[ { "sku": "NU204", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 20, "D_mm": 47, "B_mm": 14, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 101, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU204 are bore code 04 = 20 mm (code × 5 from 04 upward). The ISO 15 envelope is 47 mm outside diameter and 14 mm width — 0.787 × 1.85 × 0.551 in, with a 13.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "textile and packaging machinery rolls", "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "At 20 mm bore the small NU204 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU2 light series at 20 mm bore (47×14 mm) is the default gearbox cylindrical row; on the same bore an NU304 is larger with a much higher rating — do not replace a failed NU304 with an NU204 without re-rating L10 life.", "Before fitting NU204, machine the 20 mm shaft seat and 47 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 13.5 mm radial section.", "With a separable NU204, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU204 with the shaft turning so fresh grease or oil reaches the full 14 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 20 mm bore starved.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 20 mm inner ring home through the rollers brinells the 47 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 20 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU204 cylindrical roller bearing?", "a": "An NU204 single-row cylindrical roller bearing per ISO 15 has a 20 mm bore, 47 mm outer diameter and 14 mm width (0.787 × 1.85 × 0.551 in), a 13.5 mm radial section and roughly 101 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU204 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 04: 04 × 5 = 20 mm. The 47 mm OD and 14 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU204) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU204 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU204E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 20×47×14 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6204", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6204-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6204-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6204-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU204E", "NU204-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU205", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 25, "D_mm": 52, "B_mm": 15, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 125, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU205 are bore code 05 = 25 mm (code × 5 from 04 upward). The ISO 15 envelope is 52 mm outside diameter and 15 mm width — 0.984 × 2.047 × 0.591 in, with a 13.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "At 25 mm bore the small NU205 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU2 light series at 25 mm bore (52×15 mm) is the default gearbox cylindrical row; on the same bore an NU305 is larger with a much higher rating — do not replace a failed NU305 with an NU205 without re-rating L10 life.", "Check the shoulder geometry for NU205: a generous fillet on the 25 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 52 mm, 15 mm-wide housing bore.", "Large NU205 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 25 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 15 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU205 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 25 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Order clearance for the fit: a rotating interference inner ring on a 25 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU205; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU205 cylindrical roller bearing?", "a": "An NU205 single-row cylindrical roller bearing per ISO 15 has a 25 mm bore, 52 mm outer diameter and 15 mm width (0.984 × 2.047 × 0.591 in), a 13.5 mm radial section and roughly 125 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU205 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 05: 05 × 5 = 25 mm. The 52 mm OD and 15 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU205) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU205 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU205E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 25×52×15 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6205", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6205-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6205-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6205-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU205E", "NU205-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU206", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 30, "D_mm": 62, "B_mm": 16, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 189, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU206 are bore code 06 = 30 mm (code × 5 from 04 upward). The ISO 15 envelope is 62 mm outside diameter and 16 mm width — 1.181 × 2.441 × 0.63 in, with a 16.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "At 30 mm bore the small NU206 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU2 light series at 30 mm bore (62×16 mm) is the default gearbox cylindrical row; on the same bore an NU306 is larger with a much higher rating — do not replace a failed NU306 with an NU206 without re-rating L10 life.", "The 16 mm-wide NU206 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 30 mm bore and 62 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 16.0 mm section.", "For the interference inner ring of NU206, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 30 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 62 mm ring dents the raceways.", "Read the damage on a removed NU206: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 62 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU206; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU206: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 30 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU206 cylindrical roller bearing?", "a": "An NU206 single-row cylindrical roller bearing per ISO 15 has a 30 mm bore, 62 mm outer diameter and 16 mm width (1.181 × 2.441 × 0.63 in), a 16.0 mm radial section and roughly 189 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU206 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 06: 06 × 5 = 30 mm. The 62 mm OD and 16 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU206) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU206 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU206E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 30×62×16 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6206", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6206-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6206-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6206-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU206E", "NU206-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU207", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 35, "D_mm": 72, "B_mm": 17, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 270, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU207 are bore code 07 = 35 mm (code × 5 from 04 upward). The ISO 15 envelope is 72 mm outside diameter and 17 mm width — 1.378 × 2.835 × 0.669 in, with a 18.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "At 35 mm bore the small NU207 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU2 light series at 35 mm bore (72×17 mm) is the default gearbox cylindrical row; on the same bore an NU307 is larger with a much higher rating — do not replace a failed NU307 with an NU207 without re-rating L10 life.", "Before fitting NU207, machine the 35 mm shaft seat and 72 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 18.5 mm radial section.", "With a separable NU207, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU207 with the shaft turning so fresh grease or oil reaches the full 17 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 35 mm bore starved.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU207: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 35 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU207 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU207 cylindrical roller bearing?", "a": "An NU207 single-row cylindrical roller bearing per ISO 15 has a 35 mm bore, 72 mm outer diameter and 17 mm width (1.378 × 2.835 × 0.669 in), a 18.5 mm radial section and roughly 270 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU207 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 07: 07 × 5 = 35 mm. The 72 mm OD and 17 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU207) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU207 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU207E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 35×72×17 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6207-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6207", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6207-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6207-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU207E", "NU207-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU208", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 40, "D_mm": 80, "B_mm": 18, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 346, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU208 are bore code 08 = 40 mm (code × 5 from 04 upward). The ISO 15 envelope is 80 mm outside diameter and 18 mm width — 1.575 × 3.15 × 0.709 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "On this 40 mm-bore NU208, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 40 mm shaft reaches operating temperature.", "The NU2 light series at 40 mm bore (80×18 mm) is the default gearbox cylindrical row; on the same bore an NU308 is larger with a much higher rating — do not replace a failed NU308 with an NU208 without re-rating L10 life.", "Check the shoulder geometry for NU208: a generous fillet on the 40 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 80 mm, 18 mm-wide housing bore.", "Large NU208 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 40 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 18 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU208 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 40 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Choose the ring design for the locating task: a plain NU208 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 18 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 80 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU208 cylindrical roller bearing?", "a": "An NU208 single-row cylindrical roller bearing per ISO 15 has a 40 mm bore, 80 mm outer diameter and 18 mm width (1.575 × 3.15 × 0.709 in), a 20.0 mm radial section and roughly 346 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU208 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 08: 08 × 5 = 40 mm. The 80 mm OD and 18 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU208) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU208 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU208E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 40×80×18 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6208", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6208-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6208-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6208-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU208E", "NU208-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU209", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 45, "D_mm": 85, "B_mm": 19, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 396, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU209 are bore code 09 = 45 mm (code × 5 from 04 upward). The ISO 15 envelope is 85 mm outside diameter and 19 mm width — 1.772 × 3.346 × 0.748 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "On this 45 mm-bore NU209, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 45 mm shaft reaches operating temperature.", "The NU2 light series at 45 mm bore (85×19 mm) is the default gearbox cylindrical row; on the same bore an NU309 is larger with a much higher rating — do not replace a failed NU309 with an NU209 without re-rating L10 life.", "The 19 mm-wide NU209 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 45 mm bore and 85 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 20.0 mm section.", "For the interference inner ring of NU209, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 45 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 85 mm ring dents the raceways.", "Read the damage on a removed NU209: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 85 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Cylindrical rollers have no self-aligning capacity: line contact across the 19 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 85 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU209 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU209 cylindrical roller bearing?", "a": "An NU209 single-row cylindrical roller bearing per ISO 15 has a 45 mm bore, 85 mm outer diameter and 19 mm width (1.772 × 3.346 × 0.748 in), a 20.0 mm radial section and roughly 396 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU209 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 09: 09 × 5 = 45 mm. The 85 mm OD and 19 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU209) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU209 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU209E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 45×85×19 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6209-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6209", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6209-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6209-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU209E", "NU209-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU210", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 50, "D_mm": 90, "B_mm": 20, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 449, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU210 are bore code 10 = 50 mm (code × 5 from 04 upward). The ISO 15 envelope is 90 mm outside diameter and 20 mm width — 1.969 × 3.543 × 0.787 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "On this 50 mm-bore NU210, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 50 mm shaft reaches operating temperature.", "The NU2 light series at 50 mm bore (90×20 mm) is the default gearbox cylindrical row; on the same bore an NU310 is larger with a much higher rating — do not replace a failed NU310 with an NU210 without re-rating L10 life.", "Before fitting NU210, machine the 50 mm shaft seat and 90 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 20.0 mm radial section.", "With a separable NU210, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU210 with the shaft turning so fresh grease or oil reaches the full 20 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 50 mm bore starved.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU210 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU210 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 50×90 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU210 cylindrical roller bearing?", "a": "An NU210 single-row cylindrical roller bearing per ISO 15 has a 50 mm bore, 90 mm outer diameter and 20 mm width (1.969 × 3.543 × 0.787 in), a 20.0 mm radial section and roughly 449 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU210 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 10: 10 × 5 = 50 mm. The 90 mm OD and 20 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU210) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU210 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU210E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 50×90×20 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6210-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6210", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6210-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6210-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU210E", "NU210-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU211", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 55, "D_mm": 100, "B_mm": 21, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 587, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU211 are bore code 11 = 55 mm (code × 5 from 04 upward). The ISO 15 envelope is 100 mm outside diameter and 21 mm width — 2.165 × 3.937 × 0.827 in, with a 22.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "On this 55 mm-bore NU211, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 55 mm shaft reaches operating temperature.", "The NU2 light series at 55 mm bore (100×21 mm) is the default gearbox cylindrical row; on the same bore an NU311 is larger with a much higher rating — do not replace a failed NU311 with an NU211 without re-rating L10 life.", "Check the shoulder geometry for NU211: a generous fillet on the 55 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 100 mm, 21 mm-wide housing bore.", "Large NU211 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 55 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 21 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU211 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 55 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The rings of an NU211 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 55×100 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 55 mm inner ring home through the rollers brinells the 100 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU211 cylindrical roller bearing?", "a": "An NU211 single-row cylindrical roller bearing per ISO 15 has a 55 mm bore, 100 mm outer diameter and 21 mm width (2.165 × 3.937 × 0.827 in), a 22.5 mm radial section and roughly 587 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU211 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 11: 11 × 5 = 55 mm. The 100 mm OD and 21 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU211) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU211 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU211E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 55×100×21 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6211-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6211", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6211-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6211-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU211E", "NU211-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU212", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 60, "D_mm": 110, "B_mm": 22, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 749, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU212 are bore code 12 = 60 mm (code × 5 from 04 upward). The ISO 15 envelope is 110 mm outside diameter and 22 mm width — 2.362 × 4.331 × 0.866 in, with a 25.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "On this 60 mm-bore NU212, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 60 mm shaft reaches operating temperature.", "The NU2 light series at 60 mm bore (110×22 mm) is the default gearbox cylindrical row; on the same bore an NU312 is larger with a much higher rating — do not replace a failed NU312 with an NU212 without re-rating L10 life.", "The 22 mm-wide NU212 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 60 mm bore and 110 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 25.0 mm section.", "For the interference inner ring of NU212, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 60 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 110 mm ring dents the raceways.", "Read the damage on a removed NU212: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 110 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 60 mm inner ring home through the rollers brinells the 110 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 60 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU212 cylindrical roller bearing?", "a": "An NU212 single-row cylindrical roller bearing per ISO 15 has a 60 mm bore, 110 mm outer diameter and 22 mm width (2.362 × 4.331 × 0.866 in), a 25.0 mm radial section and roughly 749 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU212 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 12: 12 × 5 = 60 mm. The 110 mm OD and 22 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU212) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU212 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU212E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 60×110×22 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6212-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6212", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6212-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6212-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU212E", "NU212-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU213", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 65, "D_mm": 120, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 938, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU213 are bore code 13 = 65 mm (code × 5 from 04 upward). The ISO 15 envelope is 120 mm outside diameter and 23 mm width — 2.559 × 4.724 × 0.906 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "On this 65 mm-bore NU213, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 65 mm shaft reaches operating temperature.", "The NU2 light series at 65 mm bore (120×23 mm) is the default gearbox cylindrical row; on the same bore an NU313 is larger with a much higher rating — do not replace a failed NU313 with an NU213 without re-rating L10 life.", "Before fitting NU213, machine the 65 mm shaft seat and 120 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 27.5 mm radial section.", "With a separable NU213, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU213 with the shaft turning so fresh grease or oil reaches the full 23 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 65 mm bore starved.", "Order clearance for the fit: a rotating interference inner ring on a 65 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU213; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU213 cylindrical roller bearing?", "a": "An NU213 single-row cylindrical roller bearing per ISO 15 has a 65 mm bore, 120 mm outer diameter and 23 mm width (2.559 × 4.724 × 0.906 in), a 27.5 mm radial section and roughly 938 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU213 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 13: 13 × 5 = 65 mm. The 120 mm OD and 23 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU213) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU213 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU213E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 65×120×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6213-2RS", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6213-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6213", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6213-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU213E", "NU213-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU214", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 70, "D_mm": 125, "B_mm": 24, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1032, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU214 are bore code 14 = 70 mm (code × 5 from 04 upward). The ISO 15 envelope is 125 mm outside diameter and 24 mm width — 2.756 × 4.921 × 0.945 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "On this 70 mm-bore NU214, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 70 mm shaft reaches operating temperature.", "The NU2 light series at 70 mm bore (125×24 mm) is the default gearbox cylindrical row; on the same bore an NU314 is larger with a much higher rating — do not replace a failed NU314 with an NU214 without re-rating L10 life.", "Check the shoulder geometry for NU214: a generous fillet on the 70 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 125 mm, 24 mm-wide housing bore.", "Large NU214 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 70 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 24 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU214 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 70 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU214; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU214: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 70 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU214 cylindrical roller bearing?", "a": "An NU214 single-row cylindrical roller bearing per ISO 15 has a 70 mm bore, 125 mm outer diameter and 24 mm width (2.756 × 4.921 × 0.945 in), a 27.5 mm radial section and roughly 1032 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU214 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 14: 14 × 5 = 70 mm. The 125 mm OD and 24 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU214) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU214 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU214E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 70×125×24 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6214-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6214", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6214-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6214-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU214E", "NU214-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU215", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 75, "D_mm": 130, "B_mm": 25, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1130, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU215 are bore code 15 = 75 mm (code × 5 from 04 upward). The ISO 15 envelope is 130 mm outside diameter and 25 mm width — 2.953 × 5.118 × 0.984 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "On this 75 mm-bore NU215, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 75 mm shaft reaches operating temperature.", "The NU2 light series at 75 mm bore (130×25 mm) is the default gearbox cylindrical row; on the same bore an NU315 is larger with a much higher rating — do not replace a failed NU315 with an NU215 without re-rating L10 life.", "The 25 mm-wide NU215 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 75 mm bore and 130 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 27.5 mm section.", "For the interference inner ring of NU215, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 75 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 130 mm ring dents the raceways.", "Read the damage on a removed NU215: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 130 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU215: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 75 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU215 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU215 cylindrical roller bearing?", "a": "An NU215 single-row cylindrical roller bearing per ISO 15 has a 75 mm bore, 130 mm outer diameter and 25 mm width (2.953 × 5.118 × 0.984 in), a 27.5 mm radial section and roughly 1130 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU215 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 15: 15 × 5 = 75 mm. The 130 mm OD and 25 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU215) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU215 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU215E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 75×130×25 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6215-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6215", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6215-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6215-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU215E", "NU215-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU216", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 80, "D_mm": 140, "B_mm": 26, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1375, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU216 are bore code 16 = 80 mm (code × 5 from 04 upward). The ISO 15 envelope is 140 mm outside diameter and 26 mm width — 3.15 × 5.512 × 1.024 in, with a 30.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "heavy crane and winch drums", "large fan and paper machine rolls", "rolling mill roll necks and chocks", "large gear drives and reducer shafts", "cement and mining machinery drives" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "The large 80 mm-bore NU216 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 140 mm outer ring squarely, and plan lifting fixtures for the 26 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU2 light series at 80 mm bore (140×26 mm) is the default gearbox cylindrical row; on the same bore an NU316 is larger with a much higher rating — do not replace a failed NU316 with an NU216 without re-rating L10 life.", "Before fitting NU216, machine the 80 mm shaft seat and 140 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 30.0 mm radial section.", "With a separable NU216, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU216 with the shaft turning so fresh grease or oil reaches the full 26 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 80 mm bore starved.", "Choose the ring design for the locating task: a plain NU216 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 26 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 140 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU216 cylindrical roller bearing?", "a": "An NU216 single-row cylindrical roller bearing per ISO 15 has a 80 mm bore, 140 mm outer diameter and 26 mm width (3.15 × 5.512 × 1.024 in), a 30.0 mm radial section and roughly 1375 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU216 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 16: 16 × 5 = 80 mm. The 140 mm OD and 26 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU216) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU216 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU216E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 80×140×26 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6216-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6216", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6216-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6216-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU216E", "NU216-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU217", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 85, "D_mm": 150, "B_mm": 28, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1714, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU217 are bore code 17 = 85 mm (code × 5 from 04 upward). The ISO 15 envelope is 150 mm outside diameter and 28 mm width — 3.346 × 5.906 × 1.102 in, with a 32.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "large fan and paper machine rolls", "rolling mill roll necks and chocks", "large gear drives and reducer shafts", "cement and mining machinery drives", "crusher eccentric and drum shafts" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "The large 85 mm-bore NU217 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 150 mm outer ring squarely, and plan lifting fixtures for the 28 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU2 light series at 85 mm bore (150×28 mm) is the default gearbox cylindrical row; on the same bore an NU317 is larger with a much higher rating — do not replace a failed NU317 with an NU217 without re-rating L10 life.", "Check the shoulder geometry for NU217: a generous fillet on the 85 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 150 mm, 28 mm-wide housing bore.", "Large NU217 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 85 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 28 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU217 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 85 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Cylindrical rollers have no self-aligning capacity: line contact across the 28 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 150 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU217 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU217 cylindrical roller bearing?", "a": "An NU217 single-row cylindrical roller bearing per ISO 15 has a 85 mm bore, 150 mm outer diameter and 28 mm width (3.346 × 5.906 × 1.102 in), a 32.5 mm radial section and roughly 1714 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU217 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 17: 17 × 5 = 85 mm. The 150 mm OD and 28 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU217) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU217 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU217E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 85×150×28 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6217-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6217", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6217-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6217-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU217E", "NU217-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU218", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 90, "D_mm": 160, "B_mm": 30, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2104, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU218 are bore code 18 = 90 mm (code × 5 from 04 upward). The ISO 15 envelope is 160 mm outside diameter and 30 mm width — 3.543 × 6.299 × 1.181 in, with a 35.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "rolling mill roll necks and chocks", "large gear drives and reducer shafts", "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "The large 90 mm-bore NU218 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 160 mm outer ring squarely, and plan lifting fixtures for the 30 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU2 light series at 90 mm bore (160×30 mm) is the default gearbox cylindrical row; on the same bore an NU318 is larger with a much higher rating — do not replace a failed NU318 with an NU218 without re-rating L10 life.", "The 30 mm-wide NU218 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 90 mm bore and 160 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 35.0 mm section.", "For the interference inner ring of NU218, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 90 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 160 mm ring dents the raceways.", "Read the damage on a removed NU218: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 160 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU218 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU218 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 90×160 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU218 cylindrical roller bearing?", "a": "An NU218 single-row cylindrical roller bearing per ISO 15 has a 90 mm bore, 160 mm outer diameter and 30 mm width (3.543 × 6.299 × 1.181 in), a 35.0 mm radial section and roughly 2104 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU218 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 18: 18 × 5 = 90 mm. The 160 mm OD and 30 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU218) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU218 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU218E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 90×160×30 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6218-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6218", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6218-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6218-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU218E", "NU218-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU219", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 95, "D_mm": 170, "B_mm": 32, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2549, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU219 are bore code 19 = 95 mm (code × 5 from 04 upward). The ISO 15 envelope is 170 mm outside diameter and 32 mm width — 3.74 × 6.693 × 1.26 in, with a 37.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "large gear drives and reducer shafts", "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums", "large fan and paper machine rolls" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "The large 95 mm-bore NU219 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 170 mm outer ring squarely, and plan lifting fixtures for the 32 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU2 light series at 95 mm bore (170×32 mm) is the default gearbox cylindrical row; on the same bore an NU319 is larger with a much higher rating — do not replace a failed NU319 with an NU219 without re-rating L10 life.", "Before fitting NU219, machine the 95 mm shaft seat and 170 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 37.5 mm radial section.", "With a separable NU219, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU219 with the shaft turning so fresh grease or oil reaches the full 32 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 95 mm bore starved.", "The rings of an NU219 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 95×170 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 95 mm inner ring home through the rollers brinells the 170 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU219 cylindrical roller bearing?", "a": "An NU219 single-row cylindrical roller bearing per ISO 15 has a 95 mm bore, 170 mm outer diameter and 32 mm width (3.74 × 6.693 × 1.26 in), a 37.5 mm radial section and roughly 2549 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU219 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 19: 19 × 5 = 95 mm. The 170 mm OD and 32 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU219) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU219 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU219E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 95×170×32 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6219-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6219", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6219-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6219-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU219E", "NU219-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU220", "brand": "GENERIC-ISO", "series": "NU200-series", "type": "cylindrical_roller", "d_mm": 100, "D_mm": 180, "B_mm": 34, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 3052, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU220 are bore code 20 = 100 mm (code × 5 from 04 upward). The ISO 15 envelope is 180 mm outside diameter and 34 mm width — 3.937 × 7.087 × 1.339 in, with a 40.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums", "large fan and paper machine rolls", "rolling mill roll necks and chocks" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "The large 100 mm-bore NU220 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 180 mm outer ring squarely, and plan lifting fixtures for the 34 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU2 light series at 100 mm bore (180×34 mm) is the default gearbox cylindrical row; on the same bore an NU320 is larger with a much higher rating — do not replace a failed NU320 with an NU220 without re-rating L10 life.", "Check the shoulder geometry for NU220: a generous fillet on the 100 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 180 mm, 34 mm-wide housing bore.", "Large NU220 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 100 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 34 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU220 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 100 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 100 mm inner ring home through the rollers brinells the 180 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 100 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU220 cylindrical roller bearing?", "a": "An NU220 single-row cylindrical roller bearing per ISO 15 has a 100 mm bore, 180 mm outer diameter and 34 mm width (3.937 × 7.087 × 1.339 in), a 40.0 mm radial section and roughly 3052 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU220 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 20: 20 × 5 = 100 mm. The 180 mm OD and 34 mm width come from the ISO 15 dimension series (NU200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU220) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU220 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU220E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 100×180×34 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6220-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6220", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6220-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6220-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU220E", "NU220-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU304", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 20, "D_mm": 52, "B_mm": 15, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 138, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU304 are bore code 04 = 20 mm (code × 5 from 04 upward). The ISO 15 envelope is 52 mm outside diameter and 15 mm width — 0.787 × 2.047 × 0.591 in, with a 16.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "At 20 mm bore the small NU304 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU3 medium series at 20 mm bore uses the 52 mm OD and 15 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU204, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU304, machine the 20 mm shaft seat and 52 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 16.0 mm radial section.", "With a separable NU304, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU304 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 20 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Order clearance for the fit: a rotating interference inner ring on a 20 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU304; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU304 cylindrical roller bearing?", "a": "An NU304 single-row cylindrical roller bearing per ISO 15 has a 20 mm bore, 52 mm outer diameter and 15 mm width (0.787 × 2.047 × 0.591 in), a 16.0 mm radial section and roughly 138 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU304 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 04: 04 × 5 = 20 mm. The 52 mm OD and 15 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU304) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU304 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU304E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 20×52×15 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6304", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6304-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6304-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6304-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU304E", "NU304-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU305", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 25, "D_mm": 62, "B_mm": 17, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 219, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU305 are bore code 05 = 25 mm (code × 5 from 04 upward). The ISO 15 envelope is 62 mm outside diameter and 17 mm width — 0.984 × 2.441 × 0.669 in, with a 18.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "At 25 mm bore the small NU305 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU3 medium series at 25 mm bore uses the 62 mm OD and 17 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU205, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU305: a generous fillet on the 25 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 62 mm, 17 mm-wide housing bore.", "Large NU305 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 25 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 17 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU305: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 62 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU305; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU305: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 25 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU305 cylindrical roller bearing?", "a": "An NU305 single-row cylindrical roller bearing per ISO 15 has a 25 mm bore, 62 mm outer diameter and 17 mm width (0.984 × 2.441 × 0.669 in), a 18.5 mm radial section and roughly 219 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU305 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 05: 05 × 5 = 25 mm. The 62 mm OD and 17 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU305) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU305 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU305E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 25×62×17 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6305", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6305-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6305-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6305-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU305E", "NU305-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU306", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 30, "D_mm": 72, "B_mm": 19, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 326, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU306 are bore code 06 = 30 mm (code × 5 from 04 upward). The ISO 15 envelope is 72 mm outside diameter and 19 mm width — 1.181 × 2.835 × 0.748 in, with a 21.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts", "small gearbox layshafts and pinion shafts" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "At 30 mm bore the small NU306 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU3 medium series at 30 mm bore uses the 72 mm OD and 19 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU206, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "The 19 mm-wide NU306 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 30 mm bore and 72 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 21.0 mm section.", "For the interference inner ring of NU306, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 30 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 72 mm ring dents the raceways.", "Relubricate NU306 with the shaft turning so fresh grease or oil reaches the full 19 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 30 mm bore starved.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU306: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 30 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU306 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU306 cylindrical roller bearing?", "a": "An NU306 single-row cylindrical roller bearing per ISO 15 has a 30 mm bore, 72 mm outer diameter and 19 mm width (1.181 × 2.835 × 0.748 in), a 21.0 mm radial section and roughly 326 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU306 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 06: 06 × 5 = 30 mm. The 72 mm OD and 19 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU306) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU306 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU306E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 30×72×19 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6306", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6306-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6306-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6306-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU306E", "NU306-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU307", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 35, "D_mm": 80, "B_mm": 21, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 436, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU307 are bore code 07 = 35 mm (code × 5 from 04 upward). The ISO 15 envelope is 80 mm outside diameter and 21 mm width — 1.378 × 3.15 × 0.827 in, with a 22.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "At 35 mm bore the small NU307 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU3 medium series at 35 mm bore uses the 80 mm OD and 21 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU207, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU307, machine the 35 mm shaft seat and 80 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 22.5 mm radial section.", "With a separable NU307, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU307 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 35 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Choose the ring design for the locating task: a plain NU307 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 21 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 80 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU307 cylindrical roller bearing?", "a": "An NU307 single-row cylindrical roller bearing per ISO 15 has a 35 mm bore, 80 mm outer diameter and 21 mm width (1.378 × 3.15 × 0.827 in), a 22.5 mm radial section and roughly 436 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU307 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 07: 07 × 5 = 35 mm. The 80 mm OD and 21 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU307) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU307 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU307E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 35×80×21 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6307-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6307", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6307-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6307-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU307E", "NU307-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU308", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 40, "D_mm": 90, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 599, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU308 are bore code 08 = 40 mm (code × 5 from 04 upward). The ISO 15 envelope is 90 mm outside diameter and 23 mm width — 1.575 × 3.543 × 0.906 in, with a 25.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "On this 40 mm-bore NU308, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 40 mm shaft reaches operating temperature.", "The NU3 medium series at 40 mm bore uses the 90 mm OD and 23 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU208, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU308: a generous fillet on the 40 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 90 mm, 23 mm-wide housing bore.", "Large NU308 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 40 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 23 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU308: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 90 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Cylindrical rollers have no self-aligning capacity: line contact across the 23 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 90 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU308 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU308 cylindrical roller bearing?", "a": "An NU308 single-row cylindrical roller bearing per ISO 15 has a 40 mm bore, 90 mm outer diameter and 23 mm width (1.575 × 3.543 × 0.906 in), a 25.0 mm radial section and roughly 599 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU308 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 08: 08 × 5 = 40 mm. The 90 mm OD and 23 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU308) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU308 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU308E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 40×90×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6308", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6308-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6308-RSR", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6308-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU308E", "NU308-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU309", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 45, "D_mm": 100, "B_mm": 25, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 799, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU309 are bore code 09 = 45 mm (code × 5 from 04 upward). The ISO 15 envelope is 100 mm outside diameter and 25 mm width — 1.772 × 3.937 × 0.984 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "On this 45 mm-bore NU309, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 45 mm shaft reaches operating temperature.", "The NU3 medium series at 45 mm bore uses the 100 mm OD and 25 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU209, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "The 25 mm-wide NU309 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 45 mm bore and 100 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 27.5 mm section.", "For the interference inner ring of NU309, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 45 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 100 mm ring dents the raceways.", "Relubricate NU309 with the shaft turning so fresh grease or oil reaches the full 25 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 45 mm bore starved.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU309 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU309 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 45×100 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU309 cylindrical roller bearing?", "a": "An NU309 single-row cylindrical roller bearing per ISO 15 has a 45 mm bore, 100 mm outer diameter and 25 mm width (1.772 × 3.937 × 0.984 in), a 27.5 mm radial section and roughly 799 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU309 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 09: 09 × 5 = 45 mm. The 100 mm OD and 25 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU309) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU309 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU309E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 45×100×25 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6309-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6309", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6309-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6309-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU309E", "NU309-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU310", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 50, "D_mm": 110, "B_mm": 27, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1039, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU310 are bore code 10 = 50 mm (code × 5 from 04 upward). The ISO 15 envelope is 110 mm outside diameter and 27 mm width — 1.969 × 4.331 × 1.063 in, with a 30.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "On this 50 mm-bore NU310, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 50 mm shaft reaches operating temperature.", "The NU3 medium series at 50 mm bore uses the 110 mm OD and 27 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU210, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU310, machine the 50 mm shaft seat and 110 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 30.0 mm radial section.", "With a separable NU310, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU310 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 50 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The rings of an NU310 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 50×110 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 50 mm inner ring home through the rollers brinells the 110 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU310 cylindrical roller bearing?", "a": "An NU310 single-row cylindrical roller bearing per ISO 15 has a 50 mm bore, 110 mm outer diameter and 27 mm width (1.969 × 4.331 × 1.063 in), a 30.0 mm radial section and roughly 1039 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU310 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 10: 10 × 5 = 50 mm. The 110 mm OD and 27 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU310) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU310 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU310E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 50×110×27 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6310-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6310", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6310-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6310-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU310E", "NU310-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU311", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 55, "D_mm": 120, "B_mm": 29, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1322, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU311 are bore code 11 = 55 mm (code × 5 from 04 upward). The ISO 15 envelope is 120 mm outside diameter and 29 mm width — 2.165 × 4.724 × 1.142 in, with a 32.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "On this 55 mm-bore NU311, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 55 mm shaft reaches operating temperature.", "The NU3 medium series at 55 mm bore uses the 120 mm OD and 29 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU211, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU311: a generous fillet on the 55 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 120 mm, 29 mm-wide housing bore.", "Large NU311 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 55 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 29 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU311: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 120 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 55 mm inner ring home through the rollers brinells the 120 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 55 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU311 cylindrical roller bearing?", "a": "An NU311 single-row cylindrical roller bearing per ISO 15 has a 55 mm bore, 120 mm outer diameter and 29 mm width (2.165 × 4.724 × 1.142 in), a 32.5 mm radial section and roughly 1322 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU311 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 11: 11 × 5 = 55 mm. The 120 mm OD and 29 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU311) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU311 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU311E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 55×120×29 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6311-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6311", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6311-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6311-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU311E", "NU311-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU312", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 60, "D_mm": 130, "B_mm": 31, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1652, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU312 are bore code 12 = 60 mm (code × 5 from 04 upward). The ISO 15 envelope is 130 mm outside diameter and 31 mm width — 2.362 × 5.118 × 1.22 in, with a 35.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "On this 60 mm-bore NU312, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 60 mm shaft reaches operating temperature.", "The NU3 medium series at 60 mm bore uses the 130 mm OD and 31 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU212, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "The 31 mm-wide NU312 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 60 mm bore and 130 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 35.0 mm section.", "For the interference inner ring of NU312, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 60 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 130 mm ring dents the raceways.", "Relubricate NU312 with the shaft turning so fresh grease or oil reaches the full 31 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 60 mm bore starved.", "Order clearance for the fit: a rotating interference inner ring on a 60 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU312; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU312 cylindrical roller bearing?", "a": "An NU312 single-row cylindrical roller bearing per ISO 15 has a 60 mm bore, 130 mm outer diameter and 31 mm width (2.362 × 5.118 × 1.22 in), a 35.0 mm radial section and roughly 1652 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU312 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 12: 12 × 5 = 60 mm. The 130 mm OD and 31 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU312) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU312 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU312E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 60×130×31 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6312-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6312", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6312-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6312-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU312E", "NU312-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU313", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 65, "D_mm": 140, "B_mm": 33, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2033, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU313 are bore code 13 = 65 mm (code × 5 from 04 upward). The ISO 15 envelope is 140 mm outside diameter and 33 mm width — 2.559 × 5.512 × 1.299 in, with a 37.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "On this 65 mm-bore NU313, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 65 mm shaft reaches operating temperature.", "The NU3 medium series at 65 mm bore uses the 140 mm OD and 33 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU213, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU313, machine the 65 mm shaft seat and 140 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 37.5 mm radial section.", "With a separable NU313, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU313 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 65 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU313; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU313: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 65 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU313 cylindrical roller bearing?", "a": "An NU313 single-row cylindrical roller bearing per ISO 15 has a 65 mm bore, 140 mm outer diameter and 33 mm width (2.559 × 5.512 × 1.299 in), a 37.5 mm radial section and roughly 2033 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU313 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 13: 13 × 5 = 65 mm. The 140 mm OD and 33 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU313) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU313 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU313E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 65×140×33 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6313-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6313", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6313-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6313-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU313E", "NU313-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU314", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 70, "D_mm": 150, "B_mm": 35, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2469, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU314 are bore code 14 = 70 mm (code × 5 from 04 upward). The ISO 15 envelope is 150 mm outside diameter and 35 mm width — 2.756 × 5.906 × 1.378 in, with a 40.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "On this 70 mm-bore NU314, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 70 mm shaft reaches operating temperature.", "The NU3 medium series at 70 mm bore uses the 150 mm OD and 35 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU214, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU314: a generous fillet on the 70 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 150 mm, 35 mm-wide housing bore.", "Large NU314 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 70 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 35 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU314: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 150 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU314: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 70 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU314 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU314 cylindrical roller bearing?", "a": "An NU314 single-row cylindrical roller bearing per ISO 15 has a 70 mm bore, 150 mm outer diameter and 35 mm width (2.756 × 5.906 × 1.378 in), a 40.0 mm radial section and roughly 2469 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU314 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 14: 14 × 5 = 70 mm. The 150 mm OD and 35 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU314) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU314 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU314E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 70×150×35 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6314-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6314", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6314-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6314-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU314E", "NU314-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU315", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 75, "D_mm": 160, "B_mm": 37, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2962, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU315 are bore code 15 = 75 mm (code × 5 from 04 upward). The ISO 15 envelope is 160 mm outside diameter and 37 mm width — 2.953 × 6.299 × 1.457 in, with a 42.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "On this 75 mm-bore NU315, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 75 mm shaft reaches operating temperature.", "The NU3 medium series at 75 mm bore uses the 160 mm OD and 37 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU215, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "The 37 mm-wide NU315 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 75 mm bore and 160 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 42.5 mm section.", "For the interference inner ring of NU315, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 75 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 160 mm ring dents the raceways.", "Relubricate NU315 with the shaft turning so fresh grease or oil reaches the full 37 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 75 mm bore starved.", "Choose the ring design for the locating task: a plain NU315 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 37 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 160 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU315 cylindrical roller bearing?", "a": "An NU315 single-row cylindrical roller bearing per ISO 15 has a 75 mm bore, 160 mm outer diameter and 37 mm width (2.953 × 6.299 × 1.457 in), a 42.5 mm radial section and roughly 2962 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU315 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 15: 15 × 5 = 75 mm. The 160 mm OD and 37 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU315) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU315 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU315E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 75×160×37 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6315-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6315", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6315-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6315-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU315E", "NU315-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU316", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 80, "D_mm": 170, "B_mm": 39, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 3517, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU316 are bore code 16 = 80 mm (code × 5 from 04 upward). The ISO 15 envelope is 170 mm outside diameter and 39 mm width — 3.15 × 6.693 × 1.535 in, with a 45.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "rolling mill roll necks and chocks", "large gear drives and reducer shafts", "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "The large 80 mm-bore NU316 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 170 mm outer ring squarely, and plan lifting fixtures for the 39 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU3 medium series at 80 mm bore uses the 170 mm OD and 39 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU216, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU316, machine the 80 mm shaft seat and 170 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 45.0 mm radial section.", "With a separable NU316, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU316 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 80 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Cylindrical rollers have no self-aligning capacity: line contact across the 39 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 170 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU316 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU316 cylindrical roller bearing?", "a": "An NU316 single-row cylindrical roller bearing per ISO 15 has a 80 mm bore, 170 mm outer diameter and 39 mm width (3.15 × 6.693 × 1.535 in), a 45.0 mm radial section and roughly 3517 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU316 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 16: 16 × 5 = 80 mm. The 170 mm OD and 39 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU316) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU316 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU316E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 80×170×39 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6316-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6316", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6316-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6316-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU316E", "NU316-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU317", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 85, "D_mm": 180, "B_mm": 41, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 4136, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU317 are bore code 17 = 85 mm (code × 5 from 04 upward). The ISO 15 envelope is 180 mm outside diameter and 41 mm width — 3.346 × 7.087 × 1.614 in, with a 47.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "large gear drives and reducer shafts", "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums", "large fan and paper machine rolls" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "The large 85 mm-bore NU317 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 180 mm outer ring squarely, and plan lifting fixtures for the 41 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU3 medium series at 85 mm bore uses the 180 mm OD and 41 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU217, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU317: a generous fillet on the 85 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 180 mm, 41 mm-wide housing bore.", "Large NU317 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 85 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 41 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU317: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 180 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU317 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU317 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 85×180 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU317 cylindrical roller bearing?", "a": "An NU317 single-row cylindrical roller bearing per ISO 15 has a 85 mm bore, 180 mm outer diameter and 41 mm width (3.346 × 7.087 × 1.614 in), a 47.5 mm radial section and roughly 4136 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU317 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 17: 17 × 5 = 85 mm. The 180 mm OD and 41 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU317) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU317 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU317E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 85×180×41 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6317-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6317", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6317-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6317-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU317E", "NU317-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU318", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 90, "D_mm": 190, "B_mm": 43, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 4825, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU318 are bore code 18 = 90 mm (code × 5 from 04 upward). The ISO 15 envelope is 190 mm outside diameter and 43 mm width — 3.543 × 7.48 × 1.693 in, with a 50.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "cement and mining machinery drives", "crusher eccentric and drum shafts", "heavy crane and winch drums", "large fan and paper machine rolls", "rolling mill roll necks and chocks" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "The large 90 mm-bore NU318 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 190 mm outer ring squarely, and plan lifting fixtures for the 43 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU3 medium series at 90 mm bore uses the 190 mm OD and 43 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU218, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "The 43 mm-wide NU318 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 90 mm bore and 190 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 50.0 mm section.", "For the interference inner ring of NU318, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 90 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 190 mm ring dents the raceways.", "Relubricate NU318 with the shaft turning so fresh grease or oil reaches the full 43 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 90 mm bore starved.", "The rings of an NU318 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 90×190 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 90 mm inner ring home through the rollers brinells the 190 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU318 cylindrical roller bearing?", "a": "An NU318 single-row cylindrical roller bearing per ISO 15 has a 90 mm bore, 190 mm outer diameter and 43 mm width (3.543 × 7.48 × 1.693 in), a 50.0 mm radial section and roughly 4825 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU318 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 18: 18 × 5 = 90 mm. The 190 mm OD and 43 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU318) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU318 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU318E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 90×190×43 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6318-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6318", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6318-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6318-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU318E", "NU318-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU319", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 95, "D_mm": 200, "B_mm": 45, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 5586, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU319 are bore code 19 = 95 mm (code × 5 from 04 upward). The ISO 15 envelope is 200 mm outside diameter and 45 mm width — 3.74 × 7.874 × 1.772 in, with a 52.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "crusher eccentric and drum shafts", "heavy crane and winch drums", "large fan and paper machine rolls", "rolling mill roll necks and chocks", "large gear drives and reducer shafts" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "The large 95 mm-bore NU319 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 200 mm outer ring squarely, and plan lifting fixtures for the 45 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU3 medium series at 95 mm bore uses the 200 mm OD and 45 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU219, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Before fitting NU319, machine the 95 mm shaft seat and 200 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 52.5 mm radial section.", "With a separable NU319, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "When reusing separable NU319 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 95 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 95 mm inner ring home through the rollers brinells the 200 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 95 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU319 cylindrical roller bearing?", "a": "An NU319 single-row cylindrical roller bearing per ISO 15 has a 95 mm bore, 200 mm outer diameter and 45 mm width (3.74 × 7.874 × 1.772 in), a 52.5 mm radial section and roughly 5586 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU319 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 19: 19 × 5 = 95 mm. The 200 mm OD and 45 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU319) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU319 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU319E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 95×200×45 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6319-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6319", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6319-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6319-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU319E", "NU319-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU320", "brand": "GENERIC-ISO", "series": "NU300-series", "type": "cylindrical_roller", "d_mm": 100, "D_mm": 215, "B_mm": 47, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 6823, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU320 are bore code 20 = 100 mm (code × 5 from 04 upward). The ISO 15 envelope is 215 mm outside diameter and 47 mm width — 3.937 × 8.465 × 1.85 in, with a 57.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "heavy crane and winch drums", "large fan and paper machine rolls", "rolling mill roll necks and chocks", "large gear drives and reducer shafts", "cement and mining machinery drives" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "The large 100 mm-bore NU320 mounts with substantial force: heat the inner ring or use hydraulic equipment, support the 215 mm outer ring squarely, and plan lifting fixtures for the 47 mm-wide roller assembly — drifting it in cold brinells the line-contact raceways.", "The NU3 medium series at 100 mm bore uses the 215 mm OD and 47 mm width for heavy radial load; it needs stiffer shaft and housing shoulders and runs lower limiting speed than an NU220, so it is a poor choice in a high-rpm gearbox stage sized for the light row.", "Check the shoulder geometry for NU320: a generous fillet on the 100 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 215 mm, 47 mm-wide housing bore.", "Large NU320 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 100 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 47 mm-wide set locks the rollers at the first hot run.", "Read the damage on a removed NU320: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 215 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Order clearance for the fit: a rotating interference inner ring on a 100 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU320; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU320 cylindrical roller bearing?", "a": "An NU320 single-row cylindrical roller bearing per ISO 15 has a 100 mm bore, 215 mm outer diameter and 47 mm width (3.937 × 8.465 × 1.85 in), a 57.5 mm radial section and roughly 6823 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU320 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 20: 20 × 5 = 100 mm. The 215 mm OD and 47 mm width come from the ISO 15 dimension series (NU300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU320) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU320 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU320E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 100×215×47 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [ { "equiv_sku": "6320", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6320-RSR", "equiv_brand": "NSK", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6320-2RS", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." }, { "equiv_sku": "6320-ZZ", "equiv_brand": "SKF", "level": "verify", "note": "Identical envelope but a different bearing type — confirm load and speed suitability before substitution." } ], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU320E", "NU320-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2205", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 25, "D_mm": 52, "B_mm": 18, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 150, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2205 are bore code 05 = 25 mm (code × 5 from 04 upward). The ISO 15 envelope is 52 mm outside diameter and 18 mm width — 0.984 × 2.047 × 0.709 in, with a 13.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "At 25 mm bore the small NU2205 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU22 wide series keeps the NU2 OD at 25 mm bore (52 mm) but widens to 18 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU205 gap leaves the wide ring loose axially.", "Check the shoulder geometry for NU2205: a generous fillet on the 25 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 52 mm, 18 mm-wide housing bore.", "Large NU2205 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 25 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 18 mm-wide set locks the rollers at the first hot run.", "Relubricate NU2205 with the shaft turning so fresh grease or oil reaches the full 18 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 25 mm bore starved.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU2205: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 25 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU2205 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU2205 cylindrical roller bearing?", "a": "An NU2205 single-row cylindrical roller bearing per ISO 15 has a 25 mm bore, 52 mm outer diameter and 18 mm width (0.984 × 2.047 × 0.709 in), a 13.5 mm radial section and roughly 150 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2205 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 05: 05 × 5 = 25 mm. The 52 mm OD and 18 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2205) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2205 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2205E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 25×52×18 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2205E", "NU2205-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2206", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 30, "D_mm": 62, "B_mm": 20, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 236, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2206 are bore code 06 = 30 mm (code × 5 from 04 upward). The ISO 15 envelope is 62 mm outside diameter and 20 mm width — 1.181 × 2.441 × 0.787 in, with a 16.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "textile and packaging machinery rolls", "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "At 30 mm bore the small NU2206 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU22 wide series keeps the NU2 OD at 30 mm bore (62 mm) but widens to 20 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU206 gap leaves the wide ring loose axially.", "The 20 mm-wide NU2206 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 30 mm bore and 62 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 16.0 mm section.", "For the interference inner ring of NU2206, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 30 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 62 mm ring dents the raceways.", "When reusing separable NU2206 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 30 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Choose the ring design for the locating task: a plain NU2206 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 20 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 62 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU2206 cylindrical roller bearing?", "a": "An NU2206 single-row cylindrical roller bearing per ISO 15 has a 30 mm bore, 62 mm outer diameter and 20 mm width (1.181 × 2.441 × 0.787 in), a 16.0 mm radial section and roughly 236 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2206 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 06: 06 × 5 = 30 mm. The 62 mm OD and 20 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2206) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2206 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2206E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 30×62×20 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2206E", "NU2206-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2207", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 35, "D_mm": 72, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 365, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2207 are bore code 07 = 35 mm (code × 5 from 04 upward). The ISO 15 envelope is 72 mm outside diameter and 23 mm width — 1.378 × 2.835 × 0.906 in, with a 18.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "At 35 mm bore the small NU2207 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU22 wide series keeps the NU2 OD at 35 mm bore (72 mm) but widens to 23 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU207 gap leaves the wide ring loose axially.", "Before fitting NU2207, machine the 35 mm shaft seat and 72 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 18.5 mm radial section.", "With a separable NU2207, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Read the damage on a removed NU2207: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 72 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Cylindrical rollers have no self-aligning capacity: line contact across the 23 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 72 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU2207 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU2207 cylindrical roller bearing?", "a": "An NU2207 single-row cylindrical roller bearing per ISO 15 has a 35 mm bore, 72 mm outer diameter and 23 mm width (1.378 × 2.835 × 0.906 in), a 18.5 mm radial section and roughly 365 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2207 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 07: 07 × 5 = 35 mm. The 72 mm OD and 23 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2207) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2207 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2207E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 35×72×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2207E", "NU2207-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2208", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 40, "D_mm": 80, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 442, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2208 are bore code 08 = 40 mm (code × 5 from 04 upward). The ISO 15 envelope is 80 mm outside diameter and 23 mm width — 1.575 × 3.15 × 0.906 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "On this 40 mm-bore NU2208, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 40 mm shaft reaches operating temperature.", "The NU22 wide series keeps the NU2 OD at 40 mm bore (80 mm) but widens to 23 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU208 gap leaves the wide ring loose axially.", "Check the shoulder geometry for NU2208: a generous fillet on the 40 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 80 mm, 23 mm-wide housing bore.", "Large NU2208 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 40 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 23 mm-wide set locks the rollers at the first hot run.", "Relubricate NU2208 with the shaft turning so fresh grease or oil reaches the full 23 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 40 mm bore starved.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU2208 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU2208 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 40×80 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU2208 cylindrical roller bearing?", "a": "An NU2208 single-row cylindrical roller bearing per ISO 15 has a 40 mm bore, 80 mm outer diameter and 23 mm width (1.575 × 3.15 × 0.906 in), a 20.0 mm radial section and roughly 442 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2208 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 08: 08 × 5 = 40 mm. The 80 mm OD and 23 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2208) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2208 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2208E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 40×80×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2208E", "NU2208-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2209", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 45, "D_mm": 85, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 479, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2209 are bore code 09 = 45 mm (code × 5 from 04 upward). The ISO 15 envelope is 85 mm outside diameter and 23 mm width — 1.772 × 3.346 × 0.906 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "On this 45 mm-bore NU2209, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 45 mm shaft reaches operating temperature.", "The NU22 wide series keeps the NU2 OD at 45 mm bore (85 mm) but widens to 23 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU209 gap leaves the wide ring loose axially.", "The 23 mm-wide NU2209 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 45 mm bore and 85 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 20.0 mm section.", "For the interference inner ring of NU2209, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 45 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 85 mm ring dents the raceways.", "When reusing separable NU2209 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 45 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The rings of an NU2209 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 45×85 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 45 mm inner ring home through the rollers brinells the 85 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU2209 cylindrical roller bearing?", "a": "An NU2209 single-row cylindrical roller bearing per ISO 15 has a 45 mm bore, 85 mm outer diameter and 23 mm width (1.772 × 3.346 × 0.906 in), a 20.0 mm radial section and roughly 479 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2209 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 09: 09 × 5 = 45 mm. The 85 mm OD and 23 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2209) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2209 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2209E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 45×85×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2209E", "NU2209-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2210", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 50, "D_mm": 90, "B_mm": 23, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 516, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2210 are bore code 10 = 50 mm (code × 5 from 04 upward). The ISO 15 envelope is 90 mm outside diameter and 23 mm width — 1.969 × 3.543 × 0.906 in, with a 20.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "On this 50 mm-bore NU2210, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 50 mm shaft reaches operating temperature.", "The NU22 wide series keeps the NU2 OD at 50 mm bore (90 mm) but widens to 23 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU210 gap leaves the wide ring loose axially.", "Before fitting NU2210, machine the 50 mm shaft seat and 90 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 20.0 mm radial section.", "With a separable NU2210, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Read the damage on a removed NU2210: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 90 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 50 mm inner ring home through the rollers brinells the 90 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 50 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU2210 cylindrical roller bearing?", "a": "An NU2210 single-row cylindrical roller bearing per ISO 15 has a 50 mm bore, 90 mm outer diameter and 23 mm width (1.969 × 3.543 × 0.906 in), a 20.0 mm radial section and roughly 516 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2210 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 10: 10 × 5 = 50 mm. The 90 mm OD and 23 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2210) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2210 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2210E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 50×90×23 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2210E", "NU2210-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2211", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 55, "D_mm": 100, "B_mm": 25, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 699, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2211 are bore code 11 = 55 mm (code × 5 from 04 upward). The ISO 15 envelope is 100 mm outside diameter and 25 mm width — 2.165 × 3.937 × 0.984 in, with a 22.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "On this 55 mm-bore NU2211, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 55 mm shaft reaches operating temperature.", "The NU22 wide series keeps the NU2 OD at 55 mm bore (100 mm) but widens to 25 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU211 gap leaves the wide ring loose axially.", "Check the shoulder geometry for NU2211: a generous fillet on the 55 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 100 mm, 25 mm-wide housing bore.", "Large NU2211 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 55 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 25 mm-wide set locks the rollers at the first hot run.", "Relubricate NU2211 with the shaft turning so fresh grease or oil reaches the full 25 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 55 mm bore starved.", "Order clearance for the fit: a rotating interference inner ring on a 55 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU2211; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU2211 cylindrical roller bearing?", "a": "An NU2211 single-row cylindrical roller bearing per ISO 15 has a 55 mm bore, 100 mm outer diameter and 25 mm width (2.165 × 3.937 × 0.984 in), a 22.5 mm radial section and roughly 699 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2211 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 11: 11 × 5 = 55 mm. The 100 mm OD and 25 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2211) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2211 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2211E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 55×100×25 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2211E", "NU2211-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2212", "brand": "GENERIC-ISO", "series": "NU2200-series", "type": "cylindrical_roller", "d_mm": 60, "D_mm": 110, "B_mm": 28, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 954, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2200-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2212 are bore code 12 = 60 mm (code × 5 from 04 upward). The ISO 15 envelope is 110 mm outside diameter and 28 mm width — 2.362 × 4.331 × 1.102 in, with a 25.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "On this 60 mm-bore NU2212, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 60 mm shaft reaches operating temperature.", "The NU22 wide series keeps the NU2 OD at 60 mm bore (110 mm) but widens to 28 mm, raising the rating inside the same housing bore; the extra width is not free — verify the shaft shoulder spacing, since an NU212 gap leaves the wide ring loose axially.", "The 28 mm-wide NU2212 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 60 mm bore and 110 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 25.0 mm section.", "For the interference inner ring of NU2212, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 60 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 110 mm ring dents the raceways.", "When reusing separable NU2212 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 60 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU2212; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU2212: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 60 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU2212 cylindrical roller bearing?", "a": "An NU2212 single-row cylindrical roller bearing per ISO 15 has a 60 mm bore, 110 mm outer diameter and 28 mm width (2.362 × 4.331 × 1.102 in), a 25.0 mm radial section and roughly 954 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2212 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 12: 12 × 5 = 60 mm. The 110 mm OD and 28 mm width come from the ISO 15 dimension series (NU2200), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2212) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2212 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2212E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 60×110×28 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2212E", "NU2212-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2305", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 25, "D_mm": 62, "B_mm": 24, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 310, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2305 are bore code 05 = 25 mm (code × 5 from 04 upward). The ISO 15 envelope is 62 mm outside diameter and 24 mm width — 0.984 × 2.441 × 0.945 in, with a 18.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "light conveyor drive shafts", "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts" ], "failure_modes": [ "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders" ], "pitfalls": [ "At 25 mm bore the small NU2305 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU23 wide medium series (25×62×24 mm) packs the highest rating of the 25 mm-bore cylindrical rows into the NU3 housing bore; the 18.5 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU305.", "Check the shoulder geometry for NU2305: a generous fillet on the 25 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 62 mm, 24 mm-wide housing bore.", "Large NU2305 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 25 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 24 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU2305 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 25 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "Choose the ring design for the locating task: a plain NU2305 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location.", "Cylindrical rollers have no self-aligning capacity: line contact across the 24 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 62 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead." ], "faq": [ { "q": "What are the dimensions of an NU2305 cylindrical roller bearing?", "a": "An NU2305 single-row cylindrical roller bearing per ISO 15 has a 25 mm bore, 62 mm outer diameter and 24 mm width (0.984 × 2.441 × 0.945 in), a 18.5 mm radial section and roughly 310 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2305 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 05: 05 × 5 = 25 mm. The 62 mm OD and 24 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2305) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2305 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2305E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 25×62×24 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2305E", "NU2305-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2306", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 30, "D_mm": 72, "B_mm": 27, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 464, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2306 are bore code 06 = 30 mm (code × 5 from 04 upward). The ISO 15 envelope is 72 mm outside diameter and 27 mm width — 1.181 × 2.835 × 1.063 in, with a 21.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "small gearbox layshafts and pinion shafts", "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls" ], "failure_modes": [ "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication" ], "pitfalls": [ "At 30 mm bore the small NU2306 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU23 wide medium series (30×72×27 mm) packs the highest rating of the 30 mm-bore cylindrical rows into the NU3 housing bore; the 21.0 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU306.", "The 27 mm-wide NU2306 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 30 mm bore and 72 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 21.0 mm section.", "For the interference inner ring of NU2306, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 30 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 72 mm ring dents the raceways.", "Read the damage on a removed NU2306: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 72 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Cylindrical rollers have no self-aligning capacity: line contact across the 27 mm-wide rollers means even a few tenths of a degree of misalignment edge-loads the 72 mm raceway; where shaft deflection is unavoidable, use a spherical roller or a self-aligning ball bearing instead.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU2306 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty." ], "faq": [ { "q": "What are the dimensions of an NU2306 cylindrical roller bearing?", "a": "An NU2306 single-row cylindrical roller bearing per ISO 15 has a 30 mm bore, 72 mm outer diameter and 27 mm width (1.181 × 2.835 × 1.063 in), a 21.0 mm radial section and roughly 464 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2306 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 06: 06 × 5 = 30 mm. The 72 mm OD and 27 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2306) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2306 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2306E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 30×72×27 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2306E", "NU2306-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2307", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 35, "D_mm": 80, "B_mm": 31, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 643, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2307 are bore code 07 = 35 mm (code × 5 from 04 upward). The ISO 15 envelope is 80 mm outside diameter and 31 mm width — 1.378 × 3.15 × 1.22 in, with a 22.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "fractional electric motor armatures", "two-wheeler and appliance transmissions", "small pump and fan rotor shafts", "textile and packaging machinery rolls", "light conveyor drive shafts" ], "failure_modes": [ "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit" ], "pitfalls": [ "At 35 mm bore the small NU2307 commonly shares a gearbox bore with a 6-series deep-groove row; do not substitute by envelope alone — the cylindrical roller carries far more radial load but no thrust, so any helical-gear axial force needs a paired angular-contact or NJ locating row.", "The NU23 wide medium series (35×80×31 mm) packs the highest rating of the 35 mm-bore cylindrical rows into the NU3 housing bore; the 22.5 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU307.", "Before fitting NU2307, machine the 35 mm shaft seat and 80 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 22.5 mm radial section.", "With a separable NU2307, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU2307 with the shaft turning so fresh grease or oil reaches the full 31 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 35 mm bore starved.", "Keep the minimum load above the skid threshold (catalogue rule of thumb roughly 1–2% of the dynamic rating); an unloaded NU2307 on an idler or in a cold-start gearbox develops roller smearing, so add a spring preload or downsize the bearing if the duty is mostly empty.", "The rings of an NU2307 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 35×80 dimensions." ], "faq": [ { "q": "What are the dimensions of an NU2307 cylindrical roller bearing?", "a": "An NU2307 single-row cylindrical roller bearing per ISO 15 has a 35 mm bore, 80 mm outer diameter and 31 mm width (1.378 × 3.15 × 1.22 in), a 22.5 mm radial section and roughly 643 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2307 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 07: 07 × 5 = 35 mm. The 80 mm OD and 31 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2307) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2307 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2307E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 35×80×31 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2307E", "NU2307-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2308", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 40, "D_mm": 90, "B_mm": 33, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 860, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2308 are bore code 08 = 40 mm (code × 5 from 04 upward). The ISO 15 envelope is 90 mm outside diameter and 33 mm width — 1.575 × 3.543 × 1.299 in, with a 25.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes" ], "failure_modes": [ "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align", "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration" ], "pitfalls": [ "On this 40 mm-bore NU2308, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 40 mm shaft reaches operating temperature.", "The NU23 wide medium series (40×90×33 mm) packs the highest rating of the 40 mm-bore cylindrical rows into the NU3 housing bore; the 25.0 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU308.", "Check the shoulder geometry for NU2308: a generous fillet on the 40 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 90 mm, 33 mm-wide housing bore.", "Large NU2308 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 40 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 33 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU2308 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 40 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The rings of an NU2308 are separable and supplied as a matched unit: never mix the outer ring of one bearing with the inner-ring/roller assembly of another — the raceway and roller complement are graded together, and cross-matching shortens life even at identical 40×90 dimensions.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 40 mm inner ring home through the rollers brinells the 90 mm outer raceway." ], "faq": [ { "q": "What are the dimensions of an NU2308 cylindrical roller bearing?", "a": "An NU2308 single-row cylindrical roller bearing per ISO 15 has a 40 mm bore, 90 mm outer diameter and 33 mm width (1.575 × 3.543 × 1.299 in), a 25.0 mm radial section and roughly 860 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2308 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 08: 08 × 5 = 40 mm. The 90 mm OD and 33 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2308) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2308 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2308E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 40×90×33 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2308E", "NU2308-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2309", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 45, "D_mm": 100, "B_mm": 36, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1151, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2309 are bore code 09 = 45 mm (code × 5 from 04 upward). The ISO 15 envelope is 100 mm outside diameter and 36 mm width — 1.772 × 3.937 × 1.417 in, with a 27.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives" ], "failure_modes": [ "roller-end and flange scoring when an NU bearing is forced to locate axially; only NJ/NUP designs carry thrust at the shoulders", "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set" ], "pitfalls": [ "On this 45 mm-bore NU2309, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 45 mm shaft reaches operating temperature.", "The NU23 wide medium series (45×100×36 mm) packs the highest rating of the 45 mm-bore cylindrical rows into the NU3 housing bore; the 27.5 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU309.", "The 36 mm-wide NU2309 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 45 mm bore and 100 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 27.5 mm section.", "For the interference inner ring of NU2309, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 45 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 100 mm ring dents the raceways.", "Read the damage on a removed NU2309: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 100 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "Apply mounting force to the ring with the interference fit — inner ring for a shaft fit, outer ring for a housing fit; pushing the 45 mm inner ring home through the rollers brinells the 100 mm outer raceway.", "Order clearance for the fit: a rotating interference inner ring on a 45 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings." ], "faq": [ { "q": "What are the dimensions of an NU2309 cylindrical roller bearing?", "a": "An NU2309 single-row cylindrical roller bearing per ISO 15 has a 45 mm bore, 100 mm outer diameter and 36 mm width (1.772 × 3.937 × 1.417 in), a 27.5 mm radial section and roughly 1151 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2309 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 09: 09 × 5 = 45 mm. The 100 mm OD and 36 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2309) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2309 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2309E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 45×100×36 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2309E", "NU2309-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2310", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 50, "D_mm": 110, "B_mm": 40, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1539, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2310 are bore code 10 = 50 mm (code × 5 from 04 upward). The ISO 15 envelope is 110 mm outside diameter and 40 mm width — 1.969 × 4.331 × 1.575 in, with a 30.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "conveyor and hoist gearcase shafts", "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts" ], "failure_modes": [ "cage fatigue and fracture after sustained over-speed with marginal lubrication", "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance" ], "pitfalls": [ "On this 50 mm-bore NU2310, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 50 mm shaft reaches operating temperature.", "The NU23 wide medium series (50×110×40 mm) packs the highest rating of the 50 mm-bore cylindrical rows into the NU3 housing bore; the 30.0 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU310.", "Before fitting NU2310, machine the 50 mm shaft seat and 110 mm housing bore with a relief or undercut so nothing bridges the chamfer; the separable rings only carry load when their full faces abut, and a large fillet pinches the 30.0 mm radial section.", "With a separable NU2310, mount the inner-ring/roller assembly on the shaft and the plain outer ring in the housing independently; check that the outer ring is free to float the specified amount after closing the housing — a pinched outer ring turns the floating bearing into an accidental locating one.", "Relubricate NU2310 with the shaft turning so fresh grease or oil reaches the full 40 mm roller length; grease forced into a stationary row packs the entry and leaves the far side of the 50 mm bore starved.", "Order clearance for the fit: a rotating interference inner ring on a 50 mm shaft plus thermal growth consumes CN play, so C3 is the normal industrial default and C4 serves hot or vibratory mounts; CN suits loose outer-ring floating arrangements in bored housings.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU2310; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope." ], "faq": [ { "q": "What are the dimensions of an NU2310 cylindrical roller bearing?", "a": "An NU2310 single-row cylindrical roller bearing per ISO 15 has a 50 mm bore, 110 mm outer diameter and 40 mm width (1.969 × 4.331 × 1.575 in), a 30.0 mm radial section and roughly 1539 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2310 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 10: 10 × 5 = 50 mm. The 110 mm OD and 40 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2310) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2310 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2310E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 50×110×40 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2310E", "NU2310-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2311", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 55, "D_mm": 120, "B_mm": 43, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 1960, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2311 are bore code 11 = 55 mm (code × 5 from 04 upward). The ISO 15 envelope is 120 mm outside diameter and 43 mm width — 2.165 × 4.724 × 1.693 in, with a 32.5 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "wind turbine gearbox intermediate shafts", "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives" ], "failure_modes": [ "fretting corrosion on an interference inner-ring seat that creeps under a loose fit", "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load" ], "pitfalls": [ "On this 55 mm-bore NU2311, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 55 mm shaft reaches operating temperature.", "The NU23 wide medium series (55×120×43 mm) packs the highest rating of the 55 mm-bore cylindrical rows into the NU3 housing bore; the 32.5 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU311.", "Check the shoulder geometry for NU2311: a generous fillet on the 55 mm shaft looks strong but stops the inner ring seating home; use the catalogue corner-relief radius and a withdrawal groove so the outer ring presses flush in the 120 mm, 43 mm-wide housing bore.", "Large NU2311 rings need real draw-up force: use a sleeve or hydraulic press against the inner ring face only, verify the 55 mm seat temperature before assembly, and never strike the roller cage — a dented cage window on the 43 mm-wide set locks the rollers at the first hot run.", "When reusing separable NU2311 rings, keep the matched pair together and inspect both seats: a crept inner ring frets a polished groove into the 55 mm journal that a new bearing will repeat unless the shaft is repaired or reclaimed.", "The E suffix denotes a reinforced design with larger rollers and higher rating than the basic NU2311; never pair a standard and an E row on the same shaft — unequal stiffness splits the load unevenly, and the two are not life-equivalent despite the same envelope.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU2311: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 55 mm bore band rather than extrapolating ball-bearing practice." ], "faq": [ { "q": "What are the dimensions of an NU2311 cylindrical roller bearing?", "a": "An NU2311 single-row cylindrical roller bearing per ISO 15 has a 55 mm bore, 120 mm outer diameter and 43 mm width (2.165 × 4.724 × 1.693 in), a 32.5 mm radial section and roughly 1960 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2311 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 11: 11 × 5 = 55 mm. The 120 mm OD and 43 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2311) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2311 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2311E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 55×120×43 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2311E", "NU2311-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 }, { "sku": "NU2312", "brand": "GENERIC-ISO", "series": "NU2300-series", "type": "cylindrical_roller", "d_mm": 60, "D_mm": 130, "B_mm": 46, "seal_type": "open", "clearance": "CN", "clearance_options": [ "CN", "C3", "C4" ], "tolerance_class": "P0", "cage_type": "steel", "weight_g": 2452, "weight_estimated": true, "standard": "ISO 15", "naming_rule_text": "In the NU2300-series (ISO 15 dimension series) the leading NU marks a single-row cylindrical roller: the outer ring has two integral shoulders and the inner ring none, so the inner-ring/roller assembly floats axially both ways and the bearing locates radially only; the last two digits of NU2312 are bore code 12 = 60 mm (code × 5 from 04 upward). The ISO 15 envelope is 130 mm outside diameter and 46 mm width — 2.362 × 5.118 × 1.811 in, with a 35.0 mm radial section height. Straight cylindrical rollers give line contact for high radial capacity at low friction, with no self-alignment; catalogue practice for a rotating inner ring is a k5 shaft seat, H7 housing and C3 clearance. NJ adds one inner shoulder (one-direction location), NUP two shoulders (full location); E denotes a reinforced roller complement — verify against the actual load direction.", "applications": [ "industrial helical and planetary gearboxes", "medium electric motor drives", "centrifugal pump and compressor shafts", "machine tool gearboxes and feed drives", "conveyor and hoist gearcase shafts" ], "failure_modes": [ "false brinelling indentations at the roller pitch when an idle bearing sits in machine vibration", "inner-ring shoulder damage from cold mounting force transmitted through the roller set", "thermal seizure when an interference fit plus hot running removes all residual C3 clearance", "roller and raceway smearing when a lightly loaded NU row skids at start-up or below the minimum load", "edge loading and rib spalling from shaft-to-housing misalignment — cylindrical rollers run on line contact and cannot self-align" ], "pitfalls": [ "On this 60 mm-bore NU2312, set C3 as the default for an interference inner-ring fit and recheck play after mounting; a row that turned freely on the bench can be fully clamped once the 60 mm shaft reaches operating temperature.", "The NU23 wide medium series (60×130×46 mm) packs the highest rating of the 60 mm-bore cylindrical rows into the NU3 housing bore; the 35.0 mm section and wide roller set tolerate no misalignment, so align the seats before selecting it over an NU312.", "The 46 mm-wide NU2312 seats against shaft and housing shoulders whose fillet must clear the ring chamfer: keep the corner radius inside the catalogue limit so the 60 mm bore and 130 mm OD faces abut square — an oversized radius lifts the ring and edge-loads the 35.0 mm section.", "For the interference inner ring of NU2312, heat to 80–100 °C with an induction heater (never a flame) and slide it dry to the 60 mm shaft shoulder; the roller assembly is fitted separately, and hammering cold through the 130 mm ring dents the raceways.", "Read the damage on a removed NU2312: uniform roller smearing points to minimum-load skidding, while spalling on one edge of the 130 mm raceway means misalignment or a tilted housing face — the two failures need opposite corrections, so inspect before ordering the replacement fit.", "At high speed, oil lubrication or a low-friction cage beats a grease-packed stamped-cage NU2312: line-contact rollers churn grease hard, so follow the catalogue speed factor (n × dm) and preload the oil jet for sizes above the 60 mm bore band rather than extrapolating ball-bearing practice.", "Choose the ring design for the locating task: a plain NU2312 (NU) floats axially in both directions and is the classic non-locating bearing of a two-bearing shaft; NJ locates in one direction, and NUP (or NJ + HJ angle ring) locates in both — do not use an NU row where the shaft needs axial location." ], "faq": [ { "q": "What are the dimensions of an NU2312 cylindrical roller bearing?", "a": "An NU2312 single-row cylindrical roller bearing per ISO 15 has a 60 mm bore, 130 mm outer diameter and 46 mm width (2.362 × 5.118 × 1.811 in), a 35.0 mm radial section and roughly 2452 g geometry-based estimated mass; catalogue masses vary with cage and E design." }, { "q": "How does the NU2312 bore code work?", "a": "The letters give the ring/shoulder design (NU = axially free, NJ = one inner shoulder, NUP = two shoulders) and the last two digits are bore code 12: 12 × 5 = 60 mm. The 130 mm OD and 46 mm width come from the ISO 15 dimension series (NU2300), which shares its boundary plan with the 6-series deep-groove envelopes." }, { "q": "What is the difference between NU, NJ, N and NUP designs?", "a": "NU (like the NU2312) has a shoulderless inner ring and floats axially in both directions; NJ has one integral inner-ring shoulder and locates the shaft in one direction; N has two inner shoulders and a shoulderless outer ring (mirror of NU); NUP adds a second, loose shoulder so the inner ring locates in both directions. Select by the shaft locating scheme, not by load rating — the envelopes are identical." }, { "q": "Can an NU2312 take axial load or misalignment?", "a": "No thrust in the NU design: any sustained axial force scores the roller ends and ring flanges, so locate the shaft with an NJ/NUP row, a paired angular-contact bearing or a deep-groove row elsewhere. Misalignment is likewise not tolerated — line contact between cylindrical rollers and raceways edges under even small angular errors; use a spherical roller bearing where shaft deflection or housing misalignment is expected." }, { "q": "What does the E suffix mean and which clearance should be ordered?", "a": "E (as in NU2312E) is the reinforced design: larger/optimised rollers raise the basic load rating over the basic designation in the same 60×130×46 mm envelope. For clearance, C3 is the usual default with an interference fit on a rotating inner ring because fit and thermal growth reduce residual play; use CN mainly for loose floating outer-ring mounts and C4 for hot or vibratory duty." } ], "cross_ref": [], "source_ref": "https://www.iso.org/obp/ui/en/#iso:std:iso:15:ed-4:v1:en", "catalog_ver": "iso15-crb-geometry", "extracted_at": "2026-09-24", "last_verified": "2026-09-24", "confidence_score": 0.7, "status": "published", "aliases": [ "NU2312E", "NU2312-E" ], "locale_variants": {}, "temp_min_c": -30, "temp_max_c": 120 } ]