NKI32-20 bearing: complete specifications & equivalents
The NKI32-20 is a DIN 616 radial bearing sized 32 x 47 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 32 mm |
| Outer diameter D | 47 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 25.1 kN |
| Basic static load rating C0 | 46.5 kN |
| Fatigue load limit Pu | 5.85 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 110 g |
| Manufacturer designation | NKI 32/20 |
| 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 | 1.26 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.787 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) | 14 of 30 |
| Bore above smallest NKI-series size | 27 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKI32-20 model number is decoded
SKF lists NKI 32/20 in the machined-ring needle roller bearings with inner ring with boundary dimensions 32×47×20 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NKI 32/20 code gives bore 32 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Catalogue mass 110 g at 32×47×20 mm makes this one of the highest capacity-per-gram choices in the machined-ring needle roller bearings with inner ring; the limit is usually the shaft's ability to serve as a raceway, not the rolling contact itself. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.
Typical equipment & failure modes
Common applications
- printing and paper-handling rollers
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
- inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact
Selection pitfalls — read before you substitute
- At 32 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 32 mm seats can bend past the compensation range long before the load rating is exhausted.
- Do not interchange envelope-identical needle families blindly: NKI 32/20 shares its 32×47×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Reference and limiting speeds are different limits: the 11,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- The 25.1/46.5 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 640); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What are the dimensions and ratings of the NKI 32/20?
A NKI 32/20 measures 32 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.26 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 25.1 kN, static C0 46.5 kN, fatigue limit Pu 5.85 kN, limiting speed 12,000 r/min, reference speed 11,000 r/min, mass about 110 g.
How is the NKI 32/20 designation read?
The letters mark a machined-ring needle roller bearing with inner ring: 32 mm bore, 20 mm width, 47 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Can the NKI 32/20 run on an unhardened shaft?
Yes — that is the point of this family. The NKI 32/20 carries its own hardened, ground inner ring on a 32 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
How should the NKI 32/20 be mounted?
Mount the inner ring on the 32 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
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.