journal), E 11 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 8x11x13 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 8x11x13 TN?",
        "a": "Slide the assembly over the ground 8 mm journal with a mounting sleeve, bore the housing to E 11 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K8X11X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K8X11X13-TN",
      "K 8x11x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K8X12X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 8x12x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 12,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.84,
    "static_load_kN": 4.75,
    "fatigue_load_limit_kN": 0.54,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 8x12x10 TN appears as a needle roller and cage assembly with complement diameter E 12 mm and width 10 mm — a self-contained roller set that turns a 8 mm shaft and its housing into a complete bearing. The designation numbers of K 8x12x10 TN state the three machine-seat dimensions — 8 mm journal, 12 mm bore-side complement diameter, 10 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 10 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the K 8x12x10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: K 8x12x10 TN shares its 8×12×10 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 30,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 4.84/4.75 kN ratings and 2 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the K 8x12x10 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 8 mm (shaft journal), E 12 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 8x12x10 TN run on an unhardened shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 8x12x10 TN be mounted?",
        "a": "Slide the assembly over the ground 8 mm journal with a mounting sleeve, bore the housing to E 12 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 8x12x10 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 8 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K8X12X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K8X12X10-TN",
      "K 8x12x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K9X12X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 9x12x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 12,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.4,
    "static_load_kN": 5.2,
    "fatigue_load_limit_kN": 0.57,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 1.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 9x12x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 9×12×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 9 (shaft journal), E 12 (assembly outside diameter) and B 10 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. The 1.5 g catalogue mass and 1.5 mm radial section ((12−9)/2) frame a rating of about 0.49 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 12 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 9x12x10 TN shares its 9×12×10 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 4.4/5.2 kN ratings and 1.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 9x12x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 9x12x10 TN?",
        "a": "Slide the assembly over the ground 9 mm journal with a mounting sleeve, bore the housing to E 12 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 9x12x10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 9x12x10 TN have?",
        "a": "A K 9x12x10 TN measures 9 mm bore/Fw × 12 mm outside diameter × 10 mm width (0.354 × 0.472 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.4 kN, static C0 5.2 kN, fatigue limit Pu 0.57 kN, limiting speed 34,000 r/min, reference speed 30,000 r/min, mass about 1.5 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K9X12X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K9X12X10-TN",
      "K 9x12x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K10X13X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 10x13x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 13,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.57,
    "static_load_kN": 5.7,
    "fatigue_load_limit_kN": 0.63,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 1.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 10x13x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 10×13×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 10 (shaft journal), E 13 (assembly outside diameter) and B 10 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 32,000 r/min limiting speed assumes a precision ground journal and bore. Catalogue mass 1.6 g at 10×13×10 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 10 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 13 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 13 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 4.57/5.7 kN ratings are SKF catalogue values for this exact execution (K 10x13x10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 4.57/5.7 kN ratings and 1.6 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 10x13x10 TN have?",
        "a": "A K 10x13x10 TN measures 10 mm bore/Fw × 13 mm outside diameter × 10 mm width (0.394 × 0.512 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.57 kN, static C0 5.7 kN, fatigue limit Pu 0.63 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 1.6 g."
      },
      {
        "q": "What does K 10x13x10 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 10 mm (shaft journal), E 13 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 10x13x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 10x13x10 TN?",
        "a": "Slide the assembly over the ground 10 mm journal with a mounting sleeve, bore the housing to E 13 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K10X13X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K10X13X10-TN",
      "K 10x13x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K10X13X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 10x13x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 13,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.94,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.9,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 2.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 10x13x13 TN denotes a needle roller and cage assembly for a 10 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 13 mm width is all the radial room it needs. K 10×13×13 is a boundary plan, not an envelope: the assembly has no rings, so E 13 mm is the needle set diameter the housing bore must match, and the 10 mm journal must be ground and hardened. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 32,000 r/min limiting speed assumes a precision ground journal and bore. For life calculation, the 5.94/8 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 13 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 13 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 28,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 5.94/8 kN ratings and 2.3 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 10x13x13 TN have?",
        "a": "A K 10x13x13 TN measures 10 mm bore/Fw × 13 mm outside diameter × 13 mm width (0.394 × 0.512 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.94 kN, static C0 8 kN, fatigue limit Pu 0.9 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 2.3 g."
      },
      {
        "q": "What does K 10x13x13 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 10 mm (shaft journal), E 13 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 10x13x13 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 10x13x13 TN?",
        "a": "Slide the assembly over the ground 10 mm journal with a mounting sleeve, bore the housing to E 13 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K10X13X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K10X13X13-TN",
      "K 10x13x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K10X14X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 10x14x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.61,
    "static_load_kN": 6.1,
    "fatigue_load_limit_kN": 0.695,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 2.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 10x14x10 TN appears as a needle roller and cage assembly with complement diameter E 14 mm and width 10 mm — a self-contained roller set that turns a 10 mm shaft and its housing into a complete bearing. In the K code K 10x14x10 TN, Fw×E×B reads directly as journal 10 mm, complement diameter 14 mm and cage width 10 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Catalogue mass 2.5 g at 10×14×10 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 10 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 14 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 5.61/6.1 kN ratings are SKF catalogue values for this exact execution (K 10x14x10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 5.61/6.1 kN ratings and 2.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 10x14x10 TN?",
        "a": "A K 10x14x10 TN measures 10 mm bore/Fw × 14 mm outside diameter × 10 mm width (0.394 × 0.551 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.61 kN, static C0 6.1 kN, fatigue limit Pu 0.695 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 2.5 g."
      },
      {
        "q": "How is the K 10x14x10 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 10 mm (shaft journal), E 14 mm (complement outside diameter, matched by the housing bore) and B 10 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 10x14x10 TN run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 10x14x10 TN be mounted?",
        "a": "Slide the assembly over the ground 10 mm journal with a mounting sleeve, bore the housing to E 14 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K10X14X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K10X14X10-TN",
      "K 10x14x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K10X14X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 10x14x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 7.21,
    "static_load_kN": 8.5,
    "fatigue_load_limit_kN": 0.98,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 4.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 10x14x13 TN denotes a needle roller and cage assembly for a 10 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 13 mm width is all the radial room it needs. The designation numbers of K 10x14x13 TN state the three machine-seat dimensions — 10 mm journal, 14 mm bore-side complement diameter, 13 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 32,000 r/min limiting speed assumes a precision ground journal and bore. For life calculation, the 7.21/8.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: K 10x14x13 TN shares its 10×14×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 28,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 7.21/8.5 kN ratings and 4.6 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 10x14x13 TN?",
        "a": "A K 10x14x13 TN measures 10 mm bore/Fw × 14 mm outside diameter × 13 mm width (0.394 × 0.551 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.21 kN, static C0 8.5 kN, fatigue limit Pu 0.98 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 4.6 g."
      },
      {
        "q": "How is the K 10x14x13 TN designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 10 mm (shaft journal), E 14 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 10x14x13 TN run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 10x14x13 TN be mounted?",
        "a": "Slide the assembly over the ground 10 mm journal with a mounting sleeve, bore the housing to E 14 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K10X14X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K10X14X13-TN",
      "K 10x14x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K10X16X12-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 10x16x12 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 16,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 7.65,
    "static_load_kN": 7.2,
    "fatigue_load_limit_kN": 0.85,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 5.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 10x16x12 TN appears as a needle roller and cage assembly with complement diameter E 16 mm and width 12 mm — a self-contained roller set that turns a 10 mm shaft and its housing into a complete bearing. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 10 (shaft journal), E 16 (assembly outside diameter) and B 12 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 12 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 7.65/7.2 kN ratings are SKF catalogue values for this exact execution (K 10x16x12 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 7.65/7.2 kN ratings and 5.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 10x16x12 TN have?",
        "a": "A K 10x16x12 TN measures 10 mm bore/Fw × 16 mm outside diameter × 12 mm width (0.394 × 0.63 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.65 kN, static C0 7.2 kN, fatigue limit Pu 0.85 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 5.5 g."
      },
      {
        "q": "What does K 10x16x12 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 10 mm (shaft journal), E 16 mm (complement outside diameter, matched by the housing bore) and B 12 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 10x16x12 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 10x16x12 TN?",
        "a": "Slide the assembly over the ground 10 mm journal with a mounting sleeve, bore the housing to E 16 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K10X16X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K10X16X12-TN",
      "K 10x16x12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K12X15X10-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 12x15x10 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 15,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.73,
    "static_load_kN": 6.2,
    "fatigue_load_limit_kN": 0.695,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 2.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 12x15x10 TN in the K series of needle roller and cage assemblies: needle rollers caged at 12×15×10 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 12×15×10 is a boundary plan, not an envelope: the assembly has no rings, so E 15 mm is the needle set diameter the housing bore must match, and the 12 mm journal must be ground and hardened. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. For life calculation, the 4.73/6.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 15 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 26,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 4.73/6.2 kN ratings and 2.9 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 12x15x10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 12x15x10 TN?",
        "a": "Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 15 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 12x15x10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 12x15x10 TN have?",
        "a": "A K 12x15x10 TN measures 12 mm bore/Fw × 15 mm outside diameter × 10 mm width (0.472 × 0.591 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.73 kN, static C0 6.2 kN, fatigue limit Pu 0.695 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 2.9 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K12X15X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K12X15X10-TN",
      "K 12x15x10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K12X15X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 12x15x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 15,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 6.16,
    "static_load_kN": 8.65,
    "fatigue_load_limit_kN": 0.98,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 2.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 12x15x13 TN denotes a needle roller and cage assembly for a 12 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 13 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 12 (shaft journal), E 15 (assembly outside diameter) and B 13 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Speed planning separates the two ceilings: 26,000 r/min thermal reference and 30,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 12 mm seat. Mounting: grind the 12 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 15 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 15 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 12x15x13 TN shares its 12×15×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 6.16/8.65 kN ratings and 2.3 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 12x15x13 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 12x15x13 TN?",
        "a": "Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 15 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 12x15x13 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 12x15x13 TN have?",
        "a": "A K 12x15x13 TN measures 12 mm bore/Fw × 15 mm outside diameter × 13 mm width (0.472 × 0.591 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 6.16 kN, static C0 8.65 kN, fatigue limit Pu 0.98 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 2.3 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K12X15X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K12X15X13-TN",
      "K 12x15x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K12X16X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 12x16x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 16,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 7.65,
    "static_load_kN": 9.5,
    "fatigue_load_limit_kN": 1.1,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 3.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 12x16x13 TN denotes a needle roller and cage assembly for a 12 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 13 mm width is all the radial room it needs. In the K code K 12x16x13 TN, Fw×E×B reads directly as journal 12 mm, complement diameter 16 mm and cage width 13 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Speed planning separates the two ceilings: 26,000 r/min thermal reference and 30,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 12 mm seat. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 13 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 7.65/9.5 kN ratings and 3.6 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 12x16x13 TN run on an unhardened shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 12x16x13 TN be mounted?",
        "a": "Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 16 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 12x16x13 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 12x16x13 TN?",
        "a": "A K 12x16x13 TN measures 12 mm bore/Fw × 16 mm outside diameter × 13 mm width (0.472 × 0.63 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.65 kN, static C0 9.5 kN, fatigue limit Pu 1.1 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 3.6 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K12X16X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K12X16X13-TN",
      "K 12x16x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K12X17X13-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 12x17x13 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 17,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 10.4,
    "fatigue_load_limit_kN": 1.22,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 4.9,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 12x17x13 TN in the K series of needle roller and cage assemblies: needle rollers caged at 12×17×13 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 12x17x13 TN, Fw×E×B reads directly as journal 12 mm, complement diameter 17 mm and cage width 13 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. The 4.9 g catalogue mass and 2.5 mm radial section ((17−12)/2) frame a rating of about 0.76 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 13 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 17 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 9.13/10.4 kN ratings and 4.9 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 12x17x13 TN run on an unhardened shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 12x17x13 TN be mounted?",
        "a": "Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 17 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 12x17x13 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 12x17x13 TN?",
        "a": "A K 12x17x13 TN measures 12 mm bore/Fw × 17 mm outside diameter × 13 mm width (0.472 × 0.669 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 10.4 kN, fatigue limit Pu 1.22 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 4.9 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K12X17X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K12X17X13-TN",
      "K 12x17x13 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K12X18X12-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 12x18x12 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 18,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 9.52,
    "static_load_kN": 10,
    "fatigue_load_limit_kN": 1.18,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 12x18x12 TN appears as a needle roller and cage assembly with complement diameter E 18 mm and width 12 mm — a self-contained roller set that turns a 12 mm shaft and its housing into a complete bearing. K 12×18×12 is a boundary plan, not an envelope: the assembly has no rings, so E 18 mm is the needle set diameter the housing bore must match, and the 12 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. The 6 g catalogue mass and 3.0 mm radial section ((18−12)/2) frame a rating of about 0.79 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: grind the 12 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 18 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 26,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 9.52/10 kN ratings and 6 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 12x18x12 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 12x18x12 TN?",
        "a": "Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 18 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 12x18x12 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 12x18x12 TN have?",
        "a": "A K 12x18x12 TN measures 12 mm bore/Fw × 18 mm outside diameter × 12 mm width (0.472 × 0.709 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.52 kN, static C0 10 kN, fatigue limit Pu 1.18 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 6 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K12X18X12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K12X18X12-TN",
      "K 12x18x12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K14X18X10",
    "brand": "SKF",
    "manufacturer_designation": "K 14x18x10",
    "series": "K-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 18,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.93,
    "static_load_kN": 8.65,
    "fatigue_load_limit_kN": 1,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 14x18x10 denotes a needle roller and cage assembly for a 14 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 10 mm width is all the radial room it needs. The designation numbers of K 14x18x10 state the three machine-seat dimensions — 14 mm journal, 18 mm bore-side complement diameter, 10 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 6.93/8.65 kN ratings and 4 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 14x18x10 run on an unhardened shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 14x18x10 be mounted?",
        "a": "Slide the assembly over the ground 14 mm journal with a mounting sleeve, bore the housing to E 18 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 14x18x10?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 14 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 14x18x10?",
        "a": "A K 14x18x10 measures 14 mm bore/Fw × 18 mm outside diameter × 10 mm width (0.551 × 0.709 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 6.93 kN, static C0 8.65 kN, fatigue limit Pu 1 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 4 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K14X18X10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K14X18X10",
      "K 14x18x10"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K14X18X13",
    "brand": "SKF",
    "manufacturer_designation": "K 14x18x13",
    "series": "K-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 18,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.92,
    "static_load_kN": 10.2,
    "fatigue_load_limit_kN": 1.18,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 6.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "The K assembly K 14x18x13 is the lowest-radial-section rolling bearing available for a 14 mm shaft: only the 13 mm wide cage-and-roller set sits between journal and bore, giving extreme compactness where even a drawn cup is too heavy a section. K 14×18×13 is a boundary plan, not an envelope: the assembly has no rings, so E 18 mm is the needle set diameter the housing bore must match, and the 14 mm journal must be ground and hardened. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 14 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 7.92/10.2 kN ratings and 6.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 14x18x13 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 14x18x13 have?",
        "a": "A K 14x18x13 measures 14 mm bore/Fw × 18 mm outside diameter × 13 mm width (0.551 × 0.709 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.92 kN, static C0 10.2 kN, fatigue limit Pu 1.18 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 6.5 g."
      },
      {
        "q": "What does K 14x18x13 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 14 mm (shaft journal), E 18 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 14x18x13 need a hardened and ground shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K14X18X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K14X18X13",
      "K 14x18x13"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K14X18X15-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 14x18x15 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 18,
    "B_mm": 15,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 1.46,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 14x18x15 TN denotes a needle roller and cage assembly for a 14 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 15 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 14 (shaft journal), E 18 (assembly outside diameter) and B 15 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. For life calculation, the 9.13/12.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: grind the 14 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 18 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 14x18x15 TN shares its 14×18×15 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 9.13/12.5 kN ratings and 5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 14x18x15 TN?",
        "a": "Slide the assembly over the ground 14 mm journal with a mounting sleeve, bore the housing to E 18 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 14x18x15 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 14x18x15 TN have?",
        "a": "A K 14x18x15 TN measures 14 mm bore/Fw × 18 mm outside diameter × 15 mm width (0.551 × 0.709 × 0.591 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12.5 kN, fatigue limit Pu 1.46 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 5 g."
      },
      {
        "q": "What does K 14x18x15 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 14 mm (shaft journal), E 18 mm (complement outside diameter, matched by the housing bore) and B 15 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K14X18X15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K14X18X15-TN",
      "K 14x18x15 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K14X18X17",
    "brand": "SKF",
    "manufacturer_designation": "K 14x18x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 18,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.5,
    "static_load_kN": 14.6,
    "fatigue_load_limit_kN": 1.7,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 14x18x17 denotes a needle roller and cage assembly for a 14 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 17 mm width is all the radial room it needs. K 14×18×17 is a boundary plan, not an envelope: the assembly has no rings, so E 18 mm is the needle set diameter the housing bore must match, and the 14 mm journal must be ground and hardened. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 10.5/14.6 kN ratings are SKF catalogue values for this exact execution (K 14x18x17); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 10.5/14.6 kN ratings and 8 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 14x18x17 have?",
        "a": "A K 14x18x17 measures 14 mm bore/Fw × 18 mm outside diameter × 17 mm width (0.551 × 0.709 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.5 kN, static C0 14.6 kN, fatigue limit Pu 1.7 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 8 g."
      },
      {
        "q": "What does K 14x18x17 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 14 mm (shaft journal), E 18 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 14x18x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 14x18x17?",
        "a": "Slide the assembly over the ground 14 mm journal with a mounting sleeve, bore the housing to E 18 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K14X18X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K14X18X17",
      "K 14x18x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K15X19X13",
    "brand": "SKF",
    "manufacturer_designation": "K 15x19x13",
    "series": "K-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 19,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.25,
    "static_load_kN": 11.2,
    "fatigue_load_limit_kN": 1.29,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 15x19x13 is a caged needle roller set, not a complete bearing: paired with a 58–64 HRC ground journal of 15 mm and a housing bore of 19 mm, it forms a full rolling bearing with the smallest possible radial space demand. The designation numbers of K 15x19x13 state the three machine-seat dimensions — 15 mm journal, 19 mm bore-side complement diameter, 13 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 15 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 19 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 8.25/11.2 kN ratings are SKF catalogue values for this exact execution (K 15x19x13); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 8.25/11.2 kN ratings and 7 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a K 15x19x13?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 15x19x13?",
        "a": "A K 15x19x13 measures 15 mm bore/Fw × 19 mm outside diameter × 13 mm width (0.591 × 0.748 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.25 kN, static C0 11.2 kN, fatigue limit Pu 1.29 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 7 g."
      },
      {
        "q": "How is the K 15x19x13 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 15 mm (shaft journal), E 19 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 15x19x13 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K15X19X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K15X19X13",
      "K 15x19x13"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K15X19X17",
    "brand": "SKF",
    "manufacturer_designation": "K 15x19x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 19,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.8,
    "static_load_kN": 15.6,
    "fatigue_load_limit_kN": 1.86,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 9.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 15x19x17 in the K series of needle roller and cage assemblies: needle rollers caged at 15×19×17 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. The designation numbers of K 15x19x17 state the three machine-seat dimensions — 15 mm journal, 19 mm bore-side complement diameter, 17 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 15 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 19 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 10.8/15.6 kN ratings and 9.5 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 15x19x17?",
        "a": "A K 15x19x17 measures 15 mm bore/Fw × 19 mm outside diameter × 17 mm width (0.591 × 0.748 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.8 kN, static C0 15.6 kN, fatigue limit Pu 1.86 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 9.5 g."
      },
      {
        "q": "How is the K 15x19x17 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 15 mm (shaft journal), E 19 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 15x19x17 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 15x19x17 be mounted?",
        "a": "Slide the assembly over the ground 15 mm journal with a mounting sleeve, bore the housing to E 19 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K15X19X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K15X19X17",
      "K 15x19x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K15X21X15",
    "brand": "SKF",
    "manufacturer_designation": "K 15x21x15",
    "series": "K-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 15,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.8,
    "static_load_kN": 16.3,
    "fatigue_load_limit_kN": 2,
    "max_rpm": 26000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 26000,
    "weight_g": 11,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 15x21x15 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 15 mm hardened shaft journal and the 21 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 15 (shaft journal), E 21 (assembly outside diameter) and B 15 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 26,000 r/min limiting speed assumes a precision ground journal and bore. Speed planning separates the two ceilings: 24,000 r/min thermal reference and 26,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 15 mm seat. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 15x21x15 shares its 15×21×15 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 13.8/16.3 kN ratings and 11 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 15x21x15 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 15x21x15 have?",
        "a": "A K 15x21x15 measures 15 mm bore/Fw × 21 mm outside diameter × 15 mm width (0.591 × 0.827 × 0.591 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.8 kN, static C0 16.3 kN, fatigue limit Pu 2 kN, limiting speed 26,000 r/min, reference speed 24,000 r/min, mass about 11 g."
      },
      {
        "q": "What does K 15x21x15 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 15 mm (shaft journal), E 21 mm (complement outside diameter, matched by the housing bore) and B 15 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 15x21x15 need a hardened and ground shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K15X21X15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K15X21X15",
      "K 15x21x15"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K15X21X21",
    "brand": "SKF",
    "manufacturer_designation": "K 15x21x21",
    "series": "K-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 21,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 18.7,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 3,
    "max_rpm": 26000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 26000,
    "weight_g": 17,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 15x21x21 in the K series of needle roller and cage assemblies: needle rollers caged at 15×21×21 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 15x21x21, Fw×E×B reads directly as journal 15 mm, complement diameter 21 mm and cage width 21 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 26,000 r/min limiting speed assumes a precision ground journal and bore. Speed planning separates the two ceilings: 24,000 r/min thermal reference and 26,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 15 mm seat. Mounting: grind the 15 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 21 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 18.7/24.5 kN ratings and 17 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 15x21x21?",
        "a": "A K 15x21x21 measures 15 mm bore/Fw × 21 mm outside diameter × 21 mm width (0.591 × 0.827 × 0.827 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 18.7 kN, static C0 24.5 kN, fatigue limit Pu 3 kN, limiting speed 26,000 r/min, reference speed 24,000 r/min, mass about 17 g."
      },
      {
        "q": "How is the K 15x21x21 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 15 mm (shaft journal), E 21 mm (complement outside diameter, matched by the housing bore) and B 21 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 15x21x21 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 15x21x21 be mounted?",
        "a": "Slide the assembly over the ground 15 mm journal with a mounting sleeve, bore the housing to E 21 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K15X21X21",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K15X21X21",
      "K 15x21x21"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K32X37X13",
    "brand": "SKF",
    "manufacturer_designation": "K 32x37x13",
    "series": "K-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 37,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.7,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 3,
    "max_rpm": 14000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 14000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 32x37x13 in the K series of needle roller and cage assemblies: needle rollers caged at 32×37×13 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 32 (shaft journal), E 37 (assembly outside diameter) and B 13 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 14,000 r/min limiting speed assumes a precision ground journal and bore. Speed planning separates the two ceilings: 13,000 r/min thermal reference and 14,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 32 mm seat. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 13 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 14.7/25.5 kN ratings are SKF catalogue values for this exact execution (K 32x37x13); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 14.7/25.5 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 32x37x13 have?",
        "a": "A K 32x37x13 measures 32 mm bore/Fw × 37 mm outside diameter × 13 mm width (1.26 × 1.457 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.7 kN, static C0 25.5 kN, fatigue limit Pu 3 kN, limiting speed 14,000 r/min, reference speed 13,000 r/min, mass about 18 g."
      },
      {
        "q": "What does K 32x37x13 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 32 mm (shaft journal), E 37 mm (complement outside diameter, matched by the housing bore) and B 13 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 32x37x13 need a hardened and ground shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 32x37x13?",
        "a": "Slide the assembly over the ground 32 mm journal with a mounting sleeve, bore the housing to E 37 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K32X37X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K32X37X13",
      "K 32x37x13"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K32X37X17",
    "brand": "SKF",
    "manufacturer_designation": "K 32x37x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 35.5,
    "fatigue_load_limit_kN": 4.25,
    "max_rpm": 14000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 14000,
    "weight_g": 19,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 32x37x17: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 32 × E 37 × B 17 mm. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 32 (shaft journal), E 37 (assembly outside diameter) and B 17 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 14,000 r/min limiting speed assumes a precision ground journal and bore. Speed planning separates the two ceilings: 13,000 r/min thermal reference and 14,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 32 mm seat. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 17 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 32x37x17 shares its 32×37×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 19/35.5 kN ratings and 19 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does K 32x37x17 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 32 mm (shaft journal), E 37 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 32x37x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 32x37x17?",
        "a": "Slide the assembly over the ground 32 mm journal with a mounting sleeve, bore the housing to E 37 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 32x37x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K32X37X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K32X37X17",
      "K 32x37x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K32X38X20",
    "brand": "SKF",
    "manufacturer_designation": "K 32x38x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 32x38x20 in the K series of needle roller and cage assemblies: needle rollers caged at 32×38×20 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. The designation numbers of K 32x38x20 state the three machine-seat dimensions — 32 mm journal, 38 mm bore-side complement diameter, 20 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Selection arithmetic: C 25.1 kN against C0 45 kN gives a C0/C ratio of 1.79, and the 5.6 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 20 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 32 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 25.1/45 kN ratings are SKF catalogue values for this exact execution (K 32x38x20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 25.1/45 kN ratings and 30 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the K 32x38x20?",
        "a": "A K 32x38x20 measures 32 mm bore/Fw × 38 mm outside diameter × 20 mm width (1.26 × 1.496 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.1 kN, static C0 45 kN, fatigue limit Pu 5.6 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 30 g."
      },
      {
        "q": "How is the K 32x38x20 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 32 mm (shaft journal), E 38 mm (complement outside diameter, matched by the housing bore) and B 20 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 32x38x20 run on an unhardened shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 32x38x20 be mounted?",
        "a": "Slide the assembly over the ground 32 mm journal with a mounting sleeve, bore the housing to E 38 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K32X38X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K32X38X20",
      "K 32x38x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K32X40X25",
    "brand": "SKF",
    "manufacturer_designation": "K 32x40x25",
    "series": "K-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 40,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.8,
    "static_load_kN": 58.5,
    "fatigue_load_limit_kN": 7.2,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 32x40x25 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 32 mm hardened shaft journal and the 40 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. The designation numbers of K 32x40x25 state the three machine-seat dimensions — 32 mm journal, 40 mm bore-side complement diameter, 25 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. For life calculation, the 35.8/58.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: grind the 32 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 40 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 32 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 35.8/58.5 kN ratings are SKF catalogue values for this exact execution (K 32x40x25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 35.8/58.5 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 32x40x25 run on an unhardened shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 32x40x25 be mounted?",
        "a": "Slide the assembly over the ground 32 mm journal with a mounting sleeve, bore the housing to E 40 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 32x40x25?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 32 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 32x40x25?",
        "a": "A K 32x40x25 measures 32 mm bore/Fw × 40 mm outside diameter × 25 mm width (1.26 × 1.575 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.8 kN, static C0 58.5 kN, fatigue limit Pu 7.2 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 49 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K32X40X25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K32X40X25",
      "K 32x40x25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X40X13",
    "brand": "SKF",
    "manufacturer_designation": "K 35x40x13",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 40,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.4,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 3.25,
    "max_rpm": 13000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 13000,
    "weight_g": 19,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 35x40x13 is a caged needle roller set, not a complete bearing: paired with a 58–64 HRC ground journal of 35 mm and a housing bore of 40 mm, it forms a full rolling bearing with the smallest possible radial space demand. K 35×40×13 is a boundary plan, not an envelope: the assembly has no rings, so E 40 mm is the needle set diameter the housing bore must match, and the 35 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 35 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 40 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 15.4/28 kN ratings and 19 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 35x40x13 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 35x40x13?",
        "a": "Slide the assembly over the ground 35 mm journal with a mounting sleeve, bore the housing to E 40 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 35x40x13 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 35x40x13 have?",
        "a": "A K 35x40x13 measures 35 mm bore/Fw × 40 mm outside diameter × 13 mm width (1.378 × 1.575 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.4 kN, static C0 28 kN, fatigue limit Pu 3.25 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 19 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X40X13",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X40X13",
      "K 35x40x13"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X40X17",
    "brand": "SKF",
    "manufacturer_designation": "K 35x40x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 40,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.8,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 13000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 13000,
    "weight_g": 21,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 35x40x17 in the K series of needle roller and cage assemblies: needle rollers caged at 35×40×17 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 35×40×17 is a boundary plan, not an envelope: the assembly has no rings, so E 40 mm is the needle set diameter the housing bore must match, and the 35 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 35 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 40 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 19.8/39 kN ratings are SKF catalogue values for this exact execution (K 35x40x17); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 19.8/39 kN ratings and 21 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 35x40x17?",
        "a": "Slide the assembly over the ground 35 mm journal with a mounting sleeve, bore the housing to E 40 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 35x40x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 35x40x17 have?",
        "a": "A K 35x40x17 measures 35 mm bore/Fw × 40 mm outside diameter × 17 mm width (1.378 × 1.575 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.8 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 21 g."
      },
      {
        "q": "What does K 35x40x17 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 35 mm (shaft journal), E 40 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X40X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X40X17",
      "K 35x40x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X40X27-TN",
    "brand": "SKF",
    "manufacturer_designation": "K 35x40x27 TN",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 40,
    "B_mm": 27,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 23.8,
    "static_load_kN": 49,
    "fatigue_load_limit_kN": 6,
    "max_rpm": 13000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 13000,
    "weight_g": 39,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 35x40x27 TN: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 35 × E 40 × B 27 mm. K 35×40×27 is a boundary plan, not an envelope: the assembly has no rings, so E 40 mm is the needle set diameter the housing bore must match, and the 35 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Catalogue mass 39 g at 35×40×27 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 35 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 40 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 23.8/49 kN ratings and 39 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 35x40x27 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 35x40x27 TN have?",
        "a": "A K 35x40x27 TN measures 35 mm bore/Fw × 40 mm outside diameter × 27 mm width (1.378 × 1.575 × 1.063 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.8 kN, static C0 49 kN, fatigue limit Pu 6 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 39 g."
      },
      {
        "q": "What does K 35x40x27 TN mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 35 mm (shaft journal), E 40 mm (complement outside diameter, matched by the housing bore) and B 27 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 35x40x27 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X40X27",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X40X27-TN",
      "K 35x40x27 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X42X16",
    "brand": "SKF",
    "manufacturer_designation": "K 35x42x16",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 37.5,
    "fatigue_load_limit_kN": 4.5,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 35x42x16: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 35 × E 42 × B 16 mm. K 35×42×16 is a boundary plan, not an envelope: the assembly has no rings, so E 42 mm is the needle set diameter the housing bore must match, and the 35 mm journal must be ground and hardened. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. For life calculation, the 23.3/37.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: grind the 35 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 42 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 23.3/37.5 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 35x42x16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 35x42x16 have?",
        "a": "A K 35x42x16 measures 35 mm bore/Fw × 42 mm outside diameter × 16 mm width (1.378 × 1.654 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 37.5 kN, fatigue limit Pu 4.5 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 34 g."
      },
      {
        "q": "What does K 35x42x16 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 35 mm (shaft journal), E 42 mm (complement outside diameter, matched by the housing bore) and B 16 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 35x42x16 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X42X16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X42X16",
      "K 35x42x16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X42X18",
    "brand": "SKF",
    "manufacturer_designation": "K 35x42x18",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 44,
    "fatigue_load_limit_kN": 5.3,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 35x42x18 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 35 mm hardened shaft journal and the 42 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 35 (shaft journal), E 42 (assembly outside diameter) and B 18 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. For life calculation, the 26.4/44 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: grind the 35 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 42 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 35x42x18 shares its 35×42×18 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 26.4/44 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 35x42x18 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 35x42x18?",
        "a": "Slide the assembly over the ground 35 mm journal with a mounting sleeve, bore the housing to E 42 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 35x42x18 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 35x42x18 have?",
        "a": "A K 35x42x18 measures 35 mm bore/Fw × 42 mm outside diameter × 18 mm width (1.378 × 1.654 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26.4 kN, static C0 44 kN, fatigue limit Pu 5.3 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 34 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X42X18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X42X18",
      "K 35x42x18"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K35X45X20",
    "brand": "SKF",
    "manufacturer_designation": "K 35x45x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.2,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 6.2,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 56,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "The K assembly K 35x45x20 is the lowest-radial-section rolling bearing available for a 35 mm shaft: only the 20 mm wide cage-and-roller set sits between journal and bore, giving extreme compactness where even a drawn cup is too heavy a section. The designation numbers of K 35x45x20 state the three machine-seat dimensions — 35 mm journal, 45 mm bore-side complement diameter, 20 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Speed planning separates the two ceilings: 11,000 r/min thermal reference and 12,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 35 mm seat. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: K 35x45x20 shares its 35×45×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 35.2/50 kN ratings and 56 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 35x45x20 run on an unhardened shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 35x45x20 be mounted?",
        "a": "Slide the assembly over the ground 35 mm journal with a mounting sleeve, bore the housing to E 45 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 35x45x20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 35x45x20?",
        "a": "A K 35x45x20 measures 35 mm bore/Fw × 45 mm outside diameter × 20 mm width (1.378 × 1.772 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.2 kN, static C0 50 kN, fatigue limit Pu 6.2 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 56 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K35X45X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K35X45X20",
      "K 35x45x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K37X42X17",
    "brand": "SKF",
    "manufacturer_designation": "K 37x42x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.2,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 37x42x17 in the K series of needle roller and cage assemblies: needle rollers caged at 37×42×17 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 37x42x17, Fw×E×B reads directly as journal 37 mm, complement diameter 42 mm and cage width 17 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. For life calculation, the 21.6/43 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 17 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 37 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 37 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 21.6/43 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the K 37x42x17 be mounted?",
        "a": "Slide the assembly over the ground 37 mm journal with a mounting sleeve, bore the housing to E 42 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 37x42x17?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 37 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 37x42x17?",
        "a": "A K 37x42x17 measures 37 mm bore/Fw × 42 mm outside diameter × 17 mm width (1.457 × 1.654 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 43 kN, fatigue limit Pu 5.2 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 22 g."
      },
      {
        "q": "How is the K 37x42x17 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 37 mm (shaft journal), E 42 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K37X42X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K37X42X17",
      "K 37x42x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K38X43X17",
    "brand": "SKF",
    "manufacturer_designation": "K 38x43x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 43,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.8,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 29,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 38x43x17 in the K series of needle roller and cage assemblies: needle rollers caged at 38×43×17 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. K 38×43×17 is a boundary plan, not an envelope: the assembly has no rings, so E 43 mm is the needle set diameter the housing bore must match, and the 38 mm journal must be ground and hardened. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. For life calculation, the 19.8/39 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: grind the 38 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 43 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 38x43x17 shares its 38×43×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 19.8/39 kN ratings and 29 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 38x43x17?",
        "a": "Slide the assembly over the ground 38 mm journal with a mounting sleeve, bore the housing to E 43 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 38x43x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 38x43x17 have?",
        "a": "A K 38x43x17 measures 38 mm bore/Fw × 43 mm outside diameter × 17 mm width (1.496 × 1.693 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.8 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 29 g."
      },
      {
        "q": "What does K 38x43x17 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 38 mm (shaft journal), E 43 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K38X43X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K38X43X17",
      "K 38x43x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K38X46X32",
    "brand": "SKF",
    "manufacturer_designation": "K 38x46x32",
    "series": "K-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 46,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 52.3,
    "static_load_kN": 100,
    "fatigue_load_limit_kN": 12.5,
    "max_rpm": 12000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 12000,
    "weight_g": 76,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 38x46x32 is a caged needle roller set, not a complete bearing: paired with a 58–64 HRC ground journal of 38 mm and a housing bore of 46 mm, it forms a full rolling bearing with the smallest possible radial space demand. In the K code K 38x46x32, Fw×E×B reads directly as journal 38 mm, complement diameter 46 mm and cage width 32 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Selection arithmetic: C 52.3 kN against C0 100 kN gives a C0/C ratio of 1.91, and the 12.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 32 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 52.3/100 kN ratings and 76 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the K 38x46x32 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 38 mm (shaft journal), E 46 mm (complement outside diameter, matched by the housing bore) and B 32 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 38x46x32 run on an unhardened shaft?",
        "a": "No. In this execution the 38 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 38x46x32 be mounted?",
        "a": "Slide the assembly over the ground 38 mm journal with a mounting sleeve, bore the housing to E 46 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 38x46x32?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 38 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K38X46X32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K38X46X32",
      "K 38x46x32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K40X45X17",
    "brand": "SKF",
    "manufacturer_designation": "K 40x45x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.5,
    "static_load_kN": 41.5,
    "fatigue_load_limit_kN": 5,
    "max_rpm": 12000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 12000,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 40x45x17 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 40 mm hardened shaft journal and the 45 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 40 (shaft journal), E 45 (assembly outside diameter) and B 17 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. For life calculation, the 20.5/41.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 17 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 20.5/41.5 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 40x45x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 40x45x17?",
        "a": "Slide the assembly over the ground 40 mm journal with a mounting sleeve, bore the housing to E 45 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 40x45x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 40x45x17 have?",
        "a": "A K 40x45x17 measures 40 mm bore/Fw × 45 mm outside diameter × 17 mm width (1.575 × 1.772 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 20.5 kN, static C0 41.5 kN, fatigue limit Pu 5 kN, limiting speed 12,000 r/min, reference speed 10,000 r/min, mass about 31 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K40X45X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K40X45X17",
      "K 40x45x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K40X45X27",
    "brand": "SKF",
    "manufacturer_designation": "K 40x45x27",
    "series": "K-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 45,
    "B_mm": 27,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.4,
    "static_load_kN": 73.5,
    "fatigue_load_limit_kN": 9,
    "max_rpm": 12000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 12000,
    "weight_g": 46,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 40x45x27: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 40 × E 45 × B 27 mm. In the K code K 40x45x27, Fw×E×B reads directly as journal 40 mm, complement diameter 45 mm and cage width 27 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. For life calculation, the 31.4/73.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 31.4/73.5 kN ratings are SKF catalogue values for this exact execution (K 40x45x27); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 31.4/73.5 kN ratings and 46 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a K 40x45x27?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 40x45x27?",
        "a": "A K 40x45x27 measures 40 mm bore/Fw × 45 mm outside diameter × 27 mm width (1.575 × 1.772 × 1.063 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.4 kN, static C0 73.5 kN, fatigue limit Pu 9 kN, limiting speed 12,000 r/min, reference speed 10,000 r/min, mass about 46 g."
      },
      {
        "q": "How is the K 40x45x27 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 40 mm (shaft journal), E 45 mm (complement outside diameter, matched by the housing bore) and B 27 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 40x45x27 run on an unhardened shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K40X45X27",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K40X45X27",
      "K 40x45x27"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K40X48X20",
    "brand": "SKF",
    "manufacturer_designation": "K 40x48x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 48,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.7,
    "static_load_kN": 58.5,
    "fatigue_load_limit_kN": 7.35,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 40x48x20 appears as a needle roller and cage assembly with complement diameter E 48 mm and width 20 mm — a self-contained roller set that turns a 40 mm shaft and its housing into a complete bearing. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 40 (shaft journal), E 48 (assembly outside diameter) and B 20 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Speed planning separates the two ceilings: 10,000 r/min thermal reference and 11,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: grind the 40 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 48 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 34.7/58.5 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does K 40x48x20 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 40 mm (shaft journal), E 48 mm (complement outside diameter, matched by the housing bore) and B 20 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 40x48x20 need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 40x48x20?",
        "a": "Slide the assembly over the ground 40 mm journal with a mounting sleeve, bore the housing to E 48 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 40x48x20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K40X48X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K40X48X20",
      "K 40x48x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K42X47X17",
    "brand": "SKF",
    "manufacturer_designation": "K 42x47x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.9,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.2,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 32,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 42x47x17 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 42 mm hardened shaft journal and the 47 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. K 42×47×17 is a boundary plan, not an envelope: the assembly has no rings, so E 47 mm is the needle set diameter the housing bore must match, and the 42 mm journal must be ground and hardened. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. For life calculation, the 20.9/43 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 20.9/43 kN ratings are SKF catalogue values for this exact execution (K 42x47x17); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 20.9/43 kN ratings and 32 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 42x47x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 42x47x17?",
        "a": "Slide the assembly over the ground 42 mm journal with a mounting sleeve, bore the housing to E 47 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 42x47x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 42x47x17 have?",
        "a": "A K 42x47x17 measures 42 mm bore/Fw × 47 mm outside diameter × 17 mm width (1.654 × 1.85 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 20.9 kN, static C0 43 kN, fatigue limit Pu 5.2 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 32 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K42X47X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K42X47X17",
      "K 42x47x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K42X50X20",
    "brand": "SKF",
    "manufacturer_designation": "K 42x50x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 33.6,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 42x50x20 denotes a needle roller and cage assembly for a 42 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 20 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 42 (shaft journal), E 50 (assembly outside diameter) and B 20 (width) in millimetres — the machine parts complete the bearing. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Catalogue mass 53 g at 42×50×20 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 42 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 50 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 42x50x20 shares its 42×50×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 33.6/57 kN ratings and 53 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a K 42x50x20?",
        "a": "Slide the assembly over the ground 42 mm journal with a mounting sleeve, bore the housing to E 50 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 42x50x20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 42x50x20 have?",
        "a": "A K 42x50x20 measures 42 mm bore/Fw × 50 mm outside diameter × 20 mm width (1.654 × 1.969 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 33.6 kN, static C0 57 kN, fatigue limit Pu 7.1 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 53 g."
      },
      {
        "q": "What does K 42x50x20 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 42 mm (shaft journal), E 50 mm (complement outside diameter, matched by the housing bore) and B 20 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K42X50X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K42X50X20",
      "K 42x50x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K43X48X17",
    "brand": "SKF",
    "manufacturer_designation": "K 43x48x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 48,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.9,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.2,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 43x48x17 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 43 mm hardened shaft journal and the 48 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 43 (shaft journal), E 48 (assembly outside diameter) and B 17 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 11,000 r/min limiting speed assumes a precision ground journal and bore. The 30 g catalogue mass and 2.5 mm radial section ((48−43)/2) frame a rating of about 0.49 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 17 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 43 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 43 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 20.9/43 kN ratings are SKF catalogue values for this exact execution (K 43x48x17); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 20.9/43 kN ratings and 30 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 43x48x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 43 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 43x48x17?",
        "a": "Slide the assembly over the ground 43 mm journal with a mounting sleeve, bore the housing to E 48 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 43x48x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 43x48x17 have?",
        "a": "A K 43x48x17 measures 43 mm bore/Fw × 48 mm outside diameter × 17 mm width (1.693 × 1.89 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 20.9 kN, static C0 43 kN, fatigue limit Pu 5.2 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 30 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K43X48X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K43X48X17",
      "K 43x48x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K45X50X17",
    "brand": "SKF",
    "manufacturer_designation": "K 45x50x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 50,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 46.5,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 45x50x17 appears as a needle roller and cage assembly with complement diameter E 50 mm and width 17 mm — a self-contained roller set that turns a 45 mm shaft and its housing into a complete bearing. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 45 (shaft journal), E 50 (assembly outside diameter) and B 17 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Selection arithmetic: C 21.6 kN against C0 46.5 kN gives a C0/C ratio of 2.15, and the 5.6 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 17 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 9,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 45 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 21.6/46.5 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 45x50x17 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 45x50x17 have?",
        "a": "A K 45x50x17 measures 45 mm bore/Fw × 50 mm outside diameter × 17 mm width (1.772 × 1.969 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 46.5 kN, fatigue limit Pu 5.6 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 34 g."
      },
      {
        "q": "What does K 45x50x17 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 45 mm (shaft journal), E 50 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 45x50x17 need a hardened and ground shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K45X50X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K45X50X17",
      "K 45x50x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K45X50X27",
    "brand": "SKF",
    "manufacturer_designation": "K 45x50x27",
    "series": "K-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 50,
    "B_mm": 27,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 33,
    "static_load_kN": 81.5,
    "fatigue_load_limit_kN": 10,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 45x50x27 in the K series of needle roller and cage assemblies: needle rollers caged at 45×50×27 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 45x50x27, Fw×E×B reads directly as journal 45 mm, complement diameter 50 mm and cage width 27 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Selection arithmetic: C 33 kN against C0 81.5 kN gives a C0/C ratio of 2.47, and the 10 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 45 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 33/81.5 kN ratings are SKF catalogue values for this exact execution (K 45x50x27); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 33/81.5 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the K 45x50x27 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 45 mm (shaft journal), E 50 mm (complement outside diameter, matched by the housing bore) and B 27 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 45x50x27 run on an unhardened shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 45x50x27 be mounted?",
        "a": "Slide the assembly over the ground 45 mm journal with a mounting sleeve, bore the housing to E 50 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 45x50x27?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K45X50X27",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K45X50X27",
      "K 45x50x27"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K45X53X28",
    "brand": "SKF",
    "manufacturer_designation": "K 45x53x28",
    "series": "K-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 53,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 49.5,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 12.2,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 81,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 45x53x28 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 45 mm hardened shaft journal and the 53 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 45 (shaft journal), E 53 (assembly outside diameter) and B 28 (width) in millimetres — the machine parts complete the bearing. The TN suffix marks a glass fibre reinforced PA66 cage snapping the rollers in place — lighter and quieter than steel; assemblies are also supplied unmarked with steel cages for higher temperature duty. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: grind the 45 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 53 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: K 45x53x28 shares its 45×53×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 49.5/98 kN ratings and 81 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the K 45x53x28 have?",
        "a": "A K 45x53x28 measures 45 mm bore/Fw × 53 mm outside diameter × 28 mm width (1.772 × 2.087 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 49.5 kN, static C0 98 kN, fatigue limit Pu 12.2 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 81 g."
      },
      {
        "q": "What does K 45x53x28 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 45 mm (shaft journal), E 53 mm (complement outside diameter, matched by the housing bore) and B 28 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 45x53x28 need a hardened and ground shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 45x53x28?",
        "a": "Slide the assembly over the ground 45 mm journal with a mounting sleeve, bore the housing to E 53 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K45X53X28",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K45X53X28",
      "K 45x53x28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K47X52X17",
    "brand": "SKF",
    "manufacturer_designation": "K 47x52x17",
    "series": "K-series",
    "type": "needle",
    "d_mm": 47,
    "D_mm": 52,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22.4,
    "static_load_kN": 49,
    "fatigue_load_limit_kN": 6,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 35,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 47x52x17 appears as a needle roller and cage assembly with complement diameter E 52 mm and width 17 mm — a self-contained roller set that turns a 47 mm shaft and its housing into a complete bearing. The designation numbers of K 47x52x17 state the three machine-seat dimensions — 47 mm journal, 52 mm bore-side complement diameter, 17 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 10,000 r/min limiting speed assumes a precision ground journal and bore. Catalogue mass 35 g at 47×52×17 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 47 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 47 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 47 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 22.4/49 kN ratings are SKF catalogue values for this exact execution (K 47x52x17); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 22.4/49 kN ratings and 35 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a K 47x52x17?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 47 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 47x52x17?",
        "a": "A K 47x52x17 measures 47 mm bore/Fw × 52 mm outside diameter × 17 mm width (1.85 × 2.047 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.4 kN, static C0 49 kN, fatigue limit Pu 6 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 35 g."
      },
      {
        "q": "How is the K 47x52x17 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 47 mm (shaft journal), E 52 mm (complement outside diameter, matched by the housing bore) and B 17 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 47x52x17 run on an unhardened shaft?",
        "a": "No. In this execution the 47 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K47X52X17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K47X52X17",
      "K 47x52x17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K50X55X20",
    "brand": "SKF",
    "manufacturer_designation": "K 50x55x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.2,
    "max_rpm": 9500,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 9500,
    "weight_g": 43,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "K 50x55x20 is a needle roller and cage assembly to DIN 5402: a complement of needle rollers held by a lightweight cage, with no inner or outer ring of its own — the 50 mm hardened shaft journal and the 55 mm housing bore serve as the raceways, as tabulated in SKF catalogue PUB BU/P1 17000. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 50 (shaft journal), E 55 (assembly outside diameter) and B 20 (width) in millimetres — the machine parts complete the bearing. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 9,500 r/min limiting speed assumes a precision ground journal and bore. Catalogue mass 43 g at 50×55×20 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 50 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 55 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 8,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 25.5/60 kN ratings and 43 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 50x55x20 need a hardened and ground shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 50x55x20?",
        "a": "Slide the assembly over the ground 50 mm journal with a mounting sleeve, bore the housing to E 55 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 50x55x20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 50x55x20 have?",
        "a": "A K 50x55x20 measures 50 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.969 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.5 kN, static C0 60 kN, fatigue limit Pu 7.2 kN, limiting speed 9,500 r/min, reference speed 8,500 r/min, mass about 43 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K50X55X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K50X55X20",
      "K 50x55x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K50X55X30",
    "brand": "SKF",
    "manufacturer_designation": "K 50x55x30",
    "series": "K-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 37.4,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 12,
    "max_rpm": 9500,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 9500,
    "weight_g": 65,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "For pivots and crank pins where every millimetre of radial height counts, SKF supplies K 50x55x30: needle rollers in a pressed cage (DIN 5402 boundary plan), dimensioned Fw 50 × E 55 × B 30 mm. In the K code K 50x55x30, Fw×E×B reads directly as journal 50 mm, complement diameter 55 mm and cage width 30 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 9,500 r/min limiting speed assumes a precision ground journal and bore. Catalogue mass 65 g at 50×55×30 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 30 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 37.4/98 kN ratings are SKF catalogue values for this exact execution (K 50x55x30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 37.4/98 kN ratings and 65 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a K 50x55x30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 50x55x30?",
        "a": "A K 50x55x30 measures 50 mm bore/Fw × 55 mm outside diameter × 30 mm width (1.969 × 2.165 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 37.4 kN, static C0 98 kN, fatigue limit Pu 12 kN, limiting speed 9,500 r/min, reference speed 8,500 r/min, mass about 65 g."
      },
      {
        "q": "How is the K 50x55x30 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 50 mm (shaft journal), E 55 mm (complement outside diameter, matched by the housing bore) and B 30 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 50x55x30 run on an unhardened shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K50X55X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K50X55X30",
      "K 50x55x30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K50X57X18",
    "brand": "SKF",
    "manufacturer_designation": "K 50x57x18",
    "series": "K-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 57,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 64,
    "fatigue_load_limit_kN": 7.8,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 47,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 50x57x18 in the K series of needle roller and cage assemblies: needle rollers caged at 50×57×18 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 50 (shaft journal), E 57 (assembly outside diameter) and B 18 (width) in millimetres — the machine parts complete the bearing. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.",
    "applications": [
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 31.9/64 kN ratings and 47 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the K 50x57x18 need a hardened and ground shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a K 50x57x18?",
        "a": "Slide the assembly over the ground 50 mm journal with a mounting sleeve, bore the housing to E 57 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "Is the K 50x57x18 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 50x57x18 have?",
        "a": "A K 50x57x18 measures 50 mm bore/Fw × 57 mm outside diameter × 18 mm width (1.969 × 2.244 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 64 kN, fatigue limit Pu 7.8 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 47 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K50X57X18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K50X57X18",
      "K 50x57x18"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K50X58X25",
    "brand": "SKF",
    "manufacturer_designation": "K 50x58x25",
    "series": "K-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 58,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 41.8,
    "static_load_kN": 81.5,
    "fatigue_load_limit_kN": 10.2,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 90,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 50x58x25 appears as a needle roller and cage assembly with complement diameter E 58 mm and width 25 mm — a self-contained roller set that turns a 50 mm shaft and its housing into a complete bearing. The designation numbers of K 50x58x25 state the three machine-seat dimensions — 50 mm journal, 58 mm bore-side complement diameter, 25 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 9,000 r/min limiting speed assumes a precision ground journal and bore. For life calculation, the 41.8/81.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 25 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: K 50x58x25 shares its 50×58×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 41.8/81.5 kN ratings and 90 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the K 50x58x25 run on an unhardened shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 50x58x25 be mounted?",
        "a": "Slide the assembly over the ground 50 mm journal with a mounting sleeve, bore the housing to E 58 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 50x58x25?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 50x58x25?",
        "a": "A K 50x58x25 measures 50 mm bore/Fw × 58 mm outside diameter × 25 mm width (1.969 × 2.283 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 41.8 kN, static C0 81.5 kN, fatigue limit Pu 10.2 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 90 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K50X58X25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K50X58X25",
      "K 50x58x25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K55X60X20",
    "brand": "SKF",
    "manufacturer_designation": "K 55x60x20",
    "series": "K-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 60,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 8.15,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 55x60x20 appears as a needle roller and cage assembly with complement diameter E 60 mm and width 20 mm — a self-contained roller set that turns a 55 mm shaft and its housing into a complete bearing. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 55 (shaft journal), E 60 (assembly outside diameter) and B 20 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. The 40 g catalogue mass and 2.5 mm radial section ((60−55)/2) frame a rating of about 0.49 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: grind the 55 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 60 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 7,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 27/67 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 55x60x20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 55x60x20 have?",
        "a": "A K 55x60x20 measures 55 mm bore/Fw × 60 mm outside diameter × 20 mm width (2.165 × 2.362 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 67 kN, fatigue limit Pu 8.15 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 40 g."
      },
      {
        "q": "What does K 55x60x20 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 55 mm (shaft journal), E 60 mm (complement outside diameter, matched by the housing bore) and B 20 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 55x60x20 need a hardened and ground shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K55X60X20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K55X60X20",
      "K 55x60x20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K55X60X30",
    "brand": "SKF",
    "manufacturer_designation": "K 55x60x30",
    "series": "K-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 60,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.6,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 13.4,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 71,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 55x60x30 in the K series of needle roller and cage assemblies: needle rollers caged at 55×60×30 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 55x60x30, Fw×E×B reads directly as journal 55 mm, complement diameter 60 mm and cage width 30 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. The 71 g catalogue mass and 2.5 mm radial section ((60−55)/2) frame a rating of about 0.72 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 30 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles",
      "planetary gear pins in compact transmissions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 39.6/108 kN ratings are SKF catalogue values for this exact execution (K 55x60x30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 39.6/108 kN ratings and 71 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the K 55x60x30 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 55 mm (shaft journal), E 60 mm (complement outside diameter, matched by the housing bore) and B 30 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Can the K 55x60x30 run on an unhardened shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the K 55x60x30 be mounted?",
        "a": "Slide the assembly over the ground 55 mm journal with a mounting sleeve, bore the housing to E 60 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 55x60x30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K55X60X30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K55X60X30",
      "K 55x60x30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K55X62X18",
    "brand": "SKF",
    "manufacturer_designation": "K 55x62x18",
    "series": "K-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 62,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.1,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 8.5,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF catalogue number K 55x62x18 denotes a needle roller and cage assembly for a 55 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 18 mm width is all the radial room it needs. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 55 (shaft journal), E 62 (assembly outside diameter) and B 18 (width) in millimetres — the machine parts complete the bearing. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Speed planning separates the two ceilings: 7,500 r/min thermal reference and 8,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 55 mm seat. Lubrication reaches both raceways through the open cage windows; grease the bore and journal before assembly, since after fitting the 18 mm narrow cage cannot be relubricated through a closed housing.",
    "applications": [
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins",
      "hinge and pivot joints in printing and textile machinery",
      "universal joint crosses on commercial vehicles"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 7,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 34.1/71 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the K 55x62x18 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the K 55x62x18 have?",
        "a": "A K 55x62x18 measures 55 mm bore/Fw × 62 mm outside diameter × 18 mm width (2.165 × 2.441 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 71 kN, fatigue limit Pu 8.5 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 52 g."
      },
      {
        "q": "What does K 55x62x18 mean in SKF part numbering?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 55 mm (shaft journal), E 62 mm (complement outside diameter, matched by the housing bore) and B 18 mm width. TN marks the glass fibre reinforced PA66 cage."
      },
      {
        "q": "Does the K 55x62x18 need a hardened and ground shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K55X62X18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K55X62X18",
      "K 55x62x18"
    ],
    "locale_variants": {}
  },
  {
    "sku": "K55X63X32",
    "brand": "SKF",
    "manufacturer_designation": "K 55x63x32",
    "series": "K-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 63,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 59.4,
    "static_load_kN": 129,
    "fatigue_load_limit_kN": 16.3,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 102,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 5402",
    "naming_rule_text": "SKF lists K 55x63x32 in the K series of needle roller and cage assemblies: needle rollers caged at 55×63×32 mm, designed to run directly on a ground, hardened shaft and inside a machined housing bore. In the K code K 55x63x32, Fw×E×B reads directly as journal 55 mm, complement diameter 63 mm and cage width 32 mm; the housing bore is ground to E with H6/H7 tolerance to complete the outer raceway. SKF supplies these assemblies in single rows as tabulated; the cage quality determines the speed ceiling, and the catalogued 8,500 r/min limiting speed assumes a precision ground journal and bore. Catalogue mass 102 g at 55×63×32 mm makes this one of the highest capacity-per-gram choices in the needle roller and cage assemblies; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: grind the 55 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 63 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.",
    "applications": [
      "planetary gear pins in compact transmissions",
      "connecting rods of small compressors where radial height is critical",
      "rocker arm and rocker pin pivots on camshafts",
      "pump and gearbox idler gears running on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 59.4/129 kN ratings and 102 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the K 55x63x32 be mounted?",
        "a": "Slide the assembly over the ground 55 mm journal with a mounting sleeve, bore the housing to E 63 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded."
      },
      {
        "q": "What limits the service life of a K 55x63x32?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the K 55x63x32?",
        "a": "A K 55x63x32 measures 55 mm bore/Fw × 63 mm outside diameter × 32 mm width (2.165 × 2.48 × 1.26 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 59.4 kN, static C0 129 kN, fatigue limit Pu 16.3 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 102 g."
      },
      {
        "q": "How is the K 55x63x32 designation read?",
        "a": "K = needle roller and cage assembly (DIN 5402); the three figures give Fw 55 mm (shaft journal), E 63 mm (complement outside diameter, matched by the housing bore) and B 32 mm width. TN marks the glass fibre reinforced PA66 cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "K55X63X32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "K55X63X32",
      "K 55x63x32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0306-TN",
    "brand": "SKF",
    "manufacturer_designation": "HK 0306 TN",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 3,
    "D_mm": 6.5,
    "B_mm": 6,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 1.23,
    "static_load_kN": 0.88,
    "fatigue_load_limit_kN": 0.088,
    "max_rpm": 26000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 26000,
    "weight_g": 1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 0306 TN for housings where machining an outer-ring pocket is uneconomical: the 6.5 mm shell broached from sheet steel press-fits into a plain bore and runs a 3 mm hardened shaft. In HK 0306, Fw = 3 mm names the shaft that becomes the inner raceway and B = 6 mm the cup width; the shell outside diameter 6.5 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. For life calculation, the 1.23/0.88 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "At Fw 3 mm the rolling elements are under two millimetres long — handle the HK 0306 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: HK 0306 TN shares its 3×6.5×6 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 1.23/0.88 kN ratings and 1 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 0306 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 3 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.8 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0306 TN?",
        "a": "A HK 0306 TN measures 3 mm bore/Fw × 6.5 mm outside diameter × 6 mm width (0.118 × 0.256 × 0.236 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.23 kN, static C0 0.88 kN, fatigue limit Pu 0.088 kN, limiting speed 26,000 r/min, reference speed 24,000 r/min, mass about 1 g."
      },
      {
        "q": "How is the HK 0306 TN designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 3 mm, the last two the width 6 mm, the shell OD 6.5 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 0306 TN run on an unhardened shaft?",
        "a": "No. In this execution the 3 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0306",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0306-TN",
      "HK 0306 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0408",
    "brand": "SKF",
    "manufacturer_designation": "HK 0408",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 4,
    "D_mm": 8,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 1.76,
    "static_load_kN": 1.37,
    "fatigue_load_limit_kN": 0.14,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 0408 gives the smallest radial section of any caged needle bearing with its own outer ring: 4 mm Fw, 8 mm OD and 8 mm width, the shell pressed directly into the housing bore. Reading the code: HK marks the open-end drawn cup series, the first two digits (04) give the 4 mm under-roller diameter Fw, the last two (08) the 8 mm width; the 8 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. The 2 g catalogue mass and 2.0 mm radial section ((8−4)/2) frame a rating of about 0.44 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 8 mm section.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "At Fw 4 mm the rolling elements are under two millimetres long — handle the HK 0408 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 0408 shares its 4×8×8 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 1.76/1.37 kN ratings and 2 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 0408?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 0408 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 0408 have?",
        "a": "A HK 0408 measures 4 mm bore/Fw × 8 mm outside diameter × 8 mm width (0.157 × 0.315 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.76 kN, static C0 1.37 kN, fatigue limit Pu 0.14 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 2 g."
      },
      {
        "q": "What does HK 0408 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 4 mm, the last two the width 8 mm, the shell OD 8 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0408",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0408",
      "HK 0408"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0509",
    "brand": "SKF",
    "manufacturer_designation": "HK 0509",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 9,
    "B_mm": 9,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 2.38,
    "static_load_kN": 2.08,
    "fatigue_load_limit_kN": 0.22,
    "max_rpm": 24000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 24000,
    "weight_g": 2,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 5 mm shaft in a thin housing wall, SKF catalogue execution HK 0509 offers a 9 mm wide, 9 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. SKF's HK numbering puts the shaft size first: 05 → Fw 5 mm (the ground, hardened journal), 09 → width 9 mm, with the 9 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Speed planning separates the two ceilings: 22,000 r/min thermal reference and 24,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 5 mm seat. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the HK 0509 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Hardness is load capacity: in families without an inner ring the 5 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 2.38/2.08 kN ratings are SKF catalogue values for this exact execution (HK 0509); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 2.38/2.08 kN ratings and 2 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the HK 0509 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 0509?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 5 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0509?",
        "a": "A HK 0509 measures 5 mm bore/Fw × 9 mm outside diameter × 9 mm width (0.197 × 0.354 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.38 kN, static C0 2.08 kN, fatigue limit Pu 0.22 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 2 g."
      },
      {
        "q": "How is the HK 0509 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 5 mm, the last two the width 9 mm, the shell OD 9 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0509",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0509",
      "HK 0509"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0608",
    "brand": "SKF",
    "manufacturer_designation": "HK 0608",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 10,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 2.01,
    "static_load_kN": 1.73,
    "fatigue_load_limit_kN": 0.18,
    "max_rpm": 22000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 22000,
    "weight_g": 2.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 0608 denotes a 6×10×8 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. SKF's HK numbering puts the shaft size first: 06 → Fw 6 mm (the ground, hardened journal), 08 → width 8 mm, with the 10 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Selection arithmetic: C 2.01 kN against C0 1.73 kN gives a C0/C ratio of 0.86, and the 0.18 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the HK 0608 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Hardness is load capacity: in families without an inner ring the 6 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 2.01/1.73 kN ratings are SKF catalogue values for this exact execution (HK 0608); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 2.01/1.73 kN ratings and 2.1 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 0608?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 6 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0608?",
        "a": "A HK 0608 measures 6 mm bore/Fw × 10 mm outside diameter × 8 mm width (0.236 × 0.394 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.01 kN, static C0 1.73 kN, fatigue limit Pu 0.18 kN, limiting speed 22,000 r/min, reference speed 20,000 r/min, mass about 2.1 g."
      },
      {
        "q": "How is the HK 0608 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 6 mm, the last two the width 8 mm, the shell OD 10 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 0608 run on an unhardened shaft?",
        "a": "No. In this execution the 6 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0608",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0608",
      "HK 0608"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0609",
    "brand": "SKF",
    "manufacturer_designation": "HK 0609",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 10,
    "B_mm": 9,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 2.81,
    "static_load_kN": 2.7,
    "fatigue_load_limit_kN": 0.285,
    "max_rpm": 22000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 22000,
    "weight_g": 2.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 0609 for housings where machining an outer-ring pocket is uneconomical: the 10 mm shell broached from sheet steel press-fits into a plain bore and runs a 6 mm hardened shaft. Reading the code: HK marks the open-end drawn cup series, the first two digits (06) give the 6 mm under-roller diameter Fw, the last two (09) the 9 mm width; the 10 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Selection arithmetic: C 2.81 kN against C0 2.7 kN gives a C0/C ratio of 0.96, and the 0.285 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the HK 0609 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Reference and limiting speeds are different limits: the 20,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 6 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 2.81/2.7 kN ratings and 2.5 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 0609?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 0609 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 0609 have?",
        "a": "A HK 0609 measures 6 mm bore/Fw × 10 mm outside diameter × 9 mm width (0.236 × 0.394 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.81 kN, static C0 2.7 kN, fatigue limit Pu 0.285 kN, limiting speed 22,000 r/min, reference speed 20,000 r/min, mass about 2.5 g."
      },
      {
        "q": "What does HK 0609 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 6 mm, the last two the width 9 mm, the shell OD 10 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0609",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0609",
      "HK 0609"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0709",
    "brand": "SKF",
    "manufacturer_designation": "HK 0709",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 11,
    "B_mm": 9,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 3.03,
    "static_load_kN": 3.05,
    "fatigue_load_limit_kN": 0.325,
    "max_rpm": 22000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 22000,
    "weight_g": 2.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 0709 is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 11 mm outside diameter carrying a caged needle roller set for a 7 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. In HK 0709, Fw = 7 mm names the shaft that becomes the inner raceway and B = 9 mm the cup width; the shell outside diameter 11 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 2.6 g at 7×11×9 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the HK 0709 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: HK 0709 shares its 7×11×9 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 20,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 3.03/3.05 kN ratings and 2.6 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the HK 0709 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 0709?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 7 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0709?",
        "a": "A HK 0709 measures 7 mm bore/Fw × 11 mm outside diameter × 9 mm width (0.276 × 0.433 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.03 kN, static C0 3.05 kN, fatigue limit Pu 0.325 kN, limiting speed 22,000 r/min, reference speed 20,000 r/min, mass about 2.6 g."
      },
      {
        "q": "How is the HK 0709 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 7 mm, the last two the width 9 mm, the shell OD 11 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0709",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0709",
      "HK 0709"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0808",
    "brand": "SKF",
    "manufacturer_designation": "HK 0808",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 12,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 2.7,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.285,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 2.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 0808 is the standard caged drawn cup execution for a 8 mm shaft: ISO 3245 boundary dimensions (8×12×8 mm), open at both ends so the shaft can be pushed through, and rated 2.7 kN dynamic. In HK 0808, Fw = 8 mm names the shaft that becomes the inner raceway and B = 8 mm the cup width; the shell outside diameter 12 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the HK 0808 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: HK 0808 shares its 8×12×8 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 2.7/2.75 kN ratings and 2.7 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 0808?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 8 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0808?",
        "a": "A HK 0808 measures 8 mm bore/Fw × 12 mm outside diameter × 8 mm width (0.315 × 0.472 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.7 kN, static C0 2.75 kN, fatigue limit Pu 0.285 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 2.7 g."
      },
      {
        "q": "How is the HK 0808 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 8 mm, the last two the width 8 mm, the shell OD 12 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 0808 run on an unhardened shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0808",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0808",
      "HK 0808"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0810",
    "brand": "SKF",
    "manufacturer_designation": "HK 0810",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 12,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 3.69,
    "static_load_kN": 4.05,
    "fatigue_load_limit_kN": 0.44,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 0810 denotes a 8×12×10 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. The designation HK 0810 encodes geometry only — there is no bore code to decode, since the 8 mm Fw is printed directly in the first digits and the cup width 10 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the HK 0810 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 3.69/4.05 kN ratings are SKF catalogue values for this exact execution (HK 0810); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 3.69/4.05 kN ratings and 3 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 0810 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 0810 have?",
        "a": "A HK 0810 measures 8 mm bore/Fw × 12 mm outside diameter × 10 mm width (0.315 × 0.472 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.69 kN, static C0 4.05 kN, fatigue limit Pu 0.44 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 3 g."
      },
      {
        "q": "What does HK 0810 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 8 mm, the last two the width 10 mm, the shell OD 12 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 0810 need a hardened and ground shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0810",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0810",
      "HK 0810"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0812-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 0812.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 12,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 2.7,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.285,
    "max_rpm": 13000,
    "limiting_speed_rpm": 13000,
    "weight_g": 3.3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 0812.2RS is the standard caged drawn cup execution for a 8 mm shaft: ISO 3245 boundary dimensions (8×12×12 mm), open at both ends so the shaft can be pushed through, and rated 2.7 kN dynamic. In HK 0812, Fw = 8 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 12 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 2.7 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. The 3.3 g catalogue mass and 2.0 mm radial section ((12−8)/2) frame a rating of about 0.34 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the HK 0812.2RS like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: HK 0812.2RS shares its 8×12×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 2.7/2.75 kN ratings and 3.3 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 0812.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 0812.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 0812.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 8 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0812.2RS?",
        "a": "A HK 0812.2RS measures 8 mm bore/Fw × 12 mm outside diameter × 12 mm width (0.315 × 0.472 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.7 kN, static C0 2.75 kN, fatigue limit Pu 0.285 kN, limiting speed 13,000 r/min, mass about 3.3 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0812",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0812-2RS",
      "HK 0812.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0908",
    "brand": "SKF",
    "manufacturer_designation": "HK 0908",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 13,
    "B_mm": 8,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 3.52,
    "static_load_kN": 3.9,
    "fatigue_load_limit_kN": 0.415,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 3,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 0908 denotes a 9×13×8 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. SKF's HK numbering puts the shaft size first: 09 → Fw 9 mm (the ground, hardened journal), 08 → width 8 mm, with the 13 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. The 3 g catalogue mass and 2.0 mm radial section ((13−9)/2) frame a rating of about 0.39 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 13 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 3.52/3.9 kN ratings and 3 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 0908?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 9 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 0908?",
        "a": "A HK 0908 measures 9 mm bore/Fw × 13 mm outside diameter × 8 mm width (0.354 × 0.512 × 0.315 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.52 kN, static C0 3.9 kN, fatigue limit Pu 0.415 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 3 g."
      },
      {
        "q": "How is the HK 0908 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 9 mm, the last two the width 8 mm, the shell OD 13 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 0908 run on an unhardened shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0908",
      "HK 0908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0910",
    "brand": "SKF",
    "manufacturer_designation": "HK 0910",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 13,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.13,
    "static_load_kN": 4.8,
    "fatigue_load_limit_kN": 0.53,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 4,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 9 mm shaft in a thin housing wall, SKF catalogue execution HK 0910 offers a 10 mm wide, 13 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. Reading the code: HK marks the open-end drawn cup series, the first two digits (09) give the 9 mm under-roller diameter Fw, the last two (10) the 10 mm width; the 13 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. The 4 g catalogue mass and 2.0 mm radial section ((13−9)/2) frame a rating of about 0.46 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 13 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 18,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 9 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 4.13/4.8 kN ratings and 4 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 0910 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 0910 have?",
        "a": "A HK 0910 measures 9 mm bore/Fw × 13 mm outside diameter × 10 mm width (0.354 × 0.512 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.13 kN, static C0 4.8 kN, fatigue limit Pu 0.53 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 4 g."
      },
      {
        "q": "What does HK 0910 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 9 mm, the last two the width 10 mm, the shell OD 13 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 0910 need a hardened and ground shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0910",
      "HK 0910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK0912",
    "brand": "SKF",
    "manufacturer_designation": "HK 0912",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 13,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 5.12,
    "static_load_kN": 6.4,
    "fatigue_load_limit_kN": 0.72,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 4.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 0912 gives the smallest radial section of any caged needle bearing with its own outer ring: 9 mm Fw, 13 mm OD and 12 mm width, the shell pressed directly into the housing bore. The designation HK 0912 encodes geometry only — there is no bore code to decode, since the 9 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. The 4.6 g catalogue mass and 2.0 mm radial section ((13−9)/2) frame a rating of about 0.57 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 13 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 0912 shares its 9×13×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 5.12/6.4 kN ratings and 4.6 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 0912 need a hardened and ground shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 0912?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 0912 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 0912 have?",
        "a": "A HK 0912 measures 9 mm bore/Fw × 13 mm outside diameter × 12 mm width (0.354 × 0.512 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.12 kN, static C0 6.4 kN, fatigue limit Pu 0.72 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 4.6 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK0912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK0912",
      "HK 0912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1010",
    "brand": "SKF",
    "manufacturer_designation": "HK 1010",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.29,
    "static_load_kN": 5.3,
    "fatigue_load_limit_kN": 0.57,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 4.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 1010 gives the smallest radial section of any caged needle bearing with its own outer ring: 10 mm Fw, 14 mm OD and 10 mm width, the shell pressed directly into the housing bore. In HK 1010, Fw = 10 mm names the shaft that becomes the inner raceway and B = 10 mm the cup width; the shell outside diameter 14 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Catalogue mass 4.1 g at 10×14×10 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 4.29/5.3 kN ratings are SKF catalogue values for this exact execution (HK 1010); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 4.29/5.3 kN ratings and 4.1 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 1010 run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1010 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1010?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 10 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1010?",
        "a": "A HK 1010 measures 10 mm bore/Fw × 14 mm outside diameter × 10 mm width (0.394 × 0.551 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.29 kN, static C0 5.3 kN, fatigue limit Pu 0.57 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 4.1 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1010",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1010",
      "HK 1010"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1012",
    "brand": "SKF",
    "manufacturer_designation": "HK 1012",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 5.39,
    "static_load_kN": 6.95,
    "fatigue_load_limit_kN": 0.78,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 4.8,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 1012 for housings where machining an outer-ring pocket is uneconomical: the 14 mm shell broached from sheet steel press-fits into a plain bore and runs a 10 mm hardened shaft. SKF's HK numbering puts the shaft size first: 10 → Fw 10 mm (the ground, hardened journal), 12 → width 12 mm, with the 14 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Catalogue mass 4.8 g at 10×14×12 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 1012 shares its 10×14×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 18,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 5.39/6.95 kN ratings and 4.8 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the HK 1012?",
        "a": "A HK 1012 measures 10 mm bore/Fw × 14 mm outside diameter × 12 mm width (0.394 × 0.551 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.39 kN, static C0 6.95 kN, fatigue limit Pu 0.78 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 4.8 g."
      },
      {
        "q": "How is the HK 1012 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 10 mm, the last two the width 12 mm, the shell OD 14 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1012 run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1012 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1012",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1012",
      "HK 1012"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1014-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 1014.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 14,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.29,
    "static_load_kN": 5.3,
    "fatigue_load_limit_kN": 0.57,
    "max_rpm": 12000,
    "limiting_speed_rpm": 12000,
    "weight_g": 4.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 1014.2RS for housings where machining an outer-ring pocket is uneconomical: the 14 mm shell broached from sheet steel press-fits into a plain bore and runs a 10 mm hardened shaft. In HK 1014, Fw = 10 mm names the shaft that becomes the inner raceway and B = 14 mm the cup width; the shell outside diameter 14 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 4.29 kN C against the open bearing of the same code. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Catalogue mass 4.6 g at 10×14×14 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 14 mm section.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 4.29/5.3 kN ratings are SKF catalogue values for this exact execution (HK 1014.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 4.29/5.3 kN ratings and 4.6 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 1014.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 10 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1014.2RS?",
        "a": "A HK 1014.2RS measures 10 mm bore/Fw × 14 mm outside diameter × 14 mm width (0.394 × 0.551 × 0.551 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.29 kN, static C0 5.3 kN, fatigue limit Pu 0.57 kN, limiting speed 12,000 r/min, mass about 4.6 g."
      },
      {
        "q": "How is the HK 1014.2RS designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 10 mm, the last two the width 14 mm, the shell OD 14 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1014.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1014",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1014-2RS",
      "HK 1014.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1015",
    "brand": "SKF",
    "manufacturer_designation": "HK 1015",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 14,
    "B_mm": 15,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.6,
    "static_load_kN": 9,
    "fatigue_load_limit_kN": 1.02,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 10 mm shaft in a thin housing wall, SKF catalogue execution HK 1015 offers a 15 mm wide, 14 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 1015 encodes geometry only — there is no bore code to decode, since the 10 mm Fw is printed directly in the first digits and the cup width 15 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Catalogue mass 6 g at 10×14×15 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 14 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 6.6/9 kN ratings are SKF catalogue values for this exact execution (HK 1015); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 6.6/9 kN ratings and 6 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 1015 need a hardened and ground shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 1015?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1015 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 1015 have?",
        "a": "A HK 1015 measures 10 mm bore/Fw × 14 mm outside diameter × 15 mm width (0.394 × 0.551 × 0.591 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 6.6 kN, static C0 9 kN, fatigue limit Pu 1.02 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 6 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1015",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1015",
      "HK 1015"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1210",
    "brand": "SKF",
    "manufacturer_designation": "HK 1210",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 16,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.84,
    "static_load_kN": 6.4,
    "fatigue_load_limit_kN": 0.71,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 4.6,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 1210 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 12 for the 12 mm under-roller diameter and 10 for the 10 mm width. SKF's HK numbering puts the shaft size first: 12 → Fw 12 mm (the ground, hardened journal), 10 → width 10 mm, with the 16 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 1210 shares its 12×16×10 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 16,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 4.84/6.4 kN ratings and 4.6 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the HK 1210 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1210?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1210?",
        "a": "A HK 1210 measures 12 mm bore/Fw × 16 mm outside diameter × 10 mm width (0.472 × 0.63 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.84 kN, static C0 6.4 kN, fatigue limit Pu 0.71 kN, limiting speed 18,000 r/min, reference speed 16,000 r/min, mass about 4.6 g."
      },
      {
        "q": "How is the HK 1210 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 12 mm, the last two the width 10 mm, the shell OD 16 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1210",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1210",
      "HK 1210"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1212",
    "brand": "SKF",
    "manufacturer_designation": "HK 1212",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 18,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.27,
    "static_load_kN": 7.35,
    "fatigue_load_limit_kN": 0.85,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 9.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 12 mm shaft in a thin housing wall, SKF catalogue execution HK 1212 offers a 12 mm wide, 18 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. In HK 1212, Fw = 12 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 18 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 6.27/7.35 kN ratings and 9.5 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 1212 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 12 mm, the last two the width 12 mm, the shell OD 18 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1212 run on an unhardened shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1212 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1212?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1212",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1212",
      "HK 1212"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1216-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 1216.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 18,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.27,
    "static_load_kN": 7.35,
    "fatigue_load_limit_kN": 0.85,
    "max_rpm": 10000,
    "limiting_speed_rpm": 10000,
    "weight_g": 11,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 1216.2RS is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 18 mm outside diameter carrying a caged needle roller set for a 12 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. In HK 1216, Fw = 12 mm names the shaft that becomes the inner raceway and B = 16 mm the cup width; the shell outside diameter 18 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 6.27 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Selection arithmetic: C 6.27 kN against C0 7.35 kN gives a C0/C ratio of 1.17, and the 0.85 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 18 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 6.27/7.35 kN ratings and 11 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the HK 1216.2RS?",
        "a": "A HK 1216.2RS measures 12 mm bore/Fw × 18 mm outside diameter × 16 mm width (0.472 × 0.709 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 6.27 kN, static C0 7.35 kN, fatigue limit Pu 0.85 kN, limiting speed 10,000 r/min, mass about 11 g."
      },
      {
        "q": "How is the HK 1216.2RS designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 12 mm, the last two the width 16 mm, the shell OD 18 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1216.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1216.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1216",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1216-2RS",
      "HK 1216.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1312",
    "brand": "SKF",
    "manufacturer_designation": "HK 1312",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 13,
    "D_mm": 19,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.6,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.915,
    "max_rpm": 17000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 17000,
    "weight_g": 10.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 1312 for housings where machining an outer-ring pocket is uneconomical: the 19 mm shell broached from sheet steel press-fits into a plain bore and runs a 13 mm hardened shaft. SKF's HK numbering puts the shaft size first: 13 → Fw 13 mm (the ground, hardened journal), 12 → width 12 mm, with the 19 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. The 10.5 g catalogue mass and 3.0 mm radial section ((19−13)/2) frame a rating of about 0.51 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 13 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 13 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 6.6/8 kN ratings are SKF catalogue values for this exact execution (HK 1312); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 6.6/8 kN ratings and 10.5 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 1312 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 13 mm, the last two the width 12 mm, the shell OD 19 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1312 run on an unhardened shaft?",
        "a": "No. In this execution the 13 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1312 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1312?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 13 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1312",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1312",
      "HK 1312"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1412",
    "brand": "SKF",
    "manufacturer_designation": "HK 1412",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 20,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.82,
    "static_load_kN": 8.65,
    "fatigue_load_limit_kN": 0.98,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 10.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 1412 is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 20 mm outside diameter carrying a caged needle roller set for a 14 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. Reading the code: HK marks the open-end drawn cup series, the first two digits (14) give the 14 mm under-roller diameter Fw, the last two (12) the 12 mm width; the 20 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Speed planning separates the two ceilings: 15,000 r/min thermal reference and 17,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 14 mm seat. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 20 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 14 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 6.82/8.65 kN ratings and 10.5 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 1412 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 14 mm, the last two the width 12 mm, the shell OD 20 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 1412 need a hardened and ground shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 1412?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1412 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1412",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1412",
      "HK 1412"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1512",
    "brand": "SKF",
    "manufacturer_designation": "HK 1512",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.65,
    "static_load_kN": 9.5,
    "fatigue_load_limit_kN": 1.08,
    "max_rpm": 16000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 16000,
    "weight_g": 11,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 1512 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 15 for the 15 mm under-roller diameter and 12 for the 12 mm width. In HK 1512, Fw = 15 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 21 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 7.65 kN against C0 9.5 kN gives a C0/C ratio of 1.24, and the 1.08 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 1512 shares its 15×21×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 7.65/9.5 kN ratings and 11 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 1512 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 15 mm, the last two the width 12 mm, the shell OD 21 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1512 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1512 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1512?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1512",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1512",
      "HK 1512"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1516",
    "brand": "SKF",
    "manufacturer_designation": "HK 1516",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.1,
    "static_load_kN": 14.6,
    "fatigue_load_limit_kN": 1.7,
    "max_rpm": 16000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 16000,
    "weight_g": 15,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 1516 gives the smallest radial section of any caged needle bearing with its own outer ring: 15 mm Fw, 21 mm OD and 16 mm width, the shell pressed directly into the housing bore. In HK 1516, Fw = 15 mm names the shaft that becomes the inner raceway and B = 16 mm the cup width; the shell outside diameter 21 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 10.1 kN against C0 14.6 kN gives a C0/C ratio of 1.45, and the 1.7 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 10.1/14.6 kN ratings are SKF catalogue values for this exact execution (HK 1516); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 10.1/14.6 kN ratings and 15 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 1516 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1516 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1516?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1516?",
        "a": "A HK 1516 measures 15 mm bore/Fw × 21 mm outside diameter × 16 mm width (0.591 × 0.827 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.1 kN, static C0 14.6 kN, fatigue limit Pu 1.7 kN, limiting speed 16,000 r/min, reference speed 15,000 r/min, mass about 15 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1516",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1516",
      "HK 1516"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1522",
    "brand": "SKF",
    "manufacturer_designation": "HK 1522",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 21,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13,
    "static_load_kN": 20,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 16000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 16000,
    "weight_g": 20,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 1522 denotes a 15×21×22 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. The designation HK 1522 encodes geometry only — there is no bore code to decode, since the 15 mm Fw is printed directly in the first digits and the cup width 22 mm in the last two. Double-row execution: two rows of needle rollers share the 15 mm Fw seat in one cup — double the capacity of the single-row HK at the same 21×22 mm envelope. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 13 kN against C0 20 kN gives a C0/C ratio of 1.54, and the 2.28 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 22 mm section.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 13/20 kN ratings and 20 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 1522?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1522 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 1522 have?",
        "a": "A HK 1522 measures 15 mm bore/Fw × 21 mm outside diameter × 22 mm width (0.591 × 0.827 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13 kN, static C0 20 kN, fatigue limit Pu 2.28 kN, limiting speed 16,000 r/min, reference speed 15,000 r/min, mass about 20 g."
      },
      {
        "q": "What does HK 1522 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 15 mm, the last two the width 22 mm, the shell OD 21 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1522",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1522",
      "HK 1522"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1612",
    "brand": "SKF",
    "manufacturer_designation": "HK 1612",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.37,
    "static_load_kN": 9.8,
    "fatigue_load_limit_kN": 1.12,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 1612 gives the smallest radial section of any caged needle bearing with its own outer ring: 16 mm Fw, 22 mm OD and 12 mm width, the shell pressed directly into the housing bore. The designation HK 1612 encodes geometry only — there is no bore code to decode, since the 16 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 7.37 kN against C0 9.8 kN gives a C0/C ratio of 1.33, and the 1.12 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 1612 shares its 16×22×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 7.37/9.8 kN ratings and 12 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 1612 need a hardened and ground shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 1612?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1612 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 1612 have?",
        "a": "A HK 1612 measures 16 mm bore/Fw × 22 mm outside diameter × 12 mm width (0.63 × 0.866 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 9.8 kN, fatigue limit Pu 1.12 kN, limiting speed 16,000 r/min, reference speed 14,000 r/min, mass about 12 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1612",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1612",
      "HK 1612"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1616",
    "brand": "SKF",
    "manufacturer_designation": "HK 1616",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.5,
    "static_load_kN": 15.6,
    "fatigue_load_limit_kN": 1.8,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 16,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 1616 is the standard caged drawn cup execution for a 16 mm shaft: ISO 3245 boundary dimensions (16×22×16 mm), open at both ends so the shaft can be pushed through, and rated 10.5 kN dynamic. The designation HK 1616 encodes geometry only — there is no bore code to decode, since the 16 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 10.5 kN against C0 15.6 kN gives a C0/C ratio of 1.49, and the 1.8 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 16 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 10.5/15.6 kN ratings and 16 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 1616?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1616 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 1616 have?",
        "a": "A HK 1616 measures 16 mm bore/Fw × 22 mm outside diameter × 16 mm width (0.63 × 0.866 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.5 kN, static C0 15.6 kN, fatigue limit Pu 1.8 kN, limiting speed 16,000 r/min, reference speed 14,000 r/min, mass about 16 g."
      },
      {
        "q": "What does HK 1616 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 16 mm, the last two the width 16 mm, the shell OD 22 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1616",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1616",
      "HK 1616"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1620-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 1620.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.5,
    "static_load_kN": 15.6,
    "fatigue_load_limit_kN": 1.8,
    "max_rpm": 9000,
    "limiting_speed_rpm": 9000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 1620.2RS is the standard caged drawn cup execution for a 16 mm shaft: ISO 3245 boundary dimensions (16×22×20 mm), open at both ends so the shaft can be pushed through, and rated 10.5 kN dynamic. SKF's HK numbering puts the shaft size first: 16 → Fw 16 mm (the ground, hardened journal), 20 → width 20 mm, with the 22 mm shell OD from the ISO 3245 dimension table. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 10.5 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. The 18 g catalogue mass and 3.0 mm radial section ((22−16)/2) frame a rating of about 0.66 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 1620.2RS shares its 16×22×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 10.5/15.6 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 1620.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1620.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1620.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 16 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1620.2RS?",
        "a": "A HK 1620.2RS measures 16 mm bore/Fw × 22 mm outside diameter × 20 mm width (0.63 × 0.866 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.5 kN, static C0 15.6 kN, fatigue limit Pu 1.8 kN, limiting speed 9,000 r/min, mass about 18 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1620",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1620-2RS",
      "HK 1620.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1622",
    "brand": "SKF",
    "manufacturer_designation": "HK 1622",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 22,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 19.6,
    "fatigue_load_limit_kN": 2.24,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 24,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 16 mm shaft in a thin housing wall, SKF catalogue execution HK 1622 offers a 22 mm wide, 22 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. SKF's HK numbering puts the shaft size first: 16 → Fw 16 mm (the ground, hardened journal), 22 → width 22 mm, with the 22 mm shell OD from the ISO 3245 dimension table. Double-row execution: two rows of needle rollers share the 16 mm Fw seat in one cup — double the capacity of the single-row HK at the same 22×22 mm envelope. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Selection arithmetic: C 12.8 kN against C0 19.6 kN gives a C0/C ratio of 1.53, and the 2.24 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 1622 shares its 16×22×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 12.8/19.6 kN ratings and 24 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 1622?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 16 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1622?",
        "a": "A HK 1622 measures 16 mm bore/Fw × 22 mm outside diameter × 22 mm width (0.63 × 0.866 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 19.6 kN, fatigue limit Pu 2.24 kN, limiting speed 16,000 r/min, reference speed 14,000 r/min, mass about 24 g."
      },
      {
        "q": "How is the HK 1622 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 16 mm, the last two the width 22 mm, the shell OD 22 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 1622 run on an unhardened shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1622",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1622",
      "HK 1622"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1712",
    "brand": "SKF",
    "manufacturer_designation": "HK 1712",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 23,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.65,
    "static_load_kN": 10.6,
    "fatigue_load_limit_kN": 1.2,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 13,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 1712 is the standard caged drawn cup execution for a 17 mm shaft: ISO 3245 boundary dimensions (17×23×12 mm), open at both ends so the shaft can be pushed through, and rated 7.65 kN dynamic. Reading the code: HK marks the open-end drawn cup series, the first two digits (17) give the 17 mm under-roller diameter Fw, the last two (12) the 12 mm width; the 23 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 23 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 7.65/10.6 kN ratings are SKF catalogue values for this exact execution (HK 1712); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 7.65/10.6 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 1712 need a hardened and ground shaft?",
        "a": "No. In this execution the 17 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 1712?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 1712 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 1712 have?",
        "a": "A HK 1712 measures 17 mm bore/Fw × 23 mm outside diameter × 12 mm width (0.669 × 0.906 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.65 kN, static C0 10.6 kN, fatigue limit Pu 1.2 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 13 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1712",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1712",
      "HK 1712"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1812",
    "brand": "SKF",
    "manufacturer_designation": "HK 1812",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 24,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.92,
    "static_load_kN": 11.2,
    "fatigue_load_limit_kN": 1.27,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 13,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 1812 denotes a 18×24×12 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. In HK 1812, Fw = 18 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 24 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. For life calculation, the 7.92/11.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 18 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 7.92/11.2 kN ratings are SKF catalogue values for this exact execution (HK 1812); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 7.92/11.2 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 1812 run on an unhardened shaft?",
        "a": "No. In this execution the 18 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 1812 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1812?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 18 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1812?",
        "a": "A HK 1812 measures 18 mm bore/Fw × 24 mm outside diameter × 12 mm width (0.709 × 0.945 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.92 kN, static C0 11.2 kN, fatigue limit Pu 1.27 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 13 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1812",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1812",
      "HK 1812"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1816-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 1816.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.92,
    "static_load_kN": 11.2,
    "fatigue_load_limit_kN": 1.27,
    "max_rpm": 8500,
    "limiting_speed_rpm": 8500,
    "weight_g": 15,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 18 mm shaft in a thin housing wall, SKF catalogue execution HK 1816.2RS offers a 16 mm wide, 24 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 1816.2RS encodes geometry only — there is no bore code to decode, since the 18 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 7.92 kN C against the open bearing of the same code. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 8,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 18 mm seat. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 1816.2RS shares its 18×24×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 7.92/11.2 kN ratings and 15 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 1816.2RS have?",
        "a": "A HK 1816.2RS measures 18 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.709 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.92 kN, static C0 11.2 kN, fatigue limit Pu 1.27 kN, limiting speed 8,500 r/min, mass about 15 g."
      },
      {
        "q": "What does HK 1816.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 18 mm, the last two the width 16 mm, the shell OD 24 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 1816.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 18 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 1816.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1816",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 18×24×16 mm envelope, but catalogue C/C0 differ between the executions (7.92/11.2 vs 11.2/17.6 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1816-2RS",
      "HK 1816.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK1816",
    "brand": "SKF",
    "manufacturer_designation": "HK 1816",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.2,
    "static_load_kN": 17.6,
    "fatigue_load_limit_kN": 2.04,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 18 mm shaft in a thin housing wall, SKF catalogue execution HK 1816 offers a 16 mm wide, 24 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. In HK 1816, Fw = 18 mm names the shaft that becomes the inner raceway and B = 16 mm the cup width; the shell outside diameter 24 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. For life calculation, the 11.2/17.6 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 11.2/17.6 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the HK 1816 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 1816?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 18 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 1816?",
        "a": "A HK 1816 measures 18 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.709 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.2 kN, static C0 17.6 kN, fatigue limit Pu 2.04 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 18 g."
      },
      {
        "q": "How is the HK 1816 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 18 mm, the last two the width 16 mm, the shell OD 24 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK1816-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 18×24×16 mm envelope, but catalogue C/C0 differ between the executions (11.2/17.6 vs 7.92/11.2 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK1816",
      "HK 1816"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2010",
    "brand": "SKF",
    "manufacturer_designation": "HK 2010",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.16,
    "static_load_kN": 8.5,
    "fatigue_load_limit_kN": 0.93,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 2010 gives the smallest radial section of any caged needle bearing with its own outer ring: 20 mm Fw, 26 mm OD and 10 mm width, the shell pressed directly into the housing bore. In HK 2010, Fw = 20 mm names the shaft that becomes the inner raceway and B = 10 mm the cup width; the shell outside diameter 26 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 12 g at 20×26×10 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 6.16/8.5 kN ratings and 12 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 2010 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2010 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 2010?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 2010?",
        "a": "A HK 2010 measures 20 mm bore/Fw × 26 mm outside diameter × 10 mm width (0.787 × 1.024 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 6.16 kN, static C0 8.5 kN, fatigue limit Pu 0.93 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 12 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2010",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2010",
      "HK 2010"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2012",
    "brand": "SKF",
    "manufacturer_designation": "HK 2012",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.42,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 1.4,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 2012 for housings where machining an outer-ring pocket is uneconomical: the 26 mm shell broached from sheet steel press-fits into a plain bore and runs a 20 mm hardened shaft. SKF's HK numbering puts the shaft size first: 20 → Fw 20 mm (the ground, hardened journal), 12 → width 12 mm, with the 26 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 14 g at 20×26×12 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 20 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 8.42/12.5 kN ratings are SKF catalogue values for this exact execution (HK 2012); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 8.42/12.5 kN ratings and 14 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the HK 2012?",
        "a": "A HK 2012 measures 20 mm bore/Fw × 26 mm outside diameter × 12 mm width (0.787 × 1.024 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.42 kN, static C0 12.5 kN, fatigue limit Pu 1.4 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 14 g."
      },
      {
        "q": "How is the HK 2012 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 20 mm, the last two the width 12 mm, the shell OD 26 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2012 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2012 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2012",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2012",
      "HK 2012"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2016-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2016.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.42,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 1.4,
    "max_rpm": 8000,
    "limiting_speed_rpm": 8000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 2016.2RS is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 26 mm outside diameter carrying a caged needle roller set for a 20 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. The designation HK 2016.2RS encodes geometry only — there is no bore code to decode, since the 20 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 8.42 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 2016.2RS shares its 20×26×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 8.42/12.5 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 2016.2RS have?",
        "a": "A HK 2016.2RS measures 20 mm bore/Fw × 26 mm outside diameter × 16 mm width (0.787 × 1.024 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.42 kN, static C0 12.5 kN, fatigue limit Pu 1.4 kN, limiting speed 8,000 r/min, mass about 18 g."
      },
      {
        "q": "What does HK 2016.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 20 mm, the last two the width 16 mm, the shell OD 26 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2016.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2016.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2016",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×26×16 mm envelope, but catalogue C/C0 differ between the executions (8.42/12.5 vs 12.3/20.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2016-2RS",
      "HK 2016.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2016",
    "brand": "SKF",
    "manufacturer_designation": "HK 2016",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.3,
    "static_load_kN": 20.4,
    "fatigue_load_limit_kN": 2.36,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 19,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 2016 is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 26 mm outside diameter carrying a caged needle roller set for a 20 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. SKF's HK numbering puts the shaft size first: 20 → Fw 20 mm (the ground, hardened journal), 16 → width 16 mm, with the 26 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 19 g at 20×26×16 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 12.3/20.4 kN ratings and 19 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 2016 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 20 mm, the last two the width 16 mm, the shell OD 26 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2016 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2016 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 2016?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2016-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×26×16 mm envelope, but catalogue C/C0 differ between the executions (12.3/20.4 vs 8.42/12.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2016",
      "HK 2016"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2020-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2020.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.3,
    "static_load_kN": 20.4,
    "fatigue_load_limit_kN": 2.36,
    "max_rpm": 8000,
    "limiting_speed_rpm": 8000,
    "weight_g": 23,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 20 mm shaft in a thin housing wall, SKF catalogue execution HK 2020.2RS offers a 20 mm wide, 26 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 2020.2RS encodes geometry only — there is no bore code to decode, since the 20 mm Fw is printed directly in the first digits and the cup width 20 mm in the last two. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 12.3 kN C against the open bearing of the same code. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 12.3/20.4 kN ratings are SKF catalogue values for this exact execution (HK 2020.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 12.3/20.4 kN ratings and 23 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 2020.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2020.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2020.2RS sealed?",
        "a": "Yes — this is the 2RS execution with rubber contact seals on both cup faces and a factory grease fill, sealed for life at the 20 mm seat. The open HK execution of the same code relies on the housing for sealing."
      },
      {
        "q": "Which dimensions does the HK 2020.2RS have?",
        "a": "A HK 2020.2RS measures 20 mm bore/Fw × 26 mm outside diameter × 20 mm width (0.787 × 1.024 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.3 kN, static C0 20.4 kN, fatigue limit Pu 2.36 kN, limiting speed 8,000 r/min, mass about 23 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2020",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×26×20 mm envelope, but catalogue C/C0 differ between the executions (12.3/20.4 vs 15.1/26.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2020-2RS",
      "HK 2020.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2020",
    "brand": "SKF",
    "manufacturer_designation": "HK 2020",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 26.5,
    "fatigue_load_limit_kN": 3.15,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 24,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 20 mm shaft in a thin housing wall, SKF catalogue execution HK 2020 offers a 20 mm wide, 26 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 2020 encodes geometry only — there is no bore code to decode, since the 20 mm Fw is printed directly in the first digits and the cup width 20 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 24 g at 20×26×20 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 2020 shares its 20×26×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 15.1/26.5 kN ratings and 24 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 2020 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2020 have?",
        "a": "A HK 2020 measures 20 mm bore/Fw × 26 mm outside diameter × 20 mm width (0.787 × 1.024 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 26.5 kN, fatigue limit Pu 3.15 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 24 g."
      },
      {
        "q": "What does HK 2020 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 20 mm, the last two the width 20 mm, the shell OD 26 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2020 need a hardened and ground shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2020-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×26×20 mm envelope, but catalogue C/C0 differ between the executions (15.1/26.5 vs 12.3/20.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2020",
      "HK 2020"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2030",
    "brand": "SKF",
    "manufacturer_designation": "HK 2030",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 26,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.9,
    "static_load_kN": 40.5,
    "fatigue_load_limit_kN": 4.75,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 35,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 2030 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 20 for the 20 mm under-roller diameter and 30 for the 30 mm width. SKF's HK numbering puts the shaft size first: 20 → Fw 20 mm (the ground, hardened journal), 30 → width 30 mm, with the 26 mm shell OD from the ISO 3245 dimension table. Double-row execution: two rows of needle rollers share the 20 mm Fw seat in one cup — double the capacity of the single-row HK at the same 26×30 mm envelope. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 35 g at 20×26×30 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 2030 shares its 20×26×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 20.9/40.5 kN ratings and 35 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 2030 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 20 mm, the last two the width 30 mm, the shell OD 26 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2030 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2030 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 2030?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2030",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2030",
      "HK 2030"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2210",
    "brand": "SKF",
    "manufacturer_designation": "HK 2210",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.21,
    "static_load_kN": 10.6,
    "fatigue_load_limit_kN": 1.2,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 13,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 2210 denotes a 22×28×10 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. Reading the code: HK marks the open-end drawn cup series, the first two digits (22) give the 22 mm under-roller diameter Fw, the last two (10) the 10 mm width; the 28 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 7.21/10.6 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 7.21/10.6 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 2210?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2210 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2210 have?",
        "a": "A HK 2210 measures 22 mm bore/Fw × 28 mm outside diameter × 10 mm width (0.866 × 1.102 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.21 kN, static C0 10.6 kN, fatigue limit Pu 1.2 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 13 g."
      },
      {
        "q": "What does HK 2210 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 22 mm, the last two the width 10 mm, the shell OD 28 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2210",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2210",
      "HK 2210"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2212",
    "brand": "SKF",
    "manufacturer_designation": "HK 2212",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.8,
    "static_load_kN": 13.7,
    "fatigue_load_limit_kN": 1.56,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 15,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 2212 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 22 for the 22 mm under-roller diameter and 12 for the 12 mm width. The designation HK 2212 encodes geometry only — there is no bore code to decode, since the 22 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 8.8/13.7 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 2212 shares its 22×28×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 8.8/13.7 kN ratings and 15 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 2212 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 22 mm, the last two the width 12 mm, the shell OD 28 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2212 need a hardened and ground shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2212?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2212 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2212",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2212",
      "HK 2212"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2216-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2216.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.8,
    "static_load_kN": 13.7,
    "fatigue_load_limit_kN": 1.56,
    "max_rpm": 7500,
    "limiting_speed_rpm": 7500,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 2216.2RS denotes a 22×28×16 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. Reading the code: HK marks the open-end drawn cup series, the first two digits (22) give the 22 mm under-roller diameter Fw, the last two (16) the 16 mm width; the 28 mm OD follows the ISO 3245 plan. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 8.8 kN C against the open bearing of the same code. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 8.8/13.7 kN ratings are SKF catalogue values for this exact execution (HK 2216.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 8.8/13.7 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 2216.2RS have?",
        "a": "A HK 2216.2RS measures 22 mm bore/Fw × 28 mm outside diameter × 16 mm width (0.866 × 1.102 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.8 kN, static C0 13.7 kN, fatigue limit Pu 1.56 kN, limiting speed 7,500 r/min, mass about 18 g."
      },
      {
        "q": "What does HK 2216.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 22 mm, the last two the width 16 mm, the shell OD 28 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2216.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2216.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2216",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×28×16 mm envelope, but catalogue C/C0 differ between the executions (8.8/13.7 vs 13/22.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2216-2RS",
      "HK 2216.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2216",
    "brand": "SKF",
    "manufacturer_designation": "HK 2216",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13,
    "static_load_kN": 22.4,
    "fatigue_load_limit_kN": 2.6,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 21,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 2216 gives the smallest radial section of any caged needle bearing with its own outer ring: 22 mm Fw, 28 mm OD and 16 mm width, the shell pressed directly into the housing bore. The designation HK 2216 encodes geometry only — there is no bore code to decode, since the 22 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 13/22.4 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 13/22.4 kN ratings and 21 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 2216 need a hardened and ground shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2216?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2216 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2216 have?",
        "a": "A HK 2216 measures 22 mm bore/Fw × 28 mm outside diameter × 16 mm width (0.866 × 1.102 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13 kN, static C0 22.4 kN, fatigue limit Pu 2.6 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 21 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2216-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×28×16 mm envelope, but catalogue C/C0 differ between the executions (13/22.4 vs 8.8/13.7 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2216",
      "HK 2216"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2220-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2220.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13,
    "static_load_kN": 22.4,
    "fatigue_load_limit_kN": 2.6,
    "max_rpm": 7500,
    "limiting_speed_rpm": 7500,
    "weight_g": 23,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 2220.2RS gives the smallest radial section of any caged needle bearing with its own outer ring: 22 mm Fw, 28 mm OD and 20 mm width, the shell pressed directly into the housing bore. SKF's HK numbering puts the shaft size first: 22 → Fw 22 mm (the ground, hardened journal), 20 → width 20 mm, with the 28 mm shell OD from the ISO 3245 dimension table. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 13 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Catalogue mass 23 g at 22×28×20 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 13/22.4 kN ratings are SKF catalogue values for this exact execution (HK 2220.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 13/22.4 kN ratings and 23 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 2220.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2220.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 2220.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 2220.2RS?",
        "a": "A HK 2220.2RS measures 22 mm bore/Fw × 28 mm outside diameter × 20 mm width (0.866 × 1.102 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13 kN, static C0 22.4 kN, fatigue limit Pu 2.6 kN, limiting speed 7,500 r/min, mass about 23 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2220",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×28×20 mm envelope, but catalogue C/C0 differ between the executions (13/22.4 vs 15.7/29 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2220-2RS",
      "HK 2220.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2220",
    "brand": "SKF",
    "manufacturer_designation": "HK 2220",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 28,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.7,
    "static_load_kN": 29,
    "fatigue_load_limit_kN": 3.45,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 26,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 2220 is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 28 mm outside diameter carrying a caged needle roller set for a 22 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. In HK 2220, Fw = 22 mm names the shaft that becomes the inner raceway and B = 20 mm the cup width; the shell outside diameter 28 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 15.7/29 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 15.7/29 kN ratings are SKF catalogue values for this exact execution (HK 2220); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 15.7/29 kN ratings and 26 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the HK 2220?",
        "a": "A HK 2220 measures 22 mm bore/Fw × 28 mm outside diameter × 20 mm width (0.866 × 1.102 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.7 kN, static C0 29 kN, fatigue limit Pu 3.45 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 26 g."
      },
      {
        "q": "How is the HK 2220 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 22 mm, the last two the width 20 mm, the shell OD 28 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2220 run on an unhardened shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2220 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2220-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×28×20 mm envelope, but catalogue C/C0 differ between the executions (15.7/29 vs 13/22.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2220",
      "HK 2220"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2512",
    "brand": "SKF",
    "manufacturer_designation": "HK 2512",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.5,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.76,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 20,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 2512 denotes a 25×32×12 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. The designation HK 2512 encodes geometry only — there is no bore code to decode, since the 25 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 20 g at 25×32×12 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 10.5/15.3 kN ratings and 20 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 2512 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 25 mm, the last two the width 12 mm, the shell OD 32 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2512 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2512?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2512 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2512",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2512",
      "HK 2512"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2516-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2516.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.5,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.76,
    "max_rpm": 6700,
    "limiting_speed_rpm": 6700,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 2516.2RS in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 25 for the 25 mm under-roller diameter and 16 for the 16 mm width. The designation HK 2516.2RS encodes geometry only — there is no bore code to decode, since the 25 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 10.5 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 27 g at 25×32×16 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 10.5/15.3 kN ratings and 27 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 2516.2RS have?",
        "a": "A HK 2516.2RS measures 25 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.984 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 10.5 kN, static C0 15.3 kN, fatigue limit Pu 1.76 kN, limiting speed 6,700 r/min, mass about 27 g."
      },
      {
        "q": "What does HK 2516.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 25 mm, the last two the width 16 mm, the shell OD 32 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2516.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2516.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2516",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×32×16 mm envelope, but catalogue C/C0 differ between the executions (10.5/15.3 vs 15.1/24 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2516-2RS",
      "HK 2516.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2516",
    "brand": "SKF",
    "manufacturer_designation": "HK 2516",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 24,
    "fatigue_load_limit_kN": 2.85,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 25 mm shaft in a thin housing wall, SKF catalogue execution HK 2516 offers a 16 mm wide, 32 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 2516 encodes geometry only — there is no bore code to decode, since the 25 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 25 g at 25×32×16 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 15.1/24 kN ratings are SKF catalogue values for this exact execution (HK 2516); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 15.1/24 kN ratings and 25 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 2516 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2516?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2516 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2516 have?",
        "a": "A HK 2516 measures 25 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.984 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24 kN, fatigue limit Pu 2.85 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 25 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2516-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×32×16 mm envelope, but catalogue C/C0 differ between the executions (15.1/24 vs 10.5/15.3 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2516",
      "HK 2516"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2520-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2520.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 24,
    "fatigue_load_limit_kN": 2.85,
    "max_rpm": 6700,
    "limiting_speed_rpm": 6700,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 2520.2RS is the standard caged drawn cup execution for a 25 mm shaft: ISO 3245 boundary dimensions (25×32×20 mm), open at both ends so the shaft can be pushed through, and rated 15.1 kN dynamic. In HK 2520, Fw = 25 mm names the shaft that becomes the inner raceway and B = 20 mm the cup width; the shell outside diameter 32 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 15.1 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Selection arithmetic: C 15.1 kN against C0 24 kN gives a C0/C ratio of 1.59, and the 2.85 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: HK 2520.2RS shares its 25×32×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 15.1/24 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 2520.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 2520.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 2520.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 2520.2RS?",
        "a": "A HK 2520.2RS measures 25 mm bore/Fw × 32 mm outside diameter × 20 mm width (0.984 × 1.26 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24 kN, fatigue limit Pu 2.85 kN, limiting speed 6,700 r/min, mass about 31 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2520",
        "equiv_brand": "NTN",
        "level": "partial",
        "note": "Same 25×32×20 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2520-2RS",
      "HK 2520.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2526",
    "brand": "SKF",
    "manufacturer_designation": "HK 2526",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.5,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 44,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 2526 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 25 for the 25 mm under-roller diameter and 26 for the 26 mm width. SKF's HK numbering puts the shaft size first: 25 → Fw 25 mm (the ground, hardened journal), 26 → width 26 mm, with the 32 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 44 g at 25×32×26 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 24.2/45 kN ratings and 44 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 2526?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 2526?",
        "a": "A HK 2526 measures 25 mm bore/Fw × 32 mm outside diameter × 26 mm width (0.984 × 1.26 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 45 kN, fatigue limit Pu 5.5 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 44 g."
      },
      {
        "q": "How is the HK 2526 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 25 mm, the last two the width 26 mm, the shell OD 32 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2526 run on an unhardened shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2526",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2526",
      "HK 2526"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2530-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2530.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.5,
    "max_rpm": 6700,
    "limiting_speed_rpm": 6700,
    "weight_g": 47,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 2530.2RS denotes a 25×32×30 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. In HK 2530, Fw = 25 mm names the shaft that becomes the inner raceway and B = 30 mm the cup width; the shell outside diameter 32 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 24.2 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. For life calculation, the 24.2/45 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 30 mm section.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 24.2/45 kN ratings are SKF catalogue values for this exact execution (HK 2530.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 24.2/45 kN ratings and 47 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 2530.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 2530.2RS?",
        "a": "A HK 2530.2RS measures 25 mm bore/Fw × 32 mm outside diameter × 30 mm width (0.984 × 1.26 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 45 kN, fatigue limit Pu 5.5 kN, limiting speed 6,700 r/min, mass about 47 g."
      },
      {
        "q": "How is the HK 2530.2RS designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 25 mm, the last two the width 30 mm, the shell OD 32 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 2530.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2530",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2530-2RS",
      "HK 2530.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2538",
    "brand": "SKF",
    "manufacturer_designation": "HK 2538",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 32,
    "B_mm": 38,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 33,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 64,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 2538 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 25 for the 25 mm under-roller diameter and 38 for the 38 mm width. The designation HK 2538 encodes geometry only — there is no bore code to decode, since the 25 mm Fw is printed directly in the first digits and the cup width 38 mm in the last two. Double-row execution: two rows of needle rollers share the 25 mm Fw seat in one cup — double the capacity of the single-row HK at the same 32×38 mm envelope. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Catalogue mass 64 g at 25×32×38 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 38 mm section.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 33/65.5 kN ratings are SKF catalogue values for this exact execution (HK 2538); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 33/65.5 kN ratings and 64 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 2538 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2538 have?",
        "a": "A HK 2538 measures 25 mm bore/Fw × 32 mm outside diameter × 38 mm width (0.984 × 1.26 × 1.496 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 33 kN, static C0 65.5 kN, fatigue limit Pu 8 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 64 g."
      },
      {
        "q": "What does HK 2538 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 25 mm, the last two the width 38 mm, the shell OD 32 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 2538 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2538",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2538",
      "HK 2538"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2816",
    "brand": "SKF",
    "manufacturer_designation": "HK 2816",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 35,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.7,
    "static_load_kN": 26.5,
    "fatigue_load_limit_kN": 3.15,
    "max_rpm": 9500,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 9500,
    "weight_g": 26.5,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 28 mm shaft in a thin housing wall, SKF catalogue execution HK 2816 offers a 16 mm wide, 35 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 2816 encodes geometry only — there is no bore code to decode, since the 28 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. The 26.5 g catalogue mass and 3.5 mm radial section ((35−28)/2) frame a rating of about 0.56 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 2816 shares its 28×35×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 15.7/26.5 kN ratings and 26.5 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 2816?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2816 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 2816 have?",
        "a": "A HK 2816 measures 28 mm bore/Fw × 35 mm outside diameter × 16 mm width (1.102 × 1.378 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.7 kN, static C0 26.5 kN, fatigue limit Pu 3.15 kN, limiting speed 9,500 r/min, reference speed 9,000 r/min, mass about 26.5 g."
      },
      {
        "q": "What does HK 2816 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 28 mm, the last two the width 16 mm, the shell OD 35 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2816",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2816",
      "HK 2816"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK2820-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 2820.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 35,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.7,
    "static_load_kN": 26.5,
    "fatigue_load_limit_kN": 3.15,
    "max_rpm": 6300,
    "limiting_speed_rpm": 6300,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 2820.2RS is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 35 mm outside diameter carrying a caged needle roller set for a 28 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. Reading the code: HK marks the open-end drawn cup series, the first two digits (28) give the 28 mm under-roller diameter Fw, the last two (20) the 20 mm width; the 35 mm OD follows the ISO 3245 plan. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 15.7 kN C against the open bearing of the same code. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Selection arithmetic: C 15.7 kN against C0 26.5 kN gives a C0/C ratio of 1.69, and the 3.15 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 15.7/26.5 kN ratings are SKF catalogue values for this exact execution (HK 2820.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 15.7/26.5 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 2820.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 2820.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 2820.2RS sealed?",
        "a": "Yes — this is the 2RS execution with rubber contact seals on both cup faces and a factory grease fill, sealed for life at the 28 mm seat. The open HK execution of the same code relies on the housing for sealing."
      },
      {
        "q": "Which dimensions does the HK 2820.2RS have?",
        "a": "A HK 2820.2RS measures 28 mm bore/Fw × 35 mm outside diameter × 20 mm width (1.102 × 1.378 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.7 kN, static C0 26.5 kN, fatigue limit Pu 3.15 kN, limiting speed 6,300 r/min, mass about 34 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK2820",
        "equiv_brand": "NTN",
        "level": "partial",
        "note": "Same 28×35×20 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK2820-2RS",
      "HK 2820.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3012",
    "brand": "SKF",
    "manufacturer_designation": "HK 3012",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.7,
    "static_load_kN": 18.3,
    "fatigue_load_limit_kN": 2.12,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 23,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 3012 for housings where machining an outer-ring pocket is uneconomical: the 37 mm shell broached from sheet steel press-fits into a plain bore and runs a 30 mm hardened shaft. Reading the code: HK marks the open-end drawn cup series, the first two digits (30) give the 30 mm under-roller diameter Fw, the last two (12) the 12 mm width; the 37 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 12 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 11.7/18.3 kN ratings are SKF catalogue values for this exact execution (HK 3012); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 11.7/18.3 kN ratings and 23 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 3012 have?",
        "a": "A HK 3012 measures 30 mm bore/Fw × 37 mm outside diameter × 12 mm width (1.181 × 1.457 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.7 kN, static C0 18.3 kN, fatigue limit Pu 2.12 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 23 g."
      },
      {
        "q": "What does HK 3012 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 12 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 3012 need a hardened and ground shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 3012?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3012",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3012",
      "HK 3012"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3016-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 3016.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.7,
    "static_load_kN": 18.3,
    "fatigue_load_limit_kN": 2.12,
    "max_rpm": 5600,
    "limiting_speed_rpm": 5600,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 3016.2RS is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 37 mm outside diameter carrying a caged needle roller set for a 30 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. In HK 3016, Fw = 30 mm names the shaft that becomes the inner raceway and B = 16 mm the cup width; the shell outside diameter 37 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 11.7 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. The 31 g catalogue mass and 3.5 mm radial section ((37−30)/2) frame a rating of about 0.39 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 16 mm section.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 11.7/18.3 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the HK 3016.2RS?",
        "a": "A HK 3016.2RS measures 30 mm bore/Fw × 37 mm outside diameter × 16 mm width (1.181 × 1.457 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.7 kN, static C0 18.3 kN, fatigue limit Pu 2.12 kN, limiting speed 5,600 r/min, mass about 31 g."
      },
      {
        "q": "How is the HK 3016.2RS designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 16 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 3016.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 3016.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3016",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×37×16 mm envelope, but catalogue C/C0 differ between the executions (11.7/18.3 vs 16.5/29 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3016-2RS",
      "HK 3016.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3016",
    "brand": "SKF",
    "manufacturer_designation": "HK 3016",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.5,
    "static_load_kN": 29,
    "fatigue_load_limit_kN": 3.4,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 3016 is an open-end drawn cup needle roller bearing to ISO 3245: a hardened, thin-walled shell of 37 mm outside diameter carrying a caged needle roller set for a 30 mm shaft, listed by SKF in SKF catalogue PUB BU/P1 17000. Reading the code: HK marks the open-end drawn cup series, the first two digits (30) give the 30 mm under-roller diameter Fw, the last two (16) the 16 mm width; the 37 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 16 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 3016 shares its 30×37×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 16.5/29 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 3016 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 16 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 3016 need a hardened and ground shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 3016?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 3016 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3016-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×37×16 mm envelope, but catalogue C/C0 differ between the executions (16.5/29 vs 11.7/18.3 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3016",
      "HK 3016"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3020",
    "brand": "SKF",
    "manufacturer_designation": "HK 3020",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.9,
    "static_load_kN": 40,
    "fatigue_load_limit_kN": 4.75,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 38,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 30 mm shaft in a thin housing wall, SKF catalogue execution HK 3020 offers a 20 mm wide, 37 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. SKF's HK numbering puts the shaft size first: 30 → Fw 30 mm (the ground, hardened journal), 20 → width 20 mm, with the 37 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: HK 3020 shares its 30×37×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 20.9/40 kN ratings and 38 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 3020?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 3020?",
        "a": "A HK 3020 measures 30 mm bore/Fw × 37 mm outside diameter × 20 mm width (1.181 × 1.457 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 20.9 kN, static C0 40 kN, fatigue limit Pu 4.75 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 38 g."
      },
      {
        "q": "How is the HK 3020 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 20 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 3020 run on an unhardened shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3020",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3020",
      "HK 3020"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3026",
    "brand": "SKF",
    "manufacturer_designation": "HK 3026",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 51,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 3026 is the standard caged drawn cup execution for a 30 mm shaft: ISO 3245 boundary dimensions (30×37×26 mm), open at both ends so the shaft can be pushed through, and rated 27 kN dynamic. In HK 3026, Fw = 30 mm names the shaft that becomes the inner raceway and B = 26 mm the cup width; the shell outside diameter 37 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: HK 3026 shares its 30×37×26 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 27/54 kN ratings and 51 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the HK 3026 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 3026?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 3026?",
        "a": "A HK 3026 measures 30 mm bore/Fw × 37 mm outside diameter × 26 mm width (1.181 × 1.457 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 54 kN, fatigue limit Pu 6.55 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 51 g."
      },
      {
        "q": "How is the HK 3026 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 26 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3026",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3026",
      "HK 3026"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3038",
    "brand": "SKF",
    "manufacturer_designation": "HK 3038",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 37,
    "B_mm": 38,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.8,
    "static_load_kN": 80,
    "fatigue_load_limit_kN": 9.5,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 76,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 3038 is the standard caged drawn cup execution for a 30 mm shaft: ISO 3245 boundary dimensions (30×37×38 mm), open at both ends so the shaft can be pushed through, and rated 35.8 kN dynamic. Reading the code: HK marks the open-end drawn cup series, the first two digits (30) give the 30 mm under-roller diameter Fw, the last two (38) the 38 mm width; the 37 mm OD follows the ISO 3245 plan. Double-row execution: two rows of needle rollers share the 30 mm Fw seat in one cup — double the capacity of the single-row HK at the same 37×38 mm envelope. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 3038 shares its 30×37×38 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 35.8/80 kN ratings and 76 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a HK 3038?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 3038 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 3038 have?",
        "a": "A HK 3038 measures 30 mm bore/Fw × 37 mm outside diameter × 38 mm width (1.181 × 1.457 × 1.496 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.8 kN, static C0 80 kN, fatigue limit Pu 9.5 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 76 g."
      },
      {
        "q": "What does HK 3038 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 38 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3038",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3038",
      "HK 3038"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3512",
    "brand": "SKF",
    "manufacturer_designation": "HK 3512",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.5,
    "static_load_kN": 21.6,
    "fatigue_load_limit_kN": 2.45,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 3512 denotes a 35×42×12 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. The designation HK 3512 encodes geometry only — there is no bore code to decode, since the 35 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Catalogue mass 27 g at 35×42×12 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 12.5/21.6 kN ratings are SKF catalogue values for this exact execution (HK 3512); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 12.5/21.6 kN ratings and 27 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 3512 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 35 mm, the last two the width 12 mm, the shell OD 42 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 3512 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 3512?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 3512 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3512",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3512",
      "HK 3512"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3516",
    "brand": "SKF",
    "manufacturer_designation": "HK 3516",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.9,
    "static_load_kN": 34,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 36,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 35 mm shaft in a thin housing wall, SKF catalogue execution HK 3516 offers a 16 mm wide, 42 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 3516 encodes geometry only — there is no bore code to decode, since the 35 mm Fw is printed directly in the first digits and the cup width 16 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Catalogue mass 36 g at 35×42×16 mm makes this one of the highest capacity-per-gram choices in the drawn cup needle roller bearings, open end; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 3516 shares its 35×42×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 17.9/34 kN ratings and 36 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 3516 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 3516?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 3516 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 3516 have?",
        "a": "A HK 3516 measures 35 mm bore/Fw × 42 mm outside diameter × 16 mm width (1.378 × 1.654 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 17.9 kN, static C0 34 kN, fatigue limit Pu 4 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 36 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3516",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3516",
      "HK 3516"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK3520-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 3520.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.9,
    "static_load_kN": 34,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 5000,
    "limiting_speed_rpm": 5000,
    "weight_g": 41,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 3520.2RS is the standard caged drawn cup execution for a 35 mm shaft: ISO 3245 boundary dimensions (35×42×20 mm), open at both ends so the shaft can be pushed through, and rated 17.9 kN dynamic. Reading the code: HK marks the open-end drawn cup series, the first two digits (35) give the 35 mm under-roller diameter Fw, the last two (20) the 20 mm width; the 42 mm OD follows the ISO 3245 plan. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 17.9 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 3520.2RS shares its 35×42×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 17.9/34 kN ratings and 41 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 3520.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 3520.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 3520.2RS sealed?",
        "a": "Yes — this is the 2RS execution with rubber contact seals on both cup faces and a factory grease fill, sealed for life at the 35 mm seat. The open HK execution of the same code relies on the housing for sealing."
      },
      {
        "q": "Which dimensions does the HK 3520.2RS have?",
        "a": "A HK 3520.2RS measures 35 mm bore/Fw × 42 mm outside diameter × 20 mm width (1.378 × 1.654 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 17.9 kN, static C0 34 kN, fatigue limit Pu 4 kN, limiting speed 5,000 r/min, mass about 41 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK3520",
        "equiv_brand": "NTN",
        "level": "partial",
        "note": "Same 35×42×20 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK3520-2RS",
      "HK 3520.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4012",
    "brand": "SKF",
    "manufacturer_designation": "HK 4012",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.4,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.8,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 4012 gives the smallest radial section of any caged needle bearing with its own outer ring: 40 mm Fw, 47 mm OD and 12 mm width, the shell pressed directly into the housing bore. Reading the code: HK marks the open-end drawn cup series, the first two digits (40) give the 40 mm under-roller diameter Fw, the last two (12) the 12 mm width; the 47 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: HK 4012 shares its 40×47×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 13.4/24.5 kN ratings and 30 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 4012 have?",
        "a": "A HK 4012 measures 40 mm bore/Fw × 47 mm outside diameter × 12 mm width (1.575 × 1.85 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.4 kN, static C0 24.5 kN, fatigue limit Pu 2.8 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 30 g."
      },
      {
        "q": "What does HK 4012 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 40 mm, the last two the width 12 mm, the shell OD 47 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 4012 need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 4012?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4012",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4012",
      "HK 4012"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4016-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 4016.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.5,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 3.15,
    "max_rpm": 4500,
    "limiting_speed_rpm": 4500,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 4016.2RS denotes a 40×47×16 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. Reading the code: HK marks the open-end drawn cup series, the first two digits (40) give the 40 mm under-roller diameter Fw, the last two (16) the 16 mm width; the 47 mm OD follows the ISO 3245 plan. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 14.5 kN C against the open bearing of the same code. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. Selection arithmetic: C 14.5 kN against C0 27.5 kN gives a C0/C ratio of 1.90, and the 3.15 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 14.5/27.5 kN ratings are SKF catalogue values for this exact execution (HK 4016.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 14.5/27.5 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 4016.2RS have?",
        "a": "A HK 4016.2RS measures 40 mm bore/Fw × 47 mm outside diameter × 16 mm width (1.575 × 1.85 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.5 kN, static C0 27.5 kN, fatigue limit Pu 3.15 kN, limiting speed 4,500 r/min, mass about 37 g."
      },
      {
        "q": "What does HK 4016.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 40 mm, the last two the width 16 mm, the shell OD 47 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 4016.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 4016.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4016",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×47×16 mm envelope, but catalogue C/C0 differ between the executions (14.5/27.5 vs 19/39 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4016-2RS",
      "HK 4016.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4016",
    "brand": "SKF",
    "manufacturer_designation": "HK 4016",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.55,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 39,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 4016 is the standard caged drawn cup execution for a 40 mm shaft: ISO 3245 boundary dimensions (40×47×16 mm), open at both ends so the shaft can be pushed through, and rated 19 kN dynamic. Reading the code: HK marks the open-end drawn cup series, the first two digits (40) give the 40 mm under-roller diameter Fw, the last two (16) the 16 mm width; the 47 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 6,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 19/39 kN ratings and 39 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does HK 4016 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 40 mm, the last two the width 16 mm, the shell OD 47 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 4016 need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 4016?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 4016 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4016-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×47×16 mm envelope, but catalogue C/C0 differ between the executions (19/39 vs 14.5/27.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4016",
      "HK 4016"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4020-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 4020.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.55,
    "max_rpm": 4500,
    "limiting_speed_rpm": 4500,
    "weight_g": 48,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "The drawn cup bearing HK 4020.2RS gives the smallest radial section of any caged needle bearing with its own outer ring: 40 mm Fw, 47 mm OD and 20 mm width, the shell pressed directly into the housing bore. SKF's HK numbering puts the shaft size first: 40 → Fw 40 mm (the ground, hardened journal), 20 → width 20 mm, with the 47 mm shell OD from the ISO 3245 dimension table. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 19 kN C against the open bearing of the same code. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 4,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 19/39 kN ratings are SKF catalogue values for this exact execution (HK 4020.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 19/39 kN ratings and 48 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 4020.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 4020.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 4020.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 4020.2RS?",
        "a": "A HK 4020.2RS measures 40 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.575 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19 kN, static C0 39 kN, fatigue limit Pu 4.55 kN, limiting speed 4,500 r/min, mass about 48 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4020",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×47×20 mm envelope, but catalogue C/C0 differ between the executions (19/39 vs 24.2/53 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4020-2RS",
      "HK 4020.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4020",
    "brand": "SKF",
    "manufacturer_designation": "HK 4020",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 53,
    "fatigue_load_limit_kN": 6.4,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 54,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 4020 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 40 for the 40 mm under-roller diameter and 20 for the 20 mm width. Reading the code: HK marks the open-end drawn cup series, the first two digits (40) give the 40 mm under-roller diameter Fw, the last two (20) the 20 mm width; the 47 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 24.2/53 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 6,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 24.2/53 kN ratings and 54 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 4020 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 4020 have?",
        "a": "A HK 4020 measures 40 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.575 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 53 kN, fatigue limit Pu 6.4 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 54 g."
      },
      {
        "q": "What does HK 4020 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 40 mm, the last two the width 20 mm, the shell OD 47 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 4020 need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4020-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×47×20 mm envelope, but catalogue C/C0 differ between the executions (24.2/53 vs 19/39 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4020",
      "HK 4020"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4512",
    "brand": "SKF",
    "manufacturer_designation": "HK 4512",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 52,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.2,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 3.2,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 33,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 4512 denotes a 45×52×12 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. SKF's HK numbering puts the shaft size first: 45 → Fw 45 mm (the ground, hardened journal), 12 → width 12 mm, with the 52 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 12 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 14.2/27.5 kN ratings and 33 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the HK 4512 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 45 mm, the last two the width 12 mm, the shell OD 52 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 4512 run on an unhardened shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 4512 be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 4512?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4512",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4512",
      "HK 4512"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK4520-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 4520.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 20.5,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.1,
    "max_rpm": 4000,
    "limiting_speed_rpm": 4000,
    "weight_g": 54,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "HK 4520.2RS is the standard caged drawn cup execution for a 45 mm shaft: ISO 3245 boundary dimensions (45×52×20 mm), open at both ends so the shaft can be pushed through, and rated 20.5 kN dynamic. SKF's HK numbering puts the shaft size first: 45 → Fw 45 mm (the ground, hardened journal), 20 → width 20 mm, with the 52 mm shell OD from the ISO 3245 dimension table. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 20.5 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. The 54 g catalogue mass and 3.5 mm radial section ((52−45)/2) frame a rating of about 0.46 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 20.5/43 kN ratings and 54 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the HK 4520.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the HK 4520.2RS be mounted?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "What limits the service life of a HK 4520.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 4520.2RS?",
        "a": "A HK 4520.2RS measures 45 mm bore/Fw × 52 mm outside diameter × 20 mm width (1.772 × 2.047 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 20.5 kN, static C0 43 kN, fatigue limit Pu 5.1 kN, limiting speed 4,000 r/min, mass about 54 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK4520",
        "equiv_brand": "NTN",
        "level": "partial",
        "note": "Same 45×52×20 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK4520-2RS",
      "HK 4520.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK5024-2RS",
    "brand": "SKF",
    "manufacturer_designation": "HK 5024.2RS",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 58,
    "B_mm": 24,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 29.2,
    "static_load_kN": 63,
    "fatigue_load_limit_kN": 7.8,
    "max_rpm": 3600,
    "limiting_speed_rpm": 3600,
    "weight_g": 81,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 5024.2RS denotes a 50×58×24 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. Reading the code: HK marks the open-end drawn cup series, the first two digits (50) give the 50 mm under-roller diameter Fw, the last two (24) the 24 mm width; the 58 mm OD follows the ISO 3245 plan. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 29.2 kN C against the open bearing of the same code. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. Selection arithmetic: C 29.2 kN against C0 63 kN gives a C0/C ratio of 2.16, and the 7.8 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives",
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 29.2/63 kN ratings and 81 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 5024.2RS have?",
        "a": "A HK 5024.2RS measures 50 mm bore/Fw × 58 mm outside diameter × 24 mm width (1.969 × 2.283 × 0.945 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 29.2 kN, static C0 63 kN, fatigue limit Pu 7.8 kN, limiting speed 3,600 r/min, mass about 81 g."
      },
      {
        "q": "What does HK 5024.2RS mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 50 mm, the last two the width 24 mm, the shell OD 58 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 5024.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 5024.2RS?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK5024",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK5024-2RS",
      "HK 5024.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK5520",
    "brand": "SKF",
    "manufacturer_designation": "HK 5520",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 63,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 30.3,
    "static_load_kN": 67,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 74,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "SKF supplies HK 5520 for housings where machining an outer-ring pocket is uneconomical: the 63 mm shell broached from sheet steel press-fits into a plain bore and runs a 55 mm hardened shaft. The designation HK 5520 encodes geometry only — there is no bore code to decode, since the 55 mm Fw is printed directly in the first digits and the cup width 20 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 30.3/67 kN ratings are SKF catalogue values for this exact execution (HK 5520); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 30.3/67 kN ratings and 74 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 5520 have?",
        "a": "A HK 5520 measures 55 mm bore/Fw × 63 mm outside diameter × 20 mm width (2.165 × 2.48 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 30.3 kN, static C0 67 kN, fatigue limit Pu 8.3 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 74 g."
      },
      {
        "q": "What does HK 5520 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 55 mm, the last two the width 20 mm, the shell OD 63 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 5520 need a hardened and ground shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 5520?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK5520",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK5520",
      "HK 5520"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK5528",
    "brand": "SKF",
    "manufacturer_designation": "HK 5528",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 63,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 41.8,
    "static_load_kN": 104,
    "fatigue_load_limit_kN": 12.9,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 105,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "Ordering number HK 5528 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 55 for the 55 mm under-roller diameter and 28 for the 28 mm width. The designation HK 5528 encodes geometry only — there is no bore code to decode, since the 55 mm Fw is printed directly in the first digits and the cup width 28 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 28 mm section.",
    "applications": [
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains",
      "steering column and pedal-box pivots in passenger cars",
      "idler gears and pulleys in small appliance drives"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 41.8/104 kN ratings and 105 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the HK 5528 need a hardened and ground shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 5528?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      },
      {
        "q": "Is the HK 5528 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 5528 have?",
        "a": "A HK 5528 measures 55 mm bore/Fw × 63 mm outside diameter × 28 mm width (2.165 × 2.48 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 41.8 kN, static C0 104 kN, fatigue limit Pu 12.9 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 105 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK5528",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK5528",
      "HK 5528"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK6012",
    "brand": "SKF",
    "manufacturer_designation": "HK 6012",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 68,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.6,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.8,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "For a 60 mm shaft in a thin housing wall, SKF catalogue execution HK 6012 offers a 12 mm wide, 68 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. The designation HK 6012 encodes geometry only — there is no bore code to decode, since the 60 mm Fw is printed directly in the first digits and the cup width 12 mm in the last two. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. The 49 g catalogue mass and 4.0 mm radial section ((68−60)/2) frame a rating of about 0.29 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 60 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 17.6/32 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the HK 6012 have?",
        "a": "A HK 6012 measures 60 mm bore/Fw × 68 mm outside diameter × 12 mm width (2.362 × 2.677 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 17.6 kN, static C0 32 kN, fatigue limit Pu 3.8 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 49 g."
      },
      {
        "q": "What does HK 6012 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 60 mm, the last two the width 12 mm, the shell OD 68 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 6012 need a hardened and ground shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a HK 6012?",
        "a": "Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK6012",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK6012",
      "HK 6012"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK6020",
    "brand": "SKF",
    "manufacturer_designation": "HK 6020",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 68,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 75,
    "fatigue_load_limit_kN": 9.3,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 81,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 6020 denotes a 60×68×20 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. In HK 6020, Fw = 60 mm names the shaft that becomes the inner raceway and B = 20 mm the cup width; the shell outside diameter 68 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. The 81 g catalogue mass and 4.0 mm radial section ((68−60)/2) frame a rating of about 0.53 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 20 mm section.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 31.9/75 kN ratings and 81 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a HK 6020?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 60 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the HK 6020?",
        "a": "A HK 6020 measures 60 mm bore/Fw × 68 mm outside diameter × 20 mm width (2.362 × 2.677 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 75 kN, fatigue limit Pu 9.3 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 81 g."
      },
      {
        "q": "How is the HK 6020 designation read?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 60 mm, the last two the width 20 mm, the shell OD 68 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Can the HK 6020 run on an unhardened shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK6020",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK6020",
      "HK 6020"
    ],
    "locale_variants": {}
  },
  {
    "sku": "HK6032",
    "brand": "SKF",
    "manufacturer_designation": "HK 6032",
    "series": "HK-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 68,
    "B_mm": 32,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 51.2,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 136,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 3245",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, HK 6032 denotes a 60×68×32 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. Reading the code: HK marks the open-end drawn cup series, the first two digits (60) give the 60 mm under-roller diameter Fw, the last two (32) the 32 mm width; the 68 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. The 136 g catalogue mass and 4.0 mm radial section ((68−60)/2) frame a rating of about 0.85 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.",
    "applications": [
      "spindle clusters of drilling and tapping units",
      "auto steering gear rack supports",
      "clutch release mechanisms and cable pulleys",
      "office equipment and power tool gear trains"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "fretting corrosion of the cup outside diameter in a soft or oversized housing bore",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 51.2/137 kN ratings are SKF catalogue values for this exact execution (HK 6032); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 51.2/137 kN ratings and 136 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the HK 6032 sealed?",
        "a": "No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill."
      },
      {
        "q": "Which dimensions does the HK 6032 have?",
        "a": "A HK 6032 measures 60 mm bore/Fw × 68 mm outside diameter × 32 mm width (2.362 × 2.677 × 1.26 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 51.2 kN, static C0 137 kN, fatigue limit Pu 17 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 136 g."
      },
      {
        "q": "What does HK 6032 mean in SKF part numbering?",
        "a": "HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 60 mm, the last two the width 32 mm, the shell OD 68 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage."
      },
      {
        "q": "Does the HK 6032 need a hardened and ground shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "HK6032",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "HK6032",
      "HK 6032"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK5-10-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 5/10 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 10,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.29,
    "static_load_kN": 2,
    "fatigue_load_limit_kN": 0.212,
    "max_rpm": 40000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 40000,
    "weight_g": 3.1,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 5/10 TN belongs to the machined-ring needle roller family: an outer ring turned and ground to 10 mm with two retaining flanges, a roller-and-cage set inside, and envelope 5×10×10 mm on a hardened 5 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 5 mm under-roller diameter and the 10 mm width, with the 10 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 2.29/2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the NK 5/10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 2.29/2 kN ratings are SKF catalogue values for this exact execution (NK 5/10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 2.29/2 kN ratings and 3.1 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 5/10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 5 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 5/10 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 5 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 5/10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 5/10 TN have?",
        "a": "A NK 5/10 TN measures 5 mm bore/Fw × 10 mm outside diameter × 10 mm width (0.197 × 0.394 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.29 kN, static C0 2 kN, fatigue limit Pu 0.212 kN, limiting speed 40,000 r/min, reference speed 36,000 r/min, mass about 3.1 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK5-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 5×10×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK5-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK5",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK5-10-TN",
      "NK 5/10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK5-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 5/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 10,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.92,
    "static_load_kN": 2.7,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 40000,
    "reference_speed_rpm": 36000,
    "limiting_speed_rpm": 40000,
    "weight_g": 3.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 5/12 TN: 5 mm Fw, 10 mm outside diameter, 12 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 5 mm Fw and 12 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 3.7 g catalogue mass and 2.5 mm radial section ((10−5)/2) frame a rating of about 0.58 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 10 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the NK 5/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Do not interchange envelope-identical needle families blindly: NK 5/12 TN shares its 5×10×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 36,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 2.92/2.7 kN ratings and 3.7 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 5/12 TN run on an unhardened shaft?",
        "a": "No. In this execution the 5 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 5/12 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 5 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 5/12 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 5 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 5/12 TN?",
        "a": "A NK 5/12 TN measures 5 mm bore/Fw × 10 mm outside diameter × 12 mm width (0.197 × 0.394 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.92 kN, static C0 2.7 kN, fatigue limit Pu 0.29 kN, limiting speed 40,000 r/min, reference speed 36,000 r/min, mass about 3.7 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK5-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK5-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 5×10×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK5",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK5-12-TN",
      "NK 5/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK6-10-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 6/10 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 12,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.55,
    "static_load_kN": 2.36,
    "fatigue_load_limit_kN": 0.25,
    "max_rpm": 38000,
    "reference_speed_rpm": 34000,
    "limiting_speed_rpm": 38000,
    "weight_g": 4.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 6/10 TN: 6 mm Fw, 12 mm outside diameter, 10 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 6 mm Fw and 10 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 2.55/2.36 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the NK 6/10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Hardness is load capacity: in families without an inner ring the 6 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 2.55/2.36 kN ratings are SKF catalogue values for this exact execution (NK 6/10 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 2.55/2.36 kN ratings and 4.7 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 6/10 TN run on an unhardened shaft?",
        "a": "No. In this execution the 6 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 6/10 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 6 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 6/10 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 6 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 6/10 TN?",
        "a": "A NK 6/10 TN measures 6 mm bore/Fw × 12 mm outside diameter × 10 mm width (0.236 × 0.472 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.55 kN, static C0 2.36 kN, fatigue limit Pu 0.25 kN, limiting speed 38,000 r/min, reference speed 34,000 r/min, mass about 4.7 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK6-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 6×12×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK6-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK6",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK6-10-TN",
      "NK 6/10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK6-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 6/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 12,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.3,
    "static_load_kN": 3.2,
    "fatigue_load_limit_kN": 0.345,
    "max_rpm": 38000,
    "reference_speed_rpm": 34000,
    "limiting_speed_rpm": 38000,
    "weight_g": 5.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 6/12 TN is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 6 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: NK gives the series and the numbers the boundary plan — 6 mm Fw for the shaft seat, 12 mm width; the 12 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 5.7 g catalogue mass and 3.0 mm radial section ((12−6)/2) frame a rating of about 0.55 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the NK 6/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 6/12 TN shares its 6×12×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 3.3/3.2 kN ratings and 5.7 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 6/12 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 6 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 6/12 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 6 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 6/12 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 6/12 TN have?",
        "a": "A NK 6/12 TN measures 6 mm bore/Fw × 12 mm outside diameter × 12 mm width (0.236 × 0.472 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.3 kN, static C0 3.2 kN, fatigue limit Pu 0.345 kN, limiting speed 38,000 r/min, reference speed 34,000 r/min, mass about 5.7 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK6-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK6-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 6×12×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK6",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK6-12-TN",
      "NK 6/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK7-10-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 7/10 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 10,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.81,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 6.8999999999999995,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 7/10 TN is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 7 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: NK gives the series and the numbers the boundary plan — 7 mm Fw for the shaft seat, 10 mm width; the 14 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 2.81/2.75 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NK 7/10 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Reference and limiting speeds are different limits: the 32,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 7 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 2.81/2.75 kN ratings and 6.8999999999999995 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 7/10 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 7 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 7/10 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 7 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 7/10 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 7/10 TN have?",
        "a": "A NK 7/10 TN measures 7 mm bore/Fw × 14 mm outside diameter × 10 mm width (0.276 × 0.551 × 0.394 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.81 kN, static C0 2.75 kN, fatigue limit Pu 0.29 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 6.8999999999999995 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK7-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 7×14×10 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK7-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK7-10-TN",
      "NK 7/10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK7-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 7/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.58,
    "static_load_kN": 3.75,
    "fatigue_load_limit_kN": 0.415,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 8.200000000000001,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 7/12 TN in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 7 mm bore seat and 14 mm OD. The NK 7/12 TN code states Fw 7 and width 12 mm directly; because the family has no inner ring, the 7 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 8.200000000000001 g catalogue mass and 3.5 mm radial section ((14−7)/2) frame a rating of about 0.51 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NK 7/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 3.58/3.75 kN ratings and 8.200000000000001 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 7/12 TN run on an unhardened shaft?",
        "a": "No. In this execution the 7 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 7/12 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 7 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 7/12 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 7 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 7/12 TN?",
        "a": "A NK 7/12 TN measures 7 mm bore/Fw × 14 mm outside diameter × 12 mm width (0.276 × 0.551 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.58 kN, static C0 3.75 kN, fatigue limit Pu 0.415 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 8.200000000000001 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK7-10-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK7-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 7×14×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK7-12-TN",
      "NK 7/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK8-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 8/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 15,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.8,
    "static_load_kN": 4.25,
    "fatigue_load_limit_kN": 0.465,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 8.7,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 8/12 TN belongs to the machined-ring needle roller family: an outer ring turned and ground to 15 mm with two retaining flanges, a roller-and-cage set inside, and envelope 8×15×12 mm on a hardened 8 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 8 mm under-roller diameter and the 12 mm width, with the 15 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 8.7 g catalogue mass and 3.5 mm radial section ((15−8)/2) frame a rating of about 0.47 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the NK 8/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 3.8/4.25 kN ratings are SKF catalogue values for this exact execution (NK 8/12 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 3.8/4.25 kN ratings and 8.7 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 8/12 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 8/12 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 8 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 8/12 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 8/12 TN have?",
        "a": "A NK 8/12 TN measures 8 mm bore/Fw × 15 mm outside diameter × 12 mm width (0.315 × 0.591 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.8 kN, static C0 4.25 kN, fatigue limit Pu 0.465 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 8.7 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK8-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 8×15×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK8-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK8-12-TN",
      "NK 8/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK8-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 8/16 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 8,
    "D_mm": 15,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.01,
    "static_load_kN": 5.85,
    "fatigue_load_limit_kN": 0.67,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 8/16 TN: 8 mm Fw, 15 mm outside diameter, 16 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. Reading the designation: NK gives the series and the numbers the boundary plan — 8 mm Fw for the shaft seat, 16 mm width; the 15 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Catalogue mass 12 g at 8×15×16 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 15 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At Fw 8 mm the rolling elements are under two millimetres long — handle the NK 8/16 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 5.01/5.85 kN ratings are SKF catalogue values for this exact execution (NK 8/16 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 5.01/5.85 kN ratings and 12 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 8/16 TN mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 8 mm and width 16 mm, OD 15 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 8/16 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 8 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 8/16 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 8 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 8/16 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK8-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK8-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 8×15×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK8",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK8-16-TN",
      "NK 8/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK9-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 9/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 16,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.4,
    "static_load_kN": 5.2,
    "fatigue_load_limit_kN": 0.57,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 10,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 9/12 TN designates a flanged, machined outer ring filled with needle rollers and a cage for a 9 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 9 mm under-roller diameter and the 12 mm width, with the 16 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 4.4/5.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 16 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 4.4/5.2 kN ratings are SKF catalogue values for this exact execution (NK 9/12 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 4.4/5.2 kN ratings and 10 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 9/12 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 9/12 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 9 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 9/12 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 9/12 TN have?",
        "a": "A NK 9/12 TN measures 9 mm bore/Fw × 16 mm outside diameter × 12 mm width (0.354 × 0.63 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.4 kN, static C0 5.2 kN, fatigue limit Pu 0.57 kN, limiting speed 34,000 r/min, reference speed 30,000 r/min, mass about 10 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK9-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 9×16×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK9-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK9",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK9-12-TN",
      "NK 9/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK9-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 9/16 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 16,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.72,
    "static_load_kN": 7.2,
    "fatigue_load_limit_kN": 0.815,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 13,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 9/16 TN is a ribbed machined-ring needle roller bearing (no inner ring) sized 9×16×16 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 9 mm shaft journal completes the bearing. The NK 9/16 TN code states Fw 9 and width 16 mm directly; because the family has no inner ring, the 9 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Catalogue mass 13 g at 9×16×16 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 16 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 9 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 5.72/7.2 kN ratings are SKF catalogue values for this exact execution (NK 9/16 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 5.72/7.2 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 9/16 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 9 mm and width 16 mm, OD 16 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 9/16 TN run on an unhardened shaft?",
        "a": "No. In this execution the 9 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 9/16 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 9 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 9/16 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 9 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK9-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK9-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 9×16×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK9",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK9-16-TN",
      "NK 9/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK10-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 10/12 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 17,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.57,
    "static_load_kN": 5.7,
    "fatigue_load_limit_kN": 0.63,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 10,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 10/12 TN belongs to the machined-ring needle roller family: an outer ring turned and ground to 17 mm with two retaining flanges, a roller-and-cage set inside, and envelope 10×17×12 mm on a hardened 10 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 10 mm Fw and 12 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 17 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 4.57/5.7 kN ratings and 10 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 10/12 TN?",
        "a": "A NK 10/12 TN measures 10 mm bore/Fw × 17 mm outside diameter × 12 mm width (0.394 × 0.669 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.57 kN, static C0 5.7 kN, fatigue limit Pu 0.63 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 10 g."
      },
      {
        "q": "How is the NK 10/12 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 10 mm and width 12 mm, OD 17 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 10/12 TN run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 10/12 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 10 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK10-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 10×17×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK10-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK10-12-TN",
      "NK 10/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK10-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 10/16 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 17,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.94,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.9,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 13,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 10/16 TN: 10 mm Fw, 17 mm outside diameter, 16 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NK 10/16 TN code states Fw 10 and width 16 mm directly; because the family has no inner ring, the 10 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 13 g catalogue mass and 3.5 mm radial section ((17−10)/2) frame a rating of about 0.59 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 17 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 5.94/8 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 10/16 TN?",
        "a": "A NK 10/16 TN measures 10 mm bore/Fw × 17 mm outside diameter × 16 mm width (0.394 × 0.669 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.94 kN, static C0 8 kN, fatigue limit Pu 0.9 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 13 g."
      },
      {
        "q": "How is the NK 10/16 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 10 mm and width 16 mm, OD 17 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 10/16 TN run on an unhardened shaft?",
        "a": "No. In this execution the 10 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 10/16 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 10 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK10-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK10-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 10×17×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK10-16-TN",
      "NK 10/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK12-12",
    "brand": "SKF",
    "manufacturer_designation": "NK 12/12",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 19,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.71,
    "static_load_kN": 8.15,
    "fatigue_load_limit_kN": 0.965,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 12/12 is a ribbed machined-ring needle roller bearing (no inner ring) sized 12×19×12 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 12 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 12 mm Fw for the shaft seat, 12 mm width; the 19 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 12 g at 12×19×12 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 26,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 6.71/8.15 kN ratings and 12 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 12/12 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 12 mm and width 12 mm, OD 19 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 12/12 need a hardened and ground shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 12/12?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 12/12 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK12-12-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 12×19×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK12-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK12-12",
      "NK 12/12"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK12-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 12/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 19,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 16,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 12/16 belongs to the machined-ring needle roller family: an outer ring turned and ground to 19 mm with two retaining flanges, a roller-and-cage set inside, and envelope 12×19×16 mm on a hardened 12 mm shaft. Reading the designation: NK gives the series and the numbers the boundary plan — 12 mm Fw for the shaft seat, 16 mm width; the 19 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 16 g at 12×19×16 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 9.13/12 kN ratings are SKF catalogue values for this exact execution (NK 12/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 9.13/12 kN ratings and 16 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 12/16 need a hardened and ground shaft?",
        "a": "No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 12/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 12/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 12/16 have?",
        "a": "A NK 12/16 measures 12 mm bore/Fw × 19 mm outside diameter × 16 mm width (0.472 × 0.748 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12 kN, fatigue limit Pu 1.43 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 16 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK12-12-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK12-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK12-16",
      "NK 12/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4900-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4900.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.37,
    "static_load_kN": 8.15,
    "fatigue_load_limit_kN": 0.965,
    "max_rpm": 12000,
    "limiting_speed_rpm": 12000,
    "weight_g": 16,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4900.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 14×22×13 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 14 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 14 mm Fw and 13 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 12,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 14 mm seat. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 14 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 7.37/8.15 kN ratings are SKF catalogue values for this exact execution (RNA 4900.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 7.37/8.15 kN ratings and 16 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4900.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 14 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4900.2RS?",
        "a": "A RNA 4900.2RS measures 14 mm bore/Fw × 22 mm outside diameter × 13 mm width (0.551 × 0.866 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 8.15 kN, fatigue limit Pu 0.965 kN, limiting speed 12,000 r/min, mass about 16 g."
      },
      {
        "q": "How is the RNA 4900.2RS designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 14 mm and width 13 mm, OD 22 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4900.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4900-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4900",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope, but catalogue C/C0 differ between the executions (7.37/8.15 vs 8.8/10.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4900-2RS",
      "RNA 4900.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4900",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4900",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.8,
    "static_load_kN": 10.4,
    "fatigue_load_limit_kN": 1.22,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 17,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4900 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 14 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The RNA 4900 code states Fw 14 and width 13 mm directly; because the family has no inner ring, the 14 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 17 g at 14×22×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 14 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 8.8/10.4 kN ratings are SKF catalogue values for this exact execution (RNA 4900); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 8.8/10.4 kN ratings and 17 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4900?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 14 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4900?",
        "a": "A RNA 4900 measures 14 mm bore/Fw × 22 mm outside diameter × 13 mm width (0.551 × 0.866 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.8 kN, static C0 10.4 kN, fatigue limit Pu 1.22 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 17 g."
      },
      {
        "q": "How is the RNA 4900 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 14 mm and width 13 mm, OD 22 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4900 run on an unhardened shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4900-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4900-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 14×22×13 mm envelope, but catalogue C/C0 differ between the executions (8.8/10.4 vs 7.37/8.15 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4900",
      "RNA 4900"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK14-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 14/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.2,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 1.5,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 21,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 14/16 designates a flanged, machined outer ring filled with needle rollers and a cage for a 14 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The NK 14/16 code states Fw 14 and width 16 mm directly; because the family has no inner ring, the 14 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 10.2/12.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 22 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 14/16 shares its 14×22×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 10.2/12.5 kN ratings and 21 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 14/16 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 14 mm and width 16 mm, OD 22 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 14/16 run on an unhardened shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 14/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 14 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 14/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 14 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK14-16-D-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 14×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK14-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 14×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK14-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK14",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK14-16",
      "NK 14/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK14-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 14/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 14,
    "D_mm": 22,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 16.6,
    "fatigue_load_limit_kN": 2,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 26,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 14/20 is a ribbed machined-ring needle roller bearing (no inner ring) sized 14×22×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 14 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 14 mm Fw for the shaft seat, 20 mm width; the 22 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 12.8/16.6 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 14 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 14 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 12.8/16.6 kN ratings and 26 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 14/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 14/20 have?",
        "a": "A NK 14/20 measures 14 mm bore/Fw × 22 mm outside diameter × 20 mm width (0.551 × 0.866 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 16.6 kN, fatigue limit Pu 2 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 26 g."
      },
      {
        "q": "What does NK 14/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 14 mm and width 20 mm, OD 22 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 14/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 14 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK14-16-D-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK14-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK14-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 14×22×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK14",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK14-20",
      "NK 14/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK15-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 15/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 23,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11,
    "static_load_kN": 14,
    "fatigue_load_limit_kN": 1.66,
    "max_rpm": 26000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 26000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 15/16: 15 mm Fw, 23 mm outside diameter, 16 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NK 15/16 code states Fw 15 and width 16 mm directly; because the family has no inner ring, the 15 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 11/14 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 23 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 11/14 kN ratings are SKF catalogue values for this exact execution (NK 15/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 11/14 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 15/16 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 15 mm and width 16 mm, OD 23 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 15/16 run on an unhardened shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 15/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 15 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 15/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK15-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×23×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK15-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK15-16",
      "NK 15/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK15-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 15/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 23,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.8,
    "static_load_kN": 18.3,
    "fatigue_load_limit_kN": 2.2,
    "max_rpm": 26000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 26000,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 15/20 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 15 mm bore seat and 23 mm OD. Reading the designation: NK gives the series and the numbers the boundary plan — 15 mm Fw for the shaft seat, 20 mm width; the 23 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 13.8/18.3 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 23 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 13.8/18.3 kN ratings are SKF catalogue values for this exact execution (NK 15/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 13.8/18.3 kN ratings and 27 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 15/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 15/20 have?",
        "a": "A NK 15/20 measures 15 mm bore/Fw × 23 mm outside diameter × 20 mm width (0.591 × 0.906 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.8 kN, static C0 18.3 kN, fatigue limit Pu 2.2 kN, limiting speed 26,000 r/min, reference speed 24,000 r/min, mass about 27 g."
      },
      {
        "q": "What does NK 15/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 15 mm and width 20 mm, OD 23 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 15/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 15 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK15-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK15-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×23×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK15-20",
      "NK 15/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4901-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4901.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.09,
    "static_load_kN": 9.65,
    "fatigue_load_limit_kN": 1.14,
    "max_rpm": 11000,
    "limiting_speed_rpm": 11000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4901.2RS belongs to the machined-ring needle roller family: an outer ring turned and ground to 24 mm with two retaining flanges, a roller-and-cage set inside, and envelope 16×24×13 mm on a hardened 16 mm shaft. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 16 mm under-roller diameter and the 13 mm width, with the 24 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 18 g at 16×24×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 24 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 16 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 8.09/9.65 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4901.2RS have?",
        "a": "A RNA 4901.2RS measures 16 mm bore/Fw × 24 mm outside diameter × 13 mm width (0.63 × 0.945 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.09 kN, static C0 9.65 kN, fatigue limit Pu 1.14 kN, limiting speed 11,000 r/min, mass about 18 g."
      },
      {
        "q": "What does RNA 4901.2RS mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 16 mm and width 13 mm, OD 24 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4901.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4901.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 16 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4901-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope, but catalogue C/C0 differ between the executions (8.09/9.65 vs 9.9/12.2 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4901-2RS",
      "RNA 4901.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4901",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4901",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.9,
    "static_load_kN": 12.2,
    "fatigue_load_limit_kN": 1.46,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 17,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4901: 16 mm Fw, 24 mm outside diameter, 13 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 16 mm under-roller diameter and the 13 mm width, with the 24 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 17 g at 16×24×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 16 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 9.9/12.2 kN ratings and 17 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 4901?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 16 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4901 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4901 have?",
        "a": "A RNA 4901 measures 16 mm bore/Fw × 24 mm outside diameter × 13 mm width (0.63 × 0.945 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.9 kN, static C0 12.2 kN, fatigue limit Pu 1.46 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 17 g."
      },
      {
        "q": "What does RNA 4901 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 16 mm and width 13 mm, OD 24 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4901-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4901-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 16×24×13 mm envelope, but catalogue C/C0 differ between the executions (9.9/12.2 vs 8.09/9.65 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4901",
      "RNA 4901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK16-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 16/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.7,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.8,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 16/16 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 16 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 16 mm under-roller diameter and the 16 mm width, with the 24 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. The 22 g catalogue mass and 4.0 mm radial section ((24−16)/2) frame a rating of about 0.73 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 11.7/15.3 kN ratings are SKF catalogue values for this exact execution (NK 16/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 11.7/15.3 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 16/16 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 16 mm and width 16 mm, OD 24 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 16/16 need a hardened and ground shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 16/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 16 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 16/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK16-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 16×24×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK16-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK16-16",
      "NK 16/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK16-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 16/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.5,
    "static_load_kN": 20,
    "fatigue_load_limit_kN": 2.4,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 28,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 16/20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 24 mm with two retaining flanges, a roller-and-cage set inside, and envelope 16×24×20 mm on a hardened 16 mm shaft. The NK 16/20 code states Fw 16 and width 20 mm directly; because the family has no inner ring, the 16 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. The 28 g catalogue mass and 4.0 mm radial section ((24−16)/2) frame a rating of about 0.91 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 24 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 14.5/20 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 16/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 16 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 16/20?",
        "a": "A NK 16/20 measures 16 mm bore/Fw × 24 mm outside diameter × 20 mm width (0.63 × 0.945 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.5 kN, static C0 20 kN, fatigue limit Pu 2.4 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 28 g."
      },
      {
        "q": "How is the NK 16/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 16 mm and width 20 mm, OD 24 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 16/20 run on an unhardened shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK16-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK16-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 16×24×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK16",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK16-20",
      "NK 16/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6901",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6901",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 16,
    "D_mm": 24,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.1,
    "static_load_kN": 23.2,
    "fatigue_load_limit_kN": 2.75,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6901 is a ribbed machined-ring needle roller bearing (no inner ring) sized 16×24×22 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 16 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 16 mm Fw and 22 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 16.1/23.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 16 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 16.1/23.2 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 6901 run on an unhardened shaft?",
        "a": "No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6901 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 16 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6901?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 16 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6901?",
        "a": "A RNA 6901 measures 16 mm bore/Fw × 24 mm outside diameter × 22 mm width (0.63 × 0.945 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.1 kN, static C0 23.2 kN, fatigue limit Pu 2.75 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 31 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6901-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 16×24×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6901",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6901",
      "RNA 6901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK17-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 17/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 25,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.1,
    "static_load_kN": 16.6,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 24,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 17/16 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 17 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 17 mm under-roller diameter and the 16 mm width, with the 25 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 24 g catalogue mass and 4.0 mm radial section ((25−17)/2) frame a rating of about 0.71 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 25 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 17/16 shares its 17×25×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 12.1/16.6 kN ratings and 24 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 17/16 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 17 mm and width 16 mm, OD 25 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 17/16 need a hardened and ground shaft?",
        "a": "No. In this execution the 17 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 17/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 17 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 17/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK17-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×25×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK17-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK17-16",
      "NK 17/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK17-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 17/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 25,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 22,
    "fatigue_load_limit_kN": 2.65,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 17/20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 25 mm with two retaining flanges, a roller-and-cage set inside, and envelope 17×25×20 mm on a hardened 17 mm shaft. The NK 17/20 code states Fw 17 and width 20 mm directly; because the family has no inner ring, the 17 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 30 g catalogue mass and 4.0 mm radial section ((25−17)/2) frame a rating of about 0.89 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 25 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 17/20 shares its 17×25×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 15.1/22 kN ratings and 30 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 17/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 17/20?",
        "a": "A NK 17/20 measures 17 mm bore/Fw × 25 mm outside diameter × 20 mm width (0.669 × 0.984 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 22 kN, fatigue limit Pu 2.65 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 30 g."
      },
      {
        "q": "How is the NK 17/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 17 mm and width 20 mm, OD 25 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 17/20 run on an unhardened shaft?",
        "a": "No. In this execution the 17 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK17-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK17-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×25×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK17-20",
      "NK 17/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK18-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 18/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 26,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 17.6,
    "fatigue_load_limit_kN": 2.12,
    "max_rpm": 24000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 24000,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 18/16 is a ribbed machined-ring needle roller bearing (no inner ring) sized 18×26×16 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 18 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 18 mm Fw and 16 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 22,000 r/min thermal reference and 24,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 18 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 18/16 shares its 18×26×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 12.8/17.6 kN ratings and 25 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 18/16 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 18 mm and width 16 mm, OD 26 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 18/16 run on an unhardened shaft?",
        "a": "No. In this execution the 18 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 18/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 18 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 18/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 18 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK18-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK18-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK18-16",
      "NK 18/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK18-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 18/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 26,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.1,
    "static_load_kN": 23.6,
    "fatigue_load_limit_kN": 2.85,
    "max_rpm": 24000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 24000,
    "weight_g": 31,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 18/20 designates a flanged, machined outer ring filled with needle rollers and a cage for a 18 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 18 mm under-roller diameter and the 20 mm width, with the 26 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 22,000 r/min thermal reference and 24,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 18 mm seat. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 26 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 18 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 16.1/23.6 kN ratings and 31 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 18/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 18/20 have?",
        "a": "A NK 18/20 measures 18 mm bore/Fw × 26 mm outside diameter × 20 mm width (0.709 × 1.024 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.1 kN, static C0 23.6 kN, fatigue limit Pu 2.85 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 31 g."
      },
      {
        "q": "What does NK 18/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 18 mm and width 20 mm, OD 26 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 18/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 18 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK18-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK18-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 18×26×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK18-20",
      "NK 18/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK19-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 19/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 19,
    "D_mm": 27,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.4,
    "static_load_kN": 19,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 24000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 24000,
    "weight_g": 26,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 19/16 is a ribbed machined-ring needle roller bearing (no inner ring) sized 19×27×16 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 19 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 19 mm Fw for the shaft seat, 16 mm width; the 27 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Selection arithmetic: C 13.4 kN against C0 19 kN gives a C0/C ratio of 1.42, and the 2.28 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 19 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 27 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 20,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 19 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 13.4/19 kN ratings and 26 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 19/16 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 19 mm and width 16 mm, OD 27 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 19/16 need a hardened and ground shaft?",
        "a": "No. In this execution the 19 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 19/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 19 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 19/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK19-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK19-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK19",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK19-16",
      "NK 19/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK19-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 19/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 19,
    "D_mm": 27,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.5,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 3.05,
    "max_rpm": 24000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 24000,
    "weight_g": 32,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 19/20 designates a flanged, machined outer ring filled with needle rollers and a cage for a 19 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 19 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Selection arithmetic: C 16.5 kN against C0 25.5 kN gives a C0/C ratio of 1.55, and the 3.05 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 19 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 27 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 19 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 16.5/25.5 kN ratings are SKF catalogue values for this exact execution (NK 19/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 16.5/25.5 kN ratings and 32 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 19/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 19 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 19/20?",
        "a": "A NK 19/20 measures 19 mm bore/Fw × 27 mm outside diameter × 20 mm width (0.748 × 1.063 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.5 kN, static C0 25.5 kN, fatigue limit Pu 3.05 kN, limiting speed 24,000 r/min, reference speed 20,000 r/min, mass about 32 g."
      },
      {
        "q": "How is the NK 19/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 19 mm and width 20 mm, OD 27 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 19/20 run on an unhardened shaft?",
        "a": "No. In this execution the 19 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK19-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK19-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 19×27×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK19",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK19-20",
      "NK 19/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4902-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4902.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 9500,
    "limiting_speed_rpm": 9500,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4902.2RS: 20 mm Fw, 28 mm outside diameter, 13 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 20 mm under-roller diameter and the 13 mm width, with the 28 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 9,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 20 mm seat. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 28 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4902.2RS shares its 20×28×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 9.13/12 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4902.2RS have?",
        "a": "A RNA 4902.2RS measures 20 mm bore/Fw × 28 mm outside diameter × 13 mm width (0.787 × 1.102 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12 kN, fatigue limit Pu 1.43 kN, limiting speed 9,500 r/min, mass about 22 g."
      },
      {
        "q": "What does RNA 4902.2RS mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 20 mm and width 13 mm, OD 28 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4902.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4902.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4902-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4902",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope, but catalogue C/C0 differ between the executions (9.13/12 vs 11.2/15.3 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4902-2RS",
      "RNA 4902.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4902",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4902",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.2,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.83,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4902 designates a flanged, machined outer ring filled with needle rollers and a cage for a 20 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 20 mm Fw and 13 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 22 g at 20×28×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: RNA 4902 shares its 20×28×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 11.2/15.3 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4902 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4902 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4902?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4902?",
        "a": "A RNA 4902 measures 20 mm bore/Fw × 28 mm outside diameter × 13 mm width (0.787 × 1.102 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.2 kN, static C0 15.3 kN, fatigue limit Pu 1.83 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 22 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4902-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4902-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×28×13 mm envelope, but catalogue C/C0 differ between the executions (11.2/15.3 vs 9.13/12 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4902",
      "RNA 4902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK20-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 20/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 19.3,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 27,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 20/16 designates a flanged, machined outer ring filled with needle rollers and a cage for a 20 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 20 mm under-roller diameter and the 16 mm width, with the 28 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 20/16 shares its 20×28×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 13.2/19.3 kN ratings and 27 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NK 20/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 20/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 20/16 have?",
        "a": "A NK 20/16 measures 20 mm bore/Fw × 28 mm outside diameter × 16 mm width (0.787 × 1.102 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.2 kN, static C0 19.3 kN, fatigue limit Pu 2.28 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 27 g."
      },
      {
        "q": "What does NK 20/16 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 20 mm and width 16 mm, OD 28 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK20-16-D-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK20-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK20-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK20-16",
      "NK 20/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK20-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 20/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.5,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 3.05,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 20/20 is a ribbed machined-ring needle roller bearing (no inner ring) sized 20×28×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 20 mm shaft journal completes the bearing. The NK 20/20 code states Fw 20 and width 20 mm directly; because the family has no inner ring, the 20 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 20/20 shares its 20×28×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 16.5/25.5 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 20/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 20 mm and width 20 mm, OD 28 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 20/20 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 20/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 20/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK20-16-D-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK20-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK20-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK20-20",
      "NK 20/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6902",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6902",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 28,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.2,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6902 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 20 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: RNA gives the series and the numbers the boundary plan — 20 mm Fw for the shaft seat, 23 mm width; the 28 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 17.2/27 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 17.2/27 kN ratings are SKF catalogue values for this exact execution (RNA 6902); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 17.2/27 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 6902 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 20 mm and width 23 mm, OD 28 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6902 need a hardened and ground shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6902?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 6902 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6902-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×28×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6902",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6902",
      "RNA 6902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS20",
    "brand": "SKF",
    "manufacturer_designation": "NKS 20",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 3.25,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 32 mm with two retaining flanges, a roller-and-cage set inside, and envelope 20×32×20 mm on a hardened 20 mm shaft. The NKS 20 code states Fw 20 and width 20 mm directly; because the family has no inner ring, the 20 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 32 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKS 20 shares its 20×32×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 18,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 23.3/27 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKS 20 run on an unhardened shaft?",
        "a": "No. In this execution the 20 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NKS 20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 20?",
        "a": "A NKS 20 measures 20 mm bore/Fw × 32 mm outside diameter × 20 mm width (0.787 × 1.26 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 27 kN, fatigue limit Pu 3.25 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 49 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI20-20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope, but catalogue C/C0 differ between the executions (23.3/27 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS20",
      "NKS 20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK21-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 21/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 21,
    "D_mm": 29,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.8,
    "static_load_kN": 20.4,
    "fatigue_load_limit_kN": 2.45,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 28,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 21/16 designates a flanged, machined outer ring filled with needle rollers and a cage for a 21 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 21 mm under-roller diameter and the 16 mm width, with the 29 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 29 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 21 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 29 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 21 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 13.8/20.4 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NK 21/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 21 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 21/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 21/16 have?",
        "a": "A NK 21/16 measures 21 mm bore/Fw × 29 mm outside diameter × 16 mm width (0.827 × 1.142 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.8 kN, static C0 20.4 kN, fatigue limit Pu 2.45 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 28 g."
      },
      {
        "q": "What does NK 21/16 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 21 mm and width 16 mm, OD 29 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK21-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK21-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK21",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK21-16",
      "NK 21/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK21-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 21/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 21,
    "D_mm": 29,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.2,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 35,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 21/20 is a ribbed machined-ring needle roller bearing (no inner ring) sized 21×29×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 21 mm shaft journal completes the bearing. The NK 21/20 code states Fw 21 and width 20 mm directly; because the family has no inner ring, the 21 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 21 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 29 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 21 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 17.2/27 kN ratings are SKF catalogue values for this exact execution (NK 21/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 17.2/27 kN ratings and 35 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 21/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 21 mm and width 20 mm, OD 29 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 21/20 run on an unhardened shaft?",
        "a": "No. In this execution the 21 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 21/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 21 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 21/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 21 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK21-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK21-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 21×29×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK21",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK21-20",
      "NK 21/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4903-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4903.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.52,
    "static_load_kN": 12.9,
    "fatigue_load_limit_kN": 1.53,
    "max_rpm": 9000,
    "limiting_speed_rpm": 9000,
    "weight_g": 23,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4903.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 22×30×13 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 22 mm shaft journal completes the bearing. The RNA 4903.2RS code states Fw 22 and width 13 mm directly; because the family has no inner ring, the 22 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Catalogue mass 23 g at 22×30×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 9.52/12.9 kN ratings and 23 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4903.2RS designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 13 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4903.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4903.2RS be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4903.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4903-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4903",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope, but catalogue C/C0 differ between the executions (9.52/12.9 vs 11.4/16.3 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4903-2RS",
      "RNA 4903.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4903",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4903",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 16.3,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4903 belongs to the machined-ring needle roller family: an outer ring turned and ground to 30 mm with two retaining flanges, a roller-and-cage set inside, and envelope 22×30×13 mm on a hardened 22 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 22 mm Fw for the shaft seat, 13 mm width; the 30 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 22 g at 22×30×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4903 shares its 22×30×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 11.4/16.3 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4903 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 13 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4903 need a hardened and ground shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4903?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4903 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4903-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4903-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 22×30×13 mm envelope, but catalogue C/C0 differ between the executions (11.4/16.3 vs 9.52/12.9 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4903",
      "RNA 4903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK22-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 22/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.2,
    "static_load_kN": 21.6,
    "fatigue_load_limit_kN": 2.6,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 30,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 22/16: 22 mm Fw, 30 mm outside diameter, 16 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 22 mm Fw and 16 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 14.2/21.6 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 14.2/21.6 kN ratings are SKF catalogue values for this exact execution (NK 22/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 14.2/21.6 kN ratings and 30 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NK 22/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 22/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 22/16?",
        "a": "A NK 22/16 measures 22 mm bore/Fw × 30 mm outside diameter × 16 mm width (0.866 × 1.181 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.2 kN, static C0 21.6 kN, fatigue limit Pu 2.6 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 30 g."
      },
      {
        "q": "How is the NK 22/16 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 16 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK22-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×30×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK22-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK22-16",
      "NK 22/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK22-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 22/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.9,
    "static_load_kN": 29,
    "fatigue_load_limit_kN": 3.55,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 22/20 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 22 mm bore seat and 30 mm OD. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 22 mm under-roller diameter and the 20 mm width, with the 30 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 17.9/29 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 17.9/29 kN ratings are SKF catalogue values for this exact execution (NK 22/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 17.9/29 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 22/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 20 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 22/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 22/20?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 22/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK22-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK22-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×30×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK22-20",
      "NK 22/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6903",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6903",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 30,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 18.7,
    "static_load_kN": 30.5,
    "fatigue_load_limit_kN": 3.75,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 6903: 22 mm Fw, 30 mm outside diameter, 23 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The RNA 6903 code states Fw 22 and width 23 mm directly; because the family has no inner ring, the 22 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 18.7/30.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 18.7/30.5 kN ratings are SKF catalogue values for this exact execution (RNA 6903); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 18.7/30.5 kN ratings and 42 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 6903?",
        "a": "A RNA 6903 measures 22 mm bore/Fw × 30 mm outside diameter × 23 mm width (0.866 × 1.181 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 18.7 kN, static C0 30.5 kN, fatigue limit Pu 3.75 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 42 g."
      },
      {
        "q": "How is the RNA 6903 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 22 mm and width 23 mm, OD 30 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6903 run on an unhardened shaft?",
        "a": "No. In this execution the 22 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6903 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6903-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×30×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6903",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6903",
      "RNA 6903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK24-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 24/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.4,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.9,
    "max_rpm": 19000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 19000,
    "weight_g": 32,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 24/16 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 24 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: NK gives the series and the numbers the boundary plan — 24 mm Fw for the shaft seat, 16 mm width; the 32 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 16,000 r/min thermal reference and 19,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 24 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 24 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 24/16 shares its 24×32×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 15.4/24.5 kN ratings and 32 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 24/16 need a hardened and ground shaft?",
        "a": "No. In this execution the 24 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 24/16?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 24 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 24/16 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 24/16 have?",
        "a": "A NK 24/16 measures 24 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.945 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.4 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 19,000 r/min, reference speed 16,000 r/min, mass about 32 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK24-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK24-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK24",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK24-16",
      "NK 24/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK24-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 24/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 32.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 19000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 19000,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 24/20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 32 mm with two retaining flanges, a roller-and-cage set inside, and envelope 24×32×20 mm on a hardened 24 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 24 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 16,000 r/min thermal reference and 19,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 24 mm seat. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 32 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 24 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 24/20 shares its 24×32×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 16,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 19/32.5 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 24/20?",
        "a": "A NK 24/20 measures 24 mm bore/Fw × 32 mm outside diameter × 20 mm width (0.945 × 1.26 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19 kN, static C0 32.5 kN, fatigue limit Pu 4 kN, limiting speed 19,000 r/min, reference speed 16,000 r/min, mass about 40 g."
      },
      {
        "q": "How is the NK 24/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 24 mm and width 20 mm, OD 32 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 24/20 run on an unhardened shaft?",
        "a": "No. In this execution the 24 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 24/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 24 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK24-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK24-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 24×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK24",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK24-20",
      "NK 24/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS24",
    "brand": "SKF",
    "manufacturer_designation": "NKS 24",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 24,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 26,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 66,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's wide-section machined-ring needle roller bearings without inner ring include NKS 24: 24 mm Fw, 37 mm outside diameter, 20 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NKS 24 code states Fw 24 and width 20 mm directly; because the family has no inner ring, the 24 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 37 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 24 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 24 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 26/33.5 kN ratings are SKF catalogue values for this exact execution (NKS 24); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 26/33.5 kN ratings and 66 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKS 24 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 24 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 24?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 24 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 24?",
        "a": "A NKS 24 measures 24 mm bore/Fw × 37 mm outside diameter × 20 mm width (0.945 × 1.457 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26 kN, static C0 33.5 kN, fatigue limit Pu 4 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 66 g."
      },
      {
        "q": "How is the NKS 24 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 24 mm and width 20 mm, OD 37 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS24-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 24×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS24",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS24",
      "NKS 24"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK25-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 25/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 33,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.9,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 33,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 25/16 is a ribbed machined-ring needle roller bearing (no inner ring) sized 25×33×16 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 25 mm shaft journal completes the bearing. The NK 25/16 code states Fw 25 and width 16 mm directly; because the family has no inner ring, the 25 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Selection arithmetic: C 15.1 kN against C0 24.5 kN gives a C0/C ratio of 1.62, and the 2.9 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 33 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 33 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NK 25/16 shares its 25×33×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 16,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 15.1/24.5 kN ratings and 33 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 25/16 run on an unhardened shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 25/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 25/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 25/16?",
        "a": "A NK 25/16 measures 25 mm bore/Fw × 33 mm outside diameter × 16 mm width (0.984 × 1.299 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 18,000 r/min, reference speed 16,000 r/min, mass about 33 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK25-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×33×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK25-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK25-16",
      "NK 25/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK25-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 25/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 33,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 32.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 25/20 designates a flanged, machined outer ring filled with needle rollers and a cage for a 25 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. Reading the designation: NK gives the series and the numbers the boundary plan — 25 mm Fw for the shaft seat, 20 mm width; the 33 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Selection arithmetic: C 19 kN against C0 32.5 kN gives a C0/C ratio of 1.71, and the 4 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 33 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 16,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 19/32.5 kN ratings and 42 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 25/20 have?",
        "a": "A NK 25/20 measures 25 mm bore/Fw × 33 mm outside diameter × 20 mm width (0.984 × 1.299 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19 kN, static C0 32.5 kN, fatigue limit Pu 4 kN, limiting speed 18,000 r/min, reference speed 16,000 r/min, mass about 42 g."
      },
      {
        "q": "What does NK 25/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 25 mm and width 20 mm, OD 33 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 25/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 25/20?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK25-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK25-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×33×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK25-20",
      "NK 25/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4904-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4904.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.4,
    "static_load_kN": 22.4,
    "fatigue_load_limit_kN": 2.65,
    "max_rpm": 7500,
    "limiting_speed_rpm": 7500,
    "weight_g": 56,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4904.2RS belongs to the machined-ring needle roller family: an outer ring turned and ground to 37 mm with two retaining flanges, a roller-and-cage set inside, and envelope 25×37×17 mm on a hardened 25 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 25 mm Fw for the shaft seat, 17 mm width; the 37 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 19.4/22.4 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 19.4/22.4 kN ratings are SKF catalogue values for this exact execution (RNA 4904.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 19.4/22.4 kN ratings and 56 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 4904.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4904.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4904.2RS sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4904.2RS have?",
        "a": "A RNA 4904.2RS measures 25 mm bore/Fw × 37 mm outside diameter × 17 mm width (0.984 × 1.457 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 22.4 kN, fatigue limit Pu 2.65 kN, limiting speed 7,500 r/min, mass about 56 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4904-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×37×17 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4904",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×17 mm envelope, but catalogue C/C0 differ between the executions (19.4/22.4 vs 21.6/28 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4904-2RS",
      "RNA 4904.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4904",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4904",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 4904 in the dimension series 49 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 25 mm bore seat and 37 mm OD. The RNA 4904 code states Fw 25 and width 17 mm directly; because the family has no inner ring, the 25 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 52 g at 25×37×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 21.6/28 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 4904?",
        "a": "A RNA 4904 measures 25 mm bore/Fw × 37 mm outside diameter × 17 mm width (0.984 × 1.457 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 28 kN, fatigue limit Pu 3.35 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 52 g."
      },
      {
        "q": "How is the RNA 4904 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 25 mm and width 17 mm, OD 37 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4904 run on an unhardened shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4904 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4904-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA4904-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×17 mm envelope, but catalogue C/C0 differ between the executions (21.6/28 vs 19.4/22.4 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4904",
      "RNA 4904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6904",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6904",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.2,
    "static_load_kN": 53,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 6904 designates a flanged, machined outer ring filled with needle rollers and a cage for a 25 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 25 mm under-roller diameter and the 30 mm width, with the 37 mm outside diameter set by the dimension series 69 needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 35.2/53 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 35.2/53 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 6904 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 6904 have?",
        "a": "A RNA 6904 measures 25 mm bore/Fw × 37 mm outside diameter × 30 mm width (0.984 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.2 kN, static C0 53 kN, fatigue limit Pu 6.55 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 100 g."
      },
      {
        "q": "What does RNA 6904 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 25 mm and width 30 mm, OD 37 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6904 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6904-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NX25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 15.1/24.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NX25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 15.1/24.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (35.2/53 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6904",
      "RNA 6904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS25",
    "brand": "SKF",
    "manufacturer_designation": "NKS 25",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 36,
    "fatigue_load_limit_kN": 4.4,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 68,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKS 25 designates a flanged, machined outer ring filled with needle rollers and a cage for a 25 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 25 mm under-roller diameter and the 20 mm width, with the 38 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 38 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 38 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 27.5/36 kN ratings and 68 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKS 25 need a hardened and ground shaft?",
        "a": "No. In this execution the 25 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NKS 25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 25 have?",
        "a": "A NKS 25 measures 25 mm bore/Fw × 38 mm outside diameter × 20 mm width (0.984 × 1.496 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27.5 kN, static C0 36 kN, fatigue limit Pu 4.4 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 68 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI25-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope, but catalogue C/C0 differ between the executions (27.5/36 vs 24.6/42.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS25",
      "NKS 25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK26-16",
    "brand": "SKF",
    "manufacturer_designation": "NK 26/16",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 26,
    "D_mm": 34,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.7,
    "static_load_kN": 26,
    "fatigue_load_limit_kN": 3.1,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 26/16 is a ribbed machined-ring needle roller bearing (no inner ring) sized 26×34×16 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 26 mm shaft journal completes the bearing. The NK 26/16 code states Fw 26 and width 16 mm directly; because the family has no inner ring, the 26 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Selection arithmetic: C 15.7 kN against C0 26 kN gives a C0/C ratio of 1.66, and the 3.1 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 26 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 26 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 26 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 15.7/26 kN ratings are SKF catalogue values for this exact execution (NK 26/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 15.7/26 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 26/16 run on an unhardened shaft?",
        "a": "No. In this execution the 26 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 26/16 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 26 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 26/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 26 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 26/16?",
        "a": "A NK 26/16 measures 26 mm bore/Fw × 34 mm outside diameter × 16 mm width (1.024 × 1.339 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.7 kN, static C0 26 kN, fatigue limit Pu 3.1 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 34 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK26-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 26×34×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK26-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK26-16",
      "NK 26/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK26-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 26/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 26,
    "D_mm": 34,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.4,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.25,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 26/20 designates a flanged, machined outer ring filled with needle rollers and a cage for a 26 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. Reading the designation: NK gives the series and the numbers the boundary plan — 26 mm Fw for the shaft seat, 20 mm width; the 34 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Selection arithmetic: C 19.4 kN against C0 34.5 kN gives a C0/C ratio of 1.78, and the 4.25 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 34 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 26 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 26 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 19.4/34.5 kN ratings are SKF catalogue values for this exact execution (NK 26/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 19.4/34.5 kN ratings and 42 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 26/20 have?",
        "a": "A NK 26/20 measures 26 mm bore/Fw × 34 mm outside diameter × 20 mm width (1.024 × 1.339 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 34.5 kN, fatigue limit Pu 4.25 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 42 g."
      },
      {
        "q": "What does NK 26/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 26 mm and width 20 mm, OD 34 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 26/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 26 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 26/20?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 26 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK26-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK26-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 26×34×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK26",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK26-20",
      "NK 26/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK28-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 28/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 4.55,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 28/20 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 28 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The NK 28/20 code states Fw 28 and width 20 mm directly; because the family has no inner ring, the 28 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 52 g at 28×37×20 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NK 28/20 shares its 28×37×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 22/36.5 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 28/20?",
        "a": "A NK 28/20 measures 28 mm bore/Fw × 37 mm outside diameter × 20 mm width (1.102 × 1.457 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22 kN, static C0 36.5 kN, fatigue limit Pu 4.55 kN, limiting speed 16,000 r/min, reference speed 14,000 r/min, mass about 52 g."
      },
      {
        "q": "How is the NK 28/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 28 mm and width 20 mm, OD 37 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 28/20 run on an unhardened shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 28/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 28 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK28-20-D-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK28-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK28-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK28",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK28-20",
      "NK 28/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK28-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 28/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 82,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 28/30 belongs to the machined-ring needle roller family: an outer ring turned and ground to 37 mm with two retaining flanges, a roller-and-cage set inside, and envelope 28×37×30 mm on a hardened 28 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 28 mm under-roller diameter and the 30 mm width, with the 37 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 82 g at 28×37×30 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 37 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 28 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 31.9/60 kN ratings and 82 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 28/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 28/30?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 28 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 28/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 28/30 have?",
        "a": "A NK 28/30 measures 28 mm bore/Fw × 37 mm outside diameter × 30 mm width (1.102 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 60 kN, fatigue limit Pu 7.5 kN, limiting speed 16,000 r/min, reference speed 14,000 r/min, mass about 82 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK28-20-D-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK28-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK28-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK28",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK28-30",
      "NK 28/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-22",
    "brand": "SKF",
    "manufacturer_designation": "RNA 49/22",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 39,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.9,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 49/22 is a ribbed machined-ring needle roller bearing (no inner ring) sized 28×39×17 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 28 mm shaft journal completes the bearing. Reading the designation: RNA gives the series and the numbers the boundary plan — 28 mm Fw for the shaft seat, 17 mm width; the 39 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. The 50 g catalogue mass and 5.5 mm radial section ((39−28)/2) frame a rating of about 0.83 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 39 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 49/22 shares its 28×39×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 23.3/32 kN ratings and 50 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 49/22 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 49/22 have?",
        "a": "A RNA 49/22 measures 28 mm bore/Fw × 39 mm outside diameter × 17 mm width (1.102 × 1.535 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.9 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 50 g."
      },
      {
        "q": "What does RNA 49/22 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 28 mm and width 17 mm, OD 39 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 49/22 need a hardened and ground shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×39×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA49-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-32-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-22",
      "RNA 49/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-22",
    "brand": "SKF",
    "manufacturer_designation": "RNA 69/22",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 39,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.2,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 98,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 69/22: 28 mm Fw, 39 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 28 mm Fw and 30 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 36.9/57 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 28 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 36.9/57 kN ratings are SKF catalogue values for this exact execution (RNA 69/22); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 36.9/57 kN ratings and 98 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 69/22 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 28 mm and width 30 mm, OD 39 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 69/22 run on an unhardened shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 69/22 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 28 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 69/22?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 28 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×39×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA69-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-22",
      "RNA 69/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS28",
    "brand": "SKF",
    "manufacturer_designation": "NKS 28",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 28.6,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.75,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 84,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 28 is a ribbed machined-ring needle roller bearing (no inner ring) sized 28×42×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 28 mm shaft journal completes the bearing. The NKS 28 code states Fw 28 and width 20 mm directly; because the family has no inner ring, the 28 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 42 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 28.6/39 kN ratings and 84 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKS 28?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 28 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 28?",
        "a": "A NKS 28 measures 28 mm bore/Fw × 42 mm outside diameter × 20 mm width (1.102 × 1.654 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 28.6 kN, static C0 39 kN, fatigue limit Pu 4.75 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 84 g."
      },
      {
        "q": "How is the NKS 28 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 28 mm and width 20 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NKS 28 run on an unhardened shaft?",
        "a": "No. In this execution the 28 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS28-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI28-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope, but catalogue C/C0 differ between the executions (28.6/39 vs 26.4/48 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS28",
      "NKS 28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK29-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 29/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 29,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 42.5,
    "fatigue_load_limit_kN": 5.2,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 29/20 TN designates a flanged, machined outer ring filled with needle rollers and a cage for a 29 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 29 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 24.6/42.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 29 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 29 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 24.6/42.5 kN ratings and 50 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 29/20 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 29 mm and width 20 mm, OD 38 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 29/20 TN run on an unhardened shaft?",
        "a": "No. In this execution the 29 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 29/20 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 29 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 29/20 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 29 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK29-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 29×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK29-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK29",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK29-20-TN",
      "NK 29/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK29-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 29/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 29,
    "D_mm": 38,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 84,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 29/30 belongs to the machined-ring needle roller family: an outer ring turned and ground to 38 mm with two retaining flanges, a roller-and-cage set inside, and envelope 29×38×30 mm on a hardened 29 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 29 mm Fw and 30 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 31.9/60 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 38 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 29 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 29 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 29 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 31.9/60 kN ratings are SKF catalogue values for this exact execution (NK 29/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 31.9/60 kN ratings and 84 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 628); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 29/30 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 29 mm and width 30 mm, OD 38 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 29/30 run on an unhardened shaft?",
        "a": "No. In this execution the 29 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 29/30 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 29 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 29/30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 29 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK29-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK29-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 29×38×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK29",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK29-30",
      "NK 29/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK30-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 30/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 44,
    "fatigue_load_limit_kN": 5.5,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 30/20 TN belongs to the machined-ring needle roller family: an outer ring turned and ground to 40 mm with two retaining flanges, a roller-and-cage set inside, and envelope 30×40×20 mm on a hardened 30 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 30 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Catalogue mass 61 g at 30×40×20 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 40 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 25.1/44 kN ratings and 61 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 30/20 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 20 mm, OD 40 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 30/20 TN run on an unhardened shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 30/20 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 30/20 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK30-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×40×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK30-20-TW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×40×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK30-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK30-20-TN",
      "NK 30/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK30-30-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 30/30 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 40,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 72,
    "fatigue_load_limit_kN": 9,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 92,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 30/30 TN: 30 mm Fw, 40 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 30 mm under-roller diameter and the 30 mm width, with the 40 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 36.9/72 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 36.9/72 kN ratings are SKF catalogue values for this exact execution (NK 30/30 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 36.9/72 kN ratings and 92 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 30/30 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 30/30 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 30/30 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 30/30 TN have?",
        "a": "A NK 30/30 TN measures 30 mm bore/Fw × 40 mm outside diameter × 30 mm width (1.181 × 1.575 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 72 kN, fatigue limit Pu 9 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 92 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK30-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK30-20-TW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK30-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×40×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK30-30-TN",
      "NK 30/30 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4905-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4905.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 3.25,
    "max_rpm": 6300,
    "limiting_speed_rpm": 6300,
    "weight_g": 60,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4905.2RS: 30 mm Fw, 42 mm outside diameter, 17 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. Reading the designation: RNA gives the series and the numbers the boundary plan — 30 mm Fw for the shaft seat, 17 mm width; the 42 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Selection arithmetic: C 21.6 kN against C0 27.5 kN gives a C0/C ratio of 1.27, and the 3.25 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 42 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 21.6/27.5 kN ratings and 60 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 4905.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4905.2RS sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4905.2RS have?",
        "a": "A RNA 4905.2RS measures 30 mm bore/Fw × 42 mm outside diameter × 17 mm width (1.181 × 1.654 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 27.5 kN, fatigue limit Pu 3.25 kN, limiting speed 6,300 r/min, mass about 60 g."
      },
      {
        "q": "What does RNA 4905.2RS mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 17 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4905-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×42×17 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4905",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×17 mm envelope, but catalogue C/C0 differ between the executions (21.6/27.5 vs 24.2/34.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4905-2RS",
      "RNA 4905.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4905",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4905",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.15,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 61,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4905 is a ribbed machined-ring needle roller bearing (no inner ring) sized 30×42×17 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 30 mm shaft journal completes the bearing. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 30 mm under-roller diameter and the 17 mm width, with the 42 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 61 g at 30×42×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 24.2/34.5 kN ratings are SKF catalogue values for this exact execution (RNA 4905); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 24.2/34.5 kN ratings and 61 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 4905 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4905 have?",
        "a": "A RNA 4905 measures 30 mm bore/Fw × 42 mm outside diameter × 17 mm width (1.181 × 1.654 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 34.5 kN, fatigue limit Pu 4.15 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 61 g."
      },
      {
        "q": "What does RNA 4905 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 17 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4905 need a hardened and ground shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4905-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA4905-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×17 mm envelope, but catalogue C/C0 differ between the executions (24.2/34.5 vs 21.6/27.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4905",
      "RNA 4905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6905",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6905",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 38,
    "static_load_kN": 62,
    "fatigue_load_limit_kN": 7.65,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6905 belongs to the machined-ring needle roller family: an outer ring turned and ground to 42 mm with two retaining flanges, a roller-and-cage set inside, and envelope 30×42×30 mm on a hardened 30 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 30 mm Fw and 30 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 38/62 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: RNA 6905 shares its 30×42×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 38/62 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 6905 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6905?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6905?",
        "a": "A RNA 6905 measures 30 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.181 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 38 kN, static C0 62 kN, fatigue limit Pu 7.65 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 110 g."
      },
      {
        "q": "How is the RNA 6905 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 30 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6905-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NX30-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NX30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX30-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR30",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR30-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (38/62 vs 22.9/38 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6905",
      "RNA 6905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS30",
    "brand": "SKF",
    "manufacturer_designation": "NKS 30",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.3,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 30 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 30 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 30 mm under-roller diameter and the 22 mm width, with the 45 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 31.9/43 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKS 30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 30 have?",
        "a": "A NKS 30 measures 30 mm bore/Fw × 45 mm outside diameter × 22 mm width (1.181 × 1.772 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 43 kN, fatigue limit Pu 5.3 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 100 g."
      },
      {
        "q": "What does NKS 30 mean in SKF part numbering?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 30 mm and width 22 mm, OD 45 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NKS 30 need a hardened and ground shaft?",
        "a": "No. In this execution the 30 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×45×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS30",
      "NKS 30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK32-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 32/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 48,
    "fatigue_load_limit_kN": 6,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 64,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 32/20 TN is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 32 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: NK gives the series and the numbers the boundary plan — 32 mm Fw for the shaft seat, 20 mm width; the 42 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Selection arithmetic: C 26.4 kN against C0 48 kN gives a C0/C ratio of 1.82, and the 6 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 26.4/48 kN ratings are SKF catalogue values for this exact execution (NK 32/20 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 26.4/48 kN ratings and 64 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 32/20 TN mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 32 mm and width 20 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 32/20 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 32/20 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 32 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 32/20 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK32-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK32-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK32-20-TN",
      "NK 32/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK32-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 32/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.1,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 32/30 is a ribbed machined-ring needle roller bearing (no inner ring) sized 32×42×30 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 32 mm shaft journal completes the bearing. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 32 mm under-roller diameter and the 30 mm width, with the 42 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Speed planning separates the two ceilings: 12,000 r/min thermal reference and 14,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 32 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 34.1/65.5 kN ratings are SKF catalogue values for this exact execution (NK 32/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 34.1/65.5 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 32/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 32/30 have?",
        "a": "A NK 32/30 measures 32 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.26 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 65.5 kN, fatigue limit Pu 8.3 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 100 g."
      },
      {
        "q": "What does NK 32/30 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 32 mm and width 30 mm, OD 42 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 32/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK32-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK32-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK32-30",
      "NK 32/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-28",
    "brand": "SKF",
    "manufacturer_designation": "RNA 49/28",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 4.4,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 73,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 49/28 is a ribbed machined-ring needle roller bearing (no inner ring) sized 32×45×17 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 32 mm shaft journal completes the bearing. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 32 mm under-roller diameter and the 17 mm width, with the 45 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. The 73 g catalogue mass and 6.5 mm radial section ((45−32)/2) frame a rating of about 0.78 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 45 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 49/28 shares its 32×45×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 25.1/36.5 kN ratings and 73 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 49/28?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 32 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 49/28 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 49/28 have?",
        "a": "A RNA 49/28 measures 32 mm bore/Fw × 45 mm outside diameter × 17 mm width (1.26 × 1.772 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.1 kN, static C0 36.5 kN, fatigue limit Pu 4.4 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 73 g."
      },
      {
        "q": "What does RNA 49/28 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 32 mm and width 17 mm, OD 45 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-28-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA49-32-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-28",
      "RNA 49/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-28",
    "brand": "SKF",
    "manufacturer_designation": "RNA 69/28",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.6,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 69/28: 32 mm Fw, 45 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The RNA 69/28 code states Fw 32 and width 30 mm directly; because the family has no inner ring, the 32 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 39.6/65.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 32 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 39.6/65.5 kN ratings are SKF catalogue values for this exact execution (RNA 69/28); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 39.6/65.5 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 69/28?",
        "a": "A RNA 69/28 measures 32 mm bore/Fw × 45 mm outside diameter × 30 mm width (1.26 × 1.772 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.6 kN, static C0 65.5 kN, fatigue limit Pu 8.3 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 140 g."
      },
      {
        "q": "How is the RNA 69/28 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 32 mm and width 30 mm, OD 45 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 69/28 run on an unhardened shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 69/28 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 32 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-28-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-28",
      "RNA 69/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS32",
    "brand": "SKF",
    "manufacturer_designation": "NKS 32",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.1,
    "static_load_kN": 46.5,
    "fatigue_load_limit_kN": 5.7,
    "max_rpm": 13000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 13000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKS 32 designates a flanged, machined outer ring filled with needle rollers and a cage for a 32 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. Reading the designation: NKS gives the series and the numbers the boundary plan — 32 mm Fw for the shaft seat, 22 mm width; the 47 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKS 32 shares its 32×47×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 34.1/46.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKS 32 need a hardened and ground shaft?",
        "a": "No. In this execution the 32 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NKS 32?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 32 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 32 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 32 have?",
        "a": "A NKS 32 measures 32 mm bore/Fw × 47 mm outside diameter × 22 mm width (1.26 × 1.85 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 46.5 kN, fatigue limit Pu 5.7 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 110 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS32-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×47×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS32",
      "NKS 32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK35-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 35/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 52,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 69,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 35/20 TN designates a flanged, machined outer ring filled with needle rollers and a cage for a 35 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 35 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Selection arithmetic: C 27.5 kN against C0 52 kN gives a C0/C ratio of 1.89, and the 6.55 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 45 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NK 35/20 TN shares its 35×45×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 27.5/52 kN ratings and 69 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 35/20 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 35 mm and width 20 mm, OD 45 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 35/20 TN run on an unhardened shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 35/20 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 35/20 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK35-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×45×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK35-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK35-20-TN",
      "NK 35/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK35-30-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 35/30 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 35/30 TN is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 35 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 35 mm under-roller diameter and the 30 mm width, with the 45 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 35/30 TN shares its 35×45×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 40.2/85 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 35/30 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 35/30 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 35/30 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 35/30 TN have?",
        "a": "A NK 35/30 TN measures 35 mm bore/Fw × 45 mm outside diameter × 30 mm width (1.378 × 1.772 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 110 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK35-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK35-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK35-30-TN",
      "NK 35/30 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4906-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4906.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.8,
    "max_rpm": 5600,
    "limiting_speed_rpm": 5600,
    "weight_g": 69,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4906.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 35×47×17 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 35 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 35 mm Fw and 17 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: RNA 4906.2RS shares its 35×47×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 23.3/32 kN ratings and 69 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4906.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4906.2RS?",
        "a": "A RNA 4906.2RS measures 35 mm bore/Fw × 47 mm outside diameter × 17 mm width (1.378 × 1.85 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.8 kN, limiting speed 5,600 r/min, mass about 69 g."
      },
      {
        "q": "How is the RNA 4906.2RS designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 35 mm and width 17 mm, OD 47 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4906.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4906-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope, but catalogue C/C0 differ between the executions (23.3/32 vs 25.5/39 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4906-2RS",
      "RNA 4906.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4906",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4906",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 69,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4906 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 35 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 35 mm Fw and 17 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 69 g at 35×47×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 25.5/39 kN ratings are SKF catalogue values for this exact execution (RNA 4906); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 25.5/39 kN ratings and 69 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 4906 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4906?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4906?",
        "a": "A RNA 4906 measures 35 mm bore/Fw × 47 mm outside diameter × 17 mm width (1.378 × 1.85 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.5 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 69 g."
      },
      {
        "q": "How is the RNA 4906 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 35 mm and width 17 mm, OD 47 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4906-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4906-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×17 mm envelope, but catalogue C/C0 differ between the executions (25.5/39 vs 23.3/32 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4906",
      "RNA 4906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6906",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6906",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 75,
    "fatigue_load_limit_kN": 9.3,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 6906 in the dimension series 69 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 35 mm bore seat and 47 mm OD. Reading the designation: RNA gives the series and the numbers the boundary plan — 35 mm Fw for the shaft seat, 30 mm width; the 47 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 42.9/75 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 6906 shares its 35×47×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 42.9/75 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 6906 need a hardened and ground shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6906?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 6906 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 6906 have?",
        "a": "A RNA 6906 measures 35 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.378 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 75 kN, fatigue limit Pu 9.3 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 130 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6906-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NX35-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NX35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX35-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR35",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR35-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (42.9/75 vs 24.6/45 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6906",
      "RNA 6906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS35",
    "brand": "SKF",
    "manufacturer_designation": "NKS 35",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.2,
    "static_load_kN": 50,
    "fatigue_load_limit_kN": 6.2,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 35 is a ribbed machined-ring needle roller bearing (no inner ring) sized 35×50×22 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 35 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 35 mm Fw and 22 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 35.2/50 kN ratings are SKF catalogue values for this exact execution (NKS 35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 35.2/50 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKS 35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 35?",
        "a": "A NKS 35 measures 35 mm bore/Fw × 50 mm outside diameter × 22 mm width (1.378 × 1.969 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.2 kN, static C0 50 kN, fatigue limit Pu 6.2 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 120 g."
      },
      {
        "q": "How is the NKS 35 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 35 mm and width 22 mm, OD 50 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NKS 35 run on an unhardened shaft?",
        "a": "No. In this execution the 35 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×50×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS35",
      "NKS 35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK37-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 37/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 46.5,
    "fatigue_load_limit_kN": 5.85,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 77,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 37/20 is a ribbed machined-ring needle roller bearing (no inner ring) sized 37×47×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 37 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 37 mm Fw for the shaft seat, 20 mm width; the 47 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 25.1/46.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 47 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 37 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 37 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 25.1/46.5 kN ratings are SKF catalogue values for this exact execution (NK 37/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 25.1/46.5 kN ratings and 77 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 37/20 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 37 mm and width 20 mm, OD 47 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 37/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 37 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 37/20?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 37 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 37/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK37-20-D-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 37×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK37-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 37×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK37-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK37",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK37-20",
      "NK 37/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK37-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 37/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 76.5,
    "fatigue_load_limit_kN": 9.5,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 37/30 designates a flanged, machined outer ring filled with needle rollers and a cage for a 37 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The NK 37/30 code states Fw 37 and width 30 mm directly; because the family has no inner ring, the 37 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 36.9/76.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 37 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 37 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 36.9/76.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NK 37/30 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 37 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 37/30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 37 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 37/30?",
        "a": "A NK 37/30 measures 37 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.457 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 76.5 kN, fatigue limit Pu 9.5 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 110 g."
      },
      {
        "q": "How is the NK 37/30 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 37 mm and width 30 mm, OD 47 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK37-20-D-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK37-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK37-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 37×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK37",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK37-30",
      "NK 37/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS37",
    "brand": "SKF",
    "manufacturer_designation": "NKS 37",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 37,
    "D_mm": 52,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 12000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 12000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's wide-section machined-ring needle roller bearings without inner ring include NKS 37: 37 mm Fw, 52 mm outside diameter, 22 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NKS 37 code states Fw 37 and width 22 mm directly; because the family has no inner ring, the 37 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 37 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 37 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NKS 37 shares its 37×52×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 36.9/54 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKS 37 run on an unhardened shaft?",
        "a": "No. In this execution the 37 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NKS 37 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 37 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 37?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 37 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 37?",
        "a": "A NKS 37 measures 37 mm bore/Fw × 52 mm outside diameter × 22 mm width (1.457 × 2.047 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 54 kN, fatigue limit Pu 6.55 kN, limiting speed 12,000 r/min, reference speed 10,000 r/min, mass about 120 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS37-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 37×52×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS37",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS37",
      "NKS 37"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK38-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 38/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 48,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 49,
    "fatigue_load_limit_kN": 6.1,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 79,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 38/20 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 38 mm bore seat and 48 mm OD. The NK 38/20 code states Fw 38 and width 20 mm directly; because the family has no inner ring, the 38 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 79 g catalogue mass and 5.0 mm radial section ((48−38)/2) frame a rating of about 0.67 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 25.5/49 kN ratings and 79 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 38/20 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 38 mm and width 20 mm, OD 48 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 38/20 run on an unhardened shaft?",
        "a": "No. In this execution the 38 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 38/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 38 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 38/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 38 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK38-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 38×48×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK38-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK38",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK38-20",
      "NK 38/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK38-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 38/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 48,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 37.4,
    "static_load_kN": 80,
    "fatigue_load_limit_kN": 10,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 38/30: 38 mm Fw, 48 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 38 mm under-roller diameter and the 30 mm width, with the 48 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Speed planning separates the two ceilings: 11,000 r/min thermal reference and 12,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 38 mm seat. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 48 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 38/30 shares its 38×48×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 37.4/80 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 38/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 38 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 38/30?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 38 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 38/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 38/30 have?",
        "a": "A NK 38/30 measures 38 mm bore/Fw × 48 mm outside diameter × 30 mm width (1.496 × 1.89 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 37.4 kN, static C0 80 kN, fatigue limit Pu 10 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 120 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK38-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK38-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 38×48×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK38",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK38-30",
      "NK 38/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK40-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 40/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 29.7,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 78,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 40/20 TN in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 40 mm bore seat and 50 mm OD. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 40 mm under-roller diameter and the 20 mm width, with the 50 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 29.7/60 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 29.7/60 kN ratings are SKF catalogue values for this exact execution (NK 40/20 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 29.7/60 kN ratings and 78 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 40/20 TN mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 40 mm and width 20 mm, OD 50 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 40/20 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 40/20 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 40/20 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK40-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK40-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK40-20-TN",
      "NK 40/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK40-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 40/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 50,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 38,
    "static_load_kN": 83,
    "fatigue_load_limit_kN": 10.4,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 40/30 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 40 mm bore seat and 50 mm OD. The NK 40/30 code states Fw 40 and width 30 mm directly; because the family has no inner ring, the 40 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 130 g at 40×50×30 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 38/83 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 40/30?",
        "a": "A NK 40/30 measures 40 mm bore/Fw × 50 mm outside diameter × 30 mm width (1.575 × 1.969 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 38 kN, static C0 83 kN, fatigue limit Pu 10.4 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 130 g."
      },
      {
        "q": "How is the NK 40/30 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 40 mm and width 30 mm, OD 50 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 40/30 run on an unhardened shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 40/30 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK40-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK40-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×50×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK40-30",
      "NK 40/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA49-32",
    "brand": "SKF",
    "manufacturer_designation": "RNA 49/32",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 30.8,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 6.3,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 89,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 49/32 designates a flanged, machined outer ring filled with needle rollers and a cage for a 40 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The RNA 49/32 code states Fw 40 and width 20 mm directly; because the family has no inner ring, the 40 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. The 89 g catalogue mass and 6.0 mm radial section ((52−40)/2) frame a rating of about 0.77 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: RNA 49/32 shares its 40×52×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 30.8/51 kN ratings and 89 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 49/32 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 40 mm and width 20 mm, OD 52 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 49/32 run on an unhardened shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 49/32 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 49/32?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA49-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA49-32-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×52×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA49-32",
      "RNA 49/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA69-32",
    "brand": "SKF",
    "manufacturer_designation": "RNA 69/32",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 52,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 90,
    "fatigue_load_limit_kN": 10.8,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 69/32 in the dimension series 69 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 40 mm bore seat and 52 mm OD. Reading the designation: RNA gives the series and the numbers the boundary plan — 40 mm Fw for the shaft seat, 36 mm width; the 52 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 47.3/90 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 47.3/90 kN ratings are SKF catalogue values for this exact execution (RNA 69/32); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 47.3/90 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 69/32?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 69/32 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 69/32 have?",
        "a": "A RNA 69/32 measures 40 mm bore/Fw × 52 mm outside diameter × 36 mm width (1.575 × 2.047 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 47.3 kN, static C0 90 kN, fatigue limit Pu 10.8 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 160 g."
      },
      {
        "q": "What does RNA 69/32 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 40 mm and width 36 mm, OD 52 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA69-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RNA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×52×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA69-32",
      "RNA 69/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS40",
    "brand": "SKF",
    "manufacturer_designation": "NKS 40",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 38,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 40 belongs to the machined-ring needle roller family: an outer ring turned and ground to 55 mm with two retaining flanges, a roller-and-cage set inside, and envelope 40×55×22 mm on a hardened 40 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 40 mm Fw and 22 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 38/57 kN ratings are SKF catalogue values for this exact execution (NKS 40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 38/57 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKS 40 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 40 mm and width 22 mm, OD 55 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NKS 40 run on an unhardened shaft?",
        "a": "No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NKS 40 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 40?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS40-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×55×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS40",
      "NKS 40"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK42-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 42/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27,
    "static_load_kN": 53,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 86,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 42/20 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 42 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The NK 42/20 code states Fw 42 and width 20 mm directly; because the family has no inner ring, the 42 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 27/53 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NK 42/20 shares its 42×52×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 27/53 kN ratings and 86 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 42/20 run on an unhardened shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 42/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 42 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 42/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 42 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 42/20?",
        "a": "A NK 42/20 measures 42 mm bore/Fw × 52 mm outside diameter × 20 mm width (1.654 × 2.047 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 53 kN, fatigue limit Pu 6.55 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 86 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK42-20-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK42-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK42",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK42-20",
      "NK 42/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK42-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 42/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 52,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.1,
    "static_load_kN": 86.5,
    "fatigue_load_limit_kN": 10.8,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 42/30 belongs to the machined-ring needle roller family: an outer ring turned and ground to 52 mm with two retaining flanges, a roller-and-cage set inside, and envelope 42×52×30 mm on a hardened 42 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 42 mm under-roller diameter and the 30 mm width, with the 52 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 39.1/86.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 42 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 39.1/86.5 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 42/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 42/30 have?",
        "a": "A NK 42/30 measures 42 mm bore/Fw × 52 mm outside diameter × 30 mm width (1.654 × 2.047 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 86.5 kN, fatigue limit Pu 10.8 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 130 g."
      },
      {
        "q": "What does NK 42/30 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 42 mm and width 30 mm, OD 52 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 42/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK42-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK42-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×52×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK42",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK42-30",
      "NK 42/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4907-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4907.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.3,
    "max_rpm": 4800,
    "limiting_speed_rpm": 4800,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4907.2RS belongs to the machined-ring needle roller family: an outer ring turned and ground to 55 mm with two retaining flanges, a roller-and-cage set inside, and envelope 42×55×20 mm on a hardened 42 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 42 mm Fw and 20 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 4,800 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 42 mm seat. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 27/43 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 4907.2RS?",
        "a": "A RNA 4907.2RS measures 42 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.654 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 43 kN, fatigue limit Pu 5.3 kN, limiting speed 4,800 r/min, mass about 110 g."
      },
      {
        "q": "How is the RNA 4907.2RS designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 42 mm and width 20 mm, OD 55 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4907.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4907.2RS be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 42 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4907-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope, but catalogue C/C0 differ between the executions (27/43 vs 31.9/54 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4907-2RS",
      "RNA 4907.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4907",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4907",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.7,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4907: 42 mm Fw, 55 mm outside diameter, 20 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. Reading the designation: RNA gives the series and the numbers the boundary plan — 42 mm Fw for the shaft seat, 20 mm width; the 55 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 110 g at 42×55×20 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 42 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 31.9/54 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 4907 need a hardened and ground shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4907?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 42 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4907 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4907 have?",
        "a": "A RNA 4907 measures 42 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.654 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 54 kN, fatigue limit Pu 6.7 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 110 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4907-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4907-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 42×55×20 mm envelope, but catalogue C/C0 differ between the executions (31.9/54 vs 27/43 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4907",
      "RNA 4907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6907",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6907",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 55,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 48.4,
    "static_load_kN": 93,
    "fatigue_load_limit_kN": 11.4,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 190,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6907 is a ribbed machined-ring needle roller bearing (no inner ring) sized 42×55×36 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 42 mm shaft journal completes the bearing. The RNA 6907 code states Fw 42 and width 36 mm directly; because the family has no inner ring, the 42 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 48.4/93 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 48.4/93 kN ratings and 190 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 6907 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 42 mm and width 36 mm, OD 55 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6907 run on an unhardened shaft?",
        "a": "No. In this execution the 42 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6907 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 42 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6907?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 42 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6907-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×55×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6907",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6907",
      "RNA 6907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK43-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 43/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 53,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 55,
    "fatigue_load_limit_kN": 6.8,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 86,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 43/20 is a ribbed machined-ring needle roller bearing (no inner ring) sized 43×53×20 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 43 mm shaft journal completes the bearing. The NK 43/20 code states Fw 43 and width 20 mm directly; because the family has no inner ring, the 43 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 27.5/55 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 43 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 43 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 43 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 27.5/55 kN ratings are SKF catalogue values for this exact execution (NK 43/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 27.5/55 kN ratings and 86 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 43/20 run on an unhardened shaft?",
        "a": "No. In this execution the 43 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 43/20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 43 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 43/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 43 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 43/20?",
        "a": "A NK 43/20 measures 43 mm bore/Fw × 53 mm outside diameter × 20 mm width (1.693 × 2.087 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27.5 kN, static C0 55 kN, fatigue limit Pu 6.8 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 86 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK43-20-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NK43-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK43",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK43-20",
      "NK 43/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK43-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 43/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 53,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 90,
    "fatigue_load_limit_kN": 11.2,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 43/30 designates a flanged, machined outer ring filled with needle rollers and a cage for a 43 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 43 mm under-roller diameter and the 30 mm width, with the 53 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 40.2/90 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 53 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 43 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 43 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 40.2/90 kN ratings are SKF catalogue values for this exact execution (NK 43/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 40.2/90 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 43/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 43/30 have?",
        "a": "A NK 43/30 measures 43 mm bore/Fw × 53 mm outside diameter × 30 mm width (1.693 × 2.087 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 90 kN, fatigue limit Pu 11.2 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 130 g."
      },
      {
        "q": "What does NK 43/30 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 43 mm and width 30 mm, OD 53 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 43/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 43 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK43-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK43-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 43×53×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK43",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK43-30",
      "NK 43/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS43",
    "brand": "SKF",
    "manufacturer_designation": "NKS 43",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 43,
    "D_mm": 58,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.1,
    "static_load_kN": 61,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 43 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 43 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 43 mm under-roller diameter and the 22 mm width, with the 58 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 43 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 43 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKS 43 shares its 43×58×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 39.1/61 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKS 43?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 43 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 43 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 43 have?",
        "a": "A NKS 43 measures 43 mm bore/Fw × 58 mm outside diameter × 22 mm width (1.693 × 2.283 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 61 kN, fatigue limit Pu 7.5 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 140 g."
      },
      {
        "q": "What does NKS 43 mean in SKF part numbering?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 43 mm and width 22 mm, OD 58 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS43-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 43×58×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS43",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS43",
      "NKS 43"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK45-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 45/20 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 31.4,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 85,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 45/20 TN belongs to the machined-ring needle roller family: an outer ring turned and ground to 55 mm with two retaining flanges, a roller-and-cage set inside, and envelope 45×55×20 mm on a hardened 45 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 45 mm under-roller diameter and the 20 mm width, with the 55 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 45/20 TN shares its 45×55×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 31.4/65.5 kN ratings and 85 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 45/20 TN mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 45 mm and width 20 mm, OD 55 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 45/20 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 45/20 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 45/20 TN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK45-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK45-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK45-20-TN",
      "NK 45/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK45-30-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 45/30 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 13.7,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 45/30 TN: 45 mm Fw, 55 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NK 45/30 TN code states Fw 45 and width 30 mm directly; because the family has no inner ring, the 45 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. The 130 g catalogue mass and 5.0 mm radial section ((55−45)/2) frame a rating of about 1.02 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 45.7/108 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 45/30 TN run on an unhardened shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 45/30 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 45/30 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 45/30 TN?",
        "a": "A NK 45/30 TN measures 45 mm bore/Fw × 55 mm outside diameter × 30 mm width (1.772 × 2.165 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 45.7 kN, static C0 108 kN, fatigue limit Pu 13.7 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 130 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK45-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK45-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK45-30-TN",
      "NK 45/30 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS45",
    "brand": "SKF",
    "manufacturer_designation": "NKS 45",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 60,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 64,
    "fatigue_load_limit_kN": 8,
    "max_rpm": 10000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 10000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKS 45 designates a flanged, machined outer ring filled with needle rollers and a cage for a 45 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. Reading the designation: NKS gives the series and the numbers the boundary plan — 45 mm Fw for the shaft seat, 22 mm width; the 60 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 40.2/64 kN ratings are SKF catalogue values for this exact execution (NKS 45); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 40.2/64 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKS 45 mean in SKF part numbering?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 45 mm and width 22 mm, OD 60 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NKS 45 need a hardened and ground shaft?",
        "a": "No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NKS 45?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 45 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS45-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×60×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS45",
      "NKS 45"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK47-20",
    "brand": "SKF",
    "manufacturer_designation": "NK 47/20",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 47,
    "D_mm": 57,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 29.2,
    "static_load_kN": 61,
    "fatigue_load_limit_kN": 7.65,
    "max_rpm": 10000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 10000,
    "weight_g": 95,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 47/20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 57 mm with two retaining flanges, a roller-and-cage set inside, and envelope 47×57×20 mm on a hardened 47 mm shaft. Reading the designation: NK gives the series and the numbers the boundary plan — 47 mm Fw for the shaft seat, 20 mm width; the 57 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Selection arithmetic: C 29.2 kN against C0 61 kN gives a C0/C ratio of 2.09, and the 7.65 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 47 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 47 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 8,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 47 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 29.2/61 kN ratings and 95 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 47/20 need a hardened and ground shaft?",
        "a": "No. In this execution the 47 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 47/20?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 47 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 47/20 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 47/20 have?",
        "a": "A NK 47/20 measures 47 mm bore/Fw × 57 mm outside diameter × 20 mm width (1.85 × 2.244 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 29.2 kN, static C0 61 kN, fatigue limit Pu 7.65 kN, limiting speed 10,000 r/min, reference speed 8,500 r/min, mass about 95 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK47-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 47×57×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK47-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK47",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK47-20",
      "NK 47/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK47-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 47/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 47,
    "D_mm": 57,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 41.8,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 12.5,
    "max_rpm": 10000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 10000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 47/30 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 47 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The NK 47/30 code states Fw 47 and width 30 mm directly; because the family has no inner ring, the 47 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Selection arithmetic: C 41.8 kN against C0 98 kN gives a C0/C ratio of 2.34, and the 12.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 57 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 47 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 47 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 47 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 41.8/98 kN ratings are SKF catalogue values for this exact execution (NK 47/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 41.8/98 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 47/30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 47 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 47/30?",
        "a": "A NK 47/30 measures 47 mm bore/Fw × 57 mm outside diameter × 30 mm width (1.85 × 2.244 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 41.8 kN, static C0 98 kN, fatigue limit Pu 12.5 kN, limiting speed 10,000 r/min, reference speed 8,500 r/min, mass about 140 g."
      },
      {
        "q": "How is the NK 47/30 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 47 mm and width 30 mm, OD 57 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 47/30 run on an unhardened shaft?",
        "a": "No. In this execution the 47 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK47-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK47-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 47×57×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK47",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK47-30",
      "NK 47/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4908-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4908.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 48,
    "D_mm": 62,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 58.5,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 4000,
    "limiting_speed_rpm": 4000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4908.2RS: 48 mm Fw, 62 mm outside diameter, 22 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 48 mm under-roller diameter and the 22 mm width, with the 62 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Catalogue mass 150 g at 48×62×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 62 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 48 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 48 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 36.9/58.5 kN ratings are SKF catalogue values for this exact execution (RNA 4908.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 36.9/58.5 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4908.2RS mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 48 mm and width 22 mm, OD 62 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4908.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 48 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4908.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 48 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4908.2RS sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4908-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4908",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope, but catalogue C/C0 differ between the executions (36.9/58.5 vs 42.9/71 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4908-2RS",
      "RNA 4908.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4908",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4908",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 48,
    "D_mm": 62,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4908 designates a flanged, machined outer ring filled with needle rollers and a cage for a 48 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The RNA 4908 code states Fw 48 and width 22 mm directly; because the family has no inner ring, the 48 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 140 g at 48×62×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 48 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 48 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: RNA 4908 shares its 48×62×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 42.9/71 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4908 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 48 mm and width 22 mm, OD 62 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4908 run on an unhardened shaft?",
        "a": "No. In this execution the 48 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4908 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 48 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4908?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 48 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4908-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4908-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 48×62×22 mm envelope, but catalogue C/C0 differ between the executions (42.9/71 vs 36.9/58.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4908",
      "RNA 4908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6908",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6908",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 48,
    "D_mm": 62,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 67.1,
    "static_load_kN": 125,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6908 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 48 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 48 mm under-roller diameter and the 40 mm width, with the 62 mm outside diameter set by the dimension series 69 needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 67.1/125 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 48 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 48 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 67.1/125 kN ratings are SKF catalogue values for this exact execution (RNA 6908); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 67.1/125 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 6908 have?",
        "a": "A RNA 6908 measures 48 mm bore/Fw × 62 mm outside diameter × 40 mm width (1.89 × 2.441 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 67.1 kN, static C0 125 kN, fatigue limit Pu 15.3 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 260 g."
      },
      {
        "q": "What does RNA 6908 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 48 mm and width 40 mm, OD 62 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6908 need a hardened and ground shaft?",
        "a": "No. In this execution the 48 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6908?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 48 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6908-ZW-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "RNA6908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6908",
      "RNA 6908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK50-25-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 50/25 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 62,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 91.5,
    "fatigue_load_limit_kN": 11.2,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 50/25 TN: 50 mm Fw, 62 mm outside diameter, 25 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 50 mm Fw and 25 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 42.9/91.5 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 50/25 TN?",
        "a": "A NK 50/25 TN measures 50 mm bore/Fw × 62 mm outside diameter × 25 mm width (1.969 × 2.441 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 91.5 kN, fatigue limit Pu 11.2 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 150 g."
      },
      {
        "q": "How is the NK 50/25 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 50 mm and width 25 mm, OD 62 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 50/25 TN run on an unhardened shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 50/25 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 50 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK50-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×62×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK50-35-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK50",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK50-25-TN",
      "NK 50/25 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK50-35-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 50/35 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 62,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 58.3,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 210,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 50/35 TN is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 50 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 50 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Speed planning separates the two ceilings: 8,000 r/min thermal reference and 9,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 50 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 58.3/137 kN ratings are SKF catalogue values for this exact execution (NK 50/35 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 58.3/137 kN ratings and 210 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 50/35 TN designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 50 mm and width 35 mm, OD 62 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 50/35 TN run on an unhardened shaft?",
        "a": "No. In this execution the 50 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 50/35 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 50 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 50/35 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK50-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK50-35-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKX50-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope, but catalogue C/C0 differ between the executions (58.3/137 vs 38/78 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX50",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope, but catalogue C/C0 differ between the executions (58.3/137 vs 38/78 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR50",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope, but catalogue C/C0 differ between the executions (58.3/137 vs 38/78 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR50-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 50×62×35 mm envelope, but catalogue C/C0 differ between the executions (58.3/137 vs 38/78 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK50-35-TN",
      "NK 50/35 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS50",
    "brand": "SKF",
    "manufacturer_designation": "NKS 50",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 65,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 72,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 50 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 50 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: NKS gives the series and the numbers the boundary plan — 50 mm Fw for the shaft seat, 22 mm width; the 65 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 65 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 42.9/72 kN ratings are SKF catalogue values for this exact execution (NKS 50); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 42.9/72 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKS 50?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 50 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 50 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 50 have?",
        "a": "A NKS 50 measures 50 mm bore/Fw × 65 mm outside diameter × 22 mm width (1.969 × 2.559 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 72 kN, fatigue limit Pu 8.8 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 160 g."
      },
      {
        "q": "What does NKS 50 mean in SKF part numbering?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 50 mm and width 22 mm, OD 65 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS50-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×65×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS50",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS50",
      "NKS 50"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4909-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4909.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 52,
    "D_mm": 68,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.1,
    "static_load_kN": 64,
    "fatigue_load_limit_kN": 7.8,
    "max_rpm": 3800,
    "limiting_speed_rpm": 3800,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4909.2RS is a ribbed machined-ring needle roller bearing (no inner ring) sized 52×68×22 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 52 mm shaft journal completes the bearing. The RNA 4909.2RS code states Fw 52 and width 22 mm directly; because the family has no inner ring, the 52 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 39.1/64 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 52 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 52 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 39.1/64 kN ratings are SKF catalogue values for this exact execution (RNA 4909.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 39.1/64 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4909.2RS run on an unhardened shaft?",
        "a": "No. In this execution the 52 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4909.2RS be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 52 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4909.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 52 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4909.2RS?",
        "a": "A RNA 4909.2RS measures 52 mm bore/Fw × 68 mm outside diameter × 22 mm width (2.047 × 2.677 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 64 kN, fatigue limit Pu 7.8 kN, limiting speed 3,800 r/min, mass about 160 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4909-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4909",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope, but catalogue C/C0 differ between the executions (39.1/64 vs 45.7/78 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4909-2RS",
      "RNA 4909.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4909",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4909",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 52,
    "D_mm": 68,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.65,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4909 belongs to the machined-ring needle roller family: an outer ring turned and ground to 68 mm with two retaining flanges, a roller-and-cage set inside, and envelope 52×68×22 mm on a hardened 52 mm shaft. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 52 mm under-roller diameter and the 22 mm width, with the 68 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 180 g at 52×68×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 52 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4909 shares its 52×68×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 45.7/78 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4909 have?",
        "a": "A RNA 4909 measures 52 mm bore/Fw × 68 mm outside diameter × 22 mm width (2.047 × 2.677 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 45.7 kN, static C0 78 kN, fatigue limit Pu 9.65 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 180 g."
      },
      {
        "q": "What does RNA 4909 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 52 mm and width 22 mm, OD 68 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4909 need a hardened and ground shaft?",
        "a": "No. In this execution the 52 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4909?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 52 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4909-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4909-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 52×68×22 mm envelope, but catalogue C/C0 differ between the executions (45.7/78 vs 39.1/64 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4909",
      "RNA 4909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6909",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6909",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 52,
    "D_mm": 68,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 70.4,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 340,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 6909: 52 mm Fw, 68 mm outside diameter, 40 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 52 mm Fw and 40 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 70.4/137 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 52 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 52 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 70.4/137 kN ratings are SKF catalogue values for this exact execution (RNA 6909); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 70.4/137 kN ratings and 340 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 6909?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 52 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6909?",
        "a": "A RNA 6909 measures 52 mm bore/Fw × 68 mm outside diameter × 40 mm width (2.047 × 2.677 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 70.4 kN, static C0 137 kN, fatigue limit Pu 17 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 340 g."
      },
      {
        "q": "How is the RNA 6909 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 52 mm and width 40 mm, OD 68 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6909 run on an unhardened shaft?",
        "a": "No. In this execution the 52 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6909-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 52×68×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6909",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6909",
      "RNA 6909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK55-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 55/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 88,
    "fatigue_load_limit_kN": 10.8,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 55/25: 55 mm Fw, 68 mm outside diameter, 25 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 55 mm Fw and 25 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Catalogue mass 180 g at 55×68×25 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 40.2/88 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NK 55/25 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 55 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 55/25?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 55/25?",
        "a": "A NK 55/25 measures 55 mm bore/Fw × 68 mm outside diameter × 25 mm width (2.165 × 2.677 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 88 kN, fatigue limit Pu 10.8 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 180 g."
      },
      {
        "q": "How is the NK 55/25 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 55 mm and width 25 mm, OD 68 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK55-25-D-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK55-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK55-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK55-25",
      "NK 55/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK55-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 55/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 68,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 52.3,
    "static_load_kN": 122,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 55/35 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 55 mm bore seat and 68 mm OD. Reading the designation: NK gives the series and the numbers the boundary plan — 55 mm Fw for the shaft seat, 35 mm width; the 68 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Catalogue mass 250 g at 55×68×35 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 55/35 shares its 55×68×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 52.3/122 kN ratings and 250 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 55/35 have?",
        "a": "A NK 55/35 measures 55 mm bore/Fw × 68 mm outside diameter × 35 mm width (2.165 × 2.677 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 52.3 kN, static C0 122 kN, fatigue limit Pu 15.3 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 250 g."
      },
      {
        "q": "What does NK 55/35 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 55 mm and width 35 mm, OD 68 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 55/35 need a hardened and ground shaft?",
        "a": "No. In this execution the 55 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 55/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 55 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK55-25-D-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK55-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK55-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×68×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK55-35",
      "NK 55/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS55",
    "brand": "SKF",
    "manufacturer_designation": "NKS 55",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44.6,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.8,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 55 is a ribbed machined-ring needle roller bearing (no inner ring) sized 55×72×22 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 55 mm shaft journal completes the bearing. The NKS 55 code states Fw 55 and width 22 mm directly; because the family has no inner ring, the 55 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 72 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 44.6/78 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKS 55 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 55 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 55?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 55?",
        "a": "A NKS 55 measures 55 mm bore/Fw × 72 mm outside diameter × 22 mm width (2.165 × 2.835 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44.6 kN, static C0 78 kN, fatigue limit Pu 9.8 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 220 g."
      },
      {
        "q": "How is the NKS 55 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 55 mm and width 22 mm, OD 72 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS55-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS55",
      "NKS 55"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4910-2RS",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4910.2RS",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 58,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 69.5,
    "fatigue_load_limit_kN": 8.5,
    "max_rpm": 3400,
    "limiting_speed_rpm": 3400,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4910.2RS: 58 mm Fw, 72 mm outside diameter, 22 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 58 mm under-roller diameter and the 22 mm width, with the 72 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 160 g at 58×72×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 58 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4910.2RS shares its 58×72×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 40.2/69.5 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4910.2RS mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 58 mm and width 22 mm, OD 72 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4910.2RS need a hardened and ground shaft?",
        "a": "No. In this execution the 58 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4910.2RS?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 58 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4910.2RS sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4910-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope per ISO 15; seal variant (2RS vs OPEN) and load ratings differ — confirm sealing and rating before substituting."
      },
      {
        "equiv_sku": "RNA4910",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope, but catalogue C/C0 differ between the executions (40.2/69.5 vs 47.3/85 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4910-2RS",
      "RNA 4910.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4910",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4910",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 58,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4910 belongs to the machined-ring needle roller family: an outer ring turned and ground to 72 mm with two retaining flanges, a roller-and-cage set inside, and envelope 58×72×22 mm on a hardened 58 mm shaft. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 58 mm under-roller diameter and the 22 mm width, with the 72 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 160 g at 58×72×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 58 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 47.3/85 kN ratings are SKF catalogue values for this exact execution (RNA 4910); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 47.3/85 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4910 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 58 mm and width 22 mm, OD 72 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4910 need a hardened and ground shaft?",
        "a": "No. In this execution the 58 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4910?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 58 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4910 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4910-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4910-2RS",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 58×72×22 mm envelope, but catalogue C/C0 differ between the executions (47.3/85 vs 40.2/69.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4910",
      "RNA 4910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6910",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6910",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 58,
    "D_mm": 72,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 150,
    "fatigue_load_limit_kN": 18.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 6910: 58 mm Fw, 72 mm outside diameter, 40 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 58 mm Fw and 40 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 73.7/150 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 58 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 6910 shares its 58×72×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 7,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 73.7/150 kN ratings and 310 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 6910?",
        "a": "A RNA 6910 measures 58 mm bore/Fw × 72 mm outside diameter × 40 mm width (2.283 × 2.835 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 150 kN, fatigue limit Pu 18.6 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 310 g."
      },
      {
        "q": "How is the RNA 6910 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 58 mm and width 40 mm, OD 72 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6910 run on an unhardened shaft?",
        "a": "No. In this execution the 58 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6910 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 58 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6910-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 58×72×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6910",
      "RNA 6910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK60-25-TN",
    "brand": "SKF",
    "manufacturer_designation": "NK 60/25 TN",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 72,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 46.8,
    "static_load_kN": 110,
    "fatigue_load_limit_kN": 13.4,
    "max_rpm": 7500,
    "reference_speed_rpm": 6700,
    "limiting_speed_rpm": 7500,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 60/25 TN designates a flanged, machined outer ring filled with needle rollers and a cage for a 60 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 60 mm under-roller diameter and the 25 mm width, with the 72 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. The 170 g catalogue mass and 6.0 mm radial section ((72−60)/2) frame a rating of about 0.78 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 46.8/110 kN ratings are SKF catalogue values for this exact execution (NK 60/25 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 46.8/110 kN ratings and 170 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 60/25 TN have?",
        "a": "A NK 60/25 TN measures 60 mm bore/Fw × 72 mm outside diameter × 25 mm width (2.362 × 2.835 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 46.8 kN, static C0 110 kN, fatigue limit Pu 13.4 kN, limiting speed 7,500 r/min, reference speed 6,700 r/min, mass about 170 g."
      },
      {
        "q": "What does NK 60/25 TN mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 60 mm and width 25 mm, OD 72 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 60/25 TN need a hardened and ground shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 60/25 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 60 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK60-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK60-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK60-25-TN",
      "NK 60/25 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK60-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 60/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 72,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 55,
    "static_load_kN": 134,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 7500,
    "reference_speed_rpm": 6700,
    "limiting_speed_rpm": 7500,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 60/35 is a ribbed machined-ring needle roller bearing (no inner ring) sized 60×72×35 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 60 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 60 mm Fw for the shaft seat, 35 mm width; the 72 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Speed planning separates the two ceilings: 6,700 r/min thermal reference and 7,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 60 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 55/134 kN ratings are SKF catalogue values for this exact execution (NK 60/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 55/134 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 60/35 need a hardened and ground shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 60/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 60 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 60/35 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 60/35 have?",
        "a": "A NK 60/35 measures 60 mm bore/Fw × 72 mm outside diameter × 35 mm width (2.362 × 2.835 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 55 kN, static C0 134 kN, fatigue limit Pu 17 kN, limiting speed 7,500 r/min, reference speed 6,700 r/min, mass about 260 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK60-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK60-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×72×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK60-35",
      "NK 60/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS60",
    "brand": "SKF",
    "manufacturer_designation": "NKS 60",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 80,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 62.7,
    "static_load_kN": 104,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7500,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7500,
    "weight_g": 340,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 60 belongs to the machined-ring needle roller family: an outer ring turned and ground to 80 mm with two retaining flanges, a roller-and-cage set inside, and envelope 60×80×28 mm on a hardened 60 mm shaft. The NKS 60 code states Fw 60 and width 28 mm directly; because the family has no inner ring, the 60 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 62.7/104 kN ratings and 340 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKS 60?",
        "a": "A NKS 60 measures 60 mm bore/Fw × 80 mm outside diameter × 28 mm width (2.362 × 3.15 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 62.7 kN, static C0 104 kN, fatigue limit Pu 13.2 kN, limiting speed 7,500 r/min, reference speed 6,300 r/min, mass about 340 g."
      },
      {
        "q": "How is the NKS 60 designation read?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 60 mm and width 28 mm, OD 80 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NKS 60 run on an unhardened shaft?",
        "a": "No. In this execution the 60 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NKS 60 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 60 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS60-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×80×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS60",
      "NKS 60"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4911",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4911",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 63,
    "D_mm": 80,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 57.2,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 4911 in the dimension series 49 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 63 mm bore seat and 80 mm OD. The letters identify a flanged machined outer ring without inner ring; the figures give 63 mm Fw and 25 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 260 g at 63×80×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 63 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 63 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 57.2/106 kN ratings are SKF catalogue values for this exact execution (RNA 4911); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 57.2/106 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 4911?",
        "a": "A RNA 4911 measures 63 mm bore/Fw × 80 mm outside diameter × 25 mm width (2.48 × 3.15 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 57.2 kN, static C0 106 kN, fatigue limit Pu 13.2 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 260 g."
      },
      {
        "q": "How is the RNA 4911 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 63 mm and width 25 mm, OD 80 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4911 run on an unhardened shaft?",
        "a": "No. In this execution the 63 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4911 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 63 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4911-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 63×80×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4911",
      "RNA 4911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6911",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6911",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 63,
    "D_mm": 80,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 89.7,
    "static_load_kN": 190,
    "fatigue_load_limit_kN": 23.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 470,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 6911 designates a flanged, machined outer ring filled with needle rollers and a cage for a 63 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. Reading the designation: RNA gives the series and the numbers the boundary plan — 63 mm Fw for the shaft seat, 45 mm width; the 80 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 89.7/190 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 63 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 6911 shares its 63×80×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 89.7/190 kN ratings and 470 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 6911 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 6911 have?",
        "a": "A RNA 6911 measures 63 mm bore/Fw × 80 mm outside diameter × 45 mm width (2.48 × 3.15 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 89.7 kN, static C0 190 kN, fatigue limit Pu 23.2 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 470 g."
      },
      {
        "q": "What does RNA 6911 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 63 mm and width 45 mm, OD 80 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6911 need a hardened and ground shaft?",
        "a": "No. In this execution the 63 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6911-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 63×80×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6911",
      "RNA 6911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK65-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 65/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 78,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44,
    "static_load_kN": 104,
    "fatigue_load_limit_kN": 12.7,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 65/25 is a ribbed machined-ring needle roller bearing (no inner ring) sized 65×78×25 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 65 mm shaft journal completes the bearing. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 65 mm under-roller diameter and the 25 mm width, with the 78 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 44/104 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 78 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 44/104 kN ratings are SKF catalogue values for this exact execution (NK 65/25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 44/104 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 65/25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 65/25 have?",
        "a": "A NK 65/25 measures 65 mm bore/Fw × 78 mm outside diameter × 25 mm width (2.559 × 3.071 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44 kN, static C0 104 kN, fatigue limit Pu 12.7 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 220 g."
      },
      {
        "q": "What does NK 65/25 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 65 mm and width 25 mm, OD 78 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 65/25 need a hardened and ground shaft?",
        "a": "No. In this execution the 65 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK65-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×78×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK65-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK65",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK65-25",
      "NK 65/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK65-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 65/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 78,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 58.3,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 18.3,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 65/35 designates a flanged, machined outer ring filled with needle rollers and a cage for a 65 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 65 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. For life calculation, the 58.3/146 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 58.3/146 kN ratings and 310 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NK 65/35 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 65 mm and width 35 mm, OD 78 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 65/35 run on an unhardened shaft?",
        "a": "No. In this execution the 65 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 65/35 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 65 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 65/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 65 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK65-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK65-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×78×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK65",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK65-35",
      "NK 65/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS65",
    "brand": "SKF",
    "manufacturer_designation": "NKS 65",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 85,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 66,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 360,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKS 65 designates a flanged, machined outer ring filled with needle rollers and a cage for a 65 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 65 mm under-roller diameter and the 28 mm width, with the 85 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKS 65 shares its 65×85×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 66/114 kN ratings and 360 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKS 65 have?",
        "a": "A NKS 65 measures 65 mm bore/Fw × 85 mm outside diameter × 28 mm width (2.559 × 3.346 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 66 kN, static C0 114 kN, fatigue limit Pu 14.6 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 360 g."
      },
      {
        "q": "What does NKS 65 mean in SKF part numbering?",
        "a": "NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 65 mm and width 28 mm, OD 85 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NKS 65 need a hardened and ground shaft?",
        "a": "No. In this execution the 65 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NKS 65?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 65 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS65-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×85×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS65",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS65",
      "NKS 65"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK68-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 68/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 82,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44,
    "static_load_kN": 95,
    "fatigue_load_limit_kN": 11.8,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 240,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 68/25 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 68 mm bore seat and 82 mm OD. Reading the designation: NK gives the series and the numbers the boundary plan — 68 mm Fw for the shaft seat, 25 mm width; the 82 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Selection arithmetic: C 44 kN against C0 95 kN gives a C0/C ratio of 2.16, and the 11.8 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 82 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 68 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 68 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 44/95 kN ratings and 240 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NK 68/25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 68 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 68/25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 68/25 have?",
        "a": "A NK 68/25 measures 68 mm bore/Fw × 82 mm outside diameter × 25 mm width (2.677 × 3.228 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44 kN, static C0 95 kN, fatigue limit Pu 11.8 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 240 g."
      },
      {
        "q": "What does NK 68/25 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 68 mm and width 25 mm, OD 82 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK68-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 68×82×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK68-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK68",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK68-25",
      "NK 68/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK68-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 68/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 82,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 18.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 340,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 68/35: 68 mm Fw, 82 mm outside diameter, 35 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The NK 68/35 code states Fw 68 and width 35 mm directly; because the family has no inner ring, the 68 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Selection arithmetic: C 60.5 kN against C0 146 kN gives a C0/C ratio of 2.41, and the 18.3 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 68 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 68 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 60.5/146 kN ratings are SKF catalogue values for this exact execution (NK 68/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 60.5/146 kN ratings and 340 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 68/35?",
        "a": "A NK 68/35 measures 68 mm bore/Fw × 82 mm outside diameter × 35 mm width (2.677 × 3.228 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 60.5 kN, static C0 146 kN, fatigue limit Pu 18.3 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 340 g."
      },
      {
        "q": "How is the NK 68/35 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 68 mm and width 35 mm, OD 82 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 68/35 run on an unhardened shaft?",
        "a": "No. In this execution the 68 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 68/35 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 68 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK68-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK68-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 68×82×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK68",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK68-35",
      "NK 68/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4912",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4912",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 280,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4912 is a ribbed machined-ring needle roller bearing (no inner ring) sized 68×85×25 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 68 mm shaft journal completes the bearing. Reading the designation: RNA gives the series and the numbers the boundary plan — 68 mm Fw for the shaft seat, 25 mm width; the 85 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 280 g at 68×85×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 68 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 68 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 60.5/114 kN ratings and 280 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 4912 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4912 have?",
        "a": "A RNA 4912 measures 68 mm bore/Fw × 85 mm outside diameter × 25 mm width (2.677 × 3.346 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 60.5 kN, static C0 114 kN, fatigue limit Pu 14.3 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 280 g."
      },
      {
        "q": "What does RNA 4912 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 68 mm and width 25 mm, OD 85 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4912 need a hardened and ground shaft?",
        "a": "No. In this execution the 68 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4912-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 68×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4912",
      "RNA 4912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6912",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6912",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 68,
    "D_mm": 85,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 93.5,
    "static_load_kN": 204,
    "fatigue_load_limit_kN": 25,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 490,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6912 belongs to the machined-ring needle roller family: an outer ring turned and ground to 85 mm with two retaining flanges, a roller-and-cage set inside, and envelope 68×85×45 mm on a hardened 68 mm shaft. The RNA 6912 code states Fw 68 and width 45 mm directly; because the family has no inner ring, the 68 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 93.5/204 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 68 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 93.5/204 kN ratings and 490 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 6912 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 68 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6912?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 68 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6912?",
        "a": "A RNA 6912 measures 68 mm bore/Fw × 85 mm outside diameter × 45 mm width (2.677 × 3.346 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 93.5 kN, static C0 204 kN, fatigue limit Pu 25 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 490 g."
      },
      {
        "q": "How is the RNA 6912 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 68 mm and width 45 mm, OD 85 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6912-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 68×85×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6912",
      "RNA 6912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK70-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 70/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44.6,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 12.2,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 70/25: 70 mm Fw, 85 mm outside diameter, 25 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 70 mm Fw and 25 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 44.6/98 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NK 70/25 shares its 70×85×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 44.6/98 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 70/25?",
        "a": "A NK 70/25 measures 70 mm bore/Fw × 85 mm outside diameter × 25 mm width (2.756 × 3.346 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44.6 kN, static C0 98 kN, fatigue limit Pu 12.2 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 260 g."
      },
      {
        "q": "How is the NK 70/25 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 70 mm and width 25 mm, OD 85 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 70/25 run on an unhardened shaft?",
        "a": "No. In this execution the 70 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 70/25 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 70 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK70-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK70-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK70",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK70-25",
      "NK 70/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK70-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 70/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 85,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 61.6,
    "static_load_kN": 150,
    "fatigue_load_limit_kN": 19,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 370,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 70/35 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 70 mm bore seat and 85 mm OD. Reading the designation: NK gives the series and the numbers the boundary plan — 70 mm Fw for the shaft seat, 35 mm width; the 85 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. For life calculation, the 61.6/150 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 85 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 70 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 61.6/150 kN ratings and 370 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 70/35 need a hardened and ground shaft?",
        "a": "No. In this execution the 70 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 70/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 70 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 70/35 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 70/35 have?",
        "a": "A NK 70/35 measures 70 mm bore/Fw × 85 mm outside diameter × 35 mm width (2.756 × 3.346 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 150 kN, fatigue limit Pu 19 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 370 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK70-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK70-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×85×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK70",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK70-35",
      "NK 70/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS70",
    "brand": "SKF",
    "manufacturer_designation": "NKS 70",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 90,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 68.2,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 70 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 70 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 70 mm under-roller diameter and the 28 mm width, with the 90 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKS 70 shares its 70×90×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 68.2/120 kN ratings and 380 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKS 70 need a hardened and ground shaft?",
        "a": "No. In this execution the 70 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NKS 70?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 70 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKS 70 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKS 70 have?",
        "a": "A NKS 70 measures 70 mm bore/Fw × 90 mm outside diameter × 28 mm width (2.756 × 3.543 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 68.2 kN, static C0 120 kN, fatigue limit Pu 15.3 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 380 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS70-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×90×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS70",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS70",
      "NKS 70"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4913",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4913",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 72,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 61.6,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4913 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 72 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The RNA 4913 code states Fw 72 and width 25 mm directly; because the family has no inner ring, the 72 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 310 g at 72×90×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 72 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4913 shares its 72×90×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 61.6/120 kN ratings and 310 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 4913 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 72 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4913?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 72 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 9.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4913?",
        "a": "A RNA 4913 measures 72 mm bore/Fw × 90 mm outside diameter × 25 mm width (2.835 × 3.543 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 120 kN, fatigue limit Pu 14.6 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 310 g."
      },
      {
        "q": "How is the RNA 4913 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 72 mm and width 25 mm, OD 90 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4913-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 72×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4913",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4913",
      "RNA 4913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6913",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6913",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 72,
    "D_mm": 90,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 95.2,
    "static_load_kN": 212,
    "fatigue_load_limit_kN": 26,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 580,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 6913 in the dimension series 69 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 72 mm bore seat and 90 mm OD. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 72 mm under-roller diameter and the 45 mm width, with the 90 mm outside diameter set by the dimension series 69 needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 95.2/212 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 72 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 95.2/212 kN ratings are SKF catalogue values for this exact execution (RNA 6913); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 95.2/212 kN ratings and 580 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 6913 need a hardened and ground shaft?",
        "a": "No. In this execution the 72 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6913?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 72 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 6913 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 6913 have?",
        "a": "A RNA 6913 measures 72 mm bore/Fw × 90 mm outside diameter × 45 mm width (2.835 × 3.543 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 95.2 kN, static C0 212 kN, fatigue limit Pu 26 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 580 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6913-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 72×90×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6913",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6913",
      "RNA 6913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK73-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 73/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 73,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 52.8,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 73/25 is a ribbed machined-ring needle roller bearing (no inner ring) sized 73×90×25 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 73 mm shaft journal completes the bearing. The NK 73/25 code states Fw 73 and width 25 mm directly; because the family has no inner ring, the 73 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 5,600 r/min thermal reference and 6,300 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 73 mm seat. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 90 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 73 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 52.8/106 kN ratings and 300 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 73/25?",
        "a": "A NK 73/25 measures 73 mm bore/Fw × 90 mm outside diameter × 25 mm width (2.874 × 3.543 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 52.8 kN, static C0 106 kN, fatigue limit Pu 13.2 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 300 g."
      },
      {
        "q": "How is the NK 73/25 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 73 mm and width 25 mm, OD 90 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 73/25 run on an unhardened shaft?",
        "a": "No. In this execution the 73 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 73/25 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 73 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK73-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 73×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK73-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK73",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK73-25",
      "NK 73/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK73-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 73/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 73,
    "D_mm": 90,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.4,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 73/35 designates a flanged, machined outer ring filled with needle rollers and a cage for a 73 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 73 mm under-roller diameter and the 35 mm width, with the 90 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Speed planning separates the two ceilings: 5,600 r/min thermal reference and 6,300 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 73 mm seat. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 73 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 73/35 shares its 73×90×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 73.7/163 kN ratings and 430 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 73/35 need a hardened and ground shaft?",
        "a": "No. In this execution the 73 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 73/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 73 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 73/35 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 73/35 have?",
        "a": "A NK 73/35 measures 73 mm bore/Fw × 90 mm outside diameter × 35 mm width (2.874 × 3.543 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 163 kN, fatigue limit Pu 20.4 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 430 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK73-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK73-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 73×90×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK73",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK73-35",
      "NK 73/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK75-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 75/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 92,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 53.9,
    "static_load_kN": 110,
    "fatigue_load_limit_kN": 13.7,
    "max_rpm": 6000,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 6000,
    "weight_g": 320,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 75/25 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 75 mm bore seat and 92 mm OD. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 75 mm under-roller diameter and the 25 mm width, with the 92 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Selection arithmetic: C 53.9 kN against C0 110 kN gives a C0/C ratio of 2.04, and the 13.7 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 92 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 5,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 75 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 53.9/110 kN ratings and 320 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 75/25 have?",
        "a": "A NK 75/25 measures 75 mm bore/Fw × 92 mm outside diameter × 25 mm width (2.953 × 3.622 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 53.9 kN, static C0 110 kN, fatigue limit Pu 13.7 kN, limiting speed 6,000 r/min, reference speed 5,300 r/min, mass about 320 g."
      },
      {
        "q": "What does NK 75/25 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 75 mm and width 25 mm, OD 92 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 75/25 need a hardened and ground shaft?",
        "a": "No. In this execution the 75 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 75/25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 75 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK75-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×92×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK75-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK75",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK75-25",
      "NK 75/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK75-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 75/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 92,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 74.8,
    "static_load_kN": 170,
    "fatigue_load_limit_kN": 21.2,
    "max_rpm": 6000,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 6000,
    "weight_g": 450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 75/35: 75 mm Fw, 92 mm outside diameter, 35 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 75 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Selection arithmetic: C 74.8 kN against C0 170 kN gives a C0/C ratio of 2.27, and the 21.2 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 75 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 74.8/170 kN ratings are SKF catalogue values for this exact execution (NK 75/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 74.8/170 kN ratings and 450 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 75/35 run on an unhardened shaft?",
        "a": "No. In this execution the 75 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 75/35 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 75 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 75/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 75 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 75/35?",
        "a": "A NK 75/35 measures 75 mm bore/Fw × 92 mm outside diameter × 35 mm width (2.953 × 3.622 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 74.8 kN, static C0 170 kN, fatigue limit Pu 21.2 kN, limiting speed 6,000 r/min, reference speed 5,300 r/min, mass about 450 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK75-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK75-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×92×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK75",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK75-35",
      "NK 75/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKS75",
    "brand": "SKF",
    "manufacturer_designation": "NKS 75",
    "series": "NKS-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 95,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 70.4,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 16.6,
    "max_rpm": 6000,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 6000,
    "weight_g": 400,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKS 75 is a ribbed machined-ring needle roller bearing (no inner ring) sized 75×95×28 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 75 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 75 mm Fw and 28 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKS 75 shares its 75×95×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 70.4/132 kN ratings and 400 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKS 75 run on an unhardened shaft?",
        "a": "No. In this execution the 75 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NKS 75 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 75 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKS 75?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 75 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKS 75?",
        "a": "A NKS 75 measures 75 mm bore/Fw × 95 mm outside diameter × 28 mm width (2.953 × 3.74 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 70.4 kN, static C0 132 kN, fatigue limit Pu 16.6 kN, limiting speed 6,000 r/min, reference speed 5,300 r/min, mass about 400 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKS75-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×95×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS75",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKS75",
      "NKS 75"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK80-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 80/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 95,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 56.1,
    "static_load_kN": 127,
    "fatigue_load_limit_kN": 15.6,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 80/25 is a ribbed machined-ring needle roller bearing (no inner ring) sized 80×95×25 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 80 mm shaft journal completes the bearing. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 80 mm under-roller diameter and the 25 mm width, with the 95 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Speed planning separates the two ceilings: 5,000 r/min thermal reference and 5,600 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 80 mm seat. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NK 80/25 shares its 80×95×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 56.1/127 kN ratings and 300 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 80/25 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 80 mm and width 25 mm, OD 95 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 80/25 need a hardened and ground shaft?",
        "a": "No. In this execution the 80 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 80/25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 80 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 80/25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK80-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×95×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK80-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK80",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK80-25",
      "NK 80/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK80-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 80/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 95,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 76.5,
    "static_load_kN": 190,
    "fatigue_load_limit_kN": 24,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 80/35 designates a flanged, machined outer ring filled with needle rollers and a cage for a 80 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 80 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Speed planning separates the two ceilings: 5,000 r/min thermal reference and 5,600 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 80 mm seat. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NK 80/35 shares its 80×95×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 76.5/190 kN ratings and 430 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NK 80/35 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 80 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 80/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 80 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 80/35?",
        "a": "A NK 80/35 measures 80 mm bore/Fw × 95 mm outside diameter × 35 mm width (3.15 × 3.74 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 76.5 kN, static C0 190 kN, fatigue limit Pu 24 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 430 g."
      },
      {
        "q": "How is the NK 80/35 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 80 mm and width 35 mm, OD 95 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK80-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK80-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×95×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK80",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK80-35",
      "NK 80/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4914",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4914",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.8,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 460,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 49 needle roller bearings without inner ring include RNA 4914: 80 mm Fw, 100 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 80 mm under-roller diameter and the 30 mm width, with the 100 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 460 g at 80×100×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4914 shares its 80×100×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 84.2/163 kN ratings and 460 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 4914 need a hardened and ground shaft?",
        "a": "No. In this execution the 80 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4914?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 80 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4914 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4914 have?",
        "a": "A RNA 4914 measures 80 mm bore/Fw × 100 mm outside diameter × 30 mm width (3.15 × 3.937 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 163 kN, fatigue limit Pu 20.8 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 460 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4914-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×100×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4914",
      "RNA 4914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6914",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6914",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 100,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 128,
    "static_load_kN": 285,
    "fatigue_load_limit_kN": 36,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 860,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6914 is a ribbed machined-ring needle roller bearing (no inner ring) sized 80×100×54 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 80 mm shaft journal completes the bearing. The letters identify a flanged machined outer ring without inner ring; the figures give 80 mm Fw and 54 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 128/285 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 80 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 128/285 kN ratings are SKF catalogue values for this exact execution (RNA 6914); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 128/285 kN ratings and 860 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 6914 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 80 mm and width 54 mm, OD 100 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6914 run on an unhardened shaft?",
        "a": "No. In this execution the 80 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6914 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 80 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6914?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 80 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6914-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×100×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6914",
      "RNA 6914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK85-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 85/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 69.3,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 16.6,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 85/25 designates a flanged, machined outer ring filled with needle rollers and a cage for a 85 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The NK 85/25 code states Fw 85 and width 25 mm directly; because the family has no inner ring, the 85 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 69.3/132 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 105 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NK 85/25 shares its 85×105×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 4,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 69.3/132 kN ratings and 430 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NK 85/25?",
        "a": "A NK 85/25 measures 85 mm bore/Fw × 105 mm outside diameter × 25 mm width (3.346 × 4.134 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 69.3 kN, static C0 132 kN, fatigue limit Pu 16.6 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 430 g."
      },
      {
        "q": "How is the NK 85/25 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 85 mm and width 25 mm, OD 105 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 85/25 run on an unhardened shaft?",
        "a": "No. In this execution the 85 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 85/25 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 85 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK85-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×105×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK85-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK85",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK85-25",
      "NK 85/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4915",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4915",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 170,
    "fatigue_load_limit_kN": 21.6,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 490,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4915 designates a flanged, machined outer ring filled with needle rollers and a cage for a 85 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 85 mm Fw and 30 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 490 g at 85×105×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 84.2/170 kN ratings and 490 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4915 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 85 mm and width 30 mm, OD 105 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4915 run on an unhardened shaft?",
        "a": "No. In this execution the 85 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4915 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 85 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4915?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 85 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4915-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×105×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4915",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4915",
      "RNA 4915"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK85-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 85/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 96.8,
    "static_load_kN": 200,
    "fatigue_load_limit_kN": 26,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 85/35 is a ribbed machined-ring needle roller bearing (no inner ring) sized 85×105×35 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 85 mm shaft journal completes the bearing. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 85 mm under-roller diameter and the 35 mm width, with the 105 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 96.8/200 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 85 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 96.8/200 kN ratings and 600 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 85/35 need a hardened and ground shaft?",
        "a": "No. In this execution the 85 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 85/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 85 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 85/35 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 85/35 have?",
        "a": "A NK 85/35 measures 85 mm bore/Fw × 105 mm outside diameter × 35 mm width (3.346 × 4.134 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 96.8 kN, static C0 200 kN, fatigue limit Pu 26 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 600 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK85-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK85-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×105×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK85",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK85-35",
      "NK 85/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6915",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6915",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 105,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 130,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 940,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6915 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 85 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: RNA gives the series and the numbers the boundary plan — 85 mm Fw for the shaft seat, 54 mm width; the 105 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 130/290 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 85 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 130/290 kN ratings and 940 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 6915 have?",
        "a": "A RNA 6915 measures 85 mm bore/Fw × 105 mm outside diameter × 54 mm width (3.346 × 4.134 × 2.126 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 130 kN, static C0 290 kN, fatigue limit Pu 37.5 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 940 g."
      },
      {
        "q": "What does RNA 6915 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 85 mm and width 54 mm, OD 105 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6915 need a hardened and ground shaft?",
        "a": "No. In this execution the 85 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6915?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 85 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6915-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×105×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6915",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6915",
      "RNA 6915"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK90-25",
    "brand": "SKF",
    "manufacturer_designation": "NK 90/25",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 72.1,
    "static_load_kN": 140,
    "fatigue_load_limit_kN": 18,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 90/25 belongs to the machined-ring needle roller family: an outer ring turned and ground to 110 mm with two retaining flanges, a roller-and-cage set inside, and envelope 90×110×25 mm on a hardened 90 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 90 mm under-roller diameter and the 25 mm width, with the 110 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 110 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 72.1/140 kN ratings are SKF catalogue values for this exact execution (NK 90/25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 72.1/140 kN ratings and 450 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 90/25 need a hardened and ground shaft?",
        "a": "No. In this execution the 90 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 90/25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 90 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 90/25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 90/25 have?",
        "a": "A NK 90/25 measures 90 mm bore/Fw × 110 mm outside diameter × 25 mm width (3.543 × 4.331 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 72.1 kN, static C0 140 kN, fatigue limit Pu 18 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 450 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK90-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×110×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK90-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK90",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK90-25",
      "NK 90/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4916",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4916",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 88,
    "static_load_kN": 183,
    "fatigue_load_limit_kN": 23.2,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 520,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4916 belongs to the machined-ring needle roller family: an outer ring turned and ground to 110 mm with two retaining flanges, a roller-and-cage set inside, and envelope 90×110×30 mm on a hardened 90 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 90 mm Fw for the shaft seat, 30 mm width; the 110 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 520 g at 90×110×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 88/183 kN ratings are SKF catalogue values for this exact execution (RNA 4916); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 88/183 kN ratings and 520 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4916 have?",
        "a": "A RNA 4916 measures 90 mm bore/Fw × 110 mm outside diameter × 30 mm width (3.543 × 4.331 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 88 kN, static C0 183 kN, fatigue limit Pu 23.2 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 520 g."
      },
      {
        "q": "What does RNA 4916 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 90 mm and width 30 mm, OD 110 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4916 need a hardened and ground shaft?",
        "a": "No. In this execution the 90 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4916?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 90 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4916-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×110×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4916",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4916",
      "RNA 4916"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK90-35",
    "brand": "SKF",
    "manufacturer_designation": "NK 90/35",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 101,
    "static_load_kN": 216,
    "fatigue_load_limit_kN": 28,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 630,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 90/35 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 90 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 90 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 101/216 kN ratings and 630 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 90/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 90 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 90/35?",
        "a": "A NK 90/35 measures 90 mm bore/Fw × 110 mm outside diameter × 35 mm width (3.543 × 4.331 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 101 kN, static C0 216 kN, fatigue limit Pu 28 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 630 g."
      },
      {
        "q": "How is the NK 90/35 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 90 mm and width 35 mm, OD 110 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 90/35 run on an unhardened shaft?",
        "a": "No. In this execution the 90 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK90-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK90-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×110×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK90",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK90-35",
      "NK 90/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6916",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6916",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 110,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 134,
    "static_load_kN": 315,
    "fatigue_load_limit_kN": 40,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 69 needle roller bearings without inner ring include RNA 6916: 90 mm Fw, 110 mm outside diameter, 54 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. The RNA 6916 code states Fw 90 and width 54 mm directly; because the family has no inner ring, the 90 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 134/315 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 6916 shares its 90×110×54 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 4,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 134/315 kN ratings and 990 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 6916?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 90 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6916?",
        "a": "A RNA 6916 measures 90 mm bore/Fw × 110 mm outside diameter × 54 mm width (3.543 × 4.331 × 2.126 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 134 kN, static C0 315 kN, fatigue limit Pu 40 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 990 g."
      },
      {
        "q": "How is the RNA 6916 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 90 mm and width 54 mm, OD 110 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 6916 run on an unhardened shaft?",
        "a": "No. In this execution the 90 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6916-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×110×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6916",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6916",
      "RNA 6916"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK95-26",
    "brand": "SKF",
    "manufacturer_designation": "NK 95/26",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 115,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 18.6,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 490,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF's machined-ring needle roller bearings without inner ring include NK 95/26: 95 mm Fw, 115 mm outside diameter, 26 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 95 mm under-roller diameter and the 26 mm width, with the 115 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Selection arithmetic: C 73.7 kN against C0 146 kN gives a C0/C ratio of 1.98, and the 18.6 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 73.7/146 kN ratings are SKF catalogue values for this exact execution (NK 95/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 73.7/146 kN ratings and 490 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NK 95/26 have?",
        "a": "A NK 95/26 measures 95 mm bore/Fw × 115 mm outside diameter × 26 mm width (3.74 × 4.528 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 146 kN, fatigue limit Pu 18.6 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 490 g."
      },
      {
        "q": "What does NK 95/26 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 95 mm and width 26 mm, OD 115 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 95/26 need a hardened and ground shaft?",
        "a": "No. In this execution the 95 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 95/26?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 95 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK95-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×115×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK95-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK95",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK95-26",
      "NK 95/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK95-36",
    "brand": "SKF",
    "manufacturer_designation": "NK 95/36",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 115,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 105,
    "static_load_kN": 232,
    "fatigue_load_limit_kN": 30,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 680,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers NK 95/36 in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 95 mm bore seat and 115 mm OD. The letters identify a flanged machined outer ring without inner ring; the figures give 95 mm Fw and 36 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. Execution notes: the outer ring flanges are rolled from the ring material (no loose ribs to dislodge), the roller set is caged for low friction, and the TN option swaps in a polymer cage for quieter running. Selection arithmetic: C 105 kN against C0 232 kN gives a C0/C ratio of 2.21, and the 30 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 115 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 105/232 kN ratings and 680 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 95/36 run on an unhardened shaft?",
        "a": "No. In this execution the 95 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 95/36 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 95 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 95/36?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 95 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 95/36?",
        "a": "A NK 95/36 measures 95 mm bore/Fw × 115 mm outside diameter × 36 mm width (3.74 × 4.528 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 105 kN, static C0 232 kN, fatigue limit Pu 30 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 680 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK95-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK95-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×115×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK95",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK95-36",
      "NK 95/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK100-26",
    "brand": "SKF",
    "manufacturer_designation": "NK 100/26",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 76.5,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 19.6,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 520,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 100/26 designates a flanged, machined outer ring filled with needle rollers and a cage for a 100 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 100 mm Fw and 26 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 520 g catalogue mass and 10.0 mm radial section ((120−100)/2) frame a rating of about 0.77 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 120 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 100 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 76.5/156 kN ratings are SKF catalogue values for this exact execution (NK 100/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 76.5/156 kN ratings and 520 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NK 100/26 run on an unhardened shaft?",
        "a": "No. In this execution the 100 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the NK 100/26 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 100 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 100/26?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 100 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 100/26?",
        "a": "A NK 100/26 measures 100 mm bore/Fw × 120 mm outside diameter × 26 mm width (3.937 × 4.724 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 76.5 kN, static C0 156 kN, fatigue limit Pu 19.6 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 520 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK100-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×120×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK100-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK100",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK100-26",
      "NK 100/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4917",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4917",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 108,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 31,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 660,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 4917 in the dimension series 49 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 100 mm bore seat and 120 mm OD. The RNA 4917 code states Fw 100 and width 35 mm directly; because the family has no inner ring, the 100 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 660 g at 100×120×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 100 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 108/250 kN ratings are SKF catalogue values for this exact execution (RNA 4917); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 108/250 kN ratings and 660 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4917?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 100 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4917?",
        "a": "A RNA 4917 measures 100 mm bore/Fw × 120 mm outside diameter × 35 mm width (3.937 × 4.724 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 108 kN, static C0 250 kN, fatigue limit Pu 31 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 660 g."
      },
      {
        "q": "How is the RNA 4917 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 100 mm and width 35 mm, OD 120 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4917 run on an unhardened shaft?",
        "a": "No. In this execution the 100 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4917-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×120×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4917",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4917",
      "RNA 4917"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK100-36",
    "brand": "SKF",
    "manufacturer_designation": "NK 100/36",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 108,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 31,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 720,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 100/36 is a ribbed machined-ring needle roller bearing (no inner ring) sized 100×120×36 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 100 mm shaft journal completes the bearing. Reading the designation: NK gives the series and the numbers the boundary plan — 100 mm Fw for the shaft seat, 36 mm width; the 120 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 720 g catalogue mass and 10.0 mm radial section ((120−100)/2) frame a rating of about 1.08 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "piston-pin style pivots in hydraulic pumps",
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 108/250 kN ratings are SKF catalogue values for this exact execution (NK 100/36); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 108/250 kN ratings and 720 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NK 100/36 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 100/36 have?",
        "a": "A NK 100/36 measures 100 mm bore/Fw × 120 mm outside diameter × 36 mm width (3.937 × 4.724 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 108 kN, static C0 250 kN, fatigue limit Pu 31 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 720 g."
      },
      {
        "q": "What does NK 100/36 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 100 mm and width 36 mm, OD 120 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 100/36 need a hardened and ground shaft?",
        "a": "No. In this execution the 100 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK100-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK100-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×120×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK100",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK100-36",
      "NK 100/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6917",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6917",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 120,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 165,
    "static_load_kN": 425,
    "fatigue_load_limit_kN": 53,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 1200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 6917 designates a flanged, machined outer ring filled with needle rollers and a cage for a 100 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 100 mm under-roller diameter and the 63 mm width, with the 120 mm outside diameter set by the dimension series 69 needle roller bearings without inner ring plan. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 165/425 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 6917 shares its 100×120×63 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 165/425 kN ratings and 1200 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 6917?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 100 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 6917 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 6917 have?",
        "a": "A RNA 6917 measures 100 mm bore/Fw × 120 mm outside diameter × 63 mm width (3.937 × 4.724 × 2.48 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 165 kN, static C0 425 kN, fatigue limit Pu 53 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 1200 g."
      },
      {
        "q": "What does RNA 6917 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 100 mm and width 63 mm, OD 120 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6917-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×120×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6917",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6917",
      "RNA 6917"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK105-26",
    "brand": "SKF",
    "manufacturer_designation": "NK 105/26",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 78.1,
    "static_load_kN": 166,
    "fatigue_load_limit_kN": 20.4,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 540,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 105/26 is a ribbed machined-ring needle roller bearing (no inner ring) sized 105×125×26 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 105 mm shaft journal completes the bearing. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 105 mm under-roller diameter and the 26 mm width, with the 125 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 540 g at 105×125×26 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 105 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 78.1/166 kN ratings are SKF catalogue values for this exact execution (NK 105/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 78.1/166 kN ratings and 540 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NK 105/26 need a hardened and ground shaft?",
        "a": "No. In this execution the 105 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 105/26?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 105 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 105/26 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NK 105/26 have?",
        "a": "A NK 105/26 measures 105 mm bore/Fw × 125 mm outside diameter × 26 mm width (4.134 × 4.921 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 78.1 kN, static C0 166 kN, fatigue limit Pu 20.4 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 540 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK105-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 105×125×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK105-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK105",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK105-26",
      "NK 105/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4918",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4918",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 112,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 32.5,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 750,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4918 is a ribbed machined-ring needle roller bearing (no inner ring) sized 105×125×35 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 105 mm shaft journal completes the bearing. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 105 mm under-roller diameter and the 35 mm width, with the 125 mm outside diameter set by the dimension series 49 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 750 g at 105×125×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 105 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 3,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 105 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 112/265 kN ratings and 750 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 4918?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 105 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4918 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4918 have?",
        "a": "A RNA 4918 measures 105 mm bore/Fw × 125 mm outside diameter × 35 mm width (4.134 × 4.921 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 112 kN, static C0 265 kN, fatigue limit Pu 32.5 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 750 g."
      },
      {
        "q": "What does RNA 4918 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 105 mm and width 35 mm, OD 125 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4918-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 105×125×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4918",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4918",
      "RNA 4918"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK105-36",
    "brand": "SKF",
    "manufacturer_designation": "NK 105/36",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 112,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 32.5,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 710,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NK 105/36 designates a flanged, machined outer ring filled with needle rollers and a cage for a 105 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 105 mm Fw and 36 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 710 g at 105×125×36 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 105 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 112/265 kN ratings and 710 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NK 105/36?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 105 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 105/36?",
        "a": "A NK 105/36 measures 105 mm bore/Fw × 125 mm outside diameter × 36 mm width (4.134 × 4.921 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 112 kN, static C0 265 kN, fatigue limit Pu 32.5 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 710 g."
      },
      {
        "q": "How is the NK 105/36 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 105 mm and width 36 mm, OD 125 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the NK 105/36 run on an unhardened shaft?",
        "a": "No. In this execution the 105 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK105-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK105-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 105×125×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK105",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK105-36",
      "NK 105/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6918",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6918",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 105,
    "D_mm": 125,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 172,
    "static_load_kN": 450,
    "fatigue_load_limit_kN": 55,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 1350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 6918 belongs to the machined-ring needle roller family: an outer ring turned and ground to 125 mm with two retaining flanges, a roller-and-cage set inside, and envelope 105×125×63 mm on a hardened 105 mm shaft. The letters identify a flanged machined outer ring without inner ring; the figures give 105 mm Fw and 63 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 172/450 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 105 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 172/450 kN ratings and 1350 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 6918 run on an unhardened shaft?",
        "a": "No. In this execution the 105 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 6918 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 105 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 6918?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 105 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 6918?",
        "a": "A RNA 6918 measures 105 mm bore/Fw × 125 mm outside diameter × 63 mm width (4.134 × 4.921 × 2.48 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 172 kN, static C0 450 kN, fatigue limit Pu 55 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 1350 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6918-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 105×125×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6918",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6918",
      "RNA 6918"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK110-30",
    "brand": "SKF",
    "manufacturer_designation": "NK 110/30",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 96.8,
    "static_load_kN": 220,
    "fatigue_load_limit_kN": 27,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 650,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 110/30 belongs to the machined-ring needle roller family: an outer ring turned and ground to 130 mm with two retaining flanges, a roller-and-cage set inside, and envelope 110×130×30 mm on a hardened 110 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 110 mm under-roller diameter and the 30 mm width, with the 130 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Catalogue mass 650 g at 110×130×30 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 130 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 3,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 110 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 96.8/220 kN ratings and 650 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NK 110/30 mean in SKF part numbering?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 110 mm and width 30 mm, OD 130 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the NK 110/30 need a hardened and ground shaft?",
        "a": "No. In this execution the 110 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a NK 110/30?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 110 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NK 110/30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK110-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×130×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK110-40-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK110",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK110-30",
      "NK 110/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4919",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4919",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 114,
    "static_load_kN": 270,
    "fatigue_load_limit_kN": 33.5,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 720,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4919 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 110 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 110 mm Fw and 35 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 720 g at 110×130×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4919 shares its 110×130×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 3,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 114/270 kN ratings and 720 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4919 run on an unhardened shaft?",
        "a": "No. In this execution the 110 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4919 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 110 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4919?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 110 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4919?",
        "a": "A RNA 4919 measures 110 mm bore/Fw × 130 mm outside diameter × 35 mm width (4.331 × 5.118 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 114 kN, static C0 270 kN, fatigue limit Pu 33.5 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 720 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4919-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×130×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4919",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4919",
      "RNA 4919"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NK110-40",
    "brand": "SKF",
    "manufacturer_designation": "NK 110/40",
    "series": "NK-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 123,
    "static_load_kN": 305,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 830,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NK 110/40 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 110 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 110 mm Fw and 40 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. Catalogue mass 830 g at 110×130×40 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 110 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 123/305 kN ratings are SKF catalogue values for this exact execution (NK 110/40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 123/305 kN ratings and 830 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NK 110/40 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 110 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NK 110/40?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 110 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NK 110/40?",
        "a": "A NK 110/40 measures 110 mm bore/Fw × 130 mm outside diameter × 40 mm width (4.331 × 5.118 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 123 kN, static C0 305 kN, fatigue limit Pu 37.5 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 830 g."
      },
      {
        "q": "How is the NK 110/40 designation read?",
        "a": "NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 110 mm and width 40 mm, OD 130 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NK110-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NK110-40-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×130×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NK110",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NK110-40",
      "NK 110/40"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA6919",
    "brand": "SKF",
    "manufacturer_designation": "RNA 6919",
    "series": "RNA-69-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 130,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 172,
    "static_load_kN": 465,
    "fatigue_load_limit_kN": 56,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 1450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 6919 in the dimension series 69 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 110 mm bore seat and 130 mm OD. Reading the designation: RNA gives the series and the numbers the boundary plan — 110 mm Fw for the shaft seat, 63 mm width; the 130 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. For life calculation, the 172/465 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "guide rollers running on hardened tracks",
      "swing arms and lever pivots with oscillating duty",
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 172/465 kN ratings are SKF catalogue values for this exact execution (RNA 6919); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 172/465 kN ratings and 1450 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 6919 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 110 mm and width 63 mm, OD 130 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 6919 need a hardened and ground shaft?",
        "a": "No. In this execution the 110 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 6919?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 110 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 6919 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA6919-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×130×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA6919",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA6919",
      "RNA 6919"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4920",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4920",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 115,
    "D_mm": 140,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 125,
    "static_load_kN": 280,
    "fatigue_load_limit_kN": 34,
    "max_rpm": 4000,
    "reference_speed_rpm": 3400,
    "limiting_speed_rpm": 4000,
    "weight_g": 1150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4920 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 115 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 115 mm Fw and 40 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 1150 g at 115×140×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 140 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 115 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 125/280 kN ratings and 1150 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 4920 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 115 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4920?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 115 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4920?",
        "a": "A RNA 4920 measures 115 mm bore/Fw × 140 mm outside diameter × 40 mm width (4.528 × 5.512 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 125 kN, static C0 280 kN, fatigue limit Pu 34 kN, limiting speed 4,000 r/min, reference speed 3,400 r/min, mass about 1150 g."
      },
      {
        "q": "How is the RNA 4920 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 115 mm and width 40 mm, OD 140 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4920-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 115×140×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4920",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4920",
      "RNA 4920"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4822",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4822",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 140,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 93.5,
    "static_load_kN": 232,
    "fatigue_load_limit_kN": 27,
    "max_rpm": 3800,
    "reference_speed_rpm": 3400,
    "limiting_speed_rpm": 3800,
    "weight_g": 660,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4822 is a ribbed machined-ring needle roller bearing (no inner ring) sized 120×140×30 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 120 mm shaft journal completes the bearing. Reading the designation: RNA gives the series and the numbers the boundary plan — 120 mm Fw for the shaft seat, 30 mm width; the 140 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 660 g at 120×140×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 120 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 93.5/232 kN ratings are SKF catalogue values for this exact execution (RNA 4822); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 93.5/232 kN ratings and 660 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4822 have?",
        "a": "A RNA 4822 measures 120 mm bore/Fw × 140 mm outside diameter × 30 mm width (4.724 × 5.512 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 93.5 kN, static C0 232 kN, fatigue limit Pu 27 kN, limiting speed 3,800 r/min, reference speed 3,400 r/min, mass about 660 g."
      },
      {
        "q": "What does RNA 4822 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 120 mm and width 30 mm, OD 140 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4822 need a hardened and ground shaft?",
        "a": "No. In this execution the 120 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4822?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 120 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4822-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 120×140×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4822",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4822",
      "RNA 4822"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4922",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4922",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 125,
    "D_mm": 150,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 130,
    "static_load_kN": 300,
    "fatigue_load_limit_kN": 35.5,
    "max_rpm": 3600,
    "reference_speed_rpm": 3200,
    "limiting_speed_rpm": 3600,
    "weight_g": 1250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4922 designates a flanged, machined outer ring filled with needle rollers and a cage for a 125 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The RNA 4922 code states Fw 125 and width 40 mm directly; because the family has no inner ring, the 125 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 1250 g at 125×150×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 150 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 125 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 125 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 130/300 kN ratings are SKF catalogue values for this exact execution (RNA 4922); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 130/300 kN ratings and 1250 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4922 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 125 mm and width 40 mm, OD 150 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4922 run on an unhardened shaft?",
        "a": "No. In this execution the 125 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4922 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 125 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4922?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 125 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4922-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 125×150×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4922",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4922",
      "RNA 4922"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4824",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4824",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 150,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 99,
    "static_load_kN": 255,
    "fatigue_load_limit_kN": 29,
    "max_rpm": 3600,
    "reference_speed_rpm": 3200,
    "limiting_speed_rpm": 3600,
    "weight_g": 730,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 48 needle roller bearings without inner ring include RNA 4824: 130 mm Fw, 150 mm outside diameter, 30 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 130 mm under-roller diameter and the 30 mm width, with the 150 mm outside diameter set by the dimension series 48 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 730 g at 130×150×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 130 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 3,200 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 130 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 99/255 kN ratings and 730 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 4824?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 130 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4824 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4824 have?",
        "a": "A RNA 4824 measures 130 mm bore/Fw × 150 mm outside diameter × 30 mm width (5.118 × 5.906 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 99 kN, static C0 255 kN, fatigue limit Pu 29 kN, limiting speed 3,600 r/min, reference speed 3,200 r/min, mass about 730 g."
      },
      {
        "q": "What does RNA 4824 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 130 mm and width 30 mm, OD 150 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4824-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 130×150×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4824",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4824",
      "RNA 4824"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4924",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4924",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 135,
    "D_mm": 165,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 176,
    "static_load_kN": 405,
    "fatigue_load_limit_kN": 49,
    "max_rpm": 3400,
    "reference_speed_rpm": 3000,
    "limiting_speed_rpm": 3400,
    "weight_g": 1850,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 4924 in the dimension series 49 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 135 mm bore seat and 165 mm OD. The letters identify a flanged machined outer ring without inner ring; the figures give 135 mm Fw and 45 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 1850 g at 135×165×45 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 165 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 135 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4924 shares its 135×165×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 3,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 176/405 kN ratings and 1850 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4924?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 135 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4924?",
        "a": "A RNA 4924 measures 135 mm bore/Fw × 165 mm outside diameter × 45 mm width (5.315 × 6.496 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 176 kN, static C0 405 kN, fatigue limit Pu 49 kN, limiting speed 3,400 r/min, reference speed 3,000 r/min, mass about 1850 g."
      },
      {
        "q": "How is the RNA 4924 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 135 mm and width 45 mm, OD 165 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4924 run on an unhardened shaft?",
        "a": "No. In this execution the 135 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4924-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 135×165×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4924",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4924",
      "RNA 4924"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4826",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4826",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 145,
    "D_mm": 165,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 119,
    "static_load_kN": 325,
    "fatigue_load_limit_kN": 36.5,
    "max_rpm": 3200,
    "reference_speed_rpm": 2800,
    "limiting_speed_rpm": 3200,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4826 belongs to the machined-ring needle roller family: an outer ring turned and ground to 165 mm with two retaining flanges, a roller-and-cage set inside, and envelope 145×165×35 mm on a hardened 145 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 145 mm Fw for the shaft seat, 35 mm width; the 165 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 990 g at 145×165×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 145 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4826 shares its 145×165×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 119/325 kN ratings and 990 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4826 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 145 mm and width 35 mm, OD 165 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4826 need a hardened and ground shaft?",
        "a": "No. In this execution the 145 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4826?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 145 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4826 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4826-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 145×165×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4826",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4826",
      "RNA 4826"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4926",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4926",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 150,
    "D_mm": 180,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 198,
    "static_load_kN": 480,
    "fatigue_load_limit_kN": 57,
    "max_rpm": 3000,
    "reference_speed_rpm": 2600,
    "limiting_speed_rpm": 3000,
    "weight_g": 2200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4926 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 150 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The RNA 4926 code states Fw 150 and width 50 mm directly; because the family has no inner ring, the 150 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 2200 g at 150×180×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 180 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 150 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 198/480 kN ratings and 2200 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4926 run on an unhardened shaft?",
        "a": "No. In this execution the 150 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4926 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 150 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4926?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 150 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4926?",
        "a": "A RNA 4926 measures 150 mm bore/Fw × 180 mm outside diameter × 50 mm width (5.906 × 7.087 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 198 kN, static C0 480 kN, fatigue limit Pu 57 kN, limiting speed 3,000 r/min, reference speed 2,600 r/min, mass about 2200 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4926-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 150×180×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4926",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4926",
      "RNA 4926"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4828",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4828",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 155,
    "D_mm": 175,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 121,
    "static_load_kN": 345,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 3000,
    "reference_speed_rpm": 2600,
    "limiting_speed_rpm": 3000,
    "weight_g": 970,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4828 is a ribbed machined-ring needle roller bearing (no inner ring) sized 155×175×35 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 155 mm shaft journal completes the bearing. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 155 mm under-roller diameter and the 35 mm width, with the 175 mm outside diameter set by the dimension series 48 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 970 g at 155×175×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 155 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 121/345 kN ratings are SKF catalogue values for this exact execution (RNA 4828); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 121/345 kN ratings and 970 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the RNA 4828 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4828 have?",
        "a": "A RNA 4828 measures 155 mm bore/Fw × 175 mm outside diameter × 35 mm width (6.102 × 6.89 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 121 kN, static C0 345 kN, fatigue limit Pu 37.5 kN, limiting speed 3,000 r/min, reference speed 2,600 r/min, mass about 970 g."
      },
      {
        "q": "What does RNA 4828 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 155 mm and width 35 mm, OD 175 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4828 need a hardened and ground shaft?",
        "a": "No. In this execution the 155 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4828-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 155×175×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4828",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4828",
      "RNA 4828"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4928",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4928",
    "series": "RNA-49-series",
    "type": "needle",
    "d_mm": 160,
    "D_mm": 190,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 205,
    "static_load_kN": 510,
    "fatigue_load_limit_kN": 60,
    "max_rpm": 2800,
    "reference_speed_rpm": 2400,
    "limiting_speed_rpm": 2800,
    "weight_g": 2350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4928 designates a flanged, machined outer ring filled with needle rollers and a cage for a 160 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 160 mm Fw and 50 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 2350 g at 160×190×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 190 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 160 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 160 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 205/510 kN ratings are SKF catalogue values for this exact execution (RNA 4928); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 205/510 kN ratings and 2350 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 4928?",
        "a": "A RNA 4928 measures 160 mm bore/Fw × 190 mm outside diameter × 50 mm width (6.299 × 7.48 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 205 kN, static C0 510 kN, fatigue limit Pu 60 kN, limiting speed 2,800 r/min, reference speed 2,400 r/min, mass about 2350 g."
      },
      {
        "q": "How is the RNA 4928 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 160 mm and width 50 mm, OD 190 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4928 run on an unhardened shaft?",
        "a": "No. In this execution the 160 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4928 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 160 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4928-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 160×190×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4928",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4928",
      "RNA 4928"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4830",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4830",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 165,
    "D_mm": 190,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 147,
    "static_load_kN": 415,
    "fatigue_load_limit_kN": 46.5,
    "max_rpm": 2800,
    "reference_speed_rpm": 2400,
    "limiting_speed_rpm": 2800,
    "weight_g": 1600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4830 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 165 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 165 mm Fw and 40 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 1600 g at 165×190×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 165 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4830 shares its 165×190×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 2,400 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 147/415 kN ratings and 1600 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a RNA 4830?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 165 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4830?",
        "a": "A RNA 4830 measures 165 mm bore/Fw × 190 mm outside diameter × 40 mm width (6.496 × 7.48 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 147 kN, static C0 415 kN, fatigue limit Pu 46.5 kN, limiting speed 2,800 r/min, reference speed 2,400 r/min, mass about 1600 g."
      },
      {
        "q": "How is the RNA 4830 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 165 mm and width 40 mm, OD 190 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4830 run on an unhardened shaft?",
        "a": "No. In this execution the 165 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4830-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 165×190×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4830",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4830",
      "RNA 4830"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4832",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4832",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 175,
    "D_mm": 200,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 157,
    "static_load_kN": 450,
    "fatigue_load_limit_kN": 49,
    "max_rpm": 2600,
    "reference_speed_rpm": 2200,
    "limiting_speed_rpm": 2600,
    "weight_g": 1700,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4832 designates a flanged, machined outer ring filled with needle rollers and a cage for a 175 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The RNA 4832 code states Fw 175 and width 40 mm directly; because the family has no inner ring, the 175 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 1700 g at 175×200×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 175 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 157/450 kN ratings and 1700 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4832 run on an unhardened shaft?",
        "a": "No. In this execution the 175 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4832 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 175 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4832?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 175 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4832?",
        "a": "A RNA 4832 measures 175 mm bore/Fw × 200 mm outside diameter × 40 mm width (6.89 × 7.874 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 157 kN, static C0 450 kN, fatigue limit Pu 49 kN, limiting speed 2,600 r/min, reference speed 2,200 r/min, mass about 1700 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4832-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 175×200×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4832",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4832",
      "RNA 4832"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4834",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4834",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 185,
    "D_mm": 215,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 179,
    "static_load_kN": 520,
    "fatigue_load_limit_kN": 56,
    "max_rpm": 2400,
    "reference_speed_rpm": 2200,
    "limiting_speed_rpm": 2400,
    "weight_g": 2550,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "Where the shaft can be hardened and ground, SKF offers RNA 4834 in the dimension series 48 needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 185 mm bore seat and 215 mm OD. The letters identify a flanged machined outer ring without inner ring; the figures give 185 mm Fw and 45 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 2550 g at 185×215×45 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 185 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 185 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 179/520 kN ratings are SKF catalogue values for this exact execution (RNA 4834); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 179/520 kN ratings and 2550 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the RNA 4834?",
        "a": "A RNA 4834 measures 185 mm bore/Fw × 215 mm outside diameter × 45 mm width (7.283 × 8.465 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 179 kN, static C0 520 kN, fatigue limit Pu 56 kN, limiting speed 2,400 r/min, reference speed 2,200 r/min, mass about 2550 g."
      },
      {
        "q": "How is the RNA 4834 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 185 mm and width 45 mm, OD 215 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4834 run on an unhardened shaft?",
        "a": "No. In this execution the 185 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4834 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 185 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4834-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 185×215×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4834",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4834",
      "RNA 4834"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4836",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4836",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 195,
    "D_mm": 225,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 190,
    "static_load_kN": 570,
    "fatigue_load_limit_kN": 60,
    "max_rpm": 2400,
    "reference_speed_rpm": 2000,
    "limiting_speed_rpm": 2400,
    "weight_g": 2700,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4836 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 195 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The RNA 4836 code states Fw 195 and width 45 mm directly; because the family has no inner ring, the 195 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 2700 g at 195×225×45 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 195 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4836 shares its 195×225×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 2,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 190/570 kN ratings and 2700 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RNA 4836 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 195 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4836?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 195 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4836?",
        "a": "A RNA 4836 measures 195 mm bore/Fw × 225 mm outside diameter × 45 mm width (7.677 × 8.858 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 190 kN, static C0 570 kN, fatigue limit Pu 60 kN, limiting speed 2,400 r/min, reference speed 2,000 r/min, mass about 2700 g."
      },
      {
        "q": "How is the RNA 4836 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 195 mm and width 45 mm, OD 225 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4836-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 195×225×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4836",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4836",
      "RNA 4836"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4838",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4838",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 210,
    "D_mm": 240,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 220,
    "static_load_kN": 710,
    "fatigue_load_limit_kN": 73.5,
    "max_rpm": 2200,
    "reference_speed_rpm": 1900,
    "limiting_speed_rpm": 2200,
    "weight_g": 3200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4838 designates a flanged, machined outer ring filled with needle rollers and a cage for a 210 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 210 mm Fw and 50 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 3200 g at 210×240×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 210 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 220/710 kN ratings and 3200 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4838 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 210 mm and width 50 mm, OD 240 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4838 run on an unhardened shaft?",
        "a": "No. In this execution the 210 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4838 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 210 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4838?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 210 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4838-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 210×240×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4838",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4838",
      "RNA 4838"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4840",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4840",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 220,
    "D_mm": 250,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 224,
    "static_load_kN": 735,
    "fatigue_load_limit_kN": 75,
    "max_rpm": 2000,
    "reference_speed_rpm": 1800,
    "limiting_speed_rpm": 2000,
    "weight_g": 3350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4840 belongs to the machined-ring needle roller family: an outer ring turned and ground to 250 mm with two retaining flanges, a roller-and-cage set inside, and envelope 220×250×50 mm on a hardened 220 mm shaft. Reading the designation: RNA gives the series and the numbers the boundary plan — 220 mm Fw for the shaft seat, 50 mm width; the 250 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 3350 g at 220×250×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 250 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 220 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 1,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 220 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 224/735 kN ratings and 3350 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RNA 4840 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 220 mm and width 50 mm, OD 250 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4840 need a hardened and ground shaft?",
        "a": "No. In this execution the 220 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4840?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 220 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4840 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4840-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 220×250×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4840",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4840",
      "RNA 4840"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4844",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4844",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 240,
    "D_mm": 270,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 238,
    "static_load_kN": 815,
    "fatigue_load_limit_kN": 81.5,
    "max_rpm": 1900,
    "reference_speed_rpm": 1700,
    "limiting_speed_rpm": 1900,
    "weight_g": 3600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF's dimension series 48 needle roller bearings without inner ring include RNA 4844: 240 mm Fw, 270 mm outside diameter, 50 mm width — a machined and ground outer ring whose rolled flanges retain the needle rollers, running on the shaft as the inner raceway. Reading the designation: RNA gives the series and the numbers the boundary plan — 240 mm Fw for the shaft seat, 50 mm width; the 270 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 3600 g at 240×270×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 270 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 240 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 238/815 kN ratings are SKF catalogue values for this exact execution (RNA 4844); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 238/815 kN ratings and 3600 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RNA 4844 need a hardened and ground shaft?",
        "a": "No. In this execution the 240 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4844?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 240 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4844 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4844 have?",
        "a": "A RNA 4844 measures 240 mm bore/Fw × 270 mm outside diameter × 50 mm width (9.449 × 10.63 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 238 kN, static C0 815 kN, fatigue limit Pu 81.5 kN, limiting speed 1,900 r/min, reference speed 1,700 r/min, mass about 3600 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4844-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 240×270×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4844",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4844",
      "RNA 4844"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4848",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4848",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 265,
    "D_mm": 300,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 347,
    "static_load_kN": 1120,
    "fatigue_load_limit_kN": 112,
    "max_rpm": 1700,
    "reference_speed_rpm": 1500,
    "limiting_speed_rpm": 1700,
    "weight_g": 5400,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4848 is a ribbed machined-ring needle roller bearing (no inner ring) sized 265×300×60 mm: the ground outside diameter seats in the housing, the integral flanges hold the rollers, and the 265 mm shaft journal completes the bearing. Reading the designation: RNA gives the series and the numbers the boundary plan — 265 mm Fw for the shaft seat, 60 mm width; the 300 mm OD comes from the dimension series, and the absence of an inner ring is built into the family name. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 5400 g at 265×300×60 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 300 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 265 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RNA 4848 shares its 265×300×60 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 347/1120 kN ratings and 5400 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a RNA 4848?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 265 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RNA 4848 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RNA 4848 have?",
        "a": "A RNA 4848 measures 265 mm bore/Fw × 300 mm outside diameter × 60 mm width (10.433 × 11.811 × 2.362 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 347 kN, static C0 1120 kN, fatigue limit Pu 112 kN, limiting speed 1,700 r/min, reference speed 1,500 r/min, mass about 5400 g."
      },
      {
        "q": "What does RNA 4848 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 265 mm and width 60 mm, OD 300 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4848-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 265×300×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4848",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4848",
      "RNA 4848"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4852",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4852",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 285,
    "D_mm": 320,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 358,
    "static_load_kN": 1200,
    "fatigue_load_limit_kN": 118,
    "max_rpm": 1500,
    "reference_speed_rpm": 1400,
    "limiting_speed_rpm": 1500,
    "weight_g": 5800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RNA 4852 designates a flanged, machined outer ring filled with needle rollers and a cage for a 285 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 285 mm Fw and 60 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 5800 g at 285×320×60 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 285 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: RNA 4852 shares its 285×320×60 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 1,400 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 358/1200 kN ratings and 5800 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RNA 4852 designation read?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 285 mm and width 60 mm, OD 320 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Can the RNA 4852 run on an unhardened shaft?",
        "a": "No. In this execution the 285 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4852 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 285 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4852?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 285 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 17.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4852-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 285×320×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4852",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4852",
      "RNA 4852"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4856",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4856",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 305,
    "D_mm": 350,
    "B_mm": 69,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 429,
    "static_load_kN": 1320,
    "fatigue_load_limit_kN": 129,
    "max_rpm": 1400,
    "reference_speed_rpm": 1300,
    "limiting_speed_rpm": 1400,
    "weight_g": 9300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4856 is a machined-ring needle roller bearing without an inner ring: a solid outer ring with integral flanges guiding the caged rollers, riding directly on a 305 mm hardened shaft journal, as listed in SKF catalogue PUB BU/P1 17000. The letters identify a flanged machined outer ring without inner ring; the figures give 305 mm Fw and 69 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 9300 g at 305×350×69 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 305 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 305 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 429/1320 kN ratings are SKF catalogue values for this exact execution (RNA 4856); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 429/1320 kN ratings and 9300 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RNA 4856 run on an unhardened shaft?",
        "a": "No. In this execution the 305 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "How should the RNA 4856 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 305 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RNA 4856?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 305 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 22.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RNA 4856?",
        "a": "A RNA 4856 measures 305 mm bore/Fw × 350 mm outside diameter × 69 mm width (12.008 × 13.78 × 2.717 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 429 kN, static C0 1320 kN, fatigue limit Pu 129 kN, limiting speed 1,400 r/min, reference speed 1,300 r/min, mass about 9300 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4856-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 305×350×69 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4856",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4856",
      "RNA 4856"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RNA4860",
    "brand": "SKF",
    "manufacturer_designation": "RNA 4860",
    "series": "RNA-48-series",
    "type": "needle",
    "d_mm": 330,
    "D_mm": 380,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 594,
    "static_load_kN": 1800,
    "fatigue_load_limit_kN": 173,
    "max_rpm": 1300,
    "reference_speed_rpm": 1100,
    "limiting_speed_rpm": 1300,
    "weight_g": 12500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "RNA 4860 belongs to the machined-ring needle roller family: an outer ring turned and ground to 380 mm with two retaining flanges, a roller-and-cage set inside, and envelope 330×380×80 mm on a hardened 330 mm shaft. In SKF nomenclature RNA families drop the inner ring: the numbers after the letters give the 330 mm under-roller diameter and the 80 mm width, with the 380 mm outside diameter set by the dimension series 48 needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Catalogue mass 12500 g at 330×380×80 mm makes this one of the highest capacity-per-gram choices in the dimension series 48 needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.",
    "applications": [
      "cam followers built up from separate components",
      "crank pins and eccentrics where the hardened journal is the raceway",
      "gearbox planetary and idler gears on hardened pins",
      "piston-pin style pivots in hydraulic pumps"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "smearing of rollers and journal during idle periods because the radial section holds too little lubricant"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 330 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 594/1800 kN ratings are SKF catalogue values for this exact execution (RNA 4860); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 594/1800 kN ratings and 12500 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 636); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RNA 4860 have?",
        "a": "A RNA 4860 measures 330 mm bore/Fw × 380 mm outside diameter × 80 mm width (12.992 × 14.961 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 594 kN, static C0 1800 kN, fatigue limit Pu 173 kN, limiting speed 1,300 r/min, reference speed 1,100 r/min, mass about 12500 g."
      },
      {
        "q": "What does RNA 4860 mean in SKF part numbering?",
        "a": "RNA names a machined-ring needle roller bearing without inner ring: the figures give Fw 330 mm and width 80 mm, OD 380 mm comes from the dimension series, and the flanged outer ring retains the caged rollers."
      },
      {
        "q": "Does the RNA 4860 need a hardened and ground shaft?",
        "a": "No. In this execution the 330 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead."
      },
      {
        "q": "What mounting mistakes ruin a RNA 4860?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 330 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RNA4860-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 330×380×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "RNA4860",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RNA4860",
      "RNA 4860"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI5-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 5/12 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 15,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 3.8,
    "static_load_kN": 4.25,
    "fatigue_load_limit_kN": 0.465,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 12,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 5/12 TN provides the full machined-ring needle roller construction: ground inner ring on a 5 mm seat, flanged outer ring at 15 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The designation NKI 5/12 TN tells you the envelope — 5×15×12 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Catalogue mass 12 g at 5×15×12 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the NKI 5/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 3.8/4.25 kN ratings and 12 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKI 5/12 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 5 mm bore, 12 mm width, 15 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 5/12 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 5/12 TN carries its own hardened, ground inner ring on a 5 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 5/12 TN be mounted?",
        "a": "Mount the inner ring on the 5 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 5/12 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 5 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI5-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 5×15×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI5-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI5",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI5-12-TN",
      "NKI 5/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI5-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 5/16 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 5,
    "D_mm": 15,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.01,
    "static_load_kN": 5.85,
    "fatigue_load_limit_kN": 0.67,
    "max_rpm": 36000,
    "reference_speed_rpm": 32000,
    "limiting_speed_rpm": 36000,
    "weight_g": 15,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 5/16 TN measures 5×15×16 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The NKI 5/16 TN code gives bore 5 mm and width 16 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 15 g catalogue mass and 5.0 mm radial section ((15−5)/2) frame a rating of about 1.00 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: heat or press the inner ring onto the 5 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 16 mm assembly for free rotation before applying load.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At Fw 5 mm the rolling elements are under two millimetres long — handle the NKI 5/16 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 5.01/5.85 kN ratings and 15 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 5/16 TN?",
        "a": "A NKI 5/16 TN measures 5 mm bore/Fw × 15 mm outside diameter × 16 mm width (0.197 × 0.591 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.01 kN, static C0 5.85 kN, fatigue limit Pu 0.67 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 15 g."
      },
      {
        "q": "How is the NKI 5/16 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 5 mm bore, 16 mm width, 15 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 5/16 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 5/16 TN carries its own hardened, ground inner ring on a 5 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 5/16 TN be mounted?",
        "a": "Mount the inner ring on the 5 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI5-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI5-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 5×15×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI5",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI5-16-TN",
      "NKI 5/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI6-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 6/12 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 16,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.4,
    "static_load_kN": 5.2,
    "fatigue_load_limit_kN": 0.57,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 6/12 TN denotes a complete needle roller bearing for a 6 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 16 mm OD and 12 mm width. The designation NKI 6/12 TN tells you the envelope — 6×16×12 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 4.4 kN against C0 5.2 kN gives a C0/C ratio of 1.18, and the 0.57 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 6 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 12 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the NKI 6/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 4.4/5.2 kN ratings and 14 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKI 6/12 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 6 mm bore, 12 mm width, 16 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 6/12 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 6/12 TN carries its own hardened, ground inner ring on a 6 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 6/12 TN be mounted?",
        "a": "Mount the inner ring on the 6 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 6/12 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 6 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI6-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 6×16×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI6-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI6",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI6-12-TN",
      "NKI 6/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI6-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 6/16 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 6,
    "D_mm": 16,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.72,
    "static_load_kN": 7.2,
    "fatigue_load_limit_kN": 0.815,
    "max_rpm": 34000,
    "reference_speed_rpm": 30000,
    "limiting_speed_rpm": 34000,
    "weight_g": 17,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 6/16 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 6 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 6 mm d and 16 mm B, the 16 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 17 g catalogue mass and 5.0 mm radial section ((16−6)/2) frame a rating of about 0.95 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 16 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At Fw 6 mm the rolling elements are under two millimetres long — handle the NKI 6/16 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 5.72/7.2 kN ratings are SKF catalogue values for this exact execution (NKI 6/16 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 5.72/7.2 kN ratings and 17 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 6/16 TN have?",
        "a": "A NKI 6/16 TN measures 6 mm bore/Fw × 16 mm outside diameter × 16 mm width (0.236 × 0.63 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.72 kN, static C0 7.2 kN, fatigue limit Pu 0.815 kN, limiting speed 34,000 r/min, reference speed 30,000 r/min, mass about 17 g."
      },
      {
        "q": "What does NKI 6/16 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 6 mm bore, 16 mm width, 16 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 6/16 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 6/16 TN carries its own hardened, ground inner ring on a 6 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 6/16 TN?",
        "a": "Mount the inner ring on the 6 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI6-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI6-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 6×16×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI6",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI6-16-TN",
      "NKI 6/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI7-12-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 7/12 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 17,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 4.57,
    "static_load_kN": 5.7,
    "fatigue_load_limit_kN": 0.63,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 7/12 TN measures 7×17×12 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 7 mm bore (d), 12 mm width; the 17 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 4.57 kN against C0 5.7 kN gives a C0/C ratio of 1.25, and the 0.63 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 12 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NKI 7/12 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 4.57/5.7 kN ratings are SKF catalogue values for this exact execution (NKI 7/12 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 4.57/5.7 kN ratings and 14 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 7/12 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 7 mm bore, 12 mm width, 17 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 7/12 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 7/12 TN carries its own hardened, ground inner ring on a 7 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 7/12 TN?",
        "a": "Mount the inner ring on the 7 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 7/12 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI7-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 7×17×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI7-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI7-12-TN",
      "NKI 7/12 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI7-16-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 7/16 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 17,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.94,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.9,
    "max_rpm": 32000,
    "reference_speed_rpm": 28000,
    "limiting_speed_rpm": 32000,
    "weight_g": 18,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 7/16 TN in the machined-ring needle roller bearings with inner ring with boundary dimensions 7×17×16 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 7 mm d and 16 mm B, the 17 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. For life calculation, the 5.94/8 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 16 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NKI 7/16 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 5.94/8 kN ratings are SKF catalogue values for this exact execution (NKI 7/16 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 5.94/8 kN ratings and 18 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 7/16 TN have?",
        "a": "A NKI 7/16 TN measures 7 mm bore/Fw × 17 mm outside diameter × 16 mm width (0.276 × 0.669 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.94 kN, static C0 8 kN, fatigue limit Pu 0.9 kN, limiting speed 32,000 r/min, reference speed 28,000 r/min, mass about 18 g."
      },
      {
        "q": "What does NKI 7/16 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 7 mm bore, 16 mm width, 17 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 7/16 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 7/16 TN carries its own hardened, ground inner ring on a 7 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 7/16 TN?",
        "a": "Mount the inner ring on the 7 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI7-12-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI7-16-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 7×17×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI7",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI7-16-TN",
      "NKI 7/16 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI9-12",
    "brand": "SKF",
    "manufacturer_designation": "NKI 9/12",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 19,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 6.71,
    "static_load_kN": 8.15,
    "fatigue_load_limit_kN": 0.965,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 17,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 9/12 provides the full machined-ring needle roller construction: ground inner ring on a 9 mm seat, flanged outer ring at 19 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NKI 9/12 code gives bore 9 mm and width 12 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Selection arithmetic: C 6.71 kN against C0 8.15 kN gives a C0/C ratio of 1.21, and the 0.965 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 9 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 6.71/8.15 kN ratings are SKF catalogue values for this exact execution (NKI 9/12); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 6.71/8.15 kN ratings and 17 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKI 9/12 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 9 mm bore, 12 mm width, 19 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 9/12 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 9/12 carries its own hardened, ground inner ring on a 9 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 9/12 be mounted?",
        "a": "Mount the inner ring on the 9 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 9/12?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 9 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI9-12-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 9×19×12 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI9-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI9",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI9-12",
      "NKI 9/12"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI9-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 9/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 9,
    "D_mm": 19,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 30000,
    "reference_speed_rpm": 26000,
    "limiting_speed_rpm": 30000,
    "weight_g": 22,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 9/16 measures 9×19×16 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The NKI 9/16 code gives bore 9 mm and width 16 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Selection arithmetic: C 9.13 kN against C0 12 kN gives a C0/C ratio of 1.31, and the 1.43 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 9.13/12 kN ratings and 22 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKI 9/16 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 9/16 carries its own hardened, ground inner ring on a 9 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 9/16 be mounted?",
        "a": "Mount the inner ring on the 9 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 9/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 9 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 9/16?",
        "a": "A NKI 9/16 measures 9 mm bore/Fw × 19 mm outside diameter × 16 mm width (0.354 × 0.748 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12 kN, fatigue limit Pu 1.43 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 22 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI9-12-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI9-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI9",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI9-16",
      "NKI 9/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4900",
    "brand": "SKF",
    "manufacturer_designation": "NA 4900",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.8,
    "static_load_kN": 10.4,
    "fatigue_load_limit_kN": 1.22,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 24,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 10 mm shaft that cannot be hardened on site, NA 4900 adds a hardened, ground inner ring to the machined needle roller design: envelope 10×22×13 mm per the dimension series 49 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 10 mm bore (d), 13 mm width; the 22 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 24 g at 10×22×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4900 shares its 10×22×13 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 8.8/10.4 kN ratings and 24 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 4900 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 10 mm bore, 13 mm width, 22 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4900 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4900 carries its own hardened, ground inner ring on a 10 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4900?",
        "a": "Mount the inner ring on the 10 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4900 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4900-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 10×22×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4900",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4900",
      "NA 4900"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4900-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4900.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 14,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.37,
    "static_load_kN": 8.15,
    "fatigue_load_limit_kN": 0.965,
    "max_rpm": 12000,
    "limiting_speed_rpm": 12000,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 10 mm shaft that cannot be hardened on site, NA 4900.2RS adds a hardened, ground inner ring to the machined needle roller design: envelope 10×22×14 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 10 mm d and 14 mm B, the 22 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. For life calculation, the 7.37/8.15 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 7.37/8.15 kN ratings are SKF catalogue values for this exact execution (NA 4900.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 7.37/8.15 kN ratings and 25 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4900.2RS sealed?",
        "a": "Yes — the 2RS execution seals both faces with rubber contact seals; note its wider outer ring (B and s differ from the open execution), so housing dimensions must be re-checked."
      },
      {
        "q": "Which dimensions does the NA 4900.2RS have?",
        "a": "A NA 4900.2RS measures 10 mm bore/Fw × 22 mm outside diameter × 14 mm width (0.394 × 0.866 × 0.551 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 8.15 kN, fatigue limit Pu 0.965 kN, limiting speed 12,000 r/min, mass about 25 g."
      },
      {
        "q": "What does NA 4900.2RS mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 10 mm bore, 14 mm width, 22 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4900.2RS need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4900.2RS carries its own hardened, ground inner ring on a 10 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4900-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4900",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4900-2RS",
      "NA 4900.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI10-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 10/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 10.2,
    "static_load_kN": 12.5,
    "fatigue_load_limit_kN": 1.5,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 29,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 10/16 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 10 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 10 mm d and 16 mm B, the 22 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Selection arithmetic: C 10.2 kN against C0 12.5 kN gives a C0/C ratio of 1.23, and the 1.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 10/16 shares its 10×22×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 10.2/12.5 kN ratings and 29 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 10/16 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 10 mm bore, 16 mm width, 22 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 10/16 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 10/16 carries its own hardened, ground inner ring on a 10 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 10/16?",
        "a": "Mount the inner ring on the 10 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 10/16 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI10-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 10×22×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI10-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI10-16",
      "NKI 10/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI10-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 10/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 22,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 16.6,
    "fatigue_load_limit_kN": 2,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 10/20 provides the full machined-ring needle roller construction: ground inner ring on a 10 mm seat, flanged outer ring at 22 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NKI 10/20 code gives bore 10 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Selection arithmetic: C 12.8 kN against C0 16.6 kN gives a C0/C ratio of 1.30, and the 2 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 10 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKI 10/20 shares its 10×22×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 12.8/16.6 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 10/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 10 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 10/20?",
        "a": "A NKI 10/20 measures 10 mm bore/Fw × 22 mm outside diameter × 20 mm width (0.394 × 0.866 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 16.6 kN, fatigue limit Pu 2 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 37 g."
      },
      {
        "q": "How is the NKI 10/20 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 10 mm bore, 20 mm width, 22 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 10/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 10/20 carries its own hardened, ground inner ring on a 10 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI10-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI10-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 10×22×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI10",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI10-20",
      "NKI 10/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4901",
    "brand": "SKF",
    "manufacturer_designation": "NA 4901",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.9,
    "static_load_kN": 12.2,
    "fatigue_load_limit_kN": 1.46,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 26,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4901 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 12 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NA 4901 code gives bore 12 mm and width 13 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 26 g at 12×24×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 9.9/12.2 kN ratings and 26 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 4901?",
        "a": "A NA 4901 measures 12 mm bore/Fw × 24 mm outside diameter × 13 mm width (0.472 × 0.945 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.9 kN, static C0 12.2 kN, fatigue limit Pu 1.46 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 26 g."
      },
      {
        "q": "How is the NA 4901 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 13 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4901 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4901 carries its own hardened, ground inner ring on a 12 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4901 be mounted?",
        "a": "Mount the inner ring on the 12 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4901-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 12×24×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4901",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4901",
      "NA 4901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4901-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4901.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 14,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.09,
    "static_load_kN": 9.65,
    "fatigue_load_limit_kN": 1.14,
    "max_rpm": 11000,
    "limiting_speed_rpm": 11000,
    "weight_g": 28,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4901.2RS provides the full machined-ring needle roller construction: ground inner ring on a 12 mm seat, flanged outer ring at 24 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NA 4901.2RS code gives bore 12 mm and width 14 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 11,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 12 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 14 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 8.09/9.65 kN ratings are SKF catalogue values for this exact execution (NA 4901.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 8.09/9.65 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 4901.2RS?",
        "a": "A NA 4901.2RS measures 12 mm bore/Fw × 24 mm outside diameter × 14 mm width (0.472 × 0.945 × 0.551 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.09 kN, static C0 9.65 kN, fatigue limit Pu 1.14 kN, limiting speed 11,000 r/min, mass about 28 g."
      },
      {
        "q": "How is the NA 4901.2RS designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 14 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4901.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4901.2RS carries its own hardened, ground inner ring on a 12 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4901.2RS be mounted?",
        "a": "Mount the inner ring on the 12 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4901-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4901",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4901-2RS",
      "NA 4901.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI12-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 12/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.7,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.8,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 33,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 12 mm shaft that cannot be hardened on site, NKI 12/16 adds a hardened, ground inner ring to the machined needle roller design: envelope 12×24×16 mm per the machined-ring needle roller bearings with inner ring plan. The designation NKI 12/16 tells you the envelope — 12×24×16 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 12 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 16 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 11.7/15.3 kN ratings are SKF catalogue values for this exact execution (NKI 12/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 11.7/15.3 kN ratings and 33 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 12/16?",
        "a": "A NKI 12/16 measures 12 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.472 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.7 kN, static C0 15.3 kN, fatigue limit Pu 1.8 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 33 g."
      },
      {
        "q": "How is the NKI 12/16 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 16 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 12/16 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 12/16 carries its own hardened, ground inner ring on a 12 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 12/16 be mounted?",
        "a": "Mount the inner ring on the 12 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI12-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 12×24×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI12-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKIA5901",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×24×16 mm envelope, but catalogue C/C0 differ between the executions (11.7/15.3 vs 8.09/9.65 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI12-16",
      "NKI 12/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI12-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 12/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 14.5,
    "static_load_kN": 20,
    "fatigue_load_limit_kN": 2.4,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 12/20 denotes a complete needle roller bearing for a 12 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 24 mm OD and 20 mm width. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 12 mm d and 20 mm B, the 24 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 14.5/20 kN ratings are SKF catalogue values for this exact execution (NKI 12/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 14.5/20 kN ratings and 42 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 12/20?",
        "a": "Mount the inner ring on the 12 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 12/20 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 12/20 have?",
        "a": "A NKI 12/20 measures 12 mm bore/Fw × 24 mm outside diameter × 20 mm width (0.472 × 0.945 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.5 kN, static C0 20 kN, fatigue limit Pu 2.4 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 42 g."
      },
      {
        "q": "What does NKI 12/20 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 20 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI12-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI12-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 12×24×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI12-20",
      "NKI 12/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6901",
    "brand": "SKF",
    "manufacturer_designation": "NA 6901",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.1,
    "static_load_kN": 23.2,
    "fatigue_load_limit_kN": 2.75,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 46,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 12 mm shaft that cannot be hardened on site, NA 6901 adds a hardened, ground inner ring to the machined needle roller design: envelope 12×24×22 mm per the dimension series 69 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 12 mm d and 22 mm B, the 24 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 16.1/23.2 kN ratings and 46 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 6901 have?",
        "a": "A NA 6901 measures 12 mm bore/Fw × 24 mm outside diameter × 22 mm width (0.472 × 0.945 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.1 kN, static C0 23.2 kN, fatigue limit Pu 2.75 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 46 g."
      },
      {
        "q": "What does NA 6901 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 22 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6901 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6901 carries its own hardened, ground inner ring on a 12 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6901?",
        "a": "Mount the inner ring on the 12 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6901-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 12×24×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6901",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6901",
      "NA 6901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI15-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 15/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 27,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.4,
    "static_load_kN": 19,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 24000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 24000,
    "weight_g": 39,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 15/16 provides the full machined-ring needle roller construction: ground inner ring on a 15 mm seat, flanged outer ring at 27 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NKI 15/16 code gives bore 15 mm and width 16 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 39 g catalogue mass and 6.0 mm radial section ((27−15)/2) frame a rating of about 0.89 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 16 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 27 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKI 15/16 shares its 15×27×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 20,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 13.4/19 kN ratings and 39 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 15/16?",
        "a": "A NKI 15/16 measures 15 mm bore/Fw × 27 mm outside diameter × 16 mm width (0.591 × 1.063 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.4 kN, static C0 19 kN, fatigue limit Pu 2.28 kN, limiting speed 24,000 r/min, reference speed 20,000 r/min, mass about 39 g."
      },
      {
        "q": "How is the NKI 15/16 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 16 mm width, 27 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 15/16 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 15/16 carries its own hardened, ground inner ring on a 15 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 15/16 be mounted?",
        "a": "Mount the inner ring on the 15 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI15-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI15-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI15-16",
      "NKI 15/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI15-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 15/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 27,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 16.5,
    "static_load_kN": 25.5,
    "fatigue_load_limit_kN": 3.05,
    "max_rpm": 24000,
    "reference_speed_rpm": 20000,
    "limiting_speed_rpm": 24000,
    "weight_g": 49,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 15/20 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 15 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 15 mm bore (d), 20 mm width; the 27 mm OD follows the dimension series, and the inner ring is a separate ground component. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 49 g catalogue mass and 6.0 mm radial section ((27−15)/2) frame a rating of about 1.10 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 27 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 20,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 16.5/25.5 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 15/20?",
        "a": "Mount the inner ring on the 15 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 15/20 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 15/20 have?",
        "a": "A NKI 15/20 measures 15 mm bore/Fw × 27 mm outside diameter × 20 mm width (0.591 × 1.063 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.5 kN, static C0 25.5 kN, fatigue limit Pu 3.05 kN, limiting speed 24,000 r/min, reference speed 20,000 r/min, mass about 49 g."
      },
      {
        "q": "What does NKI 15/20 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 20 mm width, 27 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI15-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI15-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×27×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI15-20",
      "NKI 15/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4902",
    "brand": "SKF",
    "manufacturer_designation": "NA 4902",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.2,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.83,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4902 measures 15×28×13 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 15 mm d and 13 mm B, the 28 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 34 g at 15×28×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 11.2/15.3 kN ratings are SKF catalogue values for this exact execution (NA 4902); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 11.2/15.3 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4902 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4902 have?",
        "a": "A NA 4902 measures 15 mm bore/Fw × 28 mm outside diameter × 13 mm width (0.591 × 1.102 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.2 kN, static C0 15.3 kN, fatigue limit Pu 1.83 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 34 g."
      },
      {
        "q": "What does NA 4902 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 13 mm width, 28 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4902 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4902 carries its own hardened, ground inner ring on a 15 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4902-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×28×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4902",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4902",
      "NA 4902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4902-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4902.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 14,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 9500,
    "limiting_speed_rpm": 9500,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4902.2RS measures 15×28×14 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The NA 4902.2RS code gives bore 15 mm and width 14 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 15 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 14 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NA 4902.2RS shares its 15×28×14 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 9.13/12 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4902.2RS designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 14 mm width, 28 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4902.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4902.2RS carries its own hardened, ground inner ring on a 15 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4902.2RS be mounted?",
        "a": "Mount the inner ring on the 15 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4902.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4902-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4902",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4902-2RS",
      "NA 4902.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6902",
    "brand": "SKF",
    "manufacturer_designation": "NA 6902",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.2,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 64,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6902 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 15 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NA 6902 tells you the envelope — 15×28×23 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NA 6902 shares its 15×28×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 17.2/27 kN ratings and 64 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 6902?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6902?",
        "a": "A NA 6902 measures 15 mm bore/Fw × 28 mm outside diameter × 23 mm width (0.591 × 1.102 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 17.2 kN, static C0 27 kN, fatigue limit Pu 3.35 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 64 g."
      },
      {
        "q": "How is the NA 6902 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 23 mm width, 28 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 6902 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6902 carries its own hardened, ground inner ring on a 15 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6902-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×28×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6902",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6902",
      "NA 6902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS15",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 15",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 35,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 30,
    "fatigue_load_limit_kN": 3.65,
    "max_rpm": 19000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 19000,
    "weight_g": 92,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 15 provides the full machined-ring needle roller construction: ground inner ring on a 15 mm seat, flanged outer ring at 35 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 15 mm d and 20 mm B, the 35 mm outside diameter from the wide-section machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 16,000 r/min thermal reference and 19,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 15 mm seat. Mounting: heat or press the inner ring onto the 15 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 35 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 16,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 24.6/30 kN ratings and 92 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKIS 15?",
        "a": "Mount the inner ring on the 15 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKIS 15 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKIS 15 have?",
        "a": "A NKIS 15 measures 15 mm bore/Fw × 35 mm outside diameter × 20 mm width (0.591 × 1.378 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.6 kN, static C0 30 kN, fatigue limit Pu 3.65 kN, limiting speed 19,000 r/min, reference speed 16,000 r/min, mass about 92 g."
      },
      {
        "q": "What does NKIS 15 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 15 mm bore, 20 mm width, 35 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS15-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 15×35×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS15",
      "NKIS 15"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI17-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 17/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 29,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.8,
    "static_load_kN": 20.4,
    "fatigue_load_limit_kN": 2.45,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 42,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 17/16 denotes a complete needle roller bearing for a 17 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 29 mm OD and 16 mm width. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 17 mm d and 16 mm B, the 29 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Selection arithmetic: C 13.8 kN against C0 20.4 kN gives a C0/C ratio of 1.48, and the 2.45 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 29 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 13.8/20.4 kN ratings are SKF catalogue values for this exact execution (NKI 17/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 13.8/20.4 kN ratings and 42 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 17/16 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 17/16 have?",
        "a": "A NKI 17/16 measures 17 mm bore/Fw × 29 mm outside diameter × 16 mm width (0.669 × 1.142 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.8 kN, static C0 20.4 kN, fatigue limit Pu 2.45 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 42 g."
      },
      {
        "q": "What does NKI 17/16 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 17 mm bore, 16 mm width, 29 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 17/16 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 17/16 carries its own hardened, ground inner ring on a 17 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI17-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI17-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI17-16",
      "NKI 17/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI17-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 17/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 29,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 17.2,
    "static_load_kN": 27,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 17 mm shaft that cannot be hardened on site, NKI 17/20 adds a hardened, ground inner ring to the machined needle roller design: envelope 17×29×20 mm per the machined-ring needle roller bearings with inner ring plan. The NKI 17/20 code gives bore 17 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Selection arithmetic: C 17.2 kN against C0 27 kN gives a C0/C ratio of 1.57, and the 3.35 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 17 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 29 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 17.2/27 kN ratings and 53 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKI 17/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 17/20 carries its own hardened, ground inner ring on a 17 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 17/20 be mounted?",
        "a": "Mount the inner ring on the 17 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 17/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 17/20?",
        "a": "A NKI 17/20 measures 17 mm bore/Fw × 29 mm outside diameter × 20 mm width (0.669 × 1.142 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 17.2 kN, static C0 27 kN, fatigue limit Pu 3.35 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 53 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI17-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI17-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×29×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI17-20",
      "NKI 17/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4903",
    "brand": "SKF",
    "manufacturer_designation": "NA 4903",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 13,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 16.3,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 38,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4903 denotes a complete needle roller bearing for a 17 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 30 mm OD and 13 mm width. The designation NA 4903 tells you the envelope — 17×30×13 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 38 g at 17×30×13 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 17 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 11.4/16.3 kN ratings are SKF catalogue values for this exact execution (NA 4903); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 11.4/16.3 kN ratings and 38 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 4903 be mounted?",
        "a": "Mount the inner ring on the 17 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4903?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4903?",
        "a": "A NA 4903 measures 17 mm bore/Fw × 30 mm outside diameter × 13 mm width (0.669 × 1.181 × 0.512 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.4 kN, static C0 16.3 kN, fatigue limit Pu 1.96 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 38 g."
      },
      {
        "q": "How is the NA 4903 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 17 mm bore, 13 mm width, 30 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4903-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×30×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4903",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4903",
      "NA 4903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4903-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4903.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 14,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.52,
    "static_load_kN": 12.9,
    "fatigue_load_limit_kN": 1.53,
    "max_rpm": 9000,
    "limiting_speed_rpm": 9000,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 17 mm shaft that cannot be hardened on site, NA 4903.2RS adds a hardened, ground inner ring to the machined needle roller design: envelope 17×30×14 mm per the dimension series 49 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 17 mm bore (d), 14 mm width; the 30 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. The 40 g catalogue mass and 6.5 mm radial section ((30−17)/2) frame a rating of about 0.56 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4903.2RS shares its 17×30×14 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 9.52/12.9 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 4903.2RS need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4903.2RS carries its own hardened, ground inner ring on a 17 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4903.2RS?",
        "a": "Mount the inner ring on the 17 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4903.2RS sealed?",
        "a": "Yes — the 2RS execution seals both faces with rubber contact seals; note its wider outer ring (B and s differ from the open execution), so housing dimensions must be re-checked."
      },
      {
        "q": "Which dimensions does the NA 4903.2RS have?",
        "a": "A NA 4903.2RS measures 17 mm bore/Fw × 30 mm outside diameter × 14 mm width (0.669 × 1.181 × 0.551 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.52 kN, static C0 12.9 kN, fatigue limit Pu 1.53 kN, limiting speed 9,000 r/min, mass about 40 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4903-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4903",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4903-2RS",
      "NA 4903.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6903",
    "brand": "SKF",
    "manufacturer_designation": "NA 6903",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 18.7,
    "static_load_kN": 30.5,
    "fatigue_load_limit_kN": 3.75,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 72,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 6903 measures 17×30×23 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 17 mm bore (d), 23 mm width; the 30 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 6903 shares its 17×30×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 18.7/30.5 kN ratings and 72 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 6903?",
        "a": "Mount the inner ring on the 17 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6903 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6903 have?",
        "a": "A NA 6903 measures 17 mm bore/Fw × 30 mm outside diameter × 23 mm width (0.669 × 1.181 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 18.7 kN, static C0 30.5 kN, fatigue limit Pu 3.75 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 72 g."
      },
      {
        "q": "What does NA 6903 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 17 mm bore, 23 mm width, 30 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6903-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×30×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6903",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6903",
      "NA 6903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS17",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 17",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 37,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 26,
    "static_load_kN": 33.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 98,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 17 mm shaft that cannot be hardened on site, NKIS 17 adds a hardened, ground inner ring to the machined needle roller design: envelope 17×37×20 mm per the wide-section machined-ring needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 17 mm bore (d), 20 mm width; the 37 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 15,000 r/min thermal reference and 17,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 17 mm seat. Mounting: heat or press the inner ring onto the 17 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIS 17 shares its 17×37×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 26/33.5 kN ratings and 98 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIS 17 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 17 mm bore, 20 mm width, 37 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKIS 17 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKIS 17 carries its own hardened, ground inner ring on a 17 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKIS 17?",
        "a": "Mount the inner ring on the 17 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKIS 17 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS17-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 17×37×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS17",
      "NKIS 17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI20-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 20/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.4,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.9,
    "max_rpm": 19000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 19000,
    "weight_g": 48,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 20/16 in the machined-ring needle roller bearings with inner ring with boundary dimensions 20×32×16 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 20 mm d and 16 mm B, the 32 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. For life calculation, the 15.4/24.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 16 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 15.4/24.5 kN ratings are SKF catalogue values for this exact execution (NKI 20/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 15.4/24.5 kN ratings and 48 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 20/16 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 20/16 carries its own hardened, ground inner ring on a 20 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 20/16?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 20/16 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 20/16 have?",
        "a": "A NKI 20/16 measures 20 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.787 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.4 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 19,000 r/min, reference speed 16,000 r/min, mass about 48 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI20-16-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI20-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI20-16",
      "NKI 20/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI20-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 20/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 32,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 32.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 19000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 19000,
    "weight_g": 60,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 20/20 measures 20×32×20 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The NKI 20/20 code gives bore 20 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. For life calculation, the 19/32.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 19/32.5 kN ratings and 60 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 20/20?",
        "a": "A NKI 20/20 measures 20 mm bore/Fw × 32 mm outside diameter × 20 mm width (0.787 × 1.26 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19 kN, static C0 32.5 kN, fatigue limit Pu 4 kN, limiting speed 19,000 r/min, reference speed 16,000 r/min, mass about 60 g."
      },
      {
        "q": "How is the NKI 20/20 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 20 mm bore, 20 mm width, 32 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 20/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 20/20 carries its own hardened, ground inner ring on a 20 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 20/20 be mounted?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI20-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI20-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKS20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×32×20 mm envelope, but catalogue C/C0 differ between the executions (19/32.5 vs 23.3/27 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI20-20",
      "NKI 20/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4904",
    "brand": "SKF",
    "manufacturer_designation": "NA 4904",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 75,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4904 provides the full machined-ring needle roller construction: ground inner ring on a 20 mm seat, flanged outer ring at 37 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 20 mm bore (d), 17 mm width; the 37 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 75 g at 20×37×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 20 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 21.6/28 kN ratings and 75 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 4904 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4904 carries its own hardened, ground inner ring on a 20 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4904?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4904 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4904 have?",
        "a": "A NA 4904 measures 20 mm bore/Fw × 37 mm outside diameter × 17 mm width (0.787 × 1.457 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 28 kN, fatigue limit Pu 3.35 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 75 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4904-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA4904",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4904",
      "NA 4904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4904-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4904.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.4,
    "static_load_kN": 22.4,
    "fatigue_load_limit_kN": 2.65,
    "max_rpm": 7500,
    "limiting_speed_rpm": 7500,
    "weight_g": 80,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4904.2RS provides the full machined-ring needle roller construction: ground inner ring on a 20 mm seat, flanged outer ring at 37 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 20 mm bore (d), 18 mm width; the 37 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 80 g at 20×37×18 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 18 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 19.4/22.4 kN ratings are SKF catalogue values for this exact execution (NA 4904.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 19.4/22.4 kN ratings and 80 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4904.2RS?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4904.2RS sealed?",
        "a": "Yes — the 2RS execution seals both faces with rubber contact seals; note its wider outer ring (B and s differ from the open execution), so housing dimensions must be re-checked."
      },
      {
        "q": "Which dimensions does the NA 4904.2RS have?",
        "a": "A NA 4904.2RS measures 20 mm bore/Fw × 37 mm outside diameter × 18 mm width (0.787 × 1.457 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 22.4 kN, fatigue limit Pu 2.65 kN, limiting speed 7,500 r/min, mass about 80 g."
      },
      {
        "q": "What does NA 4904.2RS mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 20 mm bore, 18 mm width, 37 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4904-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4904",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4904-2RS",
      "NA 4904.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6904",
    "brand": "SKF",
    "manufacturer_designation": "NA 6904",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 35.2,
    "static_load_kN": 53,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 6904 denotes a complete needle roller bearing for a 20 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 37 mm OD and 30 mm width. The NA 6904 code gives bore 20 mm and width 30 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 35.2/53 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 6904 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6904 carries its own hardened, ground inner ring on a 20 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 6904 be mounted?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 6904?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6904?",
        "a": "A NA 6904 measures 20 mm bore/Fw × 37 mm outside diameter × 30 mm width (0.787 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 35.2 kN, static C0 53 kN, fatigue limit Pu 6.55 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 140 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6904-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×37×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6904",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6904",
      "NA 6904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS20",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 20",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 28.6,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.75,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The wide-section machined-ring needle roller bearings with inner ring execution NKIS 20 measures 20×42×20 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 20 mm d and 20 mm B, the 42 mm outside diameter from the wide-section machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 13,000 r/min thermal reference and 15,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 20 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 20 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 28.6/39 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKIS 20 have?",
        "a": "A NKIS 20 measures 20 mm bore/Fw × 42 mm outside diameter × 20 mm width (0.787 × 1.654 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 28.6 kN, static C0 39 kN, fatigue limit Pu 4.75 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 130 g."
      },
      {
        "q": "What does NKIS 20 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 20 mm bore, 20 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKIS 20 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKIS 20 carries its own hardened, ground inner ring on a 20 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKIS 20?",
        "a": "Mount the inner ring on the 20 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 20×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "PNA20-42",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×42×20 mm envelope, but catalogue C/C0 differ between the executions (28.6/39 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS20",
      "NKIS 20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI22-16",
    "brand": "SKF",
    "manufacturer_designation": "NKI 22/16",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 34,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.7,
    "static_load_kN": 26,
    "fatigue_load_limit_kN": 3.1,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 22/16 provides the full machined-ring needle roller construction: ground inner ring on a 22 mm seat, flanged outer ring at 34 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The designation NKI 22/16 tells you the envelope — 22×34×16 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: 15,000 r/min thermal reference and 17,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 22 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 34 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKI 22/16 shares its 22×34×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 15.7/26 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKI 22/16 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 22 mm bore, 16 mm width, 34 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 22/16 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 22/16 carries its own hardened, ground inner ring on a 22 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 22/16 be mounted?",
        "a": "Mount the inner ring on the 22 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 22/16?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI22-16-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×34×16 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI22-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI22-16",
      "NKI 22/16"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI22-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 22/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 34,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19.4,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.25,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 65,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 22/20 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 22 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 22 mm d and 20 mm B, the 34 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: 15,000 r/min thermal reference and 17,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 22 mm seat. Mounting: heat or press the inner ring onto the 22 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 34 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 15,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 19.4/34.5 kN ratings and 65 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 22/20 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 22/20 have?",
        "a": "A NKI 22/20 measures 22 mm bore/Fw × 34 mm outside diameter × 20 mm width (0.866 × 1.339 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19.4 kN, static C0 34.5 kN, fatigue limit Pu 4.25 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 65 g."
      },
      {
        "q": "What does NKI 22/20 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 22 mm bore, 20 mm width, 34 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 22/20 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 22/20 carries its own hardened, ground inner ring on a 22 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI22-16-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI22-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×34×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI22-20",
      "NKI 22/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-22",
    "brand": "SKF",
    "manufacturer_designation": "NA 49/22",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.9,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 80,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 22 mm shaft that cannot be hardened on site, NA 49/22 adds a hardened, ground inner ring to the machined needle roller design: envelope 22×39×17 mm per the dimension series 49 needle roller bearings with inner ring plan. The designation NA 49/22 tells you the envelope — 22×39×17 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 22 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 17 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 39 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 22 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 23.3/32 kN ratings are SKF catalogue values for this exact execution (NA 49/22); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 23.3/32 kN ratings and 80 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 49/22 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 49/22 carries its own hardened, ground inner ring on a 22 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 49/22 be mounted?",
        "a": "Mount the inner ring on the 22 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 49/22?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 49/22?",
        "a": "A NA 49/22 measures 22 mm bore/Fw × 39 mm outside diameter × 17 mm width (0.866 × 1.535 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.9 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 80 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×39×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA49-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-32-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-22",
      "NA 49/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-22",
    "brand": "SKF",
    "manufacturer_designation": "NA 69/22",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.2,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 69/22 measures 22×39×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 22 mm d and 30 mm B, the 39 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 39 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 69/22 shares its 22×39×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 36.9/57 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 69/22?",
        "a": "Mount the inner ring on the 22 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 69/22 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 69/22 have?",
        "a": "A NA 69/22 measures 22 mm bore/Fw × 39 mm outside diameter × 30 mm width (0.866 × 1.535 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 57 kN, fatigue limit Pu 7.2 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 150 g."
      },
      {
        "q": "What does NA 69/22 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 22 mm bore, 30 mm width, 39 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 22×39×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA69-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-22",
      "NA 69/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI25-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 25/20 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 42.5,
    "fatigue_load_limit_kN": 5.2,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 80,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 25/20 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 25 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 25 mm d and 20 mm B, the 38 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Speed planning separates the two ceilings: 14,000 r/min thermal reference and 15,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 25 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 38 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 24.6/42.5 kN ratings are SKF catalogue values for this exact execution (NKI 25/20 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 24.6/42.5 kN ratings and 80 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 25/20 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 25/20 TN have?",
        "a": "A NKI 25/20 TN measures 25 mm bore/Fw × 38 mm outside diameter × 20 mm width (0.984 × 1.496 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.6 kN, static C0 42.5 kN, fatigue limit Pu 5.2 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 80 g."
      },
      {
        "q": "What does NKI 25/20 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 20 mm width, 38 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 25/20 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 25/20 TN carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI25-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI25-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKS25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×38×20 mm envelope, but catalogue C/C0 differ between the executions (24.6/42.5 vs 27.5/36 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI25-20-TN",
      "NKI 25/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI25-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 25/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 38,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 25/30 measures 25×38×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 25 mm bore (d), 30 mm width; the 38 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Selection arithmetic: C 31.9 kN against C0 60 kN gives a C0/C ratio of 1.88, and the 7.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 38 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 31.9/60 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 25/30 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 30 mm width, 38 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 25/30 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 25/30 carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 25/30?",
        "a": "Mount the inner ring on the 25 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 25/30 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI25-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI25-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×38×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI25-30",
      "NKI 25/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4905",
    "brand": "SKF",
    "manufacturer_designation": "NA 4905",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.15,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 88,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4905 in the dimension series 49 needle roller bearings with inner ring with boundary dimensions 25×42×17 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 4905 code gives bore 25 mm and width 17 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 88 g at 25×42×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NA 4905 shares its 25×42×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 24.2/34.5 kN ratings and 88 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4905 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 17 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4905 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4905 carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4905 be mounted?",
        "a": "Mount the inner ring on the 25 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4905?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4905-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA4905",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4905",
      "NA 4905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4905-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4905.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 27.5,
    "fatigue_load_limit_kN": 3.25,
    "max_rpm": 6300,
    "limiting_speed_rpm": 6300,
    "weight_g": 90,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4905.2RS measures 25×42×18 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The designation NA 4905.2RS tells you the envelope — 25×42×18 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. For life calculation, the 21.6/27.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: heat or press the inner ring onto the 25 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 18 mm assembly for free rotation before applying load.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 21.6/27.5 kN ratings are SKF catalogue values for this exact execution (NA 4905.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 21.6/27.5 kN ratings and 90 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4905.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4905.2RS?",
        "a": "A NA 4905.2RS measures 25 mm bore/Fw × 42 mm outside diameter × 18 mm width (0.984 × 1.654 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 27.5 kN, fatigue limit Pu 3.25 kN, limiting speed 6,300 r/min, mass about 90 g."
      },
      {
        "q": "How is the NA 4905.2RS designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 18 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4905.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4905.2RS carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4905-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4905",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4905-2RS",
      "NA 4905.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6905",
    "brand": "SKF",
    "manufacturer_designation": "NA 6905",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 38,
    "static_load_kN": 62,
    "fatigue_load_limit_kN": 7.65,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6905 provides the full machined-ring needle roller construction: ground inner ring on a 25 mm seat, flanged outer ring at 42 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 25 mm d and 30 mm B, the 42 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 38/62 kN ratings are SKF catalogue values for this exact execution (NA 6905); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 38/62 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 6905 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 30 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6905 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6905 carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6905?",
        "a": "Mount the inner ring on the 25 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6905 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6905-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6905",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6905",
      "NA 6905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS25",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 25",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 47,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.1,
    "static_load_kN": 46.5,
    "fatigue_load_limit_kN": 5.7,
    "max_rpm": 13000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 13000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 25 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 25 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NKIS 25 tells you the envelope — 25×47×22 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 12,000 r/min thermal reference and 13,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 25 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 22 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 47 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 34.1/46.5 kN ratings are SKF catalogue values for this exact execution (NKIS 25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 34.1/46.5 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKIS 25?",
        "a": "A NKIS 25 measures 25 mm bore/Fw × 47 mm outside diameter × 22 mm width (0.984 × 1.85 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 46.5 kN, fatigue limit Pu 5.7 kN, limiting speed 13,000 r/min, reference speed 12,000 r/min, mass about 160 g."
      },
      {
        "q": "How is the NKIS 25 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 25 mm bore, 22 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKIS 25 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKIS 25 carries its own hardened, ground inner ring on a 25 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKIS 25 be mounted?",
        "a": "Mount the inner ring on the 25 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 25×47×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS25",
      "NKIS 25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI28-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 28/20 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 48,
    "fatigue_load_limit_kN": 6,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 92,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 28/20 TN denotes a complete needle roller bearing for a 28 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 42 mm OD and 20 mm width. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 28 mm bore (d), 20 mm width; the 42 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. The 92 g catalogue mass and 7.0 mm radial section ((42−28)/2) frame a rating of about 0.94 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 28 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 26.4/48 kN ratings and 92 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 28/20 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 28/20 TN have?",
        "a": "A NKI 28/20 TN measures 28 mm bore/Fw × 42 mm outside diameter × 20 mm width (1.102 × 1.654 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26.4 kN, static C0 48 kN, fatigue limit Pu 6 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 92 g."
      },
      {
        "q": "What does NKI 28/20 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 28 mm bore, 20 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 28/20 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 28/20 TN carries its own hardened, ground inner ring on a 28 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI28-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI28-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKS28",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 28×42×20 mm envelope, but catalogue C/C0 differ between the executions (26.4/48 vs 28.6/39 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI28-20-TN",
      "NKI 28/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI28-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 28/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 34.1,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 28 mm shaft that cannot be hardened on site, NKI 28/30 adds a hardened, ground inner ring to the machined needle roller design: envelope 28×42×30 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 28 mm d and 30 mm B, the 42 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. For life calculation, the 34.1/65.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 28/30 shares its 28×42×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 34.1/65.5 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 28/30 have?",
        "a": "A NKI 28/30 measures 28 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.102 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 34.1 kN, static C0 65.5 kN, fatigue limit Pu 8.3 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 140 g."
      },
      {
        "q": "What does NKI 28/30 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 28 mm bore, 30 mm width, 42 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 28/30 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 28/30 carries its own hardened, ground inner ring on a 28 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 28/30?",
        "a": "Mount the inner ring on the 28 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI28-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI28-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×42×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI28",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI28-30",
      "NKI 28/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-28",
    "brand": "SKF",
    "manufacturer_designation": "NA 49/28",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 45,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 4.4,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 98,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 28 mm shaft that cannot be hardened on site, NA 49/28 adds a hardened, ground inner ring to the machined needle roller design: envelope 28×45×17 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 28 mm d and 17 mm B, the 45 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. For life calculation, the 25.1/36.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: heat or press the inner ring onto the 28 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 17 mm assembly for free rotation before applying load.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 12,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 28 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 25.1/36.5 kN ratings and 98 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 49/28 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 28 mm bore, 17 mm width, 45 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 49/28 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 49/28 carries its own hardened, ground inner ring on a 28 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 49/28?",
        "a": "Mount the inner ring on the 28 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 49/28 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-28-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA49-32-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-28",
      "NA 49/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-28",
    "brand": "SKF",
    "manufacturer_designation": "NA 69/28",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 28,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.6,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 14000,
    "reference_speed_rpm": 12000,
    "limiting_speed_rpm": 14000,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 69/28 measures 28×45×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 28 mm bore (d), 30 mm width; the 45 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 28 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 28 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 69/28 shares its 28×45×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 39.6/65.5 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 69/28 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 69/28 carries its own hardened, ground inner ring on a 28 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 69/28?",
        "a": "Mount the inner ring on the 28 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 69/28 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 69/28 have?",
        "a": "A NA 69/28 measures 28 mm bore/Fw × 45 mm outside diameter × 30 mm width (1.102 × 1.772 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.6 kN, static C0 65.5 kN, fatigue limit Pu 8.3 kN, limiting speed 14,000 r/min, reference speed 12,000 r/min, mass about 180 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-28-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 28×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-28",
      "NA 69/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI30-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 30/20 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 52,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 30/20 TN denotes a complete needle roller bearing for a 30 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 45 mm OD and 20 mm width. The NKI 30/20 TN code gives bore 30 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NKI 30/20 TN shares its 30×45×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 27.5/52 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 30/20 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 30/20 TN?",
        "a": "A NKI 30/20 TN measures 30 mm bore/Fw × 45 mm outside diameter × 20 mm width (1.181 × 1.772 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27.5 kN, static C0 52 kN, fatigue limit Pu 6.55 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 110 g."
      },
      {
        "q": "How is the NKI 30/20 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 20 mm width, 45 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 30/20 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 30/20 TN carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI30-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×45×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI30-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI30-20-TN",
      "NKI 30/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI30-30-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 30/30 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 45,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 30/30 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 30 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 30 mm bore (d), 30 mm width; the 45 mm OD follows the dimension series, and the inner ring is a separate ground component. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 170 g catalogue mass and 7.5 mm radial section ((45−30)/2) frame a rating of about 1.34 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: heat or press the inner ring onto the 30 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 30/30 TN shares its 30×45×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 40.2/85 kN ratings and 170 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 30/30 TN have?",
        "a": "A NKI 30/30 TN measures 30 mm bore/Fw × 45 mm outside diameter × 30 mm width (1.181 × 1.772 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 170 g."
      },
      {
        "q": "What does NKI 30/30 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 30 mm width, 45 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 30/30 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 30/30 TN carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 30/30 TN?",
        "a": "Mount the inner ring on the 30 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI30-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI30-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×45×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI30-30-TN",
      "NKI 30/30 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4906",
    "brand": "SKF",
    "manufacturer_designation": "NA 4906",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 17,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 30 mm shaft that cannot be hardened on site, NA 4906 adds a hardened, ground inner ring to the machined needle roller design: envelope 30×47×17 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 30 mm d and 17 mm B, the 47 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 100 g at 30×47×17 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4906 shares its 30×47×17 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 25.5/39 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4906 have?",
        "a": "A NA 4906 measures 30 mm bore/Fw × 47 mm outside diameter × 17 mm width (1.181 × 1.85 × 0.669 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.5 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 100 g."
      },
      {
        "q": "What does NA 4906 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 17 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4906 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4906 carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4906?",
        "a": "Mount the inner ring on the 30 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4906-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×47×17 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4906",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4906",
      "NA 4906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4906-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4906.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.8,
    "max_rpm": 5600,
    "limiting_speed_rpm": 5600,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 30 mm shaft that cannot be hardened on site, NA 4906.2RS adds a hardened, ground inner ring to the machined needle roller design: envelope 30×47×18 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 30 mm d and 18 mm B, the 47 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 23.3 kN against C0 32 kN gives a C0/C ratio of 1.37, and the 3.8 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 30 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 18 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 23.3/32 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4906.2RS sealed?",
        "a": "Yes — the 2RS execution seals both faces with rubber contact seals; note its wider outer ring (B and s differ from the open execution), so housing dimensions must be re-checked."
      },
      {
        "q": "Which dimensions does the NA 4906.2RS have?",
        "a": "A NA 4906.2RS measures 30 mm bore/Fw × 47 mm outside diameter × 18 mm width (1.181 × 1.85 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.8 kN, limiting speed 5,600 r/min, mass about 100 g."
      },
      {
        "q": "What does NA 4906.2RS mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 18 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4906.2RS need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4906.2RS carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4906-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4906",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4906-2RS",
      "NA 4906.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6906",
    "brand": "SKF",
    "manufacturer_designation": "NA 6906",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 75,
    "fatigue_load_limit_kN": 9.3,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 190,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 6906 in the dimension series 69 needle roller bearings with inner ring with boundary dimensions 30×47×30 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 6906 tells you the envelope — 30×47×30 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 42.9/75 kN ratings are SKF catalogue values for this exact execution (NA 6906); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 42.9/75 kN ratings and 190 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 6906?",
        "a": "A NA 6906 measures 30 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.181 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 75 kN, fatigue limit Pu 9.3 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 190 g."
      },
      {
        "q": "How is the NA 6906 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 30 mm bore, 30 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 6906 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6906 carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 6906 be mounted?",
        "a": "Mount the inner ring on the 30 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6906-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6906",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6906",
      "NA 6906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS30",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 30",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 52,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.55,
    "max_rpm": 12000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 12000,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIS 30 in the wide-section machined-ring needle roller bearings with inner ring with boundary dimensions 30×52×22 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NKIS 30 tells you the envelope — 30×52×22 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 10,000 r/min thermal reference and 12,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 30 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 36.9/54 kN ratings are SKF catalogue values for this exact execution (NKIS 30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 36.9/54 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKIS 30 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKIS 30 carries its own hardened, ground inner ring on a 30 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKIS 30 be mounted?",
        "a": "Mount the inner ring on the 30 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKIS 30?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIS 30?",
        "a": "A NKIS 30 measures 30 mm bore/Fw × 52 mm outside diameter × 22 mm width (1.181 × 2.047 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 54 kN, fatigue limit Pu 6.55 kN, limiting speed 12,000 r/min, reference speed 10,000 r/min, mass about 180 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 30×52×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS30",
      "NKIS 30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI32-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 32/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.1,
    "static_load_kN": 46.5,
    "fatigue_load_limit_kN": 5.85,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 32/20 in the machined-ring needle roller bearings with inner ring with boundary dimensions 32×47×20 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NKI 32/20 code gives bore 32 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 110 g at 32×47×20 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NKI 32/20 shares its 32×47×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 25.1/46.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 32/20?",
        "a": "A NKI 32/20 measures 32 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.26 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.1 kN, static C0 46.5 kN, fatigue limit Pu 5.85 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 110 g."
      },
      {
        "q": "How is the NKI 32/20 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 32 mm bore, 20 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 32/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 32/20 carries its own hardened, ground inner ring on a 32 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 32/20 be mounted?",
        "a": "Mount the inner ring on the 32 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI32-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×47×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI32-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI32-20",
      "NKI 32/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI32-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 32/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 76.5,
    "fatigue_load_limit_kN": 9.5,
    "max_rpm": 12000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 12000,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 32/30 measures 32×47×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 32 mm d and 30 mm B, the 47 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 170 g at 32×47×30 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 32 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 32 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 36.9/76.5 kN ratings and 170 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 32/30 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 32/30 carries its own hardened, ground inner ring on a 32 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 32/30?",
        "a": "Mount the inner ring on the 32 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 32/30 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 32/30 have?",
        "a": "A NKI 32/30 measures 32 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.26 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 36.9 kN, static C0 76.5 kN, fatigue limit Pu 9.5 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 170 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI32-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI32-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×47×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI32",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI32-30",
      "NKI 32/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA49-32",
    "brand": "SKF",
    "manufacturer_designation": "NA 49/32",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 30.8,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 6.3,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 49/32 denotes a complete needle roller bearing for a 32 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 52 mm OD and 20 mm width. The NA 49/32 code gives bore 32 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. For life calculation, the 30.8/51 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 32 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 30.8/51 kN ratings are SKF catalogue values for this exact execution (NA 49/32); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 30.8/51 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 49/32?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 32 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 49/32?",
        "a": "A NA 49/32 measures 32 mm bore/Fw × 52 mm outside diameter × 20 mm width (1.26 × 2.047 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 30.8 kN, static C0 51 kN, fatigue limit Pu 6.3 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 160 g."
      },
      {
        "q": "How is the NA 49/32 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 32 mm bore, 20 mm width, 52 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 49/32 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 49/32 carries its own hardened, ground inner ring on a 32 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA49-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA49-32-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×52×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA49",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA49-32",
      "NA 49/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA69-32",
    "brand": "SKF",
    "manufacturer_designation": "NA 69/32",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 32,
    "D_mm": 52,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 90,
    "fatigue_load_limit_kN": 10.8,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 290,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 69/32 in the dimension series 69 needle roller bearings with inner ring with boundary dimensions 32×52×36 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 69/32 tells you the envelope — 32×52×36 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 32 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 36 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NA 69/32 shares its 32×52×36 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 47.3/90 kN ratings and 290 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 69/32?",
        "a": "A NA 69/32 measures 32 mm bore/Fw × 52 mm outside diameter × 36 mm width (1.26 × 2.047 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 47.3 kN, static C0 90 kN, fatigue limit Pu 10.8 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 290 g."
      },
      {
        "q": "How is the NA 69/32 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 32 mm bore, 36 mm width, 52 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 69/32 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 69/32 carries its own hardened, ground inner ring on a 32 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 69/32 be mounted?",
        "a": "Mount the inner ring on the 32 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA69-22-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-28-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA69-32-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 32×52×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA69",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA69-32",
      "NA 69/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI35-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 35/20 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 29.7,
    "static_load_kN": 60,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 35/20 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 35 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NKI 35/20 TN code gives bore 35 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Catalogue mass 120 g at 35×50×20 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 35 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 29.7/60 kN ratings are SKF catalogue values for this exact execution (NKI 35/20 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 29.7/60 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 35/20 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 35/20 TN?",
        "a": "A NKI 35/20 TN measures 35 mm bore/Fw × 50 mm outside diameter × 20 mm width (1.378 × 1.969 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 29.7 kN, static C0 60 kN, fatigue limit Pu 7.5 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 120 g."
      },
      {
        "q": "How is the NKI 35/20 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 35 mm bore, 20 mm width, 50 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 35/20 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 35/20 TN carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI35-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI35-20-TW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×50×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI35-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI35-20-TN",
      "NKI 35/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI35-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 35/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 50,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 38,
    "static_load_kN": 83,
    "fatigue_load_limit_kN": 10.4,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 190,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 35 mm shaft that cannot be hardened on site, NKI 35/30 adds a hardened, ground inner ring to the machined needle roller design: envelope 35×50×30 mm per the machined-ring needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 35 mm bore (d), 30 mm width; the 50 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. For life calculation, the 38/83 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 35/30 shares its 35×50×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 38/83 kN ratings and 190 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 35/30 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 35/30 carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 35/30?",
        "a": "Mount the inner ring on the 35 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 35/30 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 35/30 have?",
        "a": "A NKI 35/30 measures 35 mm bore/Fw × 50 mm outside diameter × 30 mm width (1.378 × 1.969 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 38 kN, static C0 83 kN, fatigue limit Pu 10.4 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 190 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI35-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI35-20-TW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI35-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×50×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI35-30",
      "NKI 35/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4907",
    "brand": "SKF",
    "manufacturer_designation": "NA 4907",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.7,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 170,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4907 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 35 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NA 4907 tells you the envelope — 35×55×20 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 170 g at 35×55×20 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 31.9/54 kN ratings and 170 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4907?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4907?",
        "a": "A NA 4907 measures 35 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.378 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 54 kN, fatigue limit Pu 6.7 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 170 g."
      },
      {
        "q": "How is the NA 4907 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 35 mm bore, 20 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4907 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4907 carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4907-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "PNA35-55",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×55×20 mm envelope, but catalogue C/C0 differ between the executions (31.9/54 vs 26.4/51 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4907",
      "NA 4907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4907-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4907.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 21,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27,
    "static_load_kN": 43,
    "fatigue_load_limit_kN": 5.3,
    "max_rpm": 4800,
    "limiting_speed_rpm": 4800,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4907.2RS provides the full machined-ring needle roller construction: ground inner ring on a 35 mm seat, flanged outer ring at 55 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 35 mm d and 21 mm B, the 55 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. For life calculation, the 27/43 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4907.2RS shares its 35×55×21 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 27/43 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4907.2RS have?",
        "a": "A NA 4907.2RS measures 35 mm bore/Fw × 55 mm outside diameter × 21 mm width (1.378 × 2.165 × 0.827 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27 kN, static C0 43 kN, fatigue limit Pu 5.3 kN, limiting speed 4,800 r/min, mass about 180 g."
      },
      {
        "q": "What does NA 4907.2RS mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 35 mm bore, 21 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4907.2RS need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4907.2RS carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4907.2RS?",
        "a": "Mount the inner ring on the 35 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4907-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4907",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4907-2RS",
      "NA 4907.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6907",
    "brand": "SKF",
    "manufacturer_designation": "NA 6907",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 48.4,
    "static_load_kN": 93,
    "fatigue_load_limit_kN": 11.4,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 35 mm shaft that cannot be hardened on site, NA 6907 adds a hardened, ground inner ring to the machined needle roller design: envelope 35×55×36 mm per the dimension series 69 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 35 mm bore (d), 36 mm width; the 55 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 48.4/93 kN ratings and 310 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 6907 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6907 have?",
        "a": "A NA 6907 measures 35 mm bore/Fw × 55 mm outside diameter × 36 mm width (1.378 × 2.165 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 48.4 kN, static C0 93 kN, fatigue limit Pu 11.4 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 310 g."
      },
      {
        "q": "What does NA 6907 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 35 mm bore, 36 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6907 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6907 carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6907-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×55×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6907",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6907",
      "NA 6907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS35",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 35",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 58,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.1,
    "static_load_kN": 61,
    "fatigue_load_limit_kN": 7.5,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 35 provides the full machined-ring needle roller construction: ground inner ring on a 35 mm seat, flanged outer ring at 58 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 35 mm bore (d), 22 mm width; the 58 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 9,000 r/min thermal reference and 10,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 35 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 39.1/61 kN ratings are SKF catalogue values for this exact execution (NKIS 35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 39.1/61 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKIS 35 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKIS 35 carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKIS 35?",
        "a": "Mount the inner ring on the 35 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKIS 35 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKIS 35 have?",
        "a": "A NKIS 35 measures 35 mm bore/Fw × 58 mm outside diameter × 22 mm width (1.378 × 2.283 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 61 kN, fatigue limit Pu 7.5 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 220 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 35×58×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS35",
      "NKIS 35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI38-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 38/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 53,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 55,
    "fatigue_load_limit_kN": 6.8,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 38/20 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 38 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NKI 38/20 code gives bore 38 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Selection arithmetic: C 27.5 kN against C0 55 kN gives a C0/C ratio of 2.00, and the 6.8 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 38 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 27.5/55 kN ratings are SKF catalogue values for this exact execution (NKI 38/20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 27.5/55 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 38/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 38 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 38/20?",
        "a": "A NKI 38/20 measures 38 mm bore/Fw × 53 mm outside diameter × 20 mm width (1.496 × 2.087 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27.5 kN, static C0 55 kN, fatigue limit Pu 6.8 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 130 g."
      },
      {
        "q": "How is the NKI 38/20 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 38 mm bore, 20 mm width, 53 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 38/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 38/20 carries its own hardened, ground inner ring on a 38 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI38-20-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NKI38-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI38",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI38-20",
      "NKI 38/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI38-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 38/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 38,
    "D_mm": 53,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 90,
    "fatigue_load_limit_kN": 11.2,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 210,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 38/30 provides the full machined-ring needle roller construction: ground inner ring on a 38 mm seat, flanged outer ring at 53 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 38 mm d and 30 mm B, the 53 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Selection arithmetic: C 40.2 kN against C0 90 kN gives a C0/C ratio of 2.24, and the 11.2 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 38 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 38 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 38 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 40.2/90 kN ratings are SKF catalogue values for this exact execution (NKI 38/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 40.2/90 kN ratings and 210 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 38/30 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 38 mm bore, 30 mm width, 53 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 38/30 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 38/30 carries its own hardened, ground inner ring on a 38 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 38/30?",
        "a": "Mount the inner ring on the 38 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 38/30 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI38-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI38-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 38×53×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI38",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI38-30",
      "NKI 38/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI40-20-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 40/20 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 31.4,
    "static_load_kN": 65.5,
    "fatigue_load_limit_kN": 8.3,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 40/20 TN denotes a complete needle roller bearing for a 40 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 55 mm OD and 20 mm width. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 40 mm bore (d), 20 mm width; the 55 mm OD follows the dimension series, and the inner ring is a separate ground component. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. The 140 g catalogue mass and 7.5 mm radial section ((55−40)/2) frame a rating of about 0.78 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 40/20 TN shares its 40×55×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 31.4/65.5 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 40/20 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 40/20 TN have?",
        "a": "A NKI 40/20 TN measures 40 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.575 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.4 kN, static C0 65.5 kN, fatigue limit Pu 8.3 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 140 g."
      },
      {
        "q": "What does NKI 40/20 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 20 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 40/20 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 40/20 TN carries its own hardened, ground inner ring on a 40 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×55×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI40-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI40-30-TW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "RPNA40-55",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×20 mm envelope, but catalogue C/C0 differ between the executions (31.4/65.5 vs 26.4/51 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI40-20-TN",
      "NKI 40/20 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI40-30-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 40/30 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 108,
    "fatigue_load_limit_kN": 13.7,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 40/30 TN is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 40 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NKI 40/30 TN tells you the envelope — 40×55×30 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Selection arithmetic: C 45.7 kN against C0 108 kN gives a C0/C ratio of 2.36, and the 13.7 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 45.7/108 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 40/30 TN?",
        "a": "A NKI 40/30 TN measures 40 mm bore/Fw × 55 mm outside diameter × 30 mm width (1.575 × 2.165 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 45.7 kN, static C0 108 kN, fatigue limit Pu 13.7 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 220 g."
      },
      {
        "q": "How is the NKI 40/30 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 30 mm width, 55 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 40/30 TN run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 40/30 TN carries its own hardened, ground inner ring on a 40 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 40/30 TN be mounted?",
        "a": "Mount the inner ring on the 40 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI40-30-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI40-30-TW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×55×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI40-30-TN",
      "NKI 40/30 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4908",
    "brand": "SKF",
    "manufacturer_designation": "NA 4908",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 230,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4908 measures 40×62×22 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 40 mm bore (d), 22 mm width; the 62 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 230 g at 40×62×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 42.9/71 kN ratings are SKF catalogue values for this exact execution (NA 4908); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 42.9/71 kN ratings and 230 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4908?",
        "a": "Mount the inner ring on the 40 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4908 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4908 have?",
        "a": "A NA 4908 measures 40 mm bore/Fw × 62 mm outside diameter × 22 mm width (1.575 × 2.441 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 71 kN, fatigue limit Pu 8.8 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 230 g."
      },
      {
        "q": "What does NA 4908 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 22 mm width, 62 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4908-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×62×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4908",
      "NA 4908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4908-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4908.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 36.9,
    "static_load_kN": 58.5,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 4000,
    "limiting_speed_rpm": 4000,
    "weight_g": 250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4908.2RS measures 40×62×23 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The NA 4908.2RS code gives bore 40 mm and width 23 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 4,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 23 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 36.9/58.5 kN ratings and 250 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4908.2RS designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 23 mm width, 62 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4908.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4908.2RS carries its own hardened, ground inner ring on a 40 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4908.2RS be mounted?",
        "a": "Mount the inner ring on the 40 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4908.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4908-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4908",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4908-2RS",
      "NA 4908.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6908",
    "brand": "SKF",
    "manufacturer_designation": "NA 6908",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 67.1,
    "static_load_kN": 125,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6908 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 40 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NA 6908 code gives bore 40 mm and width 40 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NA 6908 shares its 40×62×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 67.1/125 kN ratings and 430 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 6908 be mounted?",
        "a": "Mount the inner ring on the 40 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 6908?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6908?",
        "a": "A NA 6908 measures 40 mm bore/Fw × 62 mm outside diameter × 40 mm width (1.575 × 2.441 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 67.1 kN, static C0 125 kN, fatigue limit Pu 15.3 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 430 g."
      },
      {
        "q": "How is the NA 6908 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 40 mm width, 62 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6908-ZW-XL",
        "equiv_brand": "FAG",
        "level": "full",
        "note": "Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier."
      },
      {
        "equiv_sku": "NA6908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6908",
      "NA 6908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS40",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 40",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 65,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 72,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 280,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The wide-section machined-ring needle roller bearings with inner ring execution NKIS 40 measures 40×65×22 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 40 mm bore (d), 22 mm width; the 65 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 8,000 r/min thermal reference and 9,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: heat or press the inner ring onto the 40 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 22 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 42.9/72 kN ratings are SKF catalogue values for this exact execution (NKIS 40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 42.9/72 kN ratings and 280 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKIS 40 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKIS 40 have?",
        "a": "A NKIS 40 measures 40 mm bore/Fw × 65 mm outside diameter × 22 mm width (1.575 × 2.559 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 72 kN, fatigue limit Pu 8.8 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 280 g."
      },
      {
        "q": "What does NKIS 40 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 22 mm width, 65 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKIS 40 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKIS 40 carries its own hardened, ground inner ring on a 40 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS40-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 40×65×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS40",
      "NKIS 40"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI42-20",
    "brand": "SKF",
    "manufacturer_designation": "NKI 42/20",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 57,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 29.2,
    "static_load_kN": 61,
    "fatigue_load_limit_kN": 7.65,
    "max_rpm": 10000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 10000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 42/20 denotes a complete needle roller bearing for a 42 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 57 mm OD and 20 mm width. The NKI 42/20 code gives bore 42 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 140 g catalogue mass and 7.5 mm radial section ((57−42)/2) frame a rating of about 0.70 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 20 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 29.2/61 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKI 42/20 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 42 mm bore, 20 mm width, 57 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 42/20 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 42/20 carries its own hardened, ground inner ring on a 42 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 42/20 be mounted?",
        "a": "Mount the inner ring on the 42 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 42/20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 42 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI42-20-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×57×20 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI42-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI42",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI42-20",
      "NKI 42/20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI42-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 42/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 42,
    "D_mm": 57,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 41.8,
    "static_load_kN": 98,
    "fatigue_load_limit_kN": 12.5,
    "max_rpm": 10000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 10000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 42 mm shaft that cannot be hardened on site, NKI 42/30 adds a hardened, ground inner ring to the machined needle roller design: envelope 42×57×30 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 42 mm d and 30 mm B, the 57 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 220 g catalogue mass and 7.5 mm radial section ((57−42)/2) frame a rating of about 1.00 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 42/30 shares its 42×57×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 41.8/98 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 42/30?",
        "a": "Mount the inner ring on the 42 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 42/30 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 42/30 have?",
        "a": "A NKI 42/30 measures 42 mm bore/Fw × 57 mm outside diameter × 30 mm width (1.654 × 2.244 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 41.8 kN, static C0 98 kN, fatigue limit Pu 12.5 kN, limiting speed 10,000 r/min, reference speed 8,500 r/min, mass about 220 g."
      },
      {
        "q": "What does NKI 42/30 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 42 mm bore, 30 mm width, 57 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI42-20-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI42-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 42×57×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI42",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI42-30",
      "NKI 42/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI45-25-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 45/25 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 91.5,
    "fatigue_load_limit_kN": 11.2,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 220,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 45/25 TN in the machined-ring needle roller bearings with inner ring with boundary dimensions 45×62×25 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 45 mm d and 25 mm B, the 62 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Selection arithmetic: C 42.9 kN against C0 91.5 kN gives a C0/C ratio of 2.13, and the 11.2 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 25 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 42.9/91.5 kN ratings are SKF catalogue values for this exact execution (NKI 45/25 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 42.9/91.5 kN ratings and 220 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 45/25 TN?",
        "a": "Mount the inner ring on the 45 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 45/25 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 45/25 TN have?",
        "a": "A NKI 45/25 TN measures 45 mm bore/Fw × 62 mm outside diameter × 25 mm width (1.772 × 2.441 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 91.5 kN, fatigue limit Pu 11.2 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 220 g."
      },
      {
        "q": "What does NKI 45/25 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 45 mm bore, 25 mm width, 62 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI45-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×62×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI45-35-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI45-25-TN",
      "NKI 45/25 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI45-35-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 45/35 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 58.3,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 310,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 45/35 TN denotes a complete needle roller bearing for a 45 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 62 mm OD and 35 mm width. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 45 mm d and 35 mm B, the 62 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. For life calculation, the 58.3/137 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: heat or press the inner ring onto the 45 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 45 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 58.3/137 kN ratings and 310 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKI 45/35 TN sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 45/35 TN have?",
        "a": "A NKI 45/35 TN measures 45 mm bore/Fw × 62 mm outside diameter × 35 mm width (1.772 × 2.441 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 58.3 kN, static C0 137 kN, fatigue limit Pu 17 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 310 g."
      },
      {
        "q": "What does NKI 45/35 TN mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 45 mm bore, 35 mm width, 62 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 45/35 TN need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 45/35 TN carries its own hardened, ground inner ring on a 45 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI45-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI45-35-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×62×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI45-35-TN",
      "NKI 45/35 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4909",
    "brand": "SKF",
    "manufacturer_designation": "NA 4909",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.65,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 270,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4909 denotes a complete needle roller bearing for a 45 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 68 mm OD and 22 mm width. The NA 4909 code gives bore 45 mm and width 22 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 270 g at 45×68×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 45 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 45.7/78 kN ratings are SKF catalogue values for this exact execution (NA 4909); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 45.7/78 kN ratings and 270 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 4909 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4909 carries its own hardened, ground inner ring on a 45 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4909 be mounted?",
        "a": "Mount the inner ring on the 45 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4909?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4909?",
        "a": "A NA 4909 measures 45 mm bore/Fw × 68 mm outside diameter × 22 mm width (1.772 × 2.677 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 45.7 kN, static C0 78 kN, fatigue limit Pu 9.65 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 270 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4909-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×68×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4909",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4909",
      "NA 4909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4909-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4909.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 39.1,
    "static_load_kN": 64,
    "fatigue_load_limit_kN": 7.8,
    "max_rpm": 3800,
    "limiting_speed_rpm": 3800,
    "weight_g": 290,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 45 mm shaft that cannot be hardened on site, NA 4909.2RS adds a hardened, ground inner ring to the machined needle roller design: envelope 45×68×23 mm per the dimension series 49 needle roller bearings with inner ring plan. The NA 4909.2RS code gives bore 45 mm and width 23 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 45 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 23 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 45 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 39.1/64 kN ratings are SKF catalogue values for this exact execution (NA 4909.2RS); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 39.1/64 kN ratings and 290 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 4909.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4909.2RS carries its own hardened, ground inner ring on a 45 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4909.2RS be mounted?",
        "a": "Mount the inner ring on the 45 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4909.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4909.2RS?",
        "a": "A NA 4909.2RS measures 45 mm bore/Fw × 68 mm outside diameter × 23 mm width (1.772 × 2.677 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 64 kN, fatigue limit Pu 7.8 kN, limiting speed 3,800 r/min, mass about 290 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4909-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4909",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4909-2RS",
      "NA 4909.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6909",
    "brand": "SKF",
    "manufacturer_designation": "NA 6909",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 70.4,
    "static_load_kN": 137,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 6909 measures 45×68×40 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 45 mm d and 40 mm B, the 68 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 6909 shares its 45×68×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 70.4/137 kN ratings and 500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 6909 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6909 carries its own hardened, ground inner ring on a 45 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6909?",
        "a": "Mount the inner ring on the 45 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6909 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6909 have?",
        "a": "A NA 6909 measures 45 mm bore/Fw × 68 mm outside diameter × 40 mm width (1.772 × 2.677 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 70.4 kN, static C0 137 kN, fatigue limit Pu 17 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 500 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6909-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×68×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6909",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6909",
      "NA 6909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS45",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 45",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44.6,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.8,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 340,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 45 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 45 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NKIS 45 code gives bore 45 mm and width 22 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 7,000 r/min thermal reference and 8,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 45 mm seat. Mounting: heat or press the inner ring onto the 45 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 22 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 44.6/78 kN ratings and 340 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKIS 45?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 13.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIS 45?",
        "a": "A NKIS 45 measures 45 mm bore/Fw × 72 mm outside diameter × 22 mm width (1.772 × 2.835 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44.6 kN, static C0 78 kN, fatigue limit Pu 9.8 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 340 g."
      },
      {
        "q": "How is the NKIS 45 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 45 mm bore, 22 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKIS 45 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKIS 45 carries its own hardened, ground inner ring on a 45 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS45-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 45×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS45",
      "NKIS 45"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI50-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 50/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 68,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 88,
    "fatigue_load_limit_kN": 10.8,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 50/25 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 50 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 50 mm bore (d), 25 mm width; the 68 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: 7,500 r/min thermal reference and 8,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 50 mm seat. Mounting: heat or press the inner ring onto the 50 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 7,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 40.2/88 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 50/25 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 50/25 carries its own hardened, ground inner ring on a 50 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 50/25?",
        "a": "Mount the inner ring on the 50 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 50/25 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 50/25 have?",
        "a": "A NKI 50/25 measures 50 mm bore/Fw × 68 mm outside diameter × 25 mm width (1.969 × 2.677 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 40.2 kN, static C0 88 kN, fatigue limit Pu 10.8 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 260 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI50-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×68×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI50-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI50",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI50-25",
      "NKI 50/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI50-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 50/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 68,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 52.3,
    "static_load_kN": 122,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 360,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 50/35 provides the full machined-ring needle roller construction: ground inner ring on a 50 mm seat, flanged outer ring at 68 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NKI 50/35 code gives bore 50 mm and width 35 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Speed planning separates the two ceilings: 7,500 r/min thermal reference and 8,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 50 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 35 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 50 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 52.3/122 kN ratings are SKF catalogue values for this exact execution (NKI 50/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 52.3/122 kN ratings and 360 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 50/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 9.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 50/35?",
        "a": "A NKI 50/35 measures 50 mm bore/Fw × 68 mm outside diameter × 35 mm width (1.969 × 2.677 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 52.3 kN, static C0 122 kN, fatigue limit Pu 15.3 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 360 g."
      },
      {
        "q": "How is the NKI 50/35 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 50 mm bore, 35 mm width, 68 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 50/35 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 50/35 carries its own hardened, ground inner ring on a 50 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI50-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI50-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×68×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI50",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI50-35",
      "NKI 50/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4910",
    "brand": "SKF",
    "manufacturer_designation": "NA 4910",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 22,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 270,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4910 denotes a complete needle roller bearing for a 50 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 72 mm OD and 22 mm width. The NA 4910 code gives bore 50 mm and width 22 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 270 g at 50×72×22 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 50 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 22 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NA 4910 shares its 50×72×22 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 7,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 47.3/85 kN ratings and 270 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 4910 be mounted?",
        "a": "Mount the inner ring on the 50 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4910?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4910?",
        "a": "A NA 4910 measures 50 mm bore/Fw × 72 mm outside diameter × 22 mm width (1.969 × 2.835 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 47.3 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 270 g."
      },
      {
        "q": "How is the NA 4910 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 50 mm bore, 22 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4910-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×72×22 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4910",
      "NA 4910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4910-2RS",
    "brand": "SKF",
    "manufacturer_designation": "NA 4910.2RS",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "2RS",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 40.2,
    "static_load_kN": 69.5,
    "fatigue_load_limit_kN": 8.5,
    "max_rpm": 3400,
    "limiting_speed_rpm": 3400,
    "weight_g": 300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4910.2RS denotes a complete needle roller bearing for a 50 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 72 mm OD and 23 mm width. The NA 4910.2RS code gives bore 50 mm and width 23 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Speed planning separates the two ceilings: no reference speed listed for this sealed/slow execution and 3,400 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 50 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 23 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NA 4910.2RS shares its 50×72×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 40.2/69.5 kN ratings and 300 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4910.2RS designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 50 mm bore, 23 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4910.2RS run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4910.2RS carries its own hardened, ground inner ring on a 50 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4910.2RS be mounted?",
        "a": "Mount the inner ring on the 50 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4910.2RS?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4910-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4910",
        "equiv_brand": "ISO 15",
        "level": "verify",
        "note": "ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4910-2RS",
      "NA 4910.2RS"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6910",
    "brand": "SKF",
    "manufacturer_designation": "NA 6910",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 150,
    "fatigue_load_limit_kN": 18.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 520,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 6910 measures 50×72×40 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 50 mm d and 40 mm B, the 72 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 50 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 40 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 73.7/150 kN ratings are SKF catalogue values for this exact execution (NA 6910); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 73.7/150 kN ratings and 520 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 6910?",
        "a": "Mount the inner ring on the 50 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6910 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6910 have?",
        "a": "A NA 6910 measures 50 mm bore/Fw × 72 mm outside diameter × 40 mm width (1.969 × 2.835 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 150 kN, fatigue limit Pu 18.6 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 520 g."
      },
      {
        "q": "What does NA 6910 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 50 mm bore, 40 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6910-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×72×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6910",
      "NA 6910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS50",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 50",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 80,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 62.7,
    "static_load_kN": 104,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7500,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7500,
    "weight_g": 520,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIS 50 in the wide-section machined-ring needle roller bearings with inner ring with boundary dimensions 50×80×28 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NKIS 50 code gives bore 50 mm and width 28 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 6,300 r/min thermal reference and 7,500 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 50 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 28 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 62.7/104 kN ratings and 520 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKIS 50 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 50 mm bore, 28 mm width, 80 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKIS 50 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKIS 50 carries its own hardened, ground inner ring on a 50 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKIS 50 be mounted?",
        "a": "Mount the inner ring on the 50 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKIS 50?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS50-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 50×80×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS50",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS50",
      "NKIS 50"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI55-25-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKI 55/25 TN",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 46.8,
    "static_load_kN": 110,
    "fatigue_load_limit_kN": 13.4,
    "max_rpm": 7500,
    "reference_speed_rpm": 6700,
    "limiting_speed_rpm": 7500,
    "weight_g": 260,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 55 mm shaft that cannot be hardened on site, NKI 55/25 TN adds a hardened, ground inner ring to the machined needle roller design: envelope 55×72×25 mm per the machined-ring needle roller bearings with inner ring plan. The NKI 55/25 TN code gives bore 55 mm and width 25 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 55 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 46.8/110 kN ratings are SKF catalogue values for this exact execution (NKI 55/25 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 46.8/110 kN ratings and 260 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKI 55/25 TN be mounted?",
        "a": "Mount the inner ring on the 55 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 55/25 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 55/25 TN?",
        "a": "A NKI 55/25 TN measures 55 mm bore/Fw × 72 mm outside diameter × 25 mm width (2.165 × 2.835 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 46.8 kN, static C0 110 kN, fatigue limit Pu 13.4 kN, limiting speed 7,500 r/min, reference speed 6,700 r/min, mass about 260 g."
      },
      {
        "q": "How is the NKI 55/25 TN designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 55 mm bore, 25 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI55-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI55-25-TW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×72×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI55-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI55-25-TN",
      "NKI 55/25 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI55-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 55/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 72,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 55,
    "static_load_kN": 134,
    "fatigue_load_limit_kN": 17,
    "max_rpm": 7500,
    "reference_speed_rpm": 6700,
    "limiting_speed_rpm": 7500,
    "weight_g": 360,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 55/35 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 55 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 55 mm bore (d), 35 mm width; the 72 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. For life calculation, the 55/134 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: heat or press the inner ring onto the 55 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 55/134 kN ratings are SKF catalogue values for this exact execution (NKI 55/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 55/134 kN ratings and 360 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 55/35?",
        "a": "Mount the inner ring on the 55 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 55/35 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 55/35 have?",
        "a": "A NKI 55/35 measures 55 mm bore/Fw × 72 mm outside diameter × 35 mm width (2.165 × 2.835 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 55 kN, static C0 134 kN, fatigue limit Pu 17 kN, limiting speed 7,500 r/min, reference speed 6,700 r/min, mass about 360 g."
      },
      {
        "q": "What does NKI 55/35 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 55 mm bore, 35 mm width, 72 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI55-25-TV-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI55-25-TW-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI55-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×72×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI55-35",
      "NKI 55/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4911",
    "brand": "SKF",
    "manufacturer_designation": "NA 4911",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 57.2,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 390,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4911 provides the full machined-ring needle roller construction: ground inner ring on a 55 mm seat, flanged outer ring at 80 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 55 mm d and 25 mm B, the 80 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 390 g at 55×80×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 55 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4911 shares its 55×80×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 57.2/106 kN ratings and 390 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 4911 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4911 carries its own hardened, ground inner ring on a 55 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4911?",
        "a": "Mount the inner ring on the 55 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4911 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4911 have?",
        "a": "A NA 4911 measures 55 mm bore/Fw × 80 mm outside diameter × 25 mm width (2.165 × 3.15 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 57.2 kN, static C0 106 kN, fatigue limit Pu 13.2 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 390 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4911-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×80×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4911",
      "NA 4911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6911",
    "brand": "SKF",
    "manufacturer_designation": "NA 6911",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 89.7,
    "static_load_kN": 190,
    "fatigue_load_limit_kN": 23.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 780,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 6911 denotes a complete needle roller bearing for a 55 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 80 mm OD and 45 mm width. The designation NA 6911 tells you the envelope — 55×80×45 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 55 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 45 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 89.7/190 kN ratings are SKF catalogue values for this exact execution (NA 6911); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 89.7/190 kN ratings and 780 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 6911 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6911 carries its own hardened, ground inner ring on a 55 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 6911 be mounted?",
        "a": "Mount the inner ring on the 55 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 6911?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6911?",
        "a": "A NA 6911 measures 55 mm bore/Fw × 80 mm outside diameter × 45 mm width (2.165 × 3.15 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 89.7 kN, static C0 190 kN, fatigue limit Pu 23.2 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 780 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6911-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×80×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6911",
      "NA 6911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS55",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 55",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 85,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 66,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 560,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 55 provides the full machined-ring needle roller construction: ground inner ring on a 55 mm seat, flanged outer ring at 85 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 55 mm d and 28 mm B, the 85 mm outside diameter from the wide-section machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 6,000 r/min thermal reference and 6,700 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 55 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 28 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIS 55 shares its 55×85×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 66/114 kN ratings and 560 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIS 55 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 55 mm bore, 28 mm width, 85 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKIS 55 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKIS 55 carries its own hardened, ground inner ring on a 55 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKIS 55?",
        "a": "Mount the inner ring on the 55 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKIS 55 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS55-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 55×85×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS55",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS55",
      "NKIS 55"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI60-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 60/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 82,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 44,
    "static_load_kN": 95,
    "fatigue_load_limit_kN": 11.8,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 390,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 60/25 in the machined-ring needle roller bearings with inner ring with boundary dimensions 60×82×25 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NKI 60/25 tells you the envelope — 60×82×25 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 390 g at 60×82×25 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKI 60/25 shares its 60×82×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 44/95 kN ratings and 390 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKI 60/25 be mounted?",
        "a": "Mount the inner ring on the 60 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 60/25?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 60 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 60/25?",
        "a": "A NKI 60/25 measures 60 mm bore/Fw × 82 mm outside diameter × 25 mm width (2.362 × 3.228 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44 kN, static C0 95 kN, fatigue limit Pu 11.8 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 390 g."
      },
      {
        "q": "How is the NKI 60/25 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 60 mm bore, 25 mm width, 82 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI60-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×82×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI60-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI60-25",
      "NKI 60/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI60-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 60/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 82,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 18.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 550,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 60/35 measures 60×82×35 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 60 mm bore (d), 35 mm width; the 82 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 550 g at 60×82×35 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 60 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 60 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 60.5/146 kN ratings and 550 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 60/35 have?",
        "a": "A NKI 60/35 measures 60 mm bore/Fw × 82 mm outside diameter × 35 mm width (2.362 × 3.228 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 60.5 kN, static C0 146 kN, fatigue limit Pu 18.3 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 550 g."
      },
      {
        "q": "What does NKI 60/35 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 60 mm bore, 35 mm width, 82 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 60/35 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 60/35 carries its own hardened, ground inner ring on a 60 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 60/35?",
        "a": "Mount the inner ring on the 60 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI60-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI60-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×82×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI60-35",
      "NKI 60/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4912",
    "brand": "SKF",
    "manufacturer_designation": "NA 4912",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 430,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4912 in the dimension series 49 needle roller bearings with inner ring with boundary dimensions 60×85×25 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 4912 tells you the envelope — 60×85×25 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 430 g at 60×85×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 60 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 60.5/114 kN ratings and 430 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4912 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 60 mm bore, 25 mm width, 85 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4912 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4912 carries its own hardened, ground inner ring on a 60 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4912 be mounted?",
        "a": "Mount the inner ring on the 60 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4912?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 60 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4912-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×85×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4912",
      "NA 4912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6912",
    "brand": "SKF",
    "manufacturer_designation": "NA 6912",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 93.5,
    "static_load_kN": 204,
    "fatigue_load_limit_kN": 25,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 810,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6912 provides the full machined-ring needle roller construction: ground inner ring on a 60 mm seat, flanged outer ring at 85 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 60 mm bore (d), 45 mm width; the 85 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 60 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 45 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 60 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 93.5/204 kN ratings and 810 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 6912 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 60 mm bore, 45 mm width, 85 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6912 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6912 carries its own hardened, ground inner ring on a 60 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6912?",
        "a": "Mount the inner ring on the 60 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6912 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6912-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×85×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6912",
      "NA 6912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS60",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 60",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 90,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 68.2,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 15.3,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 560,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The wide-section machined-ring needle roller bearings with inner ring execution NKIS 60 measures 60×90×28 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 60 mm d and 28 mm B, the 90 mm outside diameter from the wide-section machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 5,600 r/min thermal reference and 6,300 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 60 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIS 60 shares its 60×90×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 68.2/120 kN ratings and 560 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKIS 60?",
        "a": "Mount the inner ring on the 60 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKIS 60 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKIS 60 have?",
        "a": "A NKIS 60 measures 60 mm bore/Fw × 90 mm outside diameter × 28 mm width (2.362 × 3.543 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 68.2 kN, static C0 120 kN, fatigue limit Pu 15.3 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 560 g."
      },
      {
        "q": "What does NKIS 60 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 60 mm bore, 28 mm width, 90 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS60-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 60×90×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS60",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS60",
      "NKIS 60"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI65-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 65/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 52.8,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 460,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 65/25 measures 65×90×25 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 65 mm d and 25 mm B, the 90 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Speed planning separates the two ceilings: 5,600 r/min thermal reference and 6,300 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 65 mm seat. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 25 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 5,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 65 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 52.8/106 kN ratings and 460 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 65/25 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 65/25 carries its own hardened, ground inner ring on a 65 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 65/25?",
        "a": "Mount the inner ring on the 65 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 65/25 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 65/25 have?",
        "a": "A NKI 65/25 measures 65 mm bore/Fw × 90 mm outside diameter × 25 mm width (2.559 × 3.543 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 52.8 kN, static C0 106 kN, fatigue limit Pu 13.2 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 460 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI65-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI65-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NA4913",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope, but catalogue C/C0 differ between the executions (52.8/106 vs 61.6/120 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI65-25",
      "NKI 65/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4913",
    "brand": "SKF",
    "manufacturer_designation": "NA 4913",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 61.6,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 460,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 65 mm shaft that cannot be hardened on site, NA 4913 adds a hardened, ground inner ring to the machined needle roller design: envelope 65×90×25 mm per the dimension series 49 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 65 mm bore (d), 25 mm width; the 90 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 460 g at 65×90×25 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 65 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 61.6/120 kN ratings are SKF catalogue values for this exact execution (NA 4913); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 61.6/120 kN ratings and 460 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4913 have?",
        "a": "A NA 4913 measures 65 mm bore/Fw × 90 mm outside diameter × 25 mm width (2.559 × 3.543 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 120 kN, fatigue limit Pu 14.6 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 460 g."
      },
      {
        "q": "What does NA 4913 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 65 mm bore, 25 mm width, 90 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4913 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4913 carries its own hardened, ground inner ring on a 65 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4913?",
        "a": "Mount the inner ring on the 65 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4913-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI65-25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 65×90×25 mm envelope, but catalogue C/C0 differ between the executions (61.6/120 vs 52.8/106 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4913",
      "NA 4913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI65-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 65/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.4,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 660,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 65/35 in the machined-ring needle roller bearings with inner ring with boundary dimensions 65×90×35 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NKI 65/35 tells you the envelope — 65×90×35 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Speed planning separates the two ceilings: 5,600 r/min thermal reference and 6,300 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 65 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 65 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 73.7/163 kN ratings are SKF catalogue values for this exact execution (NKI 65/35); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 73.7/163 kN ratings and 660 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 65/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 65 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 65/35?",
        "a": "A NKI 65/35 measures 65 mm bore/Fw × 90 mm outside diameter × 35 mm width (2.559 × 3.543 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 163 kN, fatigue limit Pu 20.4 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 660 g."
      },
      {
        "q": "How is the NKI 65/35 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 65 mm bore, 35 mm width, 90 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 65/35 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 65/35 carries its own hardened, ground inner ring on a 65 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI65-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI65-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×90×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI65",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI65-35",
      "NKI 65/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6913",
    "brand": "SKF",
    "manufacturer_designation": "NA 6913",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 95.2,
    "static_load_kN": 212,
    "fatigue_load_limit_kN": 26,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 830,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 6913 in the dimension series 69 needle roller bearings with inner ring with boundary dimensions 65×90×45 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 6913 code gives bore 65 mm and width 45 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 65 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 45 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 6913 shares its 65×90×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 95.2/212 kN ratings and 830 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 6913?",
        "a": "A NA 6913 measures 65 mm bore/Fw × 90 mm outside diameter × 45 mm width (2.559 × 3.543 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 95.2 kN, static C0 212 kN, fatigue limit Pu 26 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 830 g."
      },
      {
        "q": "How is the NA 6913 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 65 mm bore, 45 mm width, 90 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 6913 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6913 carries its own hardened, ground inner ring on a 65 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 6913 be mounted?",
        "a": "Mount the inner ring on the 65 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6913-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×90×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6913",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6913",
      "NA 6913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIS65",
    "brand": "SKF",
    "manufacturer_designation": "NKIS 65",
    "series": "NKIS-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 95,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 70.4,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 16.6,
    "max_rpm": 6000,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 6000,
    "weight_g": 640,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIS 65 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 65 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NKIS 65 tells you the envelope — 65×95×28 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 5,300 r/min thermal reference and 6,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 65 mm seat. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKIS 65 shares its 65×95×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,300 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 70.4/132 kN ratings and 640 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKIS 65 be mounted?",
        "a": "Mount the inner ring on the 65 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKIS 65?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 65 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIS 65?",
        "a": "A NKIS 65 measures 65 mm bore/Fw × 95 mm outside diameter × 28 mm width (2.559 × 3.74 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 70.4 kN, static C0 132 kN, fatigue limit Pu 16.6 kN, limiting speed 6,000 r/min, reference speed 5,300 r/min, mass about 640 g."
      },
      {
        "q": "How is the NKIS 65 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 65 mm bore, 28 mm width, 95 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS65-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 65×95×28 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKIS65",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIS65",
      "NKIS 65"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI70-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 70/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 95,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 56.1,
    "static_load_kN": 127,
    "fatigue_load_limit_kN": 15.6,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 510,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 70/25 denotes a complete needle roller bearing for a 70 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 95 mm OD and 25 mm width. The designation NKI 70/25 tells you the envelope — 70×95×25 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 510 g catalogue mass and 12.5 mm radial section ((95−70)/2) frame a rating of about 0.80 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 25 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 56.1/127 kN ratings and 510 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 70/25?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 70 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 70/25?",
        "a": "A NKI 70/25 measures 70 mm bore/Fw × 95 mm outside diameter × 25 mm width (2.756 × 3.74 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 56.1 kN, static C0 127 kN, fatigue limit Pu 15.6 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 510 g."
      },
      {
        "q": "How is the NKI 70/25 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 70 mm bore, 25 mm width, 95 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 70/25 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 70/25 carries its own hardened, ground inner ring on a 70 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI70-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×95×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI70-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI70",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI70-25",
      "NKI 70/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI70-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 70/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 95,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 76.5,
    "static_load_kN": 190,
    "fatigue_load_limit_kN": 24,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 720,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 70 mm shaft that cannot be hardened on site, NKI 70/35 adds a hardened, ground inner ring to the machined needle roller design: envelope 70×95×35 mm per the machined-ring needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 70 mm bore (d), 35 mm width; the 95 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 720 g catalogue mass and 12.5 mm radial section ((95−70)/2) frame a rating of about 1.09 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 70/35 shares its 70×95×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 76.5/190 kN ratings and 720 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 70/35 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 70 mm bore, 35 mm width, 95 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 70/35 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 70/35 carries its own hardened, ground inner ring on a 70 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 70/35?",
        "a": "Mount the inner ring on the 70 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 70/35 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI70-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI70-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×95×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI70",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI70-35",
      "NKI 70/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4914",
    "brand": "SKF",
    "manufacturer_designation": "NA 4914",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.8,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 730,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4914 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 70 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NA 4914 code gives bore 70 mm and width 30 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 730 g at 70×100×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 70 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 70 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 84.2/163 kN ratings are SKF catalogue values for this exact execution (NA 4914); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 84.2/163 kN ratings and 730 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4914?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 70 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4914?",
        "a": "A NA 4914 measures 70 mm bore/Fw × 100 mm outside diameter × 30 mm width (2.756 × 3.937 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 163 kN, fatigue limit Pu 20.8 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 730 g."
      },
      {
        "q": "How is the NA 4914 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 70 mm bore, 30 mm width, 100 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4914 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4914 carries its own hardened, ground inner ring on a 70 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4914-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×100×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4914",
      "NA 4914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6914",
    "brand": "SKF",
    "manufacturer_designation": "NA 6914",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 128,
    "static_load_kN": 285,
    "fatigue_load_limit_kN": 36,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 1350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 70 mm shaft that cannot be hardened on site, NA 6914 adds a hardened, ground inner ring to the machined needle roller design: envelope 70×100×54 mm per the dimension series 69 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 70 mm d and 54 mm B, the 100 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 70 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 54 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 6914 shares its 70×100×54 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 128/285 kN ratings and 1350 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 6914 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6914 have?",
        "a": "A NA 6914 measures 70 mm bore/Fw × 100 mm outside diameter × 54 mm width (2.756 × 3.937 × 2.126 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 128 kN, static C0 285 kN, fatigue limit Pu 36 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 1350 g."
      },
      {
        "q": "What does NA 6914 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 70 mm bore, 54 mm width, 100 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6914 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6914 carries its own hardened, ground inner ring on a 70 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6914-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 70×100×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6914",
      "NA 6914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI75-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 75/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 69.3,
    "static_load_kN": 132,
    "fatigue_load_limit_kN": 16.6,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 640,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 75 mm shaft that cannot be hardened on site, NKI 75/25 adds a hardened, ground inner ring to the machined needle roller design: envelope 75×105×25 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 75 mm d and 25 mm B, the 105 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 75 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKI 75/25 shares its 75×105×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 69.3/132 kN ratings and 640 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 75/25?",
        "a": "Mount the inner ring on the 75 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 75/25 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 75/25 have?",
        "a": "A NKI 75/25 measures 75 mm bore/Fw × 105 mm outside diameter × 25 mm width (2.953 × 4.134 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 69.3 kN, static C0 132 kN, fatigue limit Pu 16.6 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 640 g."
      },
      {
        "q": "What does NKI 75/25 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 75 mm bore, 25 mm width, 105 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI75-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×105×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI75-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI75",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI75-25",
      "NKI 75/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4915",
    "brand": "SKF",
    "manufacturer_designation": "NA 4915",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 170,
    "fatigue_load_limit_kN": 21.6,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 780,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4915 measures 75×105×30 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 75 mm d and 30 mm B, the 105 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 780 g at 75×105×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 75 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 75 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 84.2/170 kN ratings and 780 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4915?",
        "a": "Mount the inner ring on the 75 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4915 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4915 have?",
        "a": "A NA 4915 measures 75 mm bore/Fw × 105 mm outside diameter × 30 mm width (2.953 × 4.134 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 170 kN, fatigue limit Pu 21.6 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 780 g."
      },
      {
        "q": "What does NA 4915 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 75 mm bore, 30 mm width, 105 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4915-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×105×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4915",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4915",
      "NA 4915"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI75-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 75/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 96.8,
    "static_load_kN": 200,
    "fatigue_load_limit_kN": 26,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 910,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 75/35 denotes a complete needle roller bearing for a 75 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 105 mm OD and 35 mm width. The designation NKI 75/35 tells you the envelope — 75×105×35 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 35 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKI 75/35 shares its 75×105×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 4,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 96.8/200 kN ratings and 910 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 75/35?",
        "a": "A NKI 75/35 measures 75 mm bore/Fw × 105 mm outside diameter × 35 mm width (2.953 × 4.134 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 96.8 kN, static C0 200 kN, fatigue limit Pu 26 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 910 g."
      },
      {
        "q": "How is the NKI 75/35 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 75 mm bore, 35 mm width, 105 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 75/35 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 75/35 carries its own hardened, ground inner ring on a 75 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 75/35 be mounted?",
        "a": "Mount the inner ring on the 75 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI75-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI75-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×105×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI75",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI75-35",
      "NKI 75/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6915",
    "brand": "SKF",
    "manufacturer_designation": "NA 6915",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 75,
    "D_mm": 105,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 130,
    "static_load_kN": 290,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 5300,
    "reference_speed_rpm": 4800,
    "limiting_speed_rpm": 5300,
    "weight_g": 1450,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6915 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 75 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NA 6915 tells you the envelope — 75×105×54 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 75 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 54 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 75 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 130/290 kN ratings and 1450 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 6915 be mounted?",
        "a": "Mount the inner ring on the 75 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 6915?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 75 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6915?",
        "a": "A NA 6915 measures 75 mm bore/Fw × 105 mm outside diameter × 54 mm width (2.953 × 4.134 × 2.126 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 130 kN, static C0 290 kN, fatigue limit Pu 37.5 kN, limiting speed 5,300 r/min, reference speed 4,800 r/min, mass about 1450 g."
      },
      {
        "q": "How is the NA 6915 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 75 mm bore, 54 mm width, 105 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6915-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 75×105×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6915",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6915",
      "NA 6915"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI80-25",
    "brand": "SKF",
    "manufacturer_designation": "NKI 80/25",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 72.1,
    "static_load_kN": 140,
    "fatigue_load_limit_kN": 18,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 680,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 80/25 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 80 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 80 mm d and 25 mm B, the 110 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Selection arithmetic: C 72.1 kN against C0 140 kN gives a C0/C ratio of 1.94, and the 18 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 80 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 25 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 72.1/140 kN ratings are SKF catalogue values for this exact execution (NKI 80/25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 72.1/140 kN ratings and 680 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 80/25 have?",
        "a": "A NKI 80/25 measures 80 mm bore/Fw × 110 mm outside diameter × 25 mm width (3.15 × 4.331 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 72.1 kN, static C0 140 kN, fatigue limit Pu 18 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 680 g."
      },
      {
        "q": "What does NKI 80/25 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 80 mm bore, 25 mm width, 110 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 80/25 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 80/25 carries its own hardened, ground inner ring on a 80 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 80/25?",
        "a": "Mount the inner ring on the 80 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI80-25-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×110×25 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI80-35-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI80",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI80-25",
      "NKI 80/25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4916",
    "brand": "SKF",
    "manufacturer_designation": "NA 4916",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 88,
    "static_load_kN": 183,
    "fatigue_load_limit_kN": 23.2,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 880,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4916 denotes a complete needle roller bearing for a 80 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 110 mm OD and 30 mm width. The designation NA 4916 tells you the envelope — 80×110×30 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 880 g at 80×110×30 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 80 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 30 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 4916 shares its 80×110×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 4,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 88/183 kN ratings and 880 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 4916 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4916 carries its own hardened, ground inner ring on a 80 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4916 be mounted?",
        "a": "Mount the inner ring on the 80 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4916?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 80 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4916?",
        "a": "A NA 4916 measures 80 mm bore/Fw × 110 mm outside diameter × 30 mm width (3.15 × 4.331 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 88 kN, static C0 183 kN, fatigue limit Pu 23.2 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 880 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4916-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×110×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4916",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4916",
      "NA 4916"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI80-35",
    "brand": "SKF",
    "manufacturer_designation": "NKI 80/35",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 101,
    "static_load_kN": 216,
    "fatigue_load_limit_kN": 28,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 960,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKI 80/35 provides the full machined-ring needle roller construction: ground inner ring on a 80 mm seat, flanged outer ring at 110 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The designation NKI 80/35 tells you the envelope — 80×110×35 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. Selection arithmetic: C 101 kN against C0 216 kN gives a C0/C ratio of 2.14, and the 28 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 35 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 101/216 kN ratings and 960 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKI 80/35 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 80/35 carries its own hardened, ground inner ring on a 80 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 80/35 be mounted?",
        "a": "Mount the inner ring on the 80 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 80/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 80 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 80/35?",
        "a": "A NKI 80/35 measures 80 mm bore/Fw × 110 mm outside diameter × 35 mm width (3.15 × 4.331 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 101 kN, static C0 216 kN, fatigue limit Pu 28 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 960 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI80-25-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI80-35-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×110×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI80",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI80-35",
      "NKI 80/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6916",
    "brand": "SKF",
    "manufacturer_designation": "NA 6916",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 80,
    "D_mm": 110,
    "B_mm": 54,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 134,
    "static_load_kN": 315,
    "fatigue_load_limit_kN": 40,
    "max_rpm": 5000,
    "reference_speed_rpm": 4500,
    "limiting_speed_rpm": 5000,
    "weight_g": 1500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 69 needle roller bearings with inner ring execution NA 6916 measures 80×110×54 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 80 mm bore (d), 54 mm width; the 110 mm OD follows the dimension series, and the inner ring is a separate ground component. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 80 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 54 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 80 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 134/315 kN ratings are SKF catalogue values for this exact execution (NA 6916); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 134/315 kN ratings and 1500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 6916 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6916 carries its own hardened, ground inner ring on a 80 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6916?",
        "a": "Mount the inner ring on the 80 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 6916 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 6916 have?",
        "a": "A NA 6916 measures 80 mm bore/Fw × 110 mm outside diameter × 54 mm width (3.15 × 4.331 × 2.126 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 134 kN, static C0 315 kN, fatigue limit Pu 40 kN, limiting speed 5,000 r/min, reference speed 4,500 r/min, mass about 1500 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6916-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 80×110×54 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6916",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6916",
      "NA 6916"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI85-26",
    "brand": "SKF",
    "manufacturer_designation": "NKI 85/26",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 115,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 73.7,
    "static_load_kN": 146,
    "fatigue_load_limit_kN": 18.6,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 740,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKI 85/26 in the machined-ring needle roller bearings with inner ring with boundary dimensions 85×115×26 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 85 mm d and 26 mm B, the 115 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. The 740 g catalogue mass and 15.0 mm radial section ((115−85)/2) frame a rating of about 0.87 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 73.7/146 kN ratings are SKF catalogue values for this exact execution (NKI 85/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 73.7/146 kN ratings and 740 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKI 85/26?",
        "a": "Mount the inner ring on the 85 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 85/26 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 85/26 have?",
        "a": "A NKI 85/26 measures 85 mm bore/Fw × 115 mm outside diameter × 26 mm width (3.346 × 4.528 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 73.7 kN, static C0 146 kN, fatigue limit Pu 18.6 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 740 g."
      },
      {
        "q": "What does NKI 85/26 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 85 mm bore, 26 mm width, 115 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI85-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×115×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI85-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI85",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI85-26",
      "NKI 85/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI85-36",
    "brand": "SKF",
    "manufacturer_designation": "NKI 85/36",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 115,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 105,
    "static_load_kN": 232,
    "fatigue_load_limit_kN": 30,
    "max_rpm": 4800,
    "reference_speed_rpm": 4300,
    "limiting_speed_rpm": 4800,
    "weight_g": 1050,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The machined-ring needle roller bearings with inner ring execution NKI 85/36 measures 85×115×36 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. The designation NKI 85/36 tells you the envelope — 85×115×36 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. The 1050 g catalogue mass and 15.0 mm radial section ((115−85)/2) frame a rating of about 1.24 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: heat or press the inner ring onto the 85 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 36 mm assembly for free rotation before applying load.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 105/232 kN ratings and 1050 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 85/36?",
        "a": "A NKI 85/36 measures 85 mm bore/Fw × 115 mm outside diameter × 36 mm width (3.346 × 4.528 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 105 kN, static C0 232 kN, fatigue limit Pu 30 kN, limiting speed 4,800 r/min, reference speed 4,300 r/min, mass about 1050 g."
      },
      {
        "q": "How is the NKI 85/36 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 85 mm bore, 36 mm width, 115 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 85/36 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 85/36 carries its own hardened, ground inner ring on a 85 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 85/36 be mounted?",
        "a": "Mount the inner ring on the 85 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI85-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI85-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×115×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI85",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI85-36",
      "NKI 85/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4917",
    "brand": "SKF",
    "manufacturer_designation": "NA 4917",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 120,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 108,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 31,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 1250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4917 provides the full machined-ring needle roller construction: ground inner ring on a 85 mm seat, flanged outer ring at 120 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 85 mm bore (d), 35 mm width; the 120 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 1250 g at 85×120×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 85 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4917 shares its 85×120×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 108/250 kN ratings and 1250 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 4917 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 85 mm bore, 35 mm width, 120 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4917 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4917 carries its own hardened, ground inner ring on a 85 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4917?",
        "a": "Mount the inner ring on the 85 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4917 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4917-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×120×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4917",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4917",
      "NA 4917"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6917",
    "brand": "SKF",
    "manufacturer_designation": "NA 6917",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 85,
    "D_mm": 120,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 165,
    "static_load_kN": 425,
    "fatigue_load_limit_kN": 53,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 2200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 6917 denotes a complete needle roller bearing for a 85 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 120 mm OD and 63 mm width. The NA 6917 code gives bore 85 mm and width 63 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 85 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 63 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 85 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 85 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 165/425 kN ratings are SKF catalogue values for this exact execution (NA 6917); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 165/425 kN ratings and 2200 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 6917 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 85 mm bore, 63 mm width, 120 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 6917 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6917 carries its own hardened, ground inner ring on a 85 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 6917 be mounted?",
        "a": "Mount the inner ring on the 85 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 6917?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 85 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 17.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6917-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 85×120×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6917",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6917",
      "NA 6917"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI90-26",
    "brand": "SKF",
    "manufacturer_designation": "NKI 90/26",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 120,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 76.5,
    "static_load_kN": 156,
    "fatigue_load_limit_kN": 19.6,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 780,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 90 mm shaft that cannot be hardened on site, NKI 90/26 adds a hardened, ground inner ring to the machined needle roller design: envelope 90×120×26 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 90 mm d and 26 mm B, the 120 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 4,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 90 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 76.5/156 kN ratings and 780 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKI 90/26 have?",
        "a": "A NKI 90/26 measures 90 mm bore/Fw × 120 mm outside diameter × 26 mm width (3.543 × 4.724 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 76.5 kN, static C0 156 kN, fatigue limit Pu 19.6 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 780 g."
      },
      {
        "q": "What does NKI 90/26 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 90 mm bore, 26 mm width, 120 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 90/26 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 90/26 carries its own hardened, ground inner ring on a 90 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 90/26?",
        "a": "Mount the inner ring on the 90 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI90-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×120×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI90-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI90",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI90-26",
      "NKI 90/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI90-36",
    "brand": "SKF",
    "manufacturer_designation": "NKI 90/36",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 120,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 108,
    "static_load_kN": 250,
    "fatigue_load_limit_kN": 31,
    "max_rpm": 4500,
    "reference_speed_rpm": 4000,
    "limiting_speed_rpm": 4500,
    "weight_g": 1100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 90/36 denotes a complete needle roller bearing for a 90 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 120 mm OD and 36 mm width. The designation NKI 90/36 tells you the envelope — 90×120×36 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 90 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 36 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 90 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 108/250 kN ratings are SKF catalogue values for this exact execution (NKI 90/36); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 108/250 kN ratings and 1100 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKI 90/36 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 90/36 carries its own hardened, ground inner ring on a 90 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 90/36 be mounted?",
        "a": "Mount the inner ring on the 90 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NKI 90/36?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 90 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 90/36?",
        "a": "A NKI 90/36 measures 90 mm bore/Fw × 120 mm outside diameter × 36 mm width (3.543 × 4.724 × 1.417 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 108 kN, static C0 250 kN, fatigue limit Pu 31 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 1100 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI90-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI90-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×120×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI90",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI90-36",
      "NKI 90/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4918",
    "brand": "SKF",
    "manufacturer_designation": "NA 4918",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 125,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 112,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 32.5,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 1300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4918 in the dimension series 49 needle roller bearings with inner ring with boundary dimensions 90×125×35 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 4918 code gives bore 90 mm and width 35 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 1300 g at 90×125×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 90 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 112/265 kN ratings and 1300 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 4918?",
        "a": "A NA 4918 measures 90 mm bore/Fw × 125 mm outside diameter × 35 mm width (3.543 × 4.921 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 112 kN, static C0 265 kN, fatigue limit Pu 32.5 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 1300 g."
      },
      {
        "q": "How is the NA 4918 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 90 mm bore, 35 mm width, 125 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4918 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4918 carries its own hardened, ground inner ring on a 90 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4918 be mounted?",
        "a": "Mount the inner ring on the 90 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4918-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×125×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4918",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4918",
      "NA 4918"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6918",
    "brand": "SKF",
    "manufacturer_designation": "NA 6918",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 90,
    "D_mm": 125,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 172,
    "static_load_kN": 450,
    "fatigue_load_limit_kN": 55,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 2300,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 6918 provides the full machined-ring needle roller construction: ground inner ring on a 90 mm seat, flanged outer ring at 125 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 90 mm d and 63 mm B, the 125 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 90 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 63 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 90 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 3,800 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 90 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 172/450 kN ratings and 2300 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 644); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 6918 have?",
        "a": "A NA 6918 measures 90 mm bore/Fw × 125 mm outside diameter × 63 mm width (3.543 × 4.921 × 2.48 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 172 kN, static C0 450 kN, fatigue limit Pu 55 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 2300 g."
      },
      {
        "q": "What does NA 6918 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 90 mm bore, 63 mm width, 125 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 6918 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 6918 carries its own hardened, ground inner ring on a 90 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 6918?",
        "a": "Mount the inner ring on the 90 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6918-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 90×125×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6918",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6918",
      "NA 6918"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI95-26",
    "brand": "SKF",
    "manufacturer_designation": "NKI 95/26",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 125,
    "B_mm": 26,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 78.1,
    "static_load_kN": 166,
    "fatigue_load_limit_kN": 20.4,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 820,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 95/26 denotes a complete needle roller bearing for a 95 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 125 mm OD and 26 mm width. The NKI 95/26 code gives bore 95 mm and width 26 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 78.1 kN against C0 166 kN gives a C0/C ratio of 2.13, and the 20.4 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 26 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 95 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 78.1/166 kN ratings are SKF catalogue values for this exact execution (NKI 95/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 78.1/166 kN ratings and 820 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKI 95/26?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 95 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKI 95/26?",
        "a": "A NKI 95/26 measures 95 mm bore/Fw × 125 mm outside diameter × 26 mm width (3.74 × 4.921 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 78.1 kN, static C0 166 kN, fatigue limit Pu 20.4 kN, limiting speed 4,300 r/min, reference speed 3,800 r/min, mass about 820 g."
      },
      {
        "q": "How is the NKI 95/26 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 95 mm bore, 26 mm width, 125 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 95/26 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 95/26 carries its own hardened, ground inner ring on a 95 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI95-26-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×125×26 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI95-36-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI95",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI95-26",
      "NKI 95/26"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI95-36",
    "brand": "SKF",
    "manufacturer_designation": "NKI 95/36",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 125,
    "B_mm": 36,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 112,
    "static_load_kN": 265,
    "fatigue_load_limit_kN": 32.5,
    "max_rpm": 4300,
    "reference_speed_rpm": 3800,
    "limiting_speed_rpm": 4300,
    "weight_g": 1150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 95 mm shaft that cannot be hardened on site, NKI 95/36 adds a hardened, ground inner ring to the machined needle roller design: envelope 95×125×36 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 95 mm d and 36 mm B, the 125 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 112 kN against C0 265 kN gives a C0/C ratio of 2.37, and the 32.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 112/265 kN ratings are SKF catalogue values for this exact execution (NKI 95/36); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 112/265 kN ratings and 1150 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKI 95/36 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 95 mm bore, 36 mm width, 125 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NKI 95/36 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 95/36 carries its own hardened, ground inner ring on a 95 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 95/36?",
        "a": "Mount the inner ring on the 95 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 95/36 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI95-26-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI95-36-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×125×36 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI95",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI95-36",
      "NKI 95/36"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4919",
    "brand": "SKF",
    "manufacturer_designation": "NA 4919",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 130,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 114,
    "static_load_kN": 270,
    "fatigue_load_limit_kN": 33.5,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 1350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 95 mm shaft that cannot be hardened on site, NA 4919 adds a hardened, ground inner ring to the machined needle roller design: envelope 95×130×35 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 95 mm d and 35 mm B, the 130 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 1350 g at 95×130×35 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: heat or press the inner ring onto the 95 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 35 mm assembly for free rotation before applying load.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 114/270 kN ratings are SKF catalogue values for this exact execution (NA 4919); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 114/270 kN ratings and 1350 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4919 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4919 have?",
        "a": "A NA 4919 measures 95 mm bore/Fw × 130 mm outside diameter × 35 mm width (3.74 × 5.118 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 114 kN, static C0 270 kN, fatigue limit Pu 33.5 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 1350 g."
      },
      {
        "q": "What does NA 4919 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 95 mm bore, 35 mm width, 130 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4919 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4919 carries its own hardened, ground inner ring on a 95 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4919-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×130×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4919",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4919",
      "NA 4919"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA6919",
    "brand": "SKF",
    "manufacturer_designation": "NA 6919",
    "series": "NA-69-series",
    "type": "needle",
    "d_mm": 95,
    "D_mm": 130,
    "B_mm": 63,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 172,
    "static_load_kN": 465,
    "fatigue_load_limit_kN": 56,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 2500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 6919 in the dimension series 69 needle roller bearings with inner ring with boundary dimensions 95×130×63 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 6919 tells you the envelope — 95×130×63 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: heat or press the inner ring onto the 95 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 63 mm assembly for free rotation before applying load.",
    "applications": [
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 95 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 6919 shares its 95×130×63 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 3,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 172/465 kN ratings and 2500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 6919?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 95 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 17.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 6919?",
        "a": "A NA 6919 measures 95 mm bore/Fw × 130 mm outside diameter × 63 mm width (3.74 × 5.118 × 2.48 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 172 kN, static C0 465 kN, fatigue limit Pu 56 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 2500 g."
      },
      {
        "q": "How is the NA 6919 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 95 mm bore, 63 mm width, 130 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 6919 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 6919 carries its own hardened, ground inner ring on a 95 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA6919-ZW-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 95×130×63 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA6919",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA6919",
      "NA 6919"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI100-30",
    "brand": "SKF",
    "manufacturer_designation": "NKI 100/30",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 130,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 96.8,
    "static_load_kN": 220,
    "fatigue_load_limit_kN": 27,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKI 100/30 denotes a complete needle roller bearing for a 100 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 130 mm OD and 30 mm width. The NKI 100/30 code gives bore 100 mm and width 30 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 990 g catalogue mass and 15.0 mm radial section ((130−100)/2) frame a rating of about 0.97 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 100 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 96.8/220 kN ratings are SKF catalogue values for this exact execution (NKI 100/30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 96.8/220 kN ratings and 990 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKI 100/30?",
        "a": "A NKI 100/30 measures 100 mm bore/Fw × 130 mm outside diameter × 30 mm width (3.937 × 5.118 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 96.8 kN, static C0 220 kN, fatigue limit Pu 27 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 990 g."
      },
      {
        "q": "How is the NKI 100/30 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 100 mm bore, 30 mm width, 130 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NKI 100/30 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NKI 100/30 carries its own hardened, ground inner ring on a 100 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NKI 100/30 be mounted?",
        "a": "Mount the inner ring on the 100 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI100-30-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×130×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI100-40-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI100",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI100-30",
      "NKI 100/30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKI100-40",
    "brand": "SKF",
    "manufacturer_designation": "NKI 100/40",
    "series": "NKI-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 130,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 123,
    "static_load_kN": 305,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 4000,
    "reference_speed_rpm": 3600,
    "limiting_speed_rpm": 4000,
    "weight_g": 1350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For a 100 mm shaft that cannot be hardened on site, NKI 100/40 adds a hardened, ground inner ring to the machined needle roller design: envelope 100×130×40 mm per the machined-ring needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 100 mm d and 40 mm B, the 130 mm outside diameter from the machined-ring needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. The 1350 g catalogue mass and 15.0 mm radial section ((130−100)/2) frame a rating of about 1.23 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: heat or press the inner ring onto the 100 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 40 mm assembly for free rotation before applying load.",
    "applications": [
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads",
      "electric motor armature shafts with ground seats",
      "printing and paper-handling rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 123/305 kN ratings are SKF catalogue values for this exact execution (NKI 100/40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 123/305 kN ratings and 1350 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKI 100/40 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NKI 100/40 carries its own hardened, ground inner ring on a 100 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NKI 100/40?",
        "a": "Mount the inner ring on the 100 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NKI 100/40 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NKI 100/40 have?",
        "a": "A NKI 100/40 measures 100 mm bore/Fw × 130 mm outside diameter × 40 mm width (3.937 × 5.118 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 123 kN, static C0 305 kN, fatigue limit Pu 37.5 kN, limiting speed 4,000 r/min, reference speed 3,600 r/min, mass about 1350 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI100-30-XL",
        "equiv_brand": "FAG",
        "level": "verify",
        "note": "Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue."
      },
      {
        "equiv_sku": "NKI100-40-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×130×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NKI100",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKI100-40",
      "NKI 100/40"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4920",
    "brand": "SKF",
    "manufacturer_designation": "NA 4920",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 100,
    "D_mm": 140,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 125,
    "static_load_kN": 280,
    "fatigue_load_limit_kN": 34,
    "max_rpm": 4000,
    "reference_speed_rpm": 3400,
    "limiting_speed_rpm": 4000,
    "weight_g": 1900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 100 mm shaft that cannot be hardened on site, NA 4920 adds a hardened, ground inner ring to the machined needle roller design: envelope 100×140×40 mm per the dimension series 49 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 100 mm d and 40 mm B, the 140 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 1900 g at 100×140×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 40 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 3,400 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 100 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 125/280 kN ratings and 1900 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4920 have?",
        "a": "A NA 4920 measures 100 mm bore/Fw × 140 mm outside diameter × 40 mm width (3.937 × 5.512 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 125 kN, static C0 280 kN, fatigue limit Pu 34 kN, limiting speed 4,000 r/min, reference speed 3,400 r/min, mass about 1900 g."
      },
      {
        "q": "What does NA 4920 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 100 mm bore, 40 mm width, 140 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4920 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4920 carries its own hardened, ground inner ring on a 100 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4920?",
        "a": "Mount the inner ring on the 100 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4920-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 100×140×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4920",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4920",
      "NA 4920"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4822",
    "brand": "SKF",
    "manufacturer_designation": "NA 4822",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 140,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 93.5,
    "static_load_kN": 232,
    "fatigue_load_limit_kN": 27,
    "max_rpm": 3800,
    "reference_speed_rpm": 3400,
    "limiting_speed_rpm": 3800,
    "weight_g": 1100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4822 in the dimension series 48 needle roller bearings with inner ring with boundary dimensions 110×140×30 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 4822 tells you the envelope — 110×140×30 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 93.5 kN against C0 232 kN gives a C0/C ratio of 2.48, and the 27 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 4822 shares its 110×140×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 3,400 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 93.5/232 kN ratings and 1100 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 4822 be mounted?",
        "a": "Mount the inner ring on the 110 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4822?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 110 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4822?",
        "a": "A NA 4822 measures 110 mm bore/Fw × 140 mm outside diameter × 30 mm width (4.331 × 5.512 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 93.5 kN, static C0 232 kN, fatigue limit Pu 27 kN, limiting speed 3,800 r/min, reference speed 3,400 r/min, mass about 1100 g."
      },
      {
        "q": "How is the NA 4822 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 110 mm bore, 30 mm width, 140 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4822-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×140×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4822",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4822",
      "NA 4822"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4922",
    "brand": "SKF",
    "manufacturer_designation": "NA 4922",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 110,
    "D_mm": 150,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 130,
    "static_load_kN": 300,
    "fatigue_load_limit_kN": 35.5,
    "max_rpm": 3600,
    "reference_speed_rpm": 3200,
    "limiting_speed_rpm": 3600,
    "weight_g": 2050,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4922 measures 110×150×40 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 110 mm bore (d), 40 mm width; the 150 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 2050 g at 110×150×40 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 40 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 110 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4922 shares its 110×150×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 130/300 kN ratings and 2050 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4922?",
        "a": "Mount the inner ring on the 110 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4922 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4922 have?",
        "a": "A NA 4922 measures 110 mm bore/Fw × 150 mm outside diameter × 40 mm width (4.331 × 5.906 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 130 kN, static C0 300 kN, fatigue limit Pu 35.5 kN, limiting speed 3,600 r/min, reference speed 3,200 r/min, mass about 2050 g."
      },
      {
        "q": "What does NA 4922 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 110 mm bore, 40 mm width, 150 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4922-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 110×150×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4922",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4922",
      "NA 4922"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4824",
    "brand": "SKF",
    "manufacturer_designation": "NA 4824",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 150,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 99,
    "static_load_kN": 255,
    "fatigue_load_limit_kN": 29,
    "max_rpm": 3600,
    "reference_speed_rpm": 3200,
    "limiting_speed_rpm": 3600,
    "weight_g": 1150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4824 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 120 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NA 4824 code gives bore 120 mm and width 30 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 99 kN against C0 255 kN gives a C0/C ratio of 2.58, and the 29 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 120 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 99/255 kN ratings and 1150 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4824 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 120 mm bore, 30 mm width, 150 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4824 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4824 carries its own hardened, ground inner ring on a 120 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4824 be mounted?",
        "a": "Mount the inner ring on the 120 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4824?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 120 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4824-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 120×150×30 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4824",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4824",
      "NA 4824"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4924",
    "brand": "SKF",
    "manufacturer_designation": "NA 4924",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 120,
    "D_mm": 165,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 176,
    "static_load_kN": 405,
    "fatigue_load_limit_kN": 49,
    "max_rpm": 3400,
    "reference_speed_rpm": 3000,
    "limiting_speed_rpm": 3400,
    "weight_g": 2850,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4924 provides the full machined-ring needle roller construction: ground inner ring on a 120 mm seat, flanged outer ring at 165 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 120 mm d and 45 mm B, the 165 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 2850 g at 120×165×45 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 45 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 120 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 176/405 kN ratings are SKF catalogue values for this exact execution (NA 4924); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 176/405 kN ratings and 2850 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 4924 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 120 mm bore, 45 mm width, 165 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4924 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4924 carries its own hardened, ground inner ring on a 120 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4924?",
        "a": "Mount the inner ring on the 120 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4924 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4924-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 120×165×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4924",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4924",
      "NA 4924"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4826",
    "brand": "SKF",
    "manufacturer_designation": "NA 4826",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 165,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 119,
    "static_load_kN": 325,
    "fatigue_load_limit_kN": 36.5,
    "max_rpm": 3200,
    "reference_speed_rpm": 2800,
    "limiting_speed_rpm": 3200,
    "weight_g": 1800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4826 denotes a complete needle roller bearing for a 130 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 165 mm OD and 35 mm width. The designation NA 4826 tells you the envelope — 130×165×35 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 119 kN against C0 325 kN gives a C0/C ratio of 2.73, and the 36.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 35 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 130 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 130 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 119/325 kN ratings are SKF catalogue values for this exact execution (NA 4826); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 119/325 kN ratings and 1800 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4826?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 130 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 17.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4826?",
        "a": "A NA 4826 measures 130 mm bore/Fw × 165 mm outside diameter × 35 mm width (5.118 × 6.496 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 119 kN, static C0 325 kN, fatigue limit Pu 36.5 kN, limiting speed 3,200 r/min, reference speed 2,800 r/min, mass about 1800 g."
      },
      {
        "q": "How is the NA 4826 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 130 mm bore, 35 mm width, 165 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4826 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4826 carries its own hardened, ground inner ring on a 130 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4826-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 130×165×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4826",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4826",
      "NA 4826"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4926",
    "brand": "SKF",
    "manufacturer_designation": "NA 4926",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 130,
    "D_mm": 180,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 198,
    "static_load_kN": 480,
    "fatigue_load_limit_kN": 57,
    "max_rpm": 3000,
    "reference_speed_rpm": 2600,
    "limiting_speed_rpm": 3000,
    "weight_g": 3900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 130 mm shaft that cannot be hardened on site, NA 4926 adds a hardened, ground inner ring to the machined needle roller design: envelope 130×180×50 mm per the dimension series 49 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 130 mm bore (d), 50 mm width; the 180 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 3900 g at 130×180×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 50 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 130 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 2,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 130 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 198/480 kN ratings and 3900 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4926 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4926 have?",
        "a": "A NA 4926 measures 130 mm bore/Fw × 180 mm outside diameter × 50 mm width (5.118 × 7.087 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 198 kN, static C0 480 kN, fatigue limit Pu 57 kN, limiting speed 3,000 r/min, reference speed 2,600 r/min, mass about 3900 g."
      },
      {
        "q": "What does NA 4926 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 130 mm bore, 50 mm width, 180 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4926 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4926 carries its own hardened, ground inner ring on a 130 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4926-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 130×180×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4926",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4926",
      "NA 4926"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4828",
    "brand": "SKF",
    "manufacturer_designation": "NA 4828",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 140,
    "D_mm": 175,
    "B_mm": 35,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 121,
    "static_load_kN": 345,
    "fatigue_load_limit_kN": 37.5,
    "max_rpm": 3000,
    "reference_speed_rpm": 2600,
    "limiting_speed_rpm": 3000,
    "weight_g": 1900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4828 in the dimension series 48 needle roller bearings with inner ring with boundary dimensions 140×175×35 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 4828 code gives bore 140 mm and width 35 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 121 kN against C0 345 kN gives a C0/C ratio of 2.85, and the 37.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 35 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 140 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 4828 shares its 140×175×35 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 2,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 121/345 kN ratings and 1900 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NA 4828 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4828 carries its own hardened, ground inner ring on a 140 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4828 be mounted?",
        "a": "Mount the inner ring on the 140 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4828?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 140 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 17.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4828?",
        "a": "A NA 4828 measures 140 mm bore/Fw × 175 mm outside diameter × 35 mm width (5.512 × 6.89 × 1.378 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 121 kN, static C0 345 kN, fatigue limit Pu 37.5 kN, limiting speed 3,000 r/min, reference speed 2,600 r/min, mass about 1900 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4828-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 140×175×35 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4828",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4828",
      "NA 4828"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4928",
    "brand": "SKF",
    "manufacturer_designation": "NA 4928",
    "series": "NA-49-series",
    "type": "needle",
    "d_mm": 140,
    "D_mm": 190,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 205,
    "static_load_kN": 510,
    "fatigue_load_limit_kN": 60,
    "max_rpm": 2800,
    "reference_speed_rpm": 2400,
    "limiting_speed_rpm": 2800,
    "weight_g": 4150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 49 needle roller bearings with inner ring execution NA 4928 measures 140×190×50 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 140 mm d and 50 mm B, the 190 mm outside diameter from the dimension series 49 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 4150 g at 140×190×50 mm makes this one of the highest capacity-per-gram choices in the dimension series 49 needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 50 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "printing and paper-handling rollers",
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 140 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4928 shares its 140×190×50 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 205/510 kN ratings and 4150 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 4928 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4928 carries its own hardened, ground inner ring on a 140 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4928?",
        "a": "Mount the inner ring on the 140 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4928 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4928 have?",
        "a": "A NA 4928 measures 140 mm bore/Fw × 190 mm outside diameter × 50 mm width (5.512 × 7.48 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 205 kN, static C0 510 kN, fatigue limit Pu 60 kN, limiting speed 2,800 r/min, reference speed 2,400 r/min, mass about 4150 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4928-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 140×190×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4928",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4928",
      "NA 4928"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4830",
    "brand": "SKF",
    "manufacturer_designation": "NA 4830",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 150,
    "D_mm": 190,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 147,
    "static_load_kN": 415,
    "fatigue_load_limit_kN": 46.5,
    "max_rpm": 2800,
    "reference_speed_rpm": 2400,
    "limiting_speed_rpm": 2800,
    "weight_g": 2700,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 150 mm shaft that cannot be hardened on site, NA 4830 adds a hardened, ground inner ring to the machined needle roller design: envelope 150×190×40 mm per the dimension series 48 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 150 mm d and 40 mm B, the 190 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 147 kN against C0 415 kN gives a C0/C ratio of 2.82, and the 46.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 150 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 147/415 kN ratings are SKF catalogue values for this exact execution (NA 4830); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 147/415 kN ratings and 2700 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NA 4830 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4830 carries its own hardened, ground inner ring on a 150 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4830?",
        "a": "Mount the inner ring on the 150 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4830 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4830 have?",
        "a": "A NA 4830 measures 150 mm bore/Fw × 190 mm outside diameter × 40 mm width (5.906 × 7.48 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 147 kN, static C0 415 kN, fatigue limit Pu 46.5 kN, limiting speed 2,800 r/min, reference speed 2,400 r/min, mass about 2700 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4830-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 150×190×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4830",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4830",
      "NA 4830"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4832",
    "brand": "SKF",
    "manufacturer_designation": "NA 4832",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 160,
    "D_mm": 200,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 157,
    "static_load_kN": 450,
    "fatigue_load_limit_kN": 49,
    "max_rpm": 2600,
    "reference_speed_rpm": 2200,
    "limiting_speed_rpm": 2600,
    "weight_g": 2850,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 48 needle roller bearings with inner ring execution NA 4832 measures 160×200×40 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 160 mm bore (d), 40 mm width; the 200 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 157 kN against C0 450 kN gives a C0/C ratio of 2.87, and the 49 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 160 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 2,200 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 160 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 157/450 kN ratings and 2850 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4832 have?",
        "a": "A NA 4832 measures 160 mm bore/Fw × 200 mm outside diameter × 40 mm width (6.299 × 7.874 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 157 kN, static C0 450 kN, fatigue limit Pu 49 kN, limiting speed 2,600 r/min, reference speed 2,200 r/min, mass about 2850 g."
      },
      {
        "q": "What does NA 4832 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 160 mm bore, 40 mm width, 200 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4832 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4832 carries its own hardened, ground inner ring on a 160 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4832?",
        "a": "Mount the inner ring on the 160 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4832-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 160×200×40 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4832",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4832",
      "NA 4832"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4834",
    "brand": "SKF",
    "manufacturer_designation": "NA 4834",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 170,
    "D_mm": 215,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 179,
    "static_load_kN": 520,
    "fatigue_load_limit_kN": 56,
    "max_rpm": 2400,
    "reference_speed_rpm": 2200,
    "limiting_speed_rpm": 2400,
    "weight_g": 3950,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4834 provides the full machined-ring needle roller construction: ground inner ring on a 170 mm seat, flanged outer ring at 215 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 170 mm d and 45 mm B, the 215 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 179 kN against C0 520 kN gives a C0/C ratio of 2.91, and the 56 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 170 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4834 shares its 170×215×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 179/520 kN ratings and 3950 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4834?",
        "a": "Mount the inner ring on the 170 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4834 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4834 have?",
        "a": "A NA 4834 measures 170 mm bore/Fw × 215 mm outside diameter × 45 mm width (6.693 × 8.465 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 179 kN, static C0 520 kN, fatigue limit Pu 56 kN, limiting speed 2,400 r/min, reference speed 2,200 r/min, mass about 3950 g."
      },
      {
        "q": "What does NA 4834 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 170 mm bore, 45 mm width, 215 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4834-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 170×215×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4834",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4834",
      "NA 4834"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4836",
    "brand": "SKF",
    "manufacturer_designation": "NA 4836",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 180,
    "D_mm": 225,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 190,
    "static_load_kN": 570,
    "fatigue_load_limit_kN": 60,
    "max_rpm": 2400,
    "reference_speed_rpm": 2000,
    "limiting_speed_rpm": 2400,
    "weight_g": 4200,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 180 mm shaft that cannot be hardened on site, NA 4836 adds a hardened, ground inner ring to the machined needle roller design: envelope 180×225×45 mm per the dimension series 48 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 180 mm bore (d), 45 mm width; the 225 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 190 kN against C0 570 kN gives a C0/C ratio of 3.00, and the 60 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 180 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 190/570 kN ratings are SKF catalogue values for this exact execution (NA 4836); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 190/570 kN ratings and 4200 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NA 4836 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 180 mm bore, 45 mm width, 225 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4836 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4836 carries its own hardened, ground inner ring on a 180 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4836?",
        "a": "Mount the inner ring on the 180 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4836 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4836-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 180×225×45 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4836",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4836",
      "NA 4836"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4838",
    "brand": "SKF",
    "manufacturer_designation": "NA 4838",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 190,
    "D_mm": 240,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 220,
    "static_load_kN": 710,
    "fatigue_load_limit_kN": 73.5,
    "max_rpm": 2200,
    "reference_speed_rpm": 1900,
    "limiting_speed_rpm": 2200,
    "weight_g": 5550,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 48 needle roller bearings with inner ring execution NA 4838 measures 190×240×50 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 190 mm d and 50 mm B, the 240 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 220 kN against C0 710 kN gives a C0/C ratio of 3.23, and the 73.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 190 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 1,900 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 190 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 220/710 kN ratings and 5550 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4838 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4838 have?",
        "a": "A NA 4838 measures 190 mm bore/Fw × 240 mm outside diameter × 50 mm width (7.48 × 9.449 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 220 kN, static C0 710 kN, fatigue limit Pu 73.5 kN, limiting speed 2,200 r/min, reference speed 1,900 r/min, mass about 5550 g."
      },
      {
        "q": "What does NA 4838 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 190 mm bore, 50 mm width, 240 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4838 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4838 carries its own hardened, ground inner ring on a 190 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4838-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 190×240×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4838",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4838",
      "NA 4838"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4840",
    "brand": "SKF",
    "manufacturer_designation": "NA 4840",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 200,
    "D_mm": 250,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 224,
    "static_load_kN": 735,
    "fatigue_load_limit_kN": 75,
    "max_rpm": 2000,
    "reference_speed_rpm": 1800,
    "limiting_speed_rpm": 2000,
    "weight_g": 5800,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4840 denotes a complete needle roller bearing for a 200 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 250 mm OD and 50 mm width. The designation NA 4840 tells you the envelope — 200×250×50 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 224 kN against C0 735 kN gives a C0/C ratio of 3.28, and the 75 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 200 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 50 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 200 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 224/735 kN ratings and 5800 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4840?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 200 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 25.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4840?",
        "a": "A NA 4840 measures 200 mm bore/Fw × 250 mm outside diameter × 50 mm width (7.874 × 9.843 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 224 kN, static C0 735 kN, fatigue limit Pu 75 kN, limiting speed 2,000 r/min, reference speed 1,800 r/min, mass about 5800 g."
      },
      {
        "q": "How is the NA 4840 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 200 mm bore, 50 mm width, 250 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4840 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4840 carries its own hardened, ground inner ring on a 200 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4840-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 200×250×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4840",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4840",
      "NA 4840"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4844",
    "brand": "SKF",
    "manufacturer_designation": "NA 4844",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 220,
    "D_mm": 270,
    "B_mm": 50,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 238,
    "static_load_kN": 815,
    "fatigue_load_limit_kN": 81.5,
    "max_rpm": 1900,
    "reference_speed_rpm": 1700,
    "limiting_speed_rpm": 1900,
    "weight_g": 6350,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4844 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 220 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The designation NA 4844 tells you the envelope — 220×270×50 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 238 kN against C0 815 kN gives a C0/C ratio of 3.42, and the 81.5 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 220 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 50 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 220 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 4844 shares its 220×270×50 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 1,700 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 238/815 kN ratings and 6350 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 4844?",
        "a": "A NA 4844 measures 220 mm bore/Fw × 270 mm outside diameter × 50 mm width (8.661 × 10.63 × 1.969 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 238 kN, static C0 815 kN, fatigue limit Pu 81.5 kN, limiting speed 1,900 r/min, reference speed 1,700 r/min, mass about 6350 g."
      },
      {
        "q": "How is the NA 4844 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 220 mm bore, 50 mm width, 270 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4844 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4844 carries its own hardened, ground inner ring on a 220 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4844 be mounted?",
        "a": "Mount the inner ring on the 220 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4844-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 220×270×50 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4844",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4844",
      "NA 4844"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4848",
    "brand": "SKF",
    "manufacturer_designation": "NA 4848",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 240,
    "D_mm": 300,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 347,
    "static_load_kN": 1120,
    "fatigue_load_limit_kN": 112,
    "max_rpm": 1700,
    "reference_speed_rpm": 1500,
    "limiting_speed_rpm": 1700,
    "weight_g": 9900,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4848 in the dimension series 48 needle roller bearings with inner ring with boundary dimensions 240×300×60 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The designation NA 4848 tells you the envelope — 240×300×60 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 347 kN against C0 1120 kN gives a C0/C ratio of 3.23, and the 112 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 240 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 60 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 240 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 240 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 347/1120 kN ratings are SKF catalogue values for this exact execution (NA 4848); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 347/1120 kN ratings and 9900 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NA 4848 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 240 mm bore, 60 mm width, 300 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4848 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4848 carries its own hardened, ground inner ring on a 240 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4848 be mounted?",
        "a": "Mount the inner ring on the 240 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4848?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 240 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 30.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4848-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 240×300×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4848",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4848",
      "NA 4848"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4852",
    "brand": "SKF",
    "manufacturer_designation": "NA 4852",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 260,
    "D_mm": 320,
    "B_mm": 60,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 358,
    "static_load_kN": 1200,
    "fatigue_load_limit_kN": 118,
    "max_rpm": 1500,
    "reference_speed_rpm": 1400,
    "limiting_speed_rpm": 1500,
    "weight_g": 10500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 48 needle roller bearings with inner ring execution NA 4852 measures 260×320×60 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 260 mm d and 60 mm B, the 320 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 358 kN against C0 1200 kN gives a C0/C ratio of 3.35, and the 118 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 60 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 260 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 358/1200 kN ratings are SKF catalogue values for this exact execution (NA 4852); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 358/1200 kN ratings and 10500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4852 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4852 have?",
        "a": "A NA 4852 measures 260 mm bore/Fw × 320 mm outside diameter × 60 mm width (10.236 × 12.598 × 2.362 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 358 kN, static C0 1200 kN, fatigue limit Pu 118 kN, limiting speed 1,500 r/min, reference speed 1,400 r/min, mass about 10500 g."
      },
      {
        "q": "What does NA 4852 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 260 mm bore, 60 mm width, 320 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4852 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4852 carries its own hardened, ground inner ring on a 260 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4852-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 260×320×60 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4852",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4852",
      "NA 4852"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4856",
    "brand": "SKF",
    "manufacturer_designation": "NA 4856",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 280,
    "D_mm": 350,
    "B_mm": 69,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 429,
    "static_load_kN": 1320,
    "fatigue_load_limit_kN": 129,
    "max_rpm": 1400,
    "reference_speed_rpm": 1300,
    "limiting_speed_rpm": 1400,
    "weight_g": 15500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 280 mm shaft that cannot be hardened on site, NA 4856 adds a hardened, ground inner ring to the machined needle roller design: envelope 280×350×69 mm per the dimension series 48 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 280 mm d and 69 mm B, the 350 mm outside diameter from the dimension series 48 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 429 kN against C0 1320 kN gives a C0/C ratio of 3.08, and the 129 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 69 mm width and s offset dimensions against the open execution before reusing an existing bore.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 280 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4856 shares its 280×350×69 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 429/1320 kN ratings and 15500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NA 4856 have?",
        "a": "A NA 4856 measures 280 mm bore/Fw × 350 mm outside diameter × 69 mm width (11.024 × 13.78 × 2.717 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 429 kN, static C0 1320 kN, fatigue limit Pu 129 kN, limiting speed 1,400 r/min, reference speed 1,300 r/min, mass about 15500 g."
      },
      {
        "q": "What does NA 4856 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 280 mm bore, 69 mm width, 350 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4856 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4856 carries its own hardened, ground inner ring on a 280 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "What mounting mistakes ruin a NA 4856?",
        "a": "Mount the inner ring on the 280 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4856-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 280×350×69 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4856",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4856",
      "NA 4856"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4860",
    "brand": "SKF",
    "manufacturer_designation": "NA 4860",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 300,
    "D_mm": 380,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 594,
    "static_load_kN": 1800,
    "fatigue_load_limit_kN": 173,
    "max_rpm": 1300,
    "reference_speed_rpm": 1100,
    "limiting_speed_rpm": 1300,
    "weight_g": 22000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NA 4860 denotes a complete needle roller bearing for a 300 mm shaft — machined inner and outer rings, integral flanges on the outer ring retaining the roller set, 380 mm OD and 80 mm width. The NA 4860 code gives bore 300 mm and width 80 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 594 kN against C0 1800 kN gives a C0/C ratio of 3.03, and the 173 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 300 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NA 4860 shares its 300×380×80 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 1,100 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 594/1800 kN ratings and 22000 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NA 4860 be mounted?",
        "a": "Mount the inner ring on the 300 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "What limits the service life of a NA 4860?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 300 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 40.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4860?",
        "a": "A NA 4860 measures 300 mm bore/Fw × 380 mm outside diameter × 80 mm width (11.811 × 14.961 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 594 kN, static C0 1800 kN, fatigue limit Pu 173 kN, limiting speed 1,300 r/min, reference speed 1,100 r/min, mass about 22000 g."
      },
      {
        "q": "How is the NA 4860 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 300 mm bore, 80 mm width, 380 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4860-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 300×380×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4860",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4860",
      "NA 4860"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4864",
    "brand": "SKF",
    "manufacturer_designation": "NA 4864",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 320,
    "D_mm": 400,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 605,
    "static_load_kN": 1900,
    "fatigue_load_limit_kN": 176,
    "max_rpm": 1200,
    "reference_speed_rpm": 1100,
    "limiting_speed_rpm": 1200,
    "weight_g": 23000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "NA 4864 is a machined-ring needle roller bearing with an inner ring: flanged outer ring plus a separate 320 mm bore inner ring, so the shaft seat needs only ordinary tolerance, as tabulated by SKF in SKF catalogue PUB BU/P1 17000. The NA 4864 code gives bore 320 mm and width 80 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 605 kN against C0 1900 kN gives a C0/C ratio of 3.14, and the 176 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 320 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 320 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 605/1900 kN ratings are SKF catalogue values for this exact execution (NA 4864); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 605/1900 kN ratings and 23000 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 646); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NA 4864?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 320 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 40.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NA 4864?",
        "a": "A NA 4864 measures 320 mm bore/Fw × 400 mm outside diameter × 80 mm width (12.598 × 15.748 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 605 kN, static C0 1900 kN, fatigue limit Pu 176 kN, limiting speed 1,200 r/min, reference speed 1,100 r/min, mass about 23000 g."
      },
      {
        "q": "How is the NA 4864 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 320 mm bore, 80 mm width, 400 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4864 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4864 carries its own hardened, ground inner ring on a 320 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4864-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 320×400×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4864",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4864",
      "NA 4864"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4868",
    "brand": "SKF",
    "manufacturer_designation": "NA 4868",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 340,
    "D_mm": 420,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 616,
    "static_load_kN": 1960,
    "fatigue_load_limit_kN": 183,
    "max_rpm": 1200,
    "reference_speed_rpm": 1000,
    "limiting_speed_rpm": 1200,
    "weight_g": 24000,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "SKF lists NA 4868 in the dimension series 48 needle roller bearings with inner ring with boundary dimensions 340×420×80 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 4868 code gives bore 340 mm and width 80 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 616 kN against C0 1960 kN gives a C0/C ratio of 3.18, and the 183 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 340 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 616/1960 kN ratings and 24000 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 648); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NA 4868?",
        "a": "A NA 4868 measures 340 mm bore/Fw × 420 mm outside diameter × 80 mm width (13.386 × 16.535 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 616 kN, static C0 1960 kN, fatigue limit Pu 183 kN, limiting speed 1,200 r/min, reference speed 1,000 r/min, mass about 24000 g."
      },
      {
        "q": "How is the NA 4868 designation read?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 340 mm bore, 80 mm width, 420 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Can the NA 4868 run on an unhardened shaft?",
        "a": "Yes — that is the point of this family. The NA 4868 carries its own hardened, ground inner ring on a 340 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      },
      {
        "q": "How should the NA 4868 be mounted?",
        "a": "Mount the inner ring on the 340 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4868-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 340×420×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4868",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4868",
      "NA 4868"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4872",
    "brand": "SKF",
    "manufacturer_designation": "NA 4872",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 360,
    "D_mm": 440,
    "B_mm": 80,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 627,
    "static_load_kN": 2040,
    "fatigue_load_limit_kN": 186,
    "max_rpm": 1100,
    "reference_speed_rpm": 950,
    "limiting_speed_rpm": 1100,
    "weight_g": 25500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "The dimension series 48 needle roller bearings with inner ring execution NA 4872 measures 360×440×80 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 360 mm bore (d), 80 mm width; the 440 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 627 kN against C0 2040 kN gives a C0/C ratio of 3.25, and the 186 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 360 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 80 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 360 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NA 4872 shares its 360×440×80 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 627/2040 kN ratings and 25500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 648); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NA 4872?",
        "a": "Mount the inner ring on the 360 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth."
      },
      {
        "q": "Is the NA 4872 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4872 have?",
        "a": "A NA 4872 measures 360 mm bore/Fw × 440 mm outside diameter × 80 mm width (14.173 × 17.323 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 627 kN, static C0 2040 kN, fatigue limit Pu 186 kN, limiting speed 1,100 r/min, reference speed 950 r/min, mass about 25500 g."
      },
      {
        "q": "What does NA 4872 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 360 mm bore, 80 mm width, 440 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4872-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 360×440×80 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4872",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4872",
      "NA 4872"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NA4876",
    "brand": "SKF",
    "manufacturer_designation": "NA 4876",
    "series": "NA-48-series",
    "type": "needle",
    "d_mm": 380,
    "D_mm": 480,
    "B_mm": 100,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 968,
    "static_load_kN": 3000,
    "fatigue_load_limit_kN": 270,
    "max_rpm": 1000,
    "reference_speed_rpm": 900,
    "limiting_speed_rpm": 1000,
    "weight_g": 42500,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "ISO 1206",
    "naming_rule_text": "For a 380 mm shaft that cannot be hardened on site, NA 4876 adds a hardened, ground inner ring to the machined needle roller design: envelope 380×480×100 mm per the dimension series 48 needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 380 mm bore (d), 100 mm width; the 480 mm OD follows the dimension series, and the inner ring is a separate ground component. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 968 kN against C0 3000 kN gives a C0/C ratio of 3.10, and the 270 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 380 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 100 mm assembly for free rotation before applying load.",
    "applications": [
      "gearbox shafts where the journal cannot be hardened on site",
      "wheel and lever pivots needing a replaceable inner ring",
      "conveyor roller ends and return rollers",
      "agricultural implement pivots and cutter heads"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "inner-ring raceway spalling after the narrow ring section runs hot with excessive interference"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 380 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 900 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 380 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 968/3000 kN ratings and 42500 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 648); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NA 4876 sealed?",
        "a": "No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number."
      },
      {
        "q": "Which dimensions does the NA 4876 have?",
        "a": "A NA 4876 measures 380 mm bore/Fw × 480 mm outside diameter × 100 mm width (14.961 × 18.898 × 3.937 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 968 kN, static C0 3000 kN, fatigue limit Pu 270 kN, limiting speed 1,000 r/min, reference speed 900 r/min, mass about 42500 g."
      },
      {
        "q": "What does NA 4876 mean in SKF part numbering?",
        "a": "The letters mark a machined-ring needle roller bearing with inner ring: 380 mm bore, 100 mm width, 480 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices."
      },
      {
        "q": "Does the NA 4876 need a hardened and ground shaft?",
        "a": "Yes — that is the point of this family. The NA 4876 carries its own hardened, ground inner ring on a 380 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4876-XL",
        "equiv_brand": "FAG",
        "level": "partial",
        "note": "Same 380×480×100 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting."
      },
      {
        "equiv_sku": "NA4876",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NA4876",
      "NA 4876"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA15-28",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 15/28",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.37,
    "static_load_kN": 9.15,
    "fatigue_load_limit_kN": 1.08,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 32,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a plain needle roller bearing would edge-load on a bent frame, RPNA 15/28 from the self-aligning needle roller bearings without inner ring aligns itself: 15 mm bore, 28 mm sphered outside diameter, 12 mm width. Reading the designation: RPNA marks the self-aligning execution ( inner ring), the numbers giving 15 mm bore and 12 mm width; the sphered outside diameter 28 mm follows the series plan. Execution notes: alignment comes from the convex outer ring outside surface running in a plain sphered seat — no separate self-aligning washer is needed, and roughly ±2° of static seat error is absorbed. Speed planning separates the two ceilings: 24,000 r/min thermal reference and 28,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 15 mm seat. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.",
    "applications": [
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 7.37/9.15 kN ratings are SKF catalogue values for this exact execution (RPNA 15/28); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 7.37/9.15 kN ratings and 32 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the RPNA 15/28 have?",
        "a": "A RPNA 15/28 measures 15 mm bore/Fw × 28 mm outside diameter × 12 mm width (0.591 × 1.102 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 9.15 kN, fatigue limit Pu 1.08 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 32 g."
      },
      {
        "q": "What does RPNA 15/28 mean in SKF part numbering?",
        "a": "RPNA marks the self-aligning needle roller family (with machined rings): figures give the 15 mm seat and 12 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Does the RPNA 15/28 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 15 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a RPNA 15/28?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 15 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA15-28",
      "RPNA 15/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA18-32",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 18/32",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 18,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 17.6,
    "fatigue_load_limit_kN": 2.12,
    "max_rpm": 24000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 24000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "RPNA 18/32 is a self-aligning needle roller bearing: a heavy machined outer ring with a convex outside surface seated against an aligning ring, absorbing housing misalignment around a 18 mm raceway, as listed in SKF catalogue PUB BU/P1 17000. Reading the designation: RPNA marks the self-aligning execution ( inner ring), the numbers giving 18 mm bore and 16 mm width; the sphered outside diameter 32 mm follows the series plan. The alignment range is meant for static seat errors, not continuous swivelling under load — dynamic pivoting races the sphered surface and requires grease with extreme-pressure additives. Catalogue mass 52 g at 18×32×16 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 12.8/17.6 kN ratings are SKF catalogue values for this exact execution (RPNA 18/32); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 12.8/17.6 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the RPNA 18/32 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 18 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a RPNA 18/32?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 18 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RPNA 18/32 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the RPNA 18/32 have?",
        "a": "A RPNA 18/32 measures 18 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.709 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 17.6 kN, fatigue limit Pu 2.12 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 52 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA18",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA18-32",
      "RPNA 18/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA20-35",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 20/35",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 35,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 19.3,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 62,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "RPNA 20/35 is a self-aligning needle roller bearing: a heavy machined outer ring with a convex outside surface seated against an aligning ring, absorbing housing misalignment around a 20 mm raceway, as listed in SKF catalogue PUB BU/P1 17000. In SKF nomenclature the P in RPNA flags the pivoting, sphered outer ring; dimensions 20×35×16 mm follow the heavy-section plan, and the inner ring decision is fixed by the family letter. Execution notes: alignment comes from the convex outer ring outside surface running in a plain sphered seat — no separate self-aligning washer is needed, and roughly ±2° of static seat error is absorbed. The 62 g catalogue mass and 7.5 mm radial section ((35−20)/2) frame a rating of about 0.66 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 20 mm raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 35 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: RPNA 20/35 shares its 20×35×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 13.2/19.3 kN ratings and 62 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RPNA 20/35 mean in SKF part numbering?",
        "a": "RPNA marks the self-aligning needle roller family (with machined rings): figures give the 20 mm seat and 16 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Does the RPNA 20/35 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 20 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a RPNA 20/35?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RPNA 20/35 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA20",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA20-35",
      "RPNA 20/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA25-42",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 25/42",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 32.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "RPNA 25/42 combines machined-ring needle roller capacity with self-alignment: 25×42×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. The code RPNA 25/42 reads as alignment needle roller bearing, 25 mm bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Catalogue mass 110 g at 25×42×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 19/32.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the RPNA 25/42 designation read?",
        "a": "RPNA marks the self-aligning needle roller family (with machined rings): figures give the 25 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the RPNA 25/42 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 25 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the RPNA 25/42 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RPNA 25/42?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA25-42",
      "RPNA 25/42"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA30-47",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 30/47",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22.9,
    "static_load_kN": 38,
    "fatigue_load_limit_kN": 4.8,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "RPNA 30/47 combines machined-ring needle roller capacity with self-alignment: 30×47×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. The RPNA 30/47 figures state the 30 mm seat and 20 mm width; the letters carry the construction — machined rings, integral flanges, and the convex outside surface that aligns inside its seat. Execution notes: alignment comes from the convex outer ring outside surface running in a plain sphered seat — no separate self-aligning washer is needed, and roughly ±2° of static seat error is absorbed. Catalogue mass 130 g at 30×47×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 30 mm raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 22.9/38 kN ratings are SKF catalogue values for this exact execution (RPNA 30/47); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 22.9/38 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RPNA 30/47 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 30 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the RPNA 30/47 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RPNA 30/47?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RPNA 30/47?",
        "a": "A RPNA 30/47 measures 30 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.181 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 130 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA30-47",
      "RPNA 30/47"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA35-52",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 35/52",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF supplies RPNA 35/52 for pivots whose housings distort under load: the needle roller ring rides on a spherical seat, keeping edge loads off the 20 mm wide roller complement. The code RPNA 35/52 reads as alignment needle roller bearing, 35 mm bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. The alignment range is meant for static seat errors, not continuous swivelling under load — dynamic pivoting races the sphered surface and requires grease with extreme-pressure additives. The 130 g catalogue mass and 8.5 mm radial section ((52−35)/2) frame a rating of about 0.70 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 35 mm raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 24.6/45 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the RPNA 35/52 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RPNA 35/52?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RPNA 35/52?",
        "a": "A RPNA 35/52 measures 35 mm bore/Fw × 52 mm outside diameter × 20 mm width (1.378 × 2.047 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.6 kN, static C0 45 kN, fatigue limit Pu 5.6 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 130 g."
      },
      {
        "q": "How is the RPNA 35/52 designation read?",
        "a": "RPNA marks the self-aligning needle roller family (with machined rings): figures give the 35 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA35",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA35-52",
      "RPNA 35/52"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA40-55",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 40/55",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 6.3,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, RPNA 40/55 denotes an alignment needle roller bearing for a 40 mm shaft: machined rings, integral flanges, and a spherical outside surface that compensates static misalignment of the housing bore. The code RPNA 40/55 reads as alignment needle roller bearing, 40 mm bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. For life calculation, the 26.4/51 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 40 mm raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 26.4/51 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the RPNA 40/55 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 40 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the RPNA 40/55 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a RPNA 40/55?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 7.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the RPNA 40/55?",
        "a": "A RPNA 40/55 measures 40 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.575 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26.4 kN, static C0 51 kN, fatigue limit Pu 6.3 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 140 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI40-20-TN",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 40×55×20 mm envelope, but catalogue C/C0 differ between the executions (26.4/51 vs 31.4/65.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA40-55",
      "RPNA 40/55"
    ],
    "locale_variants": {}
  },
  {
    "sku": "RPNA45-62",
    "brand": "SKF",
    "manufacturer_designation": "RPNA 45/62",
    "series": "RPNA-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 62,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a plain needle roller bearing would edge-load on a bent frame, RPNA 45/62 from the self-aligning needle roller bearings without inner ring aligns itself: 45 mm bore, 62 mm sphered outside diameter, 20 mm width. Reading the designation: RPNA marks the self-aligning execution ( inner ring), the numbers giving 45 mm bore and 20 mm width; the sphered outside diameter 62 mm follows the series plan. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Catalogue mass 180 g at 45×62×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings without inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 45 mm raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 27.5/57 kN ratings are SKF catalogue values for this exact execution (RPNA 45/62); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The 27.5/57 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.5 of PUB BU/P1 17000 (PDF table page 650); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does RPNA 45/62 mean in SKF part numbering?",
        "a": "RPNA marks the self-aligning needle roller family (with machined rings): figures give the 45 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Does the RPNA 45/62 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 45 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a RPNA 45/62?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the RPNA 45/62 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "RPNA45",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.5 alignment needle roller bearings, without an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "RPNA45-62",
      "RPNA 45/62"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA12-28",
    "brand": "SKF",
    "manufacturer_designation": "PNA 12/28",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 28,
    "B_mm": 12,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 7.37,
    "static_load_kN": 9.15,
    "fatigue_load_limit_kN": 1.08,
    "max_rpm": 28000,
    "reference_speed_rpm": 24000,
    "limiting_speed_rpm": 28000,
    "weight_g": 37,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The self-aligning needle roller bearings with inner ring execution PNA 12/28 pairs a flanged needle roller ring (12 mm inner-ring 28 mm OD, 12 mm wide) with a sphered seat: the outer ring swivels a few degrees to follow frame deflection. In SKF nomenclature the P in PNA flags the pivoting, sphered outer ring; dimensions 12×28×12 mm follow the heavy-section plan, and the inner-ring inner ring decision is fixed by the family letter. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Speed planning separates the two ceilings: 24,000 r/min thermal reference and 28,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 12 mm seat. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.",
    "applications": [
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 7.37/9.15 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the PNA 12/28 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 12 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a PNA 12/28?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the PNA 12/28 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the PNA 12/28 have?",
        "a": "A PNA 12/28 measures 12 mm bore/Fw × 28 mm outside diameter × 12 mm width (0.472 × 1.102 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 9.15 kN, fatigue limit Pu 1.08 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 37 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA12",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA12-28",
      "PNA 12/28"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA15-32",
    "brand": "SKF",
    "manufacturer_designation": "PNA 15/32",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 32,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.8,
    "static_load_kN": 17.6,
    "fatigue_load_limit_kN": 2.12,
    "max_rpm": 24000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 24000,
    "weight_g": 62,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "PNA 15/32 combines machined-ring needle roller capacity with self-alignment: 15×32×16 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. The code PNA 15/32 reads as alignment needle roller bearing, 15 mm inner-ring bore, 16 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.",
    "applications": [
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 32 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: PNA 15/32 shares its 15×32×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 12.8/17.6 kN ratings and 62 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a PNA 15/32?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the PNA 15/32?",
        "a": "A PNA 15/32 measures 15 mm bore/Fw × 32 mm outside diameter × 16 mm width (0.591 × 1.26 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 17.6 kN, fatigue limit Pu 2.12 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 62 g."
      },
      {
        "q": "How is the PNA 15/32 designation read?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 15 mm seat and 16 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the PNA 15/32 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 15 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA15",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA15-32",
      "PNA 15/32"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA17-35",
    "brand": "SKF",
    "manufacturer_designation": "PNA 17/35",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 35,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 19.3,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 73,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF supplies PNA 17/35 for pivots whose housings distort under load: the needle roller ring inner-ring rides on a spherical seat, keeping edge loads off the 16 mm wide roller complement. The code PNA 17/35 reads as alignment needle roller bearing, 17 mm inner-ring bore, 16 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. For life calculation, the 13.2/19.3 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.",
    "applications": [
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "hard-particle indentation in unfiltered lubricant"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 35 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: PNA 17/35 shares its 17×35×16 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 13.2/19.3 kN ratings and 73 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the PNA 17/35 designation read?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 17 mm seat and 16 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the PNA 17/35 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 17 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the PNA 17/35 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 17 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a PNA 17/35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 9.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA17",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA17-35",
      "PNA 17/35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA20-42",
    "brand": "SKF",
    "manufacturer_designation": "PNA 20/42",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 42,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 19,
    "static_load_kN": 32.5,
    "fatigue_load_limit_kN": 4,
    "max_rpm": 18000,
    "reference_speed_rpm": 16000,
    "limiting_speed_rpm": 18000,
    "weight_g": 140,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The self-aligning needle roller bearings with inner ring execution PNA 20/42 pairs a flanged needle roller ring (20 mm inner-ring 42 mm OD, 20 mm wide) with a sphered seat: the outer ring swivels a few degrees to follow frame deflection. Reading the designation: PNA marks the self-aligning execution (inner-ring  inner ring), the numbers giving 20 mm inner-ring bore and 20 mm width; the sphered outside diameter 42 mm follows the series plan. The alignment range is meant for static seat errors, not continuous swivelling under load — dynamic pivoting races the sphered surface and requires grease with extreme-pressure additives. Selection arithmetic: C 19 kN against C0 32.5 kN gives a C0/C ratio of 1.71, and the 4 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 20 mm inner-ring raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: PNA 20/42 shares its 20×42×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The 19/32.5 kN ratings and 140 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a PNA 20/42?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the PNA 20/42 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the PNA 20/42 have?",
        "a": "A PNA 20/42 measures 20 mm bore/Fw × 42 mm outside diameter × 20 mm width (0.787 × 1.654 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 19 kN, static C0 32.5 kN, fatigue limit Pu 4 kN, limiting speed 18,000 r/min, reference speed 16,000 r/min, mass about 140 g."
      },
      {
        "q": "What does PNA 20/42 mean in SKF part numbering?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 20 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIS20",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 20×42×20 mm envelope, but catalogue C/C0 differ between the executions (19/32.5 vs 28.6/39 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA20-42",
      "PNA 20/42"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA22-44",
    "brand": "SKF",
    "manufacturer_designation": "PNA 22/44",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 44,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22,
    "static_load_kN": 36.5,
    "fatigue_load_limit_kN": 4.55,
    "max_rpm": 16000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 16000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, PNA 22/44 denotes an alignment needle roller bearing for a 22 mm inner-ring shaft: machined rings, integral flanges, and a spherical outside surface that compensates static misalignment of the housing bore. The code PNA 22/44 reads as alignment needle roller bearing, 22 mm inner-ring bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. Catalogue mass 150 g at 22×44×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 22 mm inner-ring raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 44 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: PNA 22/44 shares its 22×44×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 14,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "The 22/36.5 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the PNA 22/44 designation read?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 22 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the PNA 22/44 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 22 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the PNA 22/44 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a PNA 22/44?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 22 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA22",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA22-44",
      "PNA 22/44"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA25-47",
    "brand": "SKF",
    "manufacturer_designation": "PNA 25/47",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 47,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22.9,
    "static_load_kN": 38,
    "fatigue_load_limit_kN": 4.8,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "PNA 25/47 combines machined-ring needle roller capacity with self-alignment: 25×47×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. Reading the designation: PNA marks the self-aligning execution (inner-ring  inner ring), the numbers giving 25 mm inner-ring bore and 20 mm width; the sphered outside diameter 47 mm follows the series plan. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. The 160 g catalogue mass and 11.0 mm radial section ((47−25)/2) frame a rating of about 0.92 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.",
    "applications": [
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 47 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The 22.9/38 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the PNA 25/47 need a hardened and ground shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 25 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "What mounting mistakes ruin a PNA 25/47?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the PNA 25/47 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the PNA 25/47 have?",
        "a": "A PNA 25/47 measures 25 mm bore/Fw × 47 mm outside diameter × 20 mm width (0.984 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 160 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA25",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA25-47",
      "PNA 25/47"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA30-52",
    "brand": "SKF",
    "manufacturer_designation": "PNA 30/52",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 52,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, PNA 30/52 denotes an alignment needle roller bearing for a 30 mm inner-ring shaft: machined rings, integral flanges, and a spherical outside surface that compensates static misalignment of the housing bore. The PNA 30/52 figures state the 30 mm seat and 20 mm width; the letters carry the construction — machined rings, integral flanges, and the convex outside surface that aligns inside its seat. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. For life calculation, the 24.6/45 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 30 mm inner-ring raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load",
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 24.6/45 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the PNA 30/52 designation read?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 30 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the PNA 30/52 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 30 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the PNA 30/52 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a PNA 30/52?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA30",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA30-52",
      "PNA 30/52"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA35-55",
    "brand": "SKF",
    "manufacturer_designation": "PNA 35/55",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 26.4,
    "static_load_kN": 51,
    "fatigue_load_limit_kN": 6.3,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 180,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, PNA 35/55 denotes an alignment needle roller bearing for a 35 mm inner-ring shaft: machined rings, integral flanges, and a spherical outside surface that compensates static misalignment of the housing bore. The code PNA 35/55 reads as alignment needle roller bearing, 35 mm inner-ring bore, 20 mm width — the wide section is what absorbs both load and the seat-angle errors the family is designed for. The alignment range is meant for static seat errors, not continuous swivelling under load — dynamic pivoting races the sphered surface and requires grease with extreme-pressure additives. Catalogue mass 180 g at 35×55×20 mm makes this one of the highest capacity-per-gram choices in the self-aligning needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.",
    "applications": [
      "construction equipment blade and arm pivots",
      "steering knuckles and kingpin supports with seat angle errors",
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 26.4/51 kN ratings are SKF catalogue values for this exact execution (PNA 35/55); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The 26.4/51 kN ratings and 180 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the PNA 35/55 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 35 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      },
      {
        "q": "How should the PNA 35/55 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a PNA 35/55?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the PNA 35/55?",
        "a": "A PNA 35/55 measures 35 mm bore/Fw × 55 mm outside diameter × 20 mm width (1.378 × 2.165 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26.4 kN, static C0 51 kN, fatigue limit Pu 6.3 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 180 g."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NA4907",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×55×20 mm envelope, but catalogue C/C0 differ between the executions (26.4/51 vs 31.9/54 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA35-55",
      "PNA 35/55"
    ],
    "locale_variants": {}
  },
  {
    "sku": "PNA40-62",
    "brand": "SKF",
    "manufacturer_designation": "PNA 40/62",
    "series": "PNA-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 27.5,
    "static_load_kN": 57,
    "fatigue_load_limit_kN": 7.1,
    "max_rpm": 10000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 10000,
    "weight_g": 230,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "PNA 40/62 combines machined-ring needle roller capacity with self-alignment: 40×62×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. The PNA 40/62 figures state the 40 mm seat and 20 mm width; the letters carry the construction — machined rings, integral flanges, and the convex outside surface that aligns inside its seat. Execution notes: alignment comes from the convex outer ring outside surface running in a plain sphered seat — no separate self-aligning washer is needed, and roughly ±2° of static seat error is absorbed. Speed planning separates the two ceilings: 9,000 r/min thermal reference and 10,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: seat the convex outer ring surface in its sphered counterpart dry first, confirm the 40 mm inner-ring raceway rotates freely through the full alignment range, then lubricate and assemble for service.",
    "applications": [
      "pivot bearings where housing bores cannot be kept coaxial",
      "linkage eyes and clevis mounts on frames that flex",
      "agricultural machinery joints exposed to frame distortion",
      "door and gate hinges with heavy radial load"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The 27.5/57 kN ratings and 230 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a PNA 40/62?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the PNA 40/62?",
        "a": "A PNA 40/62 measures 40 mm bore/Fw × 62 mm outside diameter × 20 mm width (1.575 × 2.441 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 27.5 kN, static C0 57 kN, fatigue limit Pu 7.1 kN, limiting speed 10,000 r/min, reference speed 9,000 r/min, mass about 230 g."
      },
      {
        "q": "How is the PNA 40/62 designation read?",
        "a": "PNA marks the self-aligning needle roller family (inner-ring with machined rings): figures give the 40 mm seat and 20 mm width; the convex outer-ring outside surface aligns within roughly ±2° in its sphered seat."
      },
      {
        "q": "Can the PNA 40/62 run on an unhardened shaft?",
        "a": "Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 40 mm k5 seat. Both add the sphered outer ring for seat misalignment."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "PNA40",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "PNA40-62",
      "PNA 40/62"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5901",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5901",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 16,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.09,
    "static_load_kN": 9.65,
    "fatigue_load_limit_kN": 1.14,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5901 is the combined needle roller / angular contact ball bearings entry for a 12 mm shaft: needle rollers run the radial load while the angular contact ball set takes axial force primarily in one direction, in a single machined envelope of 12×24×16 mm. The NKIA 5901 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 12 mm; the 16 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 22,000 r/min thermal reference and 26,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 8.09/9.65 kN ratings are SKF catalogue values for this exact execution (NKIA 5901); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 8.09/9.65 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKIA 5901?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIA 5901?",
        "a": "A NKIA 5901 measures 12 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.472 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.09 kN, static C0 9.65 kN, fatigue limit Pu 1.14 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 40 g. Axial ratings of the ball part: dynamic Ca 2.07 kN (Ca), static C0a 1.92 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "How is the NKIA 5901 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595901 gives the series and 12 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 16 mm overall width."
      },
      {
        "q": "Can the NKIA 5901 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5901 rides directly on the 12 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKI12-16",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 12×24×16 mm envelope, but catalogue C/C0 differ between the executions (8.09/9.65 vs 11.7/15.3 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5901",
      "NKIA 5901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5901",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5901",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 24,
    "B_mm": 17.5,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 8.09,
    "static_load_kN": 9.65,
    "fatigue_load_limit_kN": 1.14,
    "max_rpm": 26000,
    "reference_speed_rpm": 22000,
    "limiting_speed_rpm": 26000,
    "weight_g": 43,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIB 5901 among the combined needle roller / three-point contact ball bearings: radial capacity from the needle roller set (8.09 kN C), axial capacity from the three-point contact ball part 2.07 kN (Ca), all within a 24×17.5 mm outline. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 595901 the heavy 59 dimension series around the 12 mm bore. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 22,000 r/min thermal reference and 26,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 17.5 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5901 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 8.09/9.65 kN ratings and 43 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKIB 5901 have?",
        "a": "A NKIB 5901 measures 12 mm bore/Fw × 24 mm outside diameter × 17.5 mm width (0.472 × 0.945 × 0.689 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 8.09 kN, static C0 9.65 kN, fatigue limit Pu 1.14 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 43 g. Axial ratings of the ball part: dynamic Ca 2.07 kN (Ca), static C0a 1.92 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "What does NKIB 5901 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595901 gives the series and 12 mm bore. The offset (s 16 mm) positions the ball raceway inside the 17.5 mm overall width."
      },
      {
        "q": "Does the NKIB 5901 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5901 rides directly on the 12 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIB 5901?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5901",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5901",
      "NKIB 5901"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5902",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5902",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.2,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.83,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 50,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5902 is a combined needle roller / angular ball bearing: one unit carrying radial load on the needle roller set and one-direction-leaning axial load on the ball set, 15×28×18 mm, listed by SKF in SKF catalogue PUB BU/P1 17000. In SKF nomenclature NKIA denotes the combined construction and 595902 the series/bore; the ball raceway sits offset on the inner ring, which is why the 18 mm overall width is greater than a plain needle bearing of the same bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 11.2 kN, radial C0 15.3 kN, axial dynamic 2.27 kN (Ca) and axial static 2.37 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5902 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 11.2/15.3 kN ratings and 50 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKIA 5902?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 15 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIA 5902 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIA 5902 have?",
        "a": "A NKIA 5902 measures 15 mm bore/Fw × 28 mm outside diameter × 18 mm width (0.591 × 1.102 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.2 kN, static C0 15.3 kN, fatigue limit Pu 1.83 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 50 g. Axial ratings of the ball part: dynamic Ca 2.27 kN (Ca), static C0a 2.37 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "What does NKIA 5902 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595902 gives the series and 15 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 18 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5902",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5902",
      "NKIA 5902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5902",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5902",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 28,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.2,
    "static_load_kN": 15.3,
    "fatigue_load_limit_kN": 1.83,
    "max_rpm": 22000,
    "reference_speed_rpm": 19000,
    "limiting_speed_rpm": 22000,
    "weight_g": 52,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For shafts where a separate thrust bearing would lengthen the assembly, NKIB 5902 integrates needle rollers and an three-point contact ball bearing: 15 mm bore, 28 mm OD, 20 mm overall width including the ball set offset. The NKIB 5902 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 15 mm; the 20 mm width covers both the roller cage and the offset ball set (s offset 18 mm). NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 11.2 kN, radial C0 15.3 kN, axial dynamic 2.27 kN (Ca) and axial static 2.37 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 20 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5902 shares its 15×28×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 19,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Do not treat the axial rating 2.27 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5902 facing the working thrust.",
      "The 11.2/15.3 kN ratings and 52 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKIB 5902?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIB 5902?",
        "a": "A NKIB 5902 measures 15 mm bore/Fw × 28 mm outside diameter × 20 mm width (0.591 × 1.102 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.2 kN, static C0 15.3 kN, fatigue limit Pu 1.83 kN, limiting speed 22,000 r/min, reference speed 19,000 r/min, mass about 52 g. Axial ratings of the ball part: dynamic Ca 2.27 kN (Ca), static C0a 2.37 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "How is the NKIB 5902 designation read?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595902 gives the series and 15 mm bore. The offset (s 18 mm) positions the ball raceway inside the 20 mm overall width."
      },
      {
        "q": "Can the NKIB 5902 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIB 5902 rides directly on the 15 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5902",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5902",
      "NKIB 5902"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5903",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5903",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 16.3,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 56,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKIA 5903 designates a combined bearing of the combined needle roller / angular contact ball bearings: caged needle rollers for the 17 mm radial seat share a shaft with an integral angular contact ball set rated 2.24 kN (Ca) axially. The designation NKIA 5903 identifies the two rolling elements in one unit; the 17 mm bore and 30 mm OD come from the 59-series plan, and the 18 mm width stacks roller set plus ball set. Execution notes: the ball set runs on a raceway offset by a catalogue-listed offset from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 18,000 r/min thermal reference and 20,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKIA 5903 shares its 17×30×18 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 18,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Do not treat the axial rating 2.24 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5903 facing the working thrust.",
      "The 11.4/16.3 kN ratings and 56 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKIA 5903 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5903 rides directly on the 17 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIA 5903 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 17 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIA 5903?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIA 5903?",
        "a": "A NKIA 5903 measures 17 mm bore/Fw × 30 mm outside diameter × 18 mm width (0.669 × 1.181 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.4 kN, static C0 16.3 kN, fatigue limit Pu 1.96 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 56 g. Axial ratings of the ball part: dynamic Ca 2.24 kN (Ca), static C0a 2.74 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5903",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5903",
      "NKIA 5903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5903",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5903",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 30,
    "B_mm": 20,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11.4,
    "static_load_kN": 16.3,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 20000,
    "reference_speed_rpm": 18000,
    "limiting_speed_rpm": 20000,
    "weight_g": 58,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5903 is the combined needle roller / three-point contact ball bearings entry for a 17 mm shaft: needle rollers run the radial load while the three-point contact ball set takes axial force in both directions through the three-point contact geometry, in a single machined envelope of 17×30×20 mm. In SKF nomenclature NKIB denotes the combined construction and 595903 the series/bore; the ball raceway sits offset on the inner ring, which is why the 20 mm overall width is greater than a plain needle bearing of the same bore. Execution notes: the ball set runs on a raceway offset by s 18 mm from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 18,000 r/min thermal reference and 20,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 20 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5903 shares its 17×30×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 2.24 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 11.4/16.3 kN ratings and 58 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKIB 5903?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 17 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 5903 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 5903 have?",
        "a": "A NKIB 5903 measures 17 mm bore/Fw × 30 mm outside diameter × 20 mm width (0.669 × 1.181 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.4 kN, static C0 16.3 kN, fatigue limit Pu 1.96 kN, limiting speed 20,000 r/min, reference speed 18,000 r/min, mass about 58 g. Axial ratings of the ball part: dynamic Ca 2.24 kN (Ca), static C0a 2.74 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "What does NKIB 5903 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595903 gives the series and 17 mm bore. The offset (s 18 mm) positions the ball raceway inside the 20 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5903",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5903",
      "NKIB 5903"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5904",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5904",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 100,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5904 solves compact radial-plus-thrust duty: a needle roller cage and an angular contact ball bearing built into one 23 mm wide unit with a 20 mm bore and 37 mm outside diameter. Reading the designation: the letters combine the needle roller family with the ball execution — NKIA marks angular contact — and 595904 the heavy 59 dimension series around the 20 mm bore. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Selection arithmetic for the combined unit: radial C 21.6 kN, radial C0 28 kN, axial dynamic 3.79 kN (Ca) and axial static 4.21 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIA 5904 shares its 20×37×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 3.79 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 21.6/28 kN ratings and 100 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIA 5904 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595904 gives the series and 20 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 23 mm overall width."
      },
      {
        "q": "Does the NKIA 5904 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 5904 rides directly on the 20 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIA 5904?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIA 5904 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5904",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5904",
      "NKIA 5904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5904",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5904",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 37,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 21.6,
    "static_load_kN": 28,
    "fatigue_load_limit_kN": 3.35,
    "max_rpm": 17000,
    "reference_speed_rpm": 15000,
    "limiting_speed_rpm": 17000,
    "weight_g": 110,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5904 is a combined needle roller / three-point ball bearing: one unit carrying radial load on the needle roller set and one-direction-leaning axial load on the ball set, 20×37×25 mm, listed by SKF in SKF catalogue PUB BU/P1 17000. The designation NKIB 5904 identifies the two rolling elements in one unit; the 20 mm bore and 37 mm OD come from the 59-series plan, and the 25 mm width stacks roller set plus ball set. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Selection arithmetic for the combined unit: radial C 21.6 kN, radial C0 28 kN, axial dynamic 3.79 kN (Ca) and axial static 4.21 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 25 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 21.6/28 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKIB 5904 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIB 5904 rides directly on the 20 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIB 5904 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIB 5904?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 8.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIB 5904?",
        "a": "A NKIB 5904 measures 20 mm bore/Fw × 37 mm outside diameter × 25 mm width (0.787 × 1.457 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 21.6 kN, static C0 28 kN, fatigue limit Pu 3.35 kN, limiting speed 17,000 r/min, reference speed 15,000 r/min, mass about 110 g. Axial ratings of the ball part: dynamic Ca 3.79 kN (Ca), static C0a 4.21 kN (C0a); three-point contact geometry accepts axial load in both directions."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5904",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5904",
      "NKIB 5904"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA59-22",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 59/22",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.9,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 59/22 solves compact radial-plus-thrust duty: a needle roller cage and an angular contact ball bearing built into one 23 mm wide unit with a 22 mm bore and 39 mm outside diameter. Reading the designation: the letters combine the needle roller family with the ball execution — NKIA marks angular contact — and 5922 the heavy 59 dimension series around the 22 mm bore. Execution notes: the ball set runs on a raceway offset by a catalogue-listed offset from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. The ball set also needs a minimum axial load to keep every ball tracking its raceway under the radial-axial load mix: springs or preload washers are part of the arrangement, not an afterthought. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 23 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 39 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 23.3/32 kN ratings are SKF catalogue values for this exact execution (NKIA 59/22); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Do not treat the axial rating 4.14 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 59/22 facing the working thrust.",
      "The 23.3/32 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKIA 59/22 have?",
        "a": "A NKIA 59/22 measures 22 mm bore/Fw × 39 mm outside diameter × 23 mm width (0.866 × 1.535 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.9 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 120 g. Axial ratings of the ball part: dynamic Ca 4.14 kN (Ca), static C0a 4.93 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "What does NKIA 59/22 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 5922 gives the series and 22 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 23 mm overall width."
      },
      {
        "q": "Does the NKIA 59/22 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 59/22 rides directly on the 22 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIA 59/22?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA59",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA59-22",
      "NKIA 59/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB59-22",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 59/22",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 22,
    "D_mm": 39,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 23.3,
    "static_load_kN": 32,
    "fatigue_load_limit_kN": 3.9,
    "max_rpm": 15000,
    "reference_speed_rpm": 14000,
    "limiting_speed_rpm": 15000,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 59/22 is the combined needle roller / three-point contact ball bearings entry for a 22 mm shaft: needle rollers run the radial load while the three-point contact ball set takes axial force in both directions through the three-point contact geometry, in a single machined envelope of 22×39×25 mm. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 5922 the heavy 59 dimension series around the 22 mm bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Speed ceilings differ by part: 14,000 r/min thermal reference and 15,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: press on the inner ring faces only — the ball set offset (s 23 mm) makes the unit sensitive to bending; support both rings square to the 22 mm seat and never drive through the rolling elements.",
    "applications": [
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force",
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 22 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 39 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIB 59/22 shares its 22×39×25 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 59/22 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 23.3/32 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKIB 59/22 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 59/22 rides directly on the 22 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIB 59/22?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 22 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 59/22 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 59/22 have?",
        "a": "A NKIB 59/22 measures 22 mm bore/Fw × 39 mm outside diameter × 25 mm width (0.866 × 1.535 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 23.3 kN, static C0 32 kN, fatigue limit Pu 3.9 kN, limiting speed 15,000 r/min, reference speed 14,000 r/min, mass about 120 g. Axial ratings of the ball part: dynamic Ca 4.14 kN (Ca), static C0a 4.93 kN (C0a); three-point contact geometry accepts axial load in both directions."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB59",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB59-22",
      "NKIB 59/22"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5905",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5905",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.15,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIA 5905 among the combined needle roller / angular contact ball bearings: radial capacity from the needle roller set (24.2 kN C), axial capacity from the angular contact ball part 4.24 kN (Ca), all within a 42×23 mm outline. The NKIA 5905 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 25 mm; the 23 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Speed ceilings differ by part: 13,000 r/min thermal reference and 15,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 24.2/34.5 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKIA 5905?",
        "a": "A NKIA 5905 measures 25 mm bore/Fw × 42 mm outside diameter × 23 mm width (0.984 × 1.654 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 34.5 kN, fatigue limit Pu 4.15 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 130 g. Axial ratings of the ball part: dynamic Ca 4.24 kN (Ca), static C0a 5.26 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "How is the NKIA 5905 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595905 gives the series and 25 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 23 mm overall width."
      },
      {
        "q": "Can the NKIA 5905 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5905 rides directly on the 25 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIA 5905 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5905",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5905",
      "NKIA 5905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5905",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5905",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 42,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.2,
    "static_load_kN": 34.5,
    "fatigue_load_limit_kN": 4.15,
    "max_rpm": 15000,
    "reference_speed_rpm": 13000,
    "limiting_speed_rpm": 15000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKIB 5905 designates a combined bearing of the combined needle roller / three-point contact ball bearings: caged needle rollers for the 25 mm radial seat share a shaft with an integral three-point contact ball set rated 4.24 kN (Ca) axially. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 595905 the heavy 59 dimension series around the 25 mm bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Speed ceilings differ by part: 13,000 r/min thermal reference and 15,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 25 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 42 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 24.2/34.5 kN ratings are SKF catalogue values for this exact execution (NKIB 5905); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5905 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 24.2/34.5 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIB 5905 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595905 gives the series and 25 mm bore. The offset (s 23 mm) positions the ball raceway inside the 25 mm overall width."
      },
      {
        "q": "Does the NKIB 5905 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5905 rides directly on the 25 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIB 5905?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 5905 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5905",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5905",
      "NKIB 5905"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5906",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5906",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For shafts where a separate thrust bearing would lengthen the assembly, NKIA 5906 integrates needle rollers and an angular contact ball bearing: 30 mm bore, 47 mm OD, 23 mm overall width including the ball set offset. In SKF nomenclature NKIA denotes the combined construction and 595906 the series/bore; the ball raceway sits offset on the inner ring, which is why the 23 mm overall width is greater than a plain needle bearing of the same bore. Execution notes: the ball set runs on a raceway offset by a catalogue-listed offset from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Selection arithmetic for the combined unit: radial C 25.5 kN, radial C0 39 kN, axial dynamic 4.54 kN (Ca) and axial static 6.32 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 25.5/39 kN ratings are SKF catalogue values for this exact execution (NKIA 5906); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5906 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 25.5/39 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKIA 5906 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIA 5906 have?",
        "a": "A NKIA 5906 measures 30 mm bore/Fw × 47 mm outside diameter × 23 mm width (1.181 × 1.85 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.5 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 150 g. Axial ratings of the ball part: dynamic Ca 4.54 kN (Ca), static C0a 6.32 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "What does NKIA 5906 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595906 gives the series and 30 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 23 mm overall width."
      },
      {
        "q": "Does the NKIA 5906 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 5906 rides directly on the 30 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5906",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5906",
      "NKIA 5906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5906",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5906",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 47,
    "B_mm": 25,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 25.5,
    "static_load_kN": 39,
    "fatigue_load_limit_kN": 4.65,
    "max_rpm": 13000,
    "reference_speed_rpm": 11000,
    "limiting_speed_rpm": 13000,
    "weight_g": 150,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5906 solves compact radial-plus-thrust duty: a needle roller cage and an three-point contact ball bearing built into one 25 mm wide unit with a 30 mm bore and 47 mm outside diameter. The NKIB 5906 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 30 mm; the 25 mm width covers both the roller cage and the offset ball set (s offset 23 mm). Execution notes: the ball set runs on a raceway offset by s 23 mm from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Selection arithmetic for the combined unit: radial C 25.5 kN, radial C0 39 kN, axial dynamic 4.54 kN (Ca) and axial static 6.32 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 25 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 30 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 25.5/39 kN ratings are SKF catalogue values for this exact execution (NKIB 5906); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 4.54 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5906 facing the working thrust.",
      "The 25.5/39 kN ratings and 150 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKIB 5906?",
        "a": "A NKIB 5906 measures 30 mm bore/Fw × 47 mm outside diameter × 25 mm width (1.181 × 1.85 × 0.984 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.5 kN, static C0 39 kN, fatigue limit Pu 4.65 kN, limiting speed 13,000 r/min, reference speed 11,000 r/min, mass about 150 g. Axial ratings of the ball part: dynamic Ca 4.54 kN (Ca), static C0a 6.32 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "How is the NKIB 5906 designation read?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595906 gives the series and 30 mm bore. The offset (s 23 mm) positions the ball raceway inside the 25 mm overall width."
      },
      {
        "q": "Can the NKIB 5906 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIB 5906 rides directly on the 30 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIB 5906 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5906",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5906",
      "NKIB 5906"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5907",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5907",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 27,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.7,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 240,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5907 is the combined needle roller / angular contact ball bearings entry for a 35 mm shaft: needle rollers run the radial load while the angular contact ball set takes axial force primarily in one direction, in a single machined envelope of 35×55×27 mm. The designation NKIA 5907 identifies the two rolling elements in one unit; the 35 mm bore and 55 mm OD come from the 59-series plan, and the 27 mm width stacks roller set plus ball set. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 9,500 r/min thermal reference and 11,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 31.9/54 kN ratings are SKF catalogue values for this exact execution (NKIA 5907); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 5.83 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5907 facing the working thrust.",
      "The 31.9/54 kN ratings and 240 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKIA 5907 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIA 5907?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIA 5907?",
        "a": "A NKIA 5907 measures 35 mm bore/Fw × 55 mm outside diameter × 27 mm width (1.378 × 2.165 × 1.063 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 54 kN, fatigue limit Pu 6.7 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 240 g. Axial ratings of the ball part: dynamic Ca 5.83 kN (Ca), static C0a 8.42 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "How is the NKIA 5907 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595907 gives the series and 35 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 27 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5907",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5907",
      "NKIA 5907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5907",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5907",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 55,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 31.9,
    "static_load_kN": 54,
    "fatigue_load_limit_kN": 6.7,
    "max_rpm": 11000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 11000,
    "weight_g": 250,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIB 5907 among the combined needle roller / three-point contact ball bearings: radial capacity from the needle roller set (31.9 kN C), axial capacity from the three-point contact ball part 5.83 kN (Ca), all within a 55×30 mm outline. In SKF nomenclature NKIB denotes the combined construction and 595907 the series/bore; the ball raceway sits offset on the inner ring, which is why the 30 mm overall width is greater than a plain needle bearing of the same bore. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 9,500 r/min thermal reference and 11,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 30 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 9,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 35 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 5.83 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 31.9/54 kN ratings and 250 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKIB 5907 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 5907 have?",
        "a": "A NKIB 5907 measures 35 mm bore/Fw × 55 mm outside diameter × 30 mm width (1.378 × 2.165 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 31.9 kN, static C0 54 kN, fatigue limit Pu 6.7 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 250 g. Axial ratings of the ball part: dynamic Ca 5.83 kN (Ca), static C0a 8.42 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "What does NKIB 5907 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595907 gives the series and 35 mm bore. The offset (s 27 mm) positions the ball raceway inside the 30 mm overall width."
      },
      {
        "q": "Does the NKIB 5907 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5907 rides directly on the 35 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5907",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5907",
      "NKIB 5907"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5908",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5908",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 320,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5908 is a combined needle roller / angular ball bearing: one unit carrying radial load on the needle roller set and one-direction-leaning axial load on the ball set, 40×62×30 mm, listed by SKF in SKF catalogue PUB BU/P1 17000. Reading the designation: the letters combine the needle roller family with the ball execution — NKIA marks angular contact — and 595908 the heavy 59 dimension series around the 40 mm bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 42.9 kN, radial C0 71 kN, axial dynamic 7.17 kN (Ca) and axial static 10.9 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 7.17 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 42.9/71 kN ratings and 320 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKIA 5908 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 5908 rides directly on the 40 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIA 5908?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIA 5908 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIA 5908 have?",
        "a": "A NKIA 5908 measures 40 mm bore/Fw × 62 mm outside diameter × 30 mm width (1.575 × 2.441 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 71 kN, fatigue limit Pu 8.8 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 320 g. Axial ratings of the ball part: dynamic Ca 7.17 kN (Ca), static C0a 10.9 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5908",
      "NKIA 5908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5908",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5908",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 40,
    "D_mm": 62,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 42.9,
    "static_load_kN": 71,
    "fatigue_load_limit_kN": 8.8,
    "max_rpm": 9500,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9500,
    "weight_g": 320,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For shafts where a separate thrust bearing would lengthen the assembly, NKIB 5908 integrates needle rollers and an three-point contact ball bearing: 40 mm bore, 62 mm OD, 34 mm overall width including the ball set offset. The designation NKIB 5908 identifies the two rolling elements in one unit; the 40 mm bore and 62 mm OD come from the 59-series plan, and the 34 mm width stacks roller set plus ball set. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 42.9 kN, radial C0 71 kN, axial dynamic 7.17 kN (Ca) and axial static 10.9 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 34 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5908 shares its 40×62×34 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 42.9/71 kN ratings and 320 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKIB 5908 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 40 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIB 5908?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIB 5908?",
        "a": "A NKIB 5908 measures 40 mm bore/Fw × 62 mm outside diameter × 34 mm width (1.575 × 2.441 × 1.339 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 71 kN, fatigue limit Pu 8.8 kN, limiting speed 9,500 r/min, reference speed 8,000 r/min, mass about 320 g. Axial ratings of the ball part: dynamic Ca 7.17 kN (Ca), static C0a 10.9 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "How is the NKIB 5908 designation read?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595908 gives the series and 40 mm bore. The offset (s 30 mm) positions the ball raceway inside the 34 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5908",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5908",
      "NKIB 5908"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5909",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5909",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.65,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKIA 5909 designates a combined bearing of the combined needle roller / angular contact ball bearings: caged needle rollers for the 45 mm radial seat share a shaft with an integral angular contact ball set rated 7.47 kN (Ca) axially. The NKIA 5909 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 45 mm; the 30 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). Execution notes: the ball set runs on a raceway offset by a catalogue-listed offset from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 7,500 r/min thermal reference and 8,500 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Do not interchange envelope-identical needle families blindly: NKIA 5909 shares its 45×68×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 7,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 45.7/78 kN ratings and 380 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKIA 5909 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595909 gives the series and 45 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 30 mm overall width."
      },
      {
        "q": "Can the NKIA 5909 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5909 rides directly on the 45 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIA 5909 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIA 5909?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5909",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5909",
      "NKIA 5909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5909",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5909",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 45,
    "D_mm": 68,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 45.7,
    "static_load_kN": 78,
    "fatigue_load_limit_kN": 9.65,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5909 is the combined needle roller / three-point contact ball bearings entry for a 45 mm shaft: needle rollers run the radial load while the three-point contact ball set takes axial force in both directions through the three-point contact geometry, in a single machined envelope of 45×68×34 mm. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 595909 the heavy 59 dimension series around the 45 mm bore. Execution notes: the ball set runs on a raceway offset by s 30 mm from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 7,500 r/min thermal reference and 8,500 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Life-lubricated as supplied in most sizes; where a relubrication path exists, meter grease gently — pressure through the 34 mm wide unit can lift the seals of adjacent components.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5909 shares its 45×68×34 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5909 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 45.7/78 kN ratings and 380 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NKIB 5909 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5909 rides directly on the 45 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIB 5909?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 45 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 5909 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 5909 have?",
        "a": "A NKIB 5909 measures 45 mm bore/Fw × 68 mm outside diameter × 34 mm width (1.772 × 2.677 × 1.339 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 45.7 kN, static C0 78 kN, fatigue limit Pu 9.65 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 380 g. Axial ratings of the ball part: dynamic Ca 7.47 kN (Ca), static C0a 12 kN (C0a); three-point contact geometry accepts axial load in both directions."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5909",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5909",
      "NKIB 5909"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5910",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5910",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 380,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKIA 5910 designates a combined bearing of the combined needle roller / angular contact ball bearings: caged needle rollers for the 50 mm radial seat share a shaft with an integral angular contact ball set rated 7.74 kN (Ca) axially. The NKIA 5910 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 50 mm; the 30 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 7,000 r/min thermal reference and 8,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: press on the inner ring faces only — the ball set offset (a catalogue-listed offset) makes the unit sensitive to bending; support both rings square to the 50 mm seat and never drive through the rolling elements.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 47.3/85 kN ratings and 380 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKIA 5910 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5910 rides directly on the 50 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIA 5910 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 50 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIA 5910?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 50 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 11.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIA 5910?",
        "a": "A NKIA 5910 measures 50 mm bore/Fw × 72 mm outside diameter × 30 mm width (1.969 × 2.835 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 47.3 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 380 g. Axial ratings of the ball part: dynamic Ca 7.74 kN (Ca), static C0a 13.7 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5910",
      "NKIA 5910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5910",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5910",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 50,
    "D_mm": 72,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 47.3,
    "static_load_kN": 85,
    "fatigue_load_limit_kN": 10.6,
    "max_rpm": 8000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8000,
    "weight_g": 390,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5910 is the combined needle roller / three-point contact ball bearings entry for a 50 mm shaft: needle rollers run the radial load while the three-point contact ball set takes axial force in both directions through the three-point contact geometry, in a single machined envelope of 50×72×34 mm. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 595910 the heavy 59 dimension series around the 50 mm bore. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Speed ceilings differ by part: 7,000 r/min thermal reference and 8,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 50 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 50 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 47.3/85 kN ratings are SKF catalogue values for this exact execution (NKIB 5910); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5910 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 47.3/85 kN ratings and 390 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NKIB 5910?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 50 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 5910 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 5910 have?",
        "a": "A NKIB 5910 measures 50 mm bore/Fw × 72 mm outside diameter × 34 mm width (1.969 × 2.835 × 1.339 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 47.3 kN, static C0 85 kN, fatigue limit Pu 10.6 kN, limiting speed 8,000 r/min, reference speed 7,000 r/min, mass about 390 g. Axial ratings of the ball part: dynamic Ca 7.74 kN (Ca), static C0a 13.7 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "What does NKIB 5910 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595910 gives the series and 50 mm bore. The offset (s 30 mm) positions the ball raceway inside the 34 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5910",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5910",
      "NKIB 5910"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5911",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5911",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 57.2,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 550,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5911 solves compact radial-plus-thrust duty: a needle roller cage and an angular contact ball bearing built into one 34 mm wide unit with a 55 mm bore and 80 mm outside diameter. In SKF nomenclature NKIA denotes the combined construction and 595911 the series/bore; the ball raceway sits offset on the inner ring, which is why the 34 mm overall width is greater than a plain needle bearing of the same bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 57.2 kN, radial C0 106 kN, axial dynamic 9.27 kN (Ca) and axial static 16.7 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: press on the inner ring faces only — the ball set offset (a catalogue-listed offset) makes the unit sensitive to bending; support both rings square to the 55 mm seat and never drive through the rolling elements.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "The quoted 57.2/106 kN ratings are SKF catalogue values for this exact execution (NKIA 5911); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5911 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 57.2/106 kN ratings and 550 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIA 5911 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595911 gives the series and 55 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 34 mm overall width."
      },
      {
        "q": "Does the NKIA 5911 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 5911 rides directly on the 55 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIA 5911?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 55 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIA 5911 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5911",
      "NKIA 5911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5911",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5911",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 55,
    "D_mm": 80,
    "B_mm": 38,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 57.2,
    "static_load_kN": 106,
    "fatigue_load_limit_kN": 13.2,
    "max_rpm": 7000,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7000,
    "weight_g": 560,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5911 is a combined needle roller / three-point ball bearing: one unit carrying radial load on the needle roller set and one-direction-leaning axial load on the ball set, 55×80×38 mm, listed by SKF in SKF catalogue PUB BU/P1 17000. The NKIB 5911 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 55 mm; the 38 mm width covers both the roller cage and the offset ball set (s offset 34 mm). NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Selection arithmetic for the combined unit: radial C 57.2 kN, radial C0 106 kN, axial dynamic 9.27 kN (Ca) and axial static 16.7 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 55 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 55 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 57.2/106 kN ratings are SKF catalogue values for this exact execution (NKIB 5911); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 9.27 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5911 facing the working thrust.",
      "The 57.2/106 kN ratings and 560 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NKIB 5911 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIB 5911 rides directly on the 55 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIB 5911 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 55 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIB 5911?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 55 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 12.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIB 5911?",
        "a": "A NKIB 5911 measures 55 mm bore/Fw × 80 mm outside diameter × 38 mm width (2.165 × 3.15 × 1.496 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 57.2 kN, static C0 106 kN, fatigue limit Pu 13.2 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 560 g. Axial ratings of the ball part: dynamic Ca 9.27 kN (Ca), static C0a 16.7 kN (C0a); three-point contact geometry accepts axial load in both directions."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5911",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5911",
      "NKIB 5911"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5912",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5912",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 590,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIA 5912 among the combined needle roller / angular contact ball bearings: radial capacity from the needle roller set (60.5 kN C), axial capacity from the angular contact ball part 9.58 kN (Ca), all within a 85×34 mm outline. The designation NKIA 5912 identifies the two rolling elements in one unit; the 60 mm bore and 85 mm OD come from the 59-series plan, and the 34 mm width stacks roller set plus ball set. Execution notes: the ball set runs on a raceway offset by a catalogue-listed offset from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 6,000 r/min thermal reference and 6,700 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: press on the inner ring faces only — the ball set offset (a catalogue-listed offset) makes the unit sensitive to bending; support both rings square to the 60 mm seat and never drive through the rolling elements.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Hardness is load capacity: in families without an inner ring the 60 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 60.5/114 kN ratings are SKF catalogue values for this exact execution (NKIA 5912); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 9.58 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIA 5912 facing the working thrust.",
      "The 60.5/114 kN ratings and 590 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKIA 5912?",
        "a": "A NKIA 5912 measures 60 mm bore/Fw × 85 mm outside diameter × 34 mm width (2.362 × 3.346 × 1.339 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 60.5 kN, static C0 114 kN, fatigue limit Pu 14.3 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 590 g. Axial ratings of the ball part: dynamic Ca 9.58 kN (Ca), static C0a 18 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "How is the NKIA 5912 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595912 gives the series and 60 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 34 mm overall width."
      },
      {
        "q": "Can the NKIA 5912 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIA 5912 rides directly on the 60 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIA 5912 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 60 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5912",
      "NKIA 5912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5912",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5912",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 60,
    "D_mm": 85,
    "B_mm": 38,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 60.5,
    "static_load_kN": 114,
    "fatigue_load_limit_kN": 14.3,
    "max_rpm": 6700,
    "reference_speed_rpm": 6000,
    "limiting_speed_rpm": 6700,
    "weight_g": 600,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NKIB 5912 designates a combined bearing of the combined needle roller / three-point contact ball bearings: caged needle rollers for the 60 mm radial seat share a shaft with an integral three-point contact ball set rated 9.58 kN (Ca) axially. In SKF nomenclature NKIB denotes the combined construction and 595912 the series/bore; the ball raceway sits offset on the inner ring, which is why the 38 mm overall width is greater than a plain needle bearing of the same bore. Execution notes: the ball set runs on a raceway offset by s 34 mm from the roller set centreline — this offset is why the overall width exceeds a plain needle bearing and why the units cannot be dismantled without losing preload. Speed ceilings differ by part: 6,000 r/min thermal reference and 6,700 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 60 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 6,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 60 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 9.58 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 60.5/114 kN ratings and 600 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NKIB 5912 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595912 gives the series and 60 mm bore. The offset (s 34 mm) positions the ball raceway inside the 38 mm overall width."
      },
      {
        "q": "Does the NKIB 5912 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5912 rides directly on the 60 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "What mounting mistakes ruin a NKIB 5912?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 60 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NKIB 5912 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5912",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5912",
      "NKIB 5912"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5913",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5913",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 34,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 61.6,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 640,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "For shafts where a separate thrust bearing would lengthen the assembly, NKIA 5913 integrates needle rollers and an angular contact ball bearing: 65 mm bore, 90 mm OD, 34 mm overall width including the ball set offset. Reading the designation: the letters combine the needle roller family with the ball execution — NKIA marks angular contact — and 595913 the heavy 59 dimension series around the 65 mm bore. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Selection arithmetic for the combined unit: radial C 61.6 kN, radial C0 120 kN, axial dynamic 9.96 kN (Ca) and axial static 19.2 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: press on the inner ring faces only — the ball set offset (a catalogue-listed offset) makes the unit sensitive to bending; support both rings square to the 65 mm seat and never drive through the rolling elements.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Reference and limiting speeds are different limits: the 5,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 65 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 9.96 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 61.6/120 kN ratings and 640 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKIA 5913 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIA 5913 have?",
        "a": "A NKIA 5913 measures 65 mm bore/Fw × 90 mm outside diameter × 34 mm width (2.559 × 3.543 × 1.339 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 120 kN, fatigue limit Pu 14.6 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 640 g. Axial ratings of the ball part: dynamic Ca 9.96 kN (Ca), static C0a 19.2 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "What does NKIA 5913 mean in SKF part numbering?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595913 gives the series and 65 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 34 mm overall width."
      },
      {
        "q": "Does the NKIA 5913 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIA 5913 rides directly on the 65 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5913",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5913",
      "NKIA 5913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5913",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5913",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 65,
    "D_mm": 90,
    "B_mm": 38,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 61.6,
    "static_load_kN": 120,
    "fatigue_load_limit_kN": 14.6,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 640,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIB 5913 solves compact radial-plus-thrust duty: a needle roller cage and an three-point contact ball bearing built into one 38 mm wide unit with a 65 mm bore and 90 mm outside diameter. The designation NKIB 5913 identifies the two rolling elements in one unit; the 65 mm bore and 90 mm OD come from the 59-series plan, and the 38 mm width stacks roller set plus ball set. The combined unit is greased for life at assembly in many applications; relubrication, where provided, must reach both the roller cage and the ball set through the same axial bore features. Selection arithmetic for the combined unit: radial C 61.6 kN, radial C0 120 kN, axial dynamic 9.96 kN (Ca) and axial static 19.2 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 65 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5913 shares its 65×90×38 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,600 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 61.6/120 kN ratings and 640 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NKIB 5913?",
        "a": "A NKIB 5913 measures 65 mm bore/Fw × 90 mm outside diameter × 38 mm width (2.559 × 3.543 × 1.496 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 61.6 kN, static C0 120 kN, fatigue limit Pu 14.6 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 640 g. Axial ratings of the ball part: dynamic Ca 9.96 kN (Ca), static C0a 19.2 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "How is the NKIB 5913 designation read?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595913 gives the series and 65 mm bore. The offset (s 34 mm) positions the ball raceway inside the 38 mm overall width."
      },
      {
        "q": "Can the NKIB 5913 run on an unhardened shaft?",
        "a": "The needle roller part of the NKIB 5913 rides directly on the 65 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      },
      {
        "q": "How should the NKIB 5913 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 65 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5913",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5913",
      "NKIB 5913"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIA5914",
    "brand": "SKF",
    "manufacturer_designation": "NKIA 5914",
    "series": "NKIA-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 40,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.8,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 980,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKIA 5914 is the combined needle roller / angular contact ball bearings entry for a 70 mm shaft: needle rollers run the radial load while the angular contact ball set takes axial force primarily in one direction, in a single machined envelope of 70×100×40 mm. The NKIA 5914 code breaks into series letters (needle roller + ball), dimension series 59, and the two-digit bore reference for 70 mm; the 40 mm width covers both the roller cage and the offset ball set (offset per catalogue s column). NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Speed ceilings differ by part: 5,000 r/min thermal reference and 5,600 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: press on the inner ring faces only — the ball set offset (a catalogue-listed offset) makes the unit sensitive to bending; support both rings square to the 70 mm seat and never drive through the rolling elements.",
    "applications": [
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions",
      "pump rotors with hydraulic axial pull",
      "bevel gear shafts with moderate axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Do not interchange envelope-identical needle families blindly: NKIA 5914 shares its 70×100×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 5,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the ball-raceway part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 84.2/163 kN ratings and 980 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NKIA 5914 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 70 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKIA 5914?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 70 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 15.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKIA 5914?",
        "a": "A NKIA 5914 measures 70 mm bore/Fw × 100 mm outside diameter × 40 mm width (2.756 × 3.937 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 163 kN, fatigue limit Pu 20.8 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 980 g. Axial ratings of the ball part: dynamic Ca 13.2 kN (Ca), static C0a 25 kN (C0a); angular contact geometry leans axial capacity toward one direction."
      },
      {
        "q": "How is the NKIA 5914 designation read?",
        "a": "NKIA combines a needle roller cage with an angular contact ball bearing in one unit; 595914 gives the series and 70 mm bore. The offset (a catalogue-listed offset) positions the ball raceway inside the 40 mm overall width."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIA5914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIA5914",
      "NKIA 5914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKIB5914",
    "brand": "SKF",
    "manufacturer_designation": "NKIB 5914",
    "series": "NKIB-series",
    "type": "needle",
    "d_mm": 70,
    "D_mm": 100,
    "B_mm": 45,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 84.2,
    "static_load_kN": 163,
    "fatigue_load_limit_kN": 20.8,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 990,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NKIB 5914 among the combined needle roller / three-point contact ball bearings: radial capacity from the needle roller set (84.2 kN C), axial capacity from the three-point contact ball part 13.2 kN (Ca), all within a 100×45 mm outline. Reading the designation: the letters combine the needle roller family with the ball execution — NKIB marks three-point contact — and 595914 the heavy 59 dimension series around the 70 mm bore. NKIB three-point contact ball raceways accept axial load in both directions, while NKIA angular contact ball raceways lean the axial capacity toward one direction — check the load direction before ordering either. Speed ceilings differ by part: 5,000 r/min thermal reference and 5,600 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Fit the combined unit so the ball raceway offset faces the working axial load, check rotation in both directions, and preload if required with the washer stack the catalogue recommends.",
    "applications": [
      "gearbox main shafts carrying radial plus one-direction thrust",
      "worm gear shafts with axial reaction toward the worm",
      "spindle heads needing compact radial-plus-axial support",
      "lead-screw and ball-screw support positions"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "Above 50 mm bore, thermal growth matters: the 70 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKIB 5914 shares its 70×100×45 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKIB 5914 facing the working thrust.",
      "Minimum axial load is a real requirement: below the catalogue minimum the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 84.2/163 kN ratings and 990 g mass are SKF catalogue values transcribed from ch. 7.7 of PUB BU/P1 17000 (PDF table page 654); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKIB 5914 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKIB 5914 have?",
        "a": "A NKIB 5914 measures 70 mm bore/Fw × 100 mm outside diameter × 45 mm width (2.756 × 3.937 × 1.772 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 84.2 kN, static C0 163 kN, fatigue limit Pu 20.8 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 990 g. Axial ratings of the ball part: dynamic Ca 13.2 kN (Ca), static C0a 25 kN (C0a); three-point contact geometry accepts axial load in both directions."
      },
      {
        "q": "What does NKIB 5914 mean in SKF part numbering?",
        "a": "NKIB combines a needle roller cage with an three-point contact ball bearing in one unit; 595914 gives the series and 70 mm bore. The offset (s 40 mm) positions the ball raceway inside the 45 mm overall width."
      },
      {
        "q": "Does the NKIB 5914 need a hardened and ground shaft?",
        "a": "The needle roller part of the NKIB 5914 rides directly on the 70 mm journal, so it must be hardened to 58–64 HRC and ground; the ball set runs on its own integrated raceways. There is no inner-ring variant — harden the shaft or move to a separate bearing arrangement."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKIB5914",
        "equiv_brand": "ISO 15",
        "level": "full",
        "note": "ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.7 needle roller / angular contact ball bearings",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKIB5914",
      "NKIB 5914"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX7-ZTN",
    "brand": "SKF",
    "manufacturer_designation": "NX 7 ZTN",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.81,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 6000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 6000,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NX 7 ZTN packs radial and thrust capacity into 7×14×18 mm: needle rollers caged around the shaft, thrust balls packed without a cage above them, axial dynamic rating 3.45 kN (Ca). Reading the designation: NX marks needle roller + full complement thrust ball, the number the 7 mm shaft seat; 14 mm OD and 18 mm overall height follow the series plan. Full complement thrust parts run slower than caged ones: observe the 6,000 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 2.81 kN, radial C0 2.75 kN, axial dynamic 3.45 kN (Ca) and axial static 5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. The full complement thrust set has no cage to retain the balls — hold them with grease during assembly and never rotate the shaft before the axial preload (at least factor A 0.00013) is applied.",
    "applications": [
      "small hoisting and winch drums",
      "actuator output shafts",
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NX 7 ZTN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "The quoted 2.81/2.75 kN ratings are SKF catalogue values for this exact execution (NX 7 ZTN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 3.45 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 2.81/2.75 kN ratings and 14 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What does NX 7 ZTN mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 7 mm shaft; the catalogue plan completes 14 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Does the NX 7 ZTN need a hardened and ground shaft?",
        "a": "The radial needle part of the NX 7 ZTN runs directly on the 7 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "What mounting mistakes ruin a NX 7 ZTN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 7 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NX 7 ZTN sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX7-TN",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 7×14×18 mm envelope and equivalent catalogue ratings; NX7-TN is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX7-ZTN",
      "NX 7 ZTN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX7-TN",
    "brand": "SKF",
    "manufacturer_designation": "NX 7 TN",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 7,
    "D_mm": 14,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 2.81,
    "static_load_kN": 2.75,
    "fatigue_load_limit_kN": 0.29,
    "max_rpm": 11000,
    "reference_speed_rpm": 10000,
    "limiting_speed_rpm": 11000,
    "weight_g": 14,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NX 7 TN packs radial and thrust capacity into 7×14×18 mm: needle rollers caged around the shaft, thrust balls packed without a cage above them, axial dynamic rating 3.45 kN (Ca). The number in NX 7 TN is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. The thrust washer set is keyed to the housing, the ball complement to the shaft washer — assembly orientation matters, since reverse axial shocks would unload the packed ball set. Selection arithmetic for the combined unit: radial C 2.81 kN, radial C0 2.75 kN, axial dynamic 3.45 kN (Ca) and axial static 5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At Fw 7 mm the rolling elements are under two millimetres long — handle the NX 7 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Minimum axial load is a real requirement: below factor A 0.00013 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 2.81/2.75 kN ratings and 14 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NX 7 TN designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 7 mm shaft; the catalogue plan completes 14 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Can the NX 7 TN run on an unhardened shaft?",
        "a": "The radial needle part of the NX 7 TN runs directly on the 7 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "How should the NX 7 TN be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 7 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 7 TN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 7 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX7-ZTN",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 7×14×18 mm envelope and equivalent catalogue ratings; NX7-ZTN is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX7-TN",
      "NX 7 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX10-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 10 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 19,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.95,
    "static_load_kN": 4.55,
    "fatigue_load_limit_kN": 0.53,
    "max_rpm": 5600,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 5600,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NX 10 Z is a combined needle roller / full complement thrust ball bearing: a caged needle roller set for the 10 mm radial seat stacked with a maximum-ball-count thrust ball set, per SKF catalogue PUB BU/P1 17000 ch. 7.8. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 10 mm shaft seat; 19 mm OD and 18 mm overall height follow the series plan. Full complement thrust parts run slower than caged ones: observe the 5,600 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Speed ceilings differ by part: 8,500 r/min thermal reference and 5,600 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. The full complement thrust set has no cage to retain the balls — hold them with grease during assembly and never rotate the shaft before the axial preload (at least factor A 0.00038) is applied.",
    "applications": [
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload",
      "small hoisting and winch drums",
      "actuator output shafts"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 8,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 10 Z facing the working thrust.",
      "Minimum axial load is a real requirement: below factor A 0.00038 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 4.95/4.55 kN ratings and 25 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NX 10 Z?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 10 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NX 10 Z sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NX 10 Z have?",
        "a": "A NX 10 Z measures 10 mm bore/Fw × 19 mm outside diameter × 18 mm width (0.394 × 0.748 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.95 kN, static C0 4.55 kN, fatigue limit Pu 0.53 kN, limiting speed 5,600 r/min, reference speed 8,500 r/min, mass about 25 g. Axial ratings of the thrust part: dynamic Ca 5.07 kN (Ca), static C0a 8.5 kN (C0a), minimum load factor A 0.00038; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NX 10 Z mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 10 mm shaft; the catalogue plan completes 19 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX10",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 10×19×18 mm envelope and equivalent catalogue ratings; NX10 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX10-Z",
      "NX 10 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX10",
    "brand": "SKF",
    "manufacturer_designation": "NX 10",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 19,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 4.95,
    "static_load_kN": 4.55,
    "fatigue_load_limit_kN": 0.53,
    "max_rpm": 9500,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 9500,
    "weight_g": 25,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a 10 mm shaft needs radial support plus one-direction axial location in minimal length, NX 10 from the combined needle roller / full complement thrust ball bearings stacks both functions: 19 mm OD, thrust part 5.07 kN (Ca) dynamic. In SKF nomenclature the X in NX flags the combined radial-plus-thrust construction; the figure 10 selects the size, and the catalogue adds the 19 mm envelope and 18 mm height. Full complement thrust parts run slower than caged ones: observe the 9,500 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 4.95 kN, radial C0 4.55 kN, axial dynamic 5.07 kN (Ca) and axial static 8.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Reference and limiting speeds are different limits: the 8,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Hardness is load capacity: in families without an inner ring the 10 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 10 facing the working thrust.",
      "Minimum axial load is a real requirement: below factor A 0.00038 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 4.95/4.55 kN ratings and 25 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NX 10 have?",
        "a": "A NX 10 measures 10 mm bore/Fw × 19 mm outside diameter × 18 mm width (0.394 × 0.748 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.95 kN, static C0 4.55 kN, fatigue limit Pu 0.53 kN, limiting speed 9,500 r/min, reference speed 8,500 r/min, mass about 25 g. Axial ratings of the thrust part: dynamic Ca 5.07 kN (Ca), static C0a 8.5 kN (C0a), minimum load factor A 0.00038; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NX 10 mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 10 mm shaft; the catalogue plan completes 19 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Does the NX 10 need a hardened and ground shaft?",
        "a": "The radial needle part of the NX 10 runs directly on the 10 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "What mounting mistakes ruin a NX 10?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 10 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX10-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 10×19×18 mm envelope and equivalent catalogue ratings; NX10-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX10",
      "NX 10"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX12-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 12 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 21,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 5.39,
    "static_load_kN": 5.2,
    "fatigue_load_limit_kN": 0.61,
    "max_rpm": 5300,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 5300,
    "weight_g": 28,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NX 12 Z is a combined needle roller / full complement thrust ball bearing: a caged needle roller set for the 12 mm radial seat stacked with a maximum-ball-count thrust ball set, per SKF catalogue PUB BU/P1 17000 ch. 7.8. The number in NX 12 Z is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. Full complement thrust parts run slower than caged ones: observe the 5,300 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Axial capability is one-direction: size the arrangement so working thrust pushes the thrust-washer face, and provide a mirrored unit or separate bearing for load reversals. The full complement thrust set has no cage to retain the balls — hold them with grease during assembly and never rotate the shaft before the axial preload (at least factor A 0.00048) is applied.",
    "applications": [
      "actuator output shafts",
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 12 Z facing the working thrust.",
      "Minimum axial load is a real requirement: below factor A 0.00048 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 5.39/5.2 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NX 12 Z be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 12 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 12 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 12 Z?",
        "a": "A NX 12 Z measures 12 mm bore/Fw × 21 mm outside diameter × 18 mm width (0.472 × 0.827 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.39 kN, static C0 5.2 kN, fatigue limit Pu 0.61 kN, limiting speed 5,300 r/min, reference speed 8,000 r/min, mass about 28 g. Axial ratings of the thrust part: dynamic Ca 5.27 kN (Ca), static C0a 9.65 kN (C0a), minimum load factor A 0.00048; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 12 Z designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 12 mm shaft; the catalogue plan completes 21 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX12",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 12×21×18 mm envelope and equivalent catalogue ratings; NX12 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX12-Z",
      "NX 12 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX12",
    "brand": "SKF",
    "manufacturer_designation": "NX 12",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 21,
    "B_mm": 18,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 5.39,
    "static_load_kN": 5.2,
    "fatigue_load_limit_kN": 0.61,
    "max_rpm": 9000,
    "reference_speed_rpm": 8000,
    "limiting_speed_rpm": 9000,
    "weight_g": 28,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The combined needle roller / full complement thrust ball bearings execution NX 12 measures 12×21×18 mm: radial duty on caged needle rollers, axial duty on a full complement of thrust balls rated 5.27 kN (Ca), both in one shaft position. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 12 mm shaft seat; 21 mm OD and 18 mm overall height follow the series plan. The thrust washer set is keyed to the housing, the ball complement to the shaft washer — assembly orientation matters, since reverse axial shocks would unload the packed ball set. Selection arithmetic for the combined unit: radial C 5.39 kN, radial C0 5.2 kN, axial dynamic 5.27 kN (Ca) and axial static 9.65 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NX 12 shares its 12×21×18 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 5.27 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 5.39/5.2 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NX 12?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 12 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NX 12 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NX 12 have?",
        "a": "A NX 12 measures 12 mm bore/Fw × 21 mm outside diameter × 18 mm width (0.472 × 0.827 × 0.709 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.39 kN, static C0 5.2 kN, fatigue limit Pu 0.61 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 28 g. Axial ratings of the thrust part: dynamic Ca 5.27 kN (Ca), static C0a 9.65 kN (C0a), minimum load factor A 0.00048; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NX 12 mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 12 mm shaft; the catalogue plan completes 21 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX12-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 12×21×18 mm envelope and equivalent catalogue ratings; NX12-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX12",
      "NX 12"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX15-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 15 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 24,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11,
    "static_load_kN": 14,
    "fatigue_load_limit_kN": 1.66,
    "max_rpm": 5300,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 5300,
    "weight_g": 48,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NX 15 Z denotes a combined bearing whose thrust part is filled with the maximum number of balls: highest axial capacity of the NX/NKX family at low-to-moderate speed, radial part 11 kN C. The number in NX 15 Z is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. Full complement thrust parts run slower than caged ones: observe the 5,300 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Speed ceilings differ by part: 7,500 r/min thermal reference and 5,300 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload",
      "small hoisting and winch drums",
      "actuator output shafts"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NX 15 Z shares its 15×24×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 7,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Do not treat the axial rating 6.18 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 15 Z facing the working thrust.",
      "The 11/14 kN ratings and 48 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NX 15 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 15 Z?",
        "a": "A NX 15 Z measures 15 mm bore/Fw × 24 mm outside diameter × 28 mm width (0.591 × 0.945 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11 kN, static C0 14 kN, fatigue limit Pu 1.66 kN, limiting speed 5,300 r/min, reference speed 7,500 r/min, mass about 48 g. Axial ratings of the thrust part: dynamic Ca 6.18 kN (Ca), static C0a 12.2 kN (C0a), minimum load factor A 0.00077; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 15 Z designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 15 mm shaft; the catalogue plan completes 24 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Can the NX 15 Z run on an unhardened shaft?",
        "a": "The radial needle part of the NX 15 Z runs directly on the 15 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX15",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 15×24×28 mm envelope and equivalent catalogue ratings; NX15 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX15-Z",
      "NX 15 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX15",
    "brand": "SKF",
    "manufacturer_designation": "NX 15",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 24,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11,
    "static_load_kN": 14,
    "fatigue_load_limit_kN": 1.66,
    "max_rpm": 8500,
    "reference_speed_rpm": 7500,
    "limiting_speed_rpm": 8500,
    "weight_g": 48,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NX 15 for light, slow combined loads: the full complement thrust ball set gives the greatest axial capacity for the section, while the caged needle rollers take 11 kN radial. The number in NX 15 is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. The thrust washer set is keyed to the housing, the ball complement to the shaft washer — assembly orientation matters, since reverse axial shocks would unload the packed ball set. Speed ceilings differ by part: 7,500 r/min thermal reference and 8,500 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 15 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 11/14 kN ratings are SKF catalogue values for this exact execution (NX 15); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 6.18 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 15 facing the working thrust.",
      "The 11/14 kN ratings and 48 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What are the dimensions and ratings of the NX 15?",
        "a": "A NX 15 measures 15 mm bore/Fw × 24 mm outside diameter × 28 mm width (0.591 × 0.945 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11 kN, static C0 14 kN, fatigue limit Pu 1.66 kN, limiting speed 8,500 r/min, reference speed 7,500 r/min, mass about 48 g. Axial ratings of the thrust part: dynamic Ca 6.18 kN (Ca), static C0a 12.2 kN (C0a), minimum load factor A 0.00077; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 15 designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 15 mm shaft; the catalogue plan completes 24 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Can the NX 15 run on an unhardened shaft?",
        "a": "The radial needle part of the NX 15 runs directly on the 15 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "How should the NX 15 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 15 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX15-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 15×24×28 mm envelope and equivalent catalogue ratings; NX15-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX15",
      "NX 15"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX17-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 17 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 26,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.1,
    "static_load_kN": 16.6,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 5000,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 5000,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NX 17 Z denotes a combined bearing whose thrust part is filled with the maximum number of balls: highest axial capacity of the NX/NKX family at low-to-moderate speed, radial part 12.1 kN C. The NX 17 Z code gives only the 17 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 28 mm total height. Full complement thrust parts run slower than caged ones: observe the 5,000 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 12.1 kN, radial C0 16.6 kN, axial dynamic 6.37 kN (Ca) and axial static 13.4 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not treat the axial rating 6.37 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 17 Z facing the working thrust.",
      "The 12.1/16.6 kN ratings and 53 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NX 17 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 17 Z?",
        "a": "A NX 17 Z measures 17 mm bore/Fw × 26 mm outside diameter × 28 mm width (0.669 × 1.024 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.1 kN, static C0 16.6 kN, fatigue limit Pu 1.96 kN, limiting speed 5,000 r/min, reference speed 7,000 r/min, mass about 53 g. Axial ratings of the thrust part: dynamic Ca 6.37 kN (Ca), static C0a 13.4 kN (C0a), minimum load factor A 0.00093; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 17 Z designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 17 mm shaft; the catalogue plan completes 26 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Can the NX 17 Z run on an unhardened shaft?",
        "a": "The radial needle part of the NX 17 Z runs directly on the 17 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX17",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 17×26×28 mm envelope and equivalent catalogue ratings; NX17 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX17-Z",
      "NX 17 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX17",
    "brand": "SKF",
    "manufacturer_designation": "NX 17",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 17,
    "D_mm": 26,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 12.1,
    "static_load_kN": 16.6,
    "fatigue_load_limit_kN": 1.96,
    "max_rpm": 8500,
    "reference_speed_rpm": 7000,
    "limiting_speed_rpm": 8500,
    "weight_g": 53,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NX 17 is a combined needle roller / full complement thrust ball bearing: a caged needle roller set for the 17 mm radial seat stacked with a maximum-ball-count thrust ball set, per SKF catalogue PUB BU/P1 17000 ch. 7.8. The NX 17 code gives only the 17 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 28 mm total height. Execution notes: the thrust part is filled with the maximum number of balls, giving the family's highest axial capacity, but the packed set needs a minimum axial load (factor A 0.00093) to keep every ball tracking its raceway. Speed ceilings differ by part: 7,000 r/min thermal reference and 8,500 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 17 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 26 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NX 17 shares its 17×26×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 7,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Minimum axial load is a real requirement: below factor A 0.00093 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 12.1/16.6 kN ratings and 53 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NX 17 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 17 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 17?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 17 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 17?",
        "a": "A NX 17 measures 17 mm bore/Fw × 26 mm outside diameter × 28 mm width (0.669 × 1.024 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.1 kN, static C0 16.6 kN, fatigue limit Pu 1.96 kN, limiting speed 8,500 r/min, reference speed 7,000 r/min, mass about 53 g. Axial ratings of the thrust part: dynamic Ca 6.37 kN (Ca), static C0a 13.4 kN (C0a), minimum load factor A 0.00093; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 17 designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 17 mm shaft; the catalogue plan completes 26 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX17-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 17×26×28 mm envelope and equivalent catalogue ratings; NX17-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX17",
      "NX 17"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX20-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 20 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 30,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 19.3,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 4500,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 4500,
    "weight_g": 68,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a 20 mm shaft needs radial support plus one-direction axial location in minimal length, NX 20 Z from the combined needle roller / full complement thrust ball bearings stacks both functions: 30 mm OD, thrust part 7.8 kN (Ca) dynamic. The NX 20 Z code gives only the 20 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 28 mm total height. Full complement thrust parts run slower than caged ones: observe the 4,500 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. The minimum load factor A 0.0016 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload",
      "small hoisting and winch drums"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 20 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 13.2/19.3 kN ratings are SKF catalogue values for this exact execution (NX 20 Z); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 20 Z facing the working thrust.",
      "Minimum axial load is a real requirement: below factor A 0.0016 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "The 13.2/19.3 kN ratings and 68 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NX 20 Z be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 20 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 20 Z?",
        "a": "A NX 20 Z measures 20 mm bore/Fw × 30 mm outside diameter × 28 mm width (0.787 × 1.181 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.2 kN, static C0 19.3 kN, fatigue limit Pu 2.28 kN, limiting speed 4,500 r/min, reference speed 6,300 r/min, mass about 68 g. Axial ratings of the thrust part: dynamic Ca 7.8 kN (Ca), static C0a 17.3 kN (C0a), minimum load factor A 0.0016; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 20 Z designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 20 mm shaft; the catalogue plan completes 30 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX20",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 20×30×28 mm envelope and equivalent catalogue ratings; NX20 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX20-Z",
      "NX 20 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX20",
    "brand": "SKF",
    "manufacturer_designation": "NX 20",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 20,
    "D_mm": 30,
    "B_mm": 28,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 13.2,
    "static_load_kN": 19.3,
    "fatigue_load_limit_kN": 2.28,
    "max_rpm": 7500,
    "reference_speed_rpm": 6300,
    "limiting_speed_rpm": 7500,
    "weight_g": 68,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NX 20 denotes a combined bearing whose thrust part is filled with the maximum number of balls: highest axial capacity of the NX/NKX family at low-to-moderate speed, radial part 13.2 kN C. The number in NX 20 is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. Execution notes: the thrust part is filled with the maximum number of balls, giving the family's highest axial capacity, but the packed set needs a minimum axial load (factor A 0.0016) to keep every ball tracking its raceway. Speed ceilings differ by part: 6,300 r/min thermal reference and 7,500 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 20 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 13.2/19.3 kN ratings are SKF catalogue values for this exact execution (NX 20); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Do not treat the axial rating 7.8 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 20 facing the working thrust.",
      "The 13.2/19.3 kN ratings and 68 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NX 20 run on an unhardened shaft?",
        "a": "The radial needle part of the NX 20 runs directly on the 20 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "How should the NX 20 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 20 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 20?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 20?",
        "a": "A NX 20 measures 20 mm bore/Fw × 30 mm outside diameter × 28 mm width (0.787 × 1.181 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.2 kN, static C0 19.3 kN, fatigue limit Pu 2.28 kN, limiting speed 7,500 r/min, reference speed 6,300 r/min, mass about 68 g. Axial ratings of the thrust part: dynamic Ca 7.8 kN (Ca), static C0a 17.3 kN (C0a), minimum load factor A 0.0016; the thrust set carries load in one direction only."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX20-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 20×30×28 mm envelope and equivalent catalogue ratings; NX20-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX20",
      "NX 20"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX25-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 25 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.9,
    "max_rpm": 3800,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 3800,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "In SKF catalogue PUB BU/P1 17000, NX 25 Z denotes a combined bearing whose thrust part is filled with the maximum number of balls: highest axial capacity of the NX/NKX family at low-to-moderate speed, radial part 15.1 kN C. The number in NX 25 Z is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. Full complement thrust parts run slower than caged ones: observe the 3,800 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. The minimum load factor A 0.0042 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload",
      "small hoisting and winch drums"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "corrosion pitting from condensation in intermittently operated machinery",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.",
      "The quoted 15.1/24.5 kN ratings are SKF catalogue values for this exact execution (NX 25 Z); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 12.4 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 15.1/24.5 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How should the NX 25 Z be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 25 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 25 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 25 Z?",
        "a": "A NX 25 Z measures 25 mm bore/Fw × 37 mm outside diameter × 30 mm width (0.984 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 3,800 r/min, reference speed 5,600 r/min, mass about 120 g. Axial ratings of the thrust part: dynamic Ca 12.4 kN (Ca), static C0a 28.5 kN (C0a), minimum load factor A 0.0042; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 25 Z designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 25 mm shaft; the catalogue plan completes 37 mm OD and 30 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX25",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 25×37×30 mm envelope and equivalent catalogue ratings; NX25 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6904",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 35.2/53 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX25-Z",
      "NX 25 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX25",
    "brand": "SKF",
    "manufacturer_designation": "NX 25",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 25,
    "D_mm": 37,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 15.1,
    "static_load_kN": 24.5,
    "fatigue_load_limit_kN": 2.9,
    "max_rpm": 6300,
    "reference_speed_rpm": 5600,
    "limiting_speed_rpm": 6300,
    "weight_g": 120,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The combined needle roller / full complement thrust ball bearings execution NX 25 measures 25×37×30 mm: radial duty on caged needle rollers, axial duty on a full complement of thrust balls rated 12.4 kN (Ca), both in one shaft position. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 25 mm shaft seat; 37 mm OD and 30 mm overall height follow the series plan. Full complement thrust parts run slower than caged ones: observe the 6,300 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 15.1 kN, radial C0 24.5 kN, axial dynamic 12.4 kN (Ca) and axial static 28.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 37 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 15.1/24.5 kN ratings are SKF catalogue values for this exact execution (NX 25); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 12.4 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 15.1/24.5 kN ratings and 120 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Does the NX 25 need a hardened and ground shaft?",
        "a": "The radial needle part of the NX 25 runs directly on the 25 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "What mounting mistakes ruin a NX 25?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NX 25 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NX 25 have?",
        "a": "A NX 25 measures 25 mm bore/Fw × 37 mm outside diameter × 30 mm width (0.984 × 1.457 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 15.1 kN, static C0 24.5 kN, fatigue limit Pu 2.9 kN, limiting speed 6,300 r/min, reference speed 5,600 r/min, mass about 120 g. Axial ratings of the thrust part: dynamic Ca 12.4 kN (Ca), static C0a 28.5 kN (C0a), minimum load factor A 0.0042; the thrust set carries load in one direction only."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX25-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 25×37×30 mm envelope and equivalent catalogue ratings; NX25-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6904",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 35.2/53 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKXR25-Z",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 25×37×30 mm envelope, but catalogue C/C0 differ between the executions (15.1/24.5 vs 19/32.5 kN) — boundary dimensions match, not a load-rating equivalent."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX25",
      "NX 25"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX30-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 30 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22.9,
    "static_load_kN": 38,
    "fatigue_load_limit_kN": 4.8,
    "max_rpm": 3600,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 3600,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a 30 mm shaft needs radial support plus one-direction axial location in minimal length, NX 30 Z from the combined needle roller / full complement thrust ball bearings stacks both functions: 42 mm OD, thrust part 12.7 kN (Ca) dynamic. The NX 30 Z code gives only the 30 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 30 mm total height. Full complement thrust parts run slower than caged ones: observe the 3,600 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 22.9 kN, radial C0 38 kN, axial dynamic 12.7 kN (Ca) and axial static 32.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "rolling-contact fatigue spalling after the rated L10 life",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not treat the axial rating 12.7 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 30 Z facing the working thrust.",
      "The 22.9/38 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Can the NX 30 Z run on an unhardened shaft?",
        "a": "The radial needle part of the NX 30 Z runs directly on the 30 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "How should the NX 30 Z be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 30 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NX 30 Z?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 30 Z?",
        "a": "A NX 30 Z measures 30 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.181 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 3,600 r/min, reference speed 5,300 r/min, mass about 130 g. Axial ratings of the thrust part: dynamic Ca 12.7 kN (Ca), static C0a 32.5 kN (C0a), minimum load factor A 0.0055; the thrust set carries load in one direction only."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX30",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 30×42×30 mm envelope and equivalent catalogue ratings; NX30 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6905",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (22.9/38 vs 38/62 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX30-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKX30",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR30",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR30-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX30-Z",
      "NX 30 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX30",
    "brand": "SKF",
    "manufacturer_designation": "NX 30",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 30,
    "D_mm": 42,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 22.9,
    "static_load_kN": 38,
    "fatigue_load_limit_kN": 4.8,
    "max_rpm": 6000,
    "reference_speed_rpm": 5300,
    "limiting_speed_rpm": 6000,
    "weight_g": 130,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "Where a 30 mm shaft needs radial support plus one-direction axial location in minimal length, NX 30 from the combined needle roller / full complement thrust ball bearings stacks both functions: 42 mm OD, thrust part 12.7 kN (Ca) dynamic. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 30 mm shaft seat; 42 mm OD and 30 mm overall height follow the series plan. The thrust washer set is keyed to the housing, the ball complement to the shaft washer — assembly orientation matters, since reverse axial shocks would unload the packed ball set. Selection arithmetic for the combined unit: radial C 22.9 kN, radial C0 38 kN, axial dynamic 12.7 kN (Ca) and axial static 32.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. The full complement thrust set has no cage to retain the balls — hold them with grease during assembly and never rotate the shaft before the axial preload (at least factor A 0.0055) is applied.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 22.9/38 kN ratings are SKF catalogue values for this exact execution (NX 30); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 12.7 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 22.9/38 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NX 30 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NX 30 have?",
        "a": "A NX 30 measures 30 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.181 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 6,000 r/min, reference speed 5,300 r/min, mass about 130 g. Axial ratings of the thrust part: dynamic Ca 12.7 kN (Ca), static C0a 32.5 kN (C0a), minimum load factor A 0.0055; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NX 30 mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 30 mm shaft; the catalogue plan completes 42 mm OD and 30 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Does the NX 30 need a hardened and ground shaft?",
        "a": "The radial needle part of the NX 30 runs directly on the 30 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX30-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 30×42×30 mm envelope and equivalent catalogue ratings; NX30-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6905",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (22.9/38 vs 38/62 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX30-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKX30",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR30",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR30-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX30",
      "NX 30"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX35-Z",
    "brand": "SKF",
    "manufacturer_designation": "NX 35 Z",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 3400,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 3400,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The combined needle roller / full complement thrust ball bearings execution NX 35 Z measures 35×47×30 mm: radial duty on caged needle rollers, axial duty on a full complement of thrust balls rated 13.5 kN (Ca), both in one shaft position. Reading the designation: NX marks needle roller + full complement thrust ball, the number the 35 mm shaft seat; 47 mm OD and 30 mm overall height follow the series plan. Full complement thrust parts run slower than caged ones: observe the 3,400 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 24.6 kN, radial C0 45 kN, axial dynamic 13.5 kN (Ca) and axial static 38 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "hard-particle indentation in unfiltered lubricant",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "The quoted 24.6/45 kN ratings are SKF catalogue values for this exact execution (NX 35 Z); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 13.5 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 24.6/45 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What mounting mistakes ruin a NX 35 Z?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 35 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "Is the NX 35 Z sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NX 35 Z have?",
        "a": "A NX 35 Z measures 35 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.378 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.6 kN, static C0 45 kN, fatigue limit Pu 5.6 kN, limiting speed 3,400 r/min, reference speed 5,000 r/min, mass about 160 g. Axial ratings of the thrust part: dynamic Ca 13.5 kN (Ca), static C0a 38 kN (C0a), minimum load factor A 0.0075; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NX 35 Z mean in SKF part numbering?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 35 mm shaft; the catalogue plan completes 47 mm OD and 30 mm overall height. The packed thrust set maximises axial capacity at low speed."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX35",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 35×47×30 mm envelope and equivalent catalogue ratings; NX35 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (24.6/45 vs 42.9/75 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX35-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKX35",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR35",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR35-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX35-Z",
      "NX 35 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NX35",
    "brand": "SKF",
    "manufacturer_designation": "NX 35",
    "series": "NX-series",
    "type": "needle",
    "d_mm": 35,
    "D_mm": 47,
    "B_mm": 30,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 24.6,
    "static_load_kN": 45,
    "fatigue_load_limit_kN": 5.6,
    "max_rpm": 5600,
    "reference_speed_rpm": 5000,
    "limiting_speed_rpm": 5600,
    "weight_g": 160,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF lists NX 35 for light, slow combined loads: the full complement thrust ball set gives the greatest axial capacity for the section, while the caged needle rollers take 24.6 kN radial. The NX 35 code gives only the 35 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 30 mm total height. Execution notes: the thrust part is filled with the maximum number of balls, giving the family's highest axial capacity, but the packed set needs a minimum axial load (factor A 0.0075) to keep every ball tracking its raceway. Speed ceilings differ by part: 5,000 r/min thermal reference and 5,600 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. The full complement thrust set has no cage to retain the balls — hold them with grease during assembly and never rotate the shaft before the axial preload (at least factor A 0.0075) is applied.",
    "applications": [
      "screw jack and lifting screw spindles",
      "valve and dosing pump stems with slow axial push",
      "light rotary tables under axial load",
      "oscillating pivots with steady axial preload"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Minimum axial load is a real requirement: below factor A 0.0075 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 24.6/45 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NX 35?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 35 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NX 35?",
        "a": "A NX 35 measures 35 mm bore/Fw × 47 mm outside diameter × 30 mm width (1.378 × 1.85 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.6 kN, static C0 45 kN, fatigue limit Pu 5.6 kN, limiting speed 5,600 r/min, reference speed 5,000 r/min, mass about 160 g. Axial ratings of the thrust part: dynamic Ca 13.5 kN (Ca), static C0a 38 kN (C0a), minimum load factor A 0.0075; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NX 35 designation read?",
        "a": "NX = needle roller radial part + full complement thrust ball part for a 35 mm shaft; the catalogue plan completes 47 mm OD and 30 mm overall height. The packed thrust set maximises axial capacity at low speed."
      },
      {
        "q": "Can the NX 35 run on an unhardened shaft?",
        "a": "The radial needle part of the NX 35 runs directly on the 35 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NX35-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 35×47×30 mm envelope and equivalent catalogue ratings; NX35-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "RNA6906",
        "equiv_brand": "SKF",
        "level": "partial",
        "note": "Same 35×47×30 mm envelope, but catalogue C/C0 differ between the executions (24.6/45 vs 42.9/75 kN) — boundary dimensions match, not a load-rating equivalent."
      },
      {
        "equiv_sku": "NKX35-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKX35",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR35",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR35-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (35×47×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NX35",
      "NX 35"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX10-ZTN",
    "brand": "SKF",
    "manufacturer_designation": "NKX 10 ZTN",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 19,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.94,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.9,
    "max_rpm": 8000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 8000,
    "weight_g": 36,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The combined needle roller / thrust ball bearings with caged thrust part execution NKX 10 ZTN measures 10×19×23 mm and carries radial load 5.94 kN dynamic plus one-direction axial load 9.95 kN (Ca) — the caged thrust part runs at higher speed than full complement NX types. The code NKX 10 ZTN reads as combined radial/thrust for a 10 mm shaft; the catalogue height 23 mm stacks the radial cage and the thrust set, and the 19 mm OD seats both parts in one bore. Execution notes: the Z suffix adds a shield over the thrust balls, TN a polymer cage; the open execution allows relubrication through the shaft, the Z execution is greased for life. Speed ceilings differ by part: 9,500 r/min thermal reference and 8,000 r/min limiting — the thrust element governs, since its washer faces see sliding components of contact. The caged thrust part survives moderate speed only with the Z shield intact — damaged shields admit grit straight into the ball raceways, and the narrow section leaves no margin.",
    "applications": [
      "machine tool feed spindles with one-direction thrust",
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force",
      "rotary indexing tables under combined load"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "false brinelling of standby equipment under external vibration",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not treat the axial rating 9.95 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKX 10 ZTN facing the working thrust.",
      "The 5.94/8 kN ratings and 36 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "What limits the service life of a NKX 10 ZTN?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 10 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      },
      {
        "q": "What are the dimensions and ratings of the NKX 10 ZTN?",
        "a": "A NKX 10 ZTN measures 10 mm bore/Fw × 19 mm outside diameter × 23 mm width (0.394 × 0.748 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.94 kN, static C0 8 kN, fatigue limit Pu 0.9 kN, limiting speed 8,000 r/min, reference speed 9,500 r/min, mass about 36 g. Axial ratings of the thrust part: dynamic Ca 9.95 kN (Ca), static C0a 15.3 kN (C0a), minimum load factor A 0.0012; the thrust set carries load in one direction only."
      },
      {
        "q": "How is the NKX 10 ZTN designation read?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 10 mm shaft: 19 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Can the NKX 10 ZTN run on an unhardened shaft?",
        "a": "The radial needle part of the NKX 10 ZTN runs directly on the 10 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX10-TN",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 10×19×23 mm envelope and equivalent catalogue ratings; NKX10-TN is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX10-ZTN",
      "NKX 10 ZTN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX10-TN",
    "brand": "SKF",
    "manufacturer_designation": "NKX 10 TN",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 10,
    "D_mm": 19,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "polymer_PA66",
    "dynamic_load_kN": 5.94,
    "static_load_kN": 8,
    "fatigue_load_limit_kN": 0.9,
    "max_rpm": 13000,
    "reference_speed_rpm": 9500,
    "limiting_speed_rpm": 13000,
    "weight_g": 34,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF supplies NKX 10 TN for combined-load positions at moderate speed: the caged thrust balls reduce friction and allow 9,500 r/min reference where a full complement NX would overheat. In SKF nomenclature NKX is the combined family: the number states 10 mm, and unlike NX the thrust balls are caged, trading some axial capacity for speed and friction. Execution notes: the Z suffix adds a shield over the thrust balls, TN a polymer cage; the open execution allows relubrication through the shaft, the Z execution is greased for life. Axial capability is one-direction: size the arrangement so working thrust pushes the thrust-washer face, and provide a mirrored unit or separate bearing for load reversals. The caged thrust part survives moderate speed only with the Z shield intact — damaged shields admit grit straight into the ball raceways, and the narrow section leaves no margin.",
    "applications": [
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force",
      "rotary indexing tables under combined load",
      "conveyor screw thrust ends"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 19 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKX 10 TN shares its 10×19×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Do not treat the axial rating 9.95 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKX 10 TN facing the working thrust.",
      "The 5.94/8 kN ratings and 34 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Which dimensions does the NKX 10 TN have?",
        "a": "A NKX 10 TN measures 10 mm bore/Fw × 19 mm outside diameter × 23 mm width (0.394 × 0.748 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 5.94 kN, static C0 8 kN, fatigue limit Pu 0.9 kN, limiting speed 13,000 r/min, reference speed 9,500 r/min, mass about 34 g. Axial ratings of the thrust part: dynamic Ca 9.95 kN (Ca), static C0a 15.3 kN (C0a), minimum load factor A 0.0012; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NKX 10 TN mean in SKF part numbering?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 10 mm shaft: 19 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Does the NKX 10 TN need a hardened and ground shaft?",
        "a": "The radial needle part of the NKX 10 TN runs directly on the 10 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "What mounting mistakes ruin a NKX 10 TN?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 10 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX10-ZTN",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 10×19×23 mm envelope and equivalent catalogue ratings; NKX10-ZTN is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX10-TN",
      "NKX 10 TN"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX12-Z",
    "brand": "SKF",
    "manufacturer_designation": "NKX 12 Z",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 21,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 7500,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 7500,
    "weight_g": 40,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKX 12 Z integrates two bearings in one envelope: needle rollers for the radial load on a 12 mm seat, and a cage-held thrust ball set for axial loads up to 10.4 kN (Ca) dynamic. In SKF nomenclature NKX is the combined family: the number states 12 mm, and unlike NX the thrust balls are caged, trading some axial capacity for speed and friction. The thrust part takes axial load in one direction only; mount it facing the working load and provide a separate locating bearing for reverse events. The minimum load factor A 0.0014 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. Apply the working axial load after mounting and re-check running torque; a rising torque in the first minutes signals balls climbing the washer lip under reversed thrust.",
    "applications": [
      "turntable and swivel mounts",
      "machine tool feed spindles with one-direction thrust",
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "abrasive paste formation from dust ingressing past open ends without effective housing seals",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 9.13/12 kN ratings are SKF catalogue values for this exact execution (NKX 12 Z); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Minimum axial load is a real requirement: below factor A 0.0014 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 9.13/12 kN ratings and 40 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKX 12 Z sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKX 12 Z have?",
        "a": "A NKX 12 Z measures 12 mm bore/Fw × 21 mm outside diameter × 23 mm width (0.472 × 0.827 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12 kN, fatigue limit Pu 1.43 kN, limiting speed 7,500 r/min, reference speed 9,000 r/min, mass about 40 g. Axial ratings of the thrust part: dynamic Ca 10.4 kN (Ca), static C0a 16.6 kN (C0a), minimum load factor A 0.0014; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NKX 12 Z mean in SKF part numbering?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 12 mm shaft: 21 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Does the NKX 12 Z need a hardened and ground shaft?",
        "a": "The radial needle part of the NKX 12 Z runs directly on the 12 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX12",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 12×21×23 mm envelope and equivalent catalogue ratings; NKX12 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX12-Z",
      "NKX 12 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX12",
    "brand": "SKF",
    "manufacturer_designation": "NKX 12",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 12,
    "D_mm": 21,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 9.13,
    "static_load_kN": 12,
    "fatigue_load_limit_kN": 1.43,
    "max_rpm": 13000,
    "reference_speed_rpm": 9000,
    "limiting_speed_rpm": 13000,
    "weight_g": 38,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "SKF supplies NKX 12 for combined-load positions at moderate speed: the caged thrust balls reduce friction and allow 9,000 r/min reference where a full complement NX would overheat. Reading the designation: NKX marks needle roller + caged thrust ball, the number the 12 mm shaft seat; the 21 mm OD and 23 mm overall height come from the series plan. Execution notes: the Z suffix adds a shield over the thrust balls, TN a polymer cage; the open execution allows relubrication through the shaft, the Z execution is greased for life. Axial capability is one-direction: size the arrangement so working thrust pushes the thrust-washer face, and provide a mirrored unit or separate bearing for load reversals. The caged thrust part survives moderate speed only with the Z shield intact — damaged shields admit grit straight into the ball raceways, and the narrow section leaves no margin.",
    "applications": [
      "turntable and swivel mounts",
      "machine tool feed spindles with one-direction thrust",
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "false brinelling of standby equipment under external vibration",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 21 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "The quoted 9.13/12 kN ratings are SKF catalogue values for this exact execution (NKX 12); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.",
      "Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.",
      "Minimum axial load is a real requirement: below factor A 0.0014 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "The 9.13/12 kN ratings and 38 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKX 12 sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKX 12 have?",
        "a": "A NKX 12 measures 12 mm bore/Fw × 21 mm outside diameter × 23 mm width (0.472 × 0.827 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.13 kN, static C0 12 kN, fatigue limit Pu 1.43 kN, limiting speed 13,000 r/min, reference speed 9,000 r/min, mass about 38 g. Axial ratings of the thrust part: dynamic Ca 10.4 kN (Ca), static C0a 16.6 kN (C0a), minimum load factor A 0.0014; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NKX 12 mean in SKF part numbering?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 12 mm shaft: 21 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Does the NKX 12 need a hardened and ground shaft?",
        "a": "The radial needle part of the NKX 12 runs directly on the 12 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX12-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 12×21×23 mm envelope and equivalent catalogue ratings; NKX12-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX12",
      "NKX 12"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX15-Z",
    "brand": "SKF",
    "manufacturer_designation": "NKX 15 Z",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 24,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11,
    "static_load_kN": 14,
    "fatigue_load_limit_kN": 1.66,
    "max_rpm": 7000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 7000,
    "weight_g": 47,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "NKX 15 Z is a combined needle roller / thrust ball bearing with a caged thrust part: radial load on caged needle rollers, axial load on a ball thrust set with stamped cages, per SKF catalogue PUB BU/P1 17000 ch. 7.9. In SKF nomenclature NKX is the combined family: the number states 15 mm, and unlike NX the thrust balls are caged, trading some axial capacity for speed and friction. The thrust part takes axial load in one direction only; mount it facing the working load and provide a separate locating bearing for reverse events. Axial capability is one-direction: size the arrangement so working thrust pushes the thrust-washer face, and provide a mirrored unit or separate bearing for load reversals. Apply the working axial load after mounting and re-check running torque; a rising torque in the first minutes signals balls climbing the washer lip under reversed thrust.",
    "applications": [
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force",
      "rotary indexing tables under combined load",
      "conveyor screw thrust ends"
    ],
    "failure_modes": [
      "needle edge loading and raceway denting when the shaft deflects beyond the compensation range",
      "cage pocket wear and roller skew after sustained operation with too little radial preload",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "electrical erosion on VFD-driven shafts without brush or insulated mounting",
      "thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.",
      "Do not interchange envelope-identical needle families blindly: NKX 15 Z shares its 15×24×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Do not treat the axial rating 10.6 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NKX 15 Z facing the working thrust.",
      "The 11/14 kN ratings and 47 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "Is the NKX 15 Z sealed?",
        "a": "No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty."
      },
      {
        "q": "Which dimensions does the NKX 15 Z have?",
        "a": "A NKX 15 Z measures 15 mm bore/Fw × 24 mm outside diameter × 23 mm width (0.591 × 0.945 × 0.906 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11 kN, static C0 14 kN, fatigue limit Pu 1.66 kN, limiting speed 7,000 r/min, reference speed 8,500 r/min, mass about 47 g. Axial ratings of the thrust part: dynamic Ca 10.6 kN (Ca), static C0a 18.3 kN (C0a), minimum load factor A 0.0017; the thrust set carries load in one direction only."
      },
      {
        "q": "What does NKX 15 Z mean in SKF part numbering?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 15 mm shaft: 24 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Does the NKX 15 Z need a hardened and ground shaft?",
        "a": "The radial needle part of the NKX 15 Z runs directly on the 15 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX15",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 15×24×23 mm envelope and equivalent catalogue ratings; NKX15 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "NKXR15",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (15×24×23 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR15-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (15×24×23 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX15-Z",
      "NKX 15 Z"
    ],
    "locale_variants": {}
  },
  {
    "sku": "NKX15",
    "brand": "SKF",
    "manufacturer_designation": "NKX 15",
    "series": "NKX-series",
    "type": "needle",
    "d_mm": 15,
    "D_mm": 24,
    "B_mm": 23,
    "material": "GCr15",
    "seal_type": "open",
    "clearance": "CN",
    "tolerance_class": "P0",
    "cage_type": "none",
    "dynamic_load_kN": 11,
    "static_load_kN": 14,
    "fatigue_load_limit_kN": 1.66,
    "max_rpm": 12000,
    "reference_speed_rpm": 8500,
    "limiting_speed_rpm": 12000,
    "weight_g": 44,
    "weight_estimated": false,
    "temp_min_c": -40,
    "temp_max_c": 120,
    "standard": "DIN 616",
    "naming_rule_text": "The combined needle roller / thrust ball bearings with caged thrust part execution NKX 15 measures 15×24×23 mm and carries radial load 11 kN dynamic plus one-direction axial load 10.6 kN (Ca) — the caged thrust part runs at higher speed than full complement NX types. The code NKX 15 reads as combined radial/thrust for a 15 mm shaft; the catalogue height 23 mm stacks the radial cage and the thrust set, and the 24 mm OD seats both parts in one bore. Execution notes: the Z suffix adds a shield over the thrust balls, TN a polymer cage; the open execution allows relubrication through the shaft, the Z execution is greased for life. The minimum load factor A 0.0017 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. The caged thrust part survives moderate speed only with the Z shield intact — damaged shields admit grit straight into the ball raceways, and the narrow section leaves no margin.",
    "applications": [
      "turntable and swivel mounts",
      "machine tool feed spindles with one-direction thrust",
      "pump impeller shafts with steady axial pull",
      "gear pairs generating one-direction axial force"
    ],
    "failure_modes": [
      "raceway spalling once the catalogue L10 life is exceeded or after overload events",
      "polymer cage deformation when the local temperature exceeds the 120 °C sustained limit",
      "grease starvation at the roller ends when relubrication intervals are stretched in dirty duty",
      "brinelling of raceways from impact or pressing force transmitted through the rolling elements",
      "thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry"
    ],
    "pitfalls": [
      "On a 15 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.",
      "Do not interchange envelope-identical needle families blindly: NKX 15 shares its 15×24×23 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.",
      "Reference and limiting speeds are different limits: the 8,500 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.",
      "Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.",
      "Do not treat the axial rating 10.6 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.",
      "The 11/14 kN ratings and 44 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only."
    ],
    "faq": [
      {
        "q": "How is the NKX 15 designation read?",
        "a": "NKX = needle roller radial part + caged thrust ball part for a 15 mm shaft: 24 mm OD, 23 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX."
      },
      {
        "q": "Can the NKX 15 run on an unhardened shaft?",
        "a": "The radial needle part of the NKX 15 runs directly on the 15 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table."
      },
      {
        "q": "How should the NKX 15 be mounted?",
        "a": "Press on the ring faces only with a fitting sleeve, keep everything square to the 15 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs."
      },
      {
        "q": "What limits the service life of a NKX 15?",
        "a": "Beyond the L10 rating, the practical limits are journal/raceway hardness for the 15 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.5 mm radial section leaves no reserve once a raceway is dented or ribboned."
      }
    ],
    "cross_ref": [
      {
        "equiv_sku": "NKX15-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Same 15×24×23 mm envelope and equivalent catalogue ratings; NKX15-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply."
      },
      {
        "equiv_sku": "NKXR15",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (15×24×23 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      },
      {
        "equiv_sku": "NKXR15-Z",
        "equiv_brand": "SKF",
        "level": "full",
        "note": "Envelope-identical (15×24×23 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction."
      }
    ],
    "source_ref": "https://www.skf.com/group/products/rolling-bearings/needle-roller-bearings",
    "catalog_ver": "SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part",
    "extracted_at": "2026-09-26",
    "last_verified": "2026-09-26",
    "confidence_score": 0.7,
    "status": "published",
    "aliases": [
      "NKX15",
      "NKX 15"
    ],
    "locale_variants": {}
  }
]