NKI35-30 bearing: complete specifications & equivalents
The NKI35-30 is a DIN 616 radial bearing sized 35 x 50 x 30 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 35 mm |
| Outer diameter D | 50 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 38 kN |
| Basic static load rating C0 | 83 kN |
| Fatigue load limit Pu | 10.4 kN |
| Reference speed (thermal) | 10000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 190 g |
| Manufacturer designation | NKI 35/30 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & NKI-series range
| Bore d | 1.378 in |
|---|---|
| Outer diameter D | 1.969 in |
| Width B | 1.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 7.5 mm |
| Smallest bore in NKI-series | 5 mm |
| Largest outer diameter in NKI-series | 130 mm |
| Width range across NKI-series | 12–40 mm |
| Bore position in NKI-series (smallest first) | 15 of 30 |
| Bore above smallest NKI-series size | 30 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKI35-30 model number is decoded
For a 35 mm shaft that cannot be hardened on site, NKI 35/30 adds a hardened, ground inner ring to the machined needle roller design: envelope 35×50×30 mm per the machined-ring needle roller bearings with inner ring plan. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 35 mm bore (d), 30 mm width; the 50 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. For life calculation, the 38/83 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. For NA 49 2RS executions the wider outer ring changes the housing depth: verify the 30 mm width and s offset dimensions against the open execution before reusing an existing bore.
Typical equipment & failure modes
Common applications
- agricultural implement pivots and cutter heads
- electric motor armature shafts with ground seats
- printing and paper-handling rollers
- gearbox shafts where the journal cannot be hardened on site
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- electrical erosion on VFD-driven shafts without brush or insulated mounting
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- At 35 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 35 mm seats can bend past the compensation range long before the load rating is exhausted.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- Do not interchange envelope-identical needle families blindly: NKI 35/30 shares its 35×50×30 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 38/83 kN ratings and 190 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Does the NKI 35/30 need a hardened and ground shaft?
Yes — that is the point of this family. The NKI 35/30 carries its own hardened, ground inner ring on a 35 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
What mounting mistakes ruin a NKI 35/30?
Mount the inner ring on the 35 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
Is the NKI 35/30 sealed?
No — the open execution relies on housing seals; 2RS executions of the 49 series add contact seals with a wider outer ring as a separate order number.
Which dimensions does the NKI 35/30 have?
A NKI 35/30 measures 35 mm bore/Fw × 50 mm outside diameter × 30 mm width (1.378 × 1.969 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 38 kN, static C0 83 kN, fatigue limit Pu 10.4 kN, limiting speed 11,000 r/min, reference speed 10,000 r/min, mass about 190 g.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring on 2026-09-26. Read our editorial & correction policy.