NKI10-20 bearing: complete specifications & equivalents
The NKI10-20 is a DIN 616 radial bearing sized 10 x 22 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 | 10 mm |
| Outer diameter D | 22 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 12.8 kN |
| Basic static load rating C0 | 16.6 kN |
| Fatigue load limit Pu | 2 kN |
| Reference speed (thermal) | 24000 rpm |
| Limiting speed (mechanical) | 28000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 37 g |
| Manufacturer designation | NKI 10/20 |
| 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 | 0.394 in |
|---|---|
| Outer diameter D | 0.866 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6 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) | 5 of 30 |
| Bore above smallest NKI-series size | 5 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKI10-20 model number is decoded
NKI 10/20 provides the full machined-ring needle roller construction: ground inner ring on a 10 mm seat, flanged outer ring at 22 mm, caged needles between them — the standard choice when a replaceable inner raceway is required. The NKI 10/20 code gives bore 10 mm and width 20 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Selection arithmetic: C 12.8 kN against C0 16.6 kN gives a C0/C ratio of 1.30, and the 2 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: heat or press the inner ring onto the 10 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 20 mm assembly for free rotation before applying load.
Typical equipment & failure modes
Common applications
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- On a 10 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 22 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Do not interchange envelope-identical needle families blindly: NKI 10/20 shares its 10×22×20 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Reference and limiting speeds are different limits: the 24,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- The 12.8/16.6 kN ratings and 37 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What limits the service life of a NKI 10/20?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 10 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NKI 10/20?
A NKI 10/20 measures 10 mm bore/Fw × 22 mm outside diameter × 20 mm width (0.394 × 0.866 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 12.8 kN, static C0 16.6 kN, fatigue limit Pu 2 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 37 g.
How is the NKI 10/20 designation read?
The letters mark a machined-ring needle roller bearing with inner ring: 10 mm bore, 20 mm width, 22 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Can the NKI 10/20 run on an unhardened shaft?
Yes — that is the point of this family. The NKI 10/20 carries its own hardened, ground inner ring on a 10 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
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.