NKIS40 bearing: complete specifications & equivalents
The NKIS40 is a DIN 616 radial bearing sized 40 x 65 x 22 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 65 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 42.9 kN |
| Basic static load rating C0 | 72 kN |
| Fatigue load limit Pu | 8.8 kN |
| Reference speed (thermal) | 8000 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 280 g |
| Manufacturer designation | NKIS 40 |
| 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 & NKIS-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.559 in |
| Width B | 0.866 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in NKIS-series | 15 mm |
| Largest outer diameter in NKIS-series | 95 mm |
| Width range across NKIS-series | 20–28 mm |
| Bore position in NKIS-series (smallest first) | 7 of 12 |
| Bore above smallest NKIS-series size | 25 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKIS40 model number is decoded
The wide-section machined-ring needle roller bearings with inner ring execution NKIS 40 measures 40×65×22 mm: needle rollers caged between a flanged outer ring and a ground inner ring, used wherever the journal cannot serve as a raceway. Reading the designation: the letters name the series with inner ring, the numbers the boundary plan — 40 mm bore (d), 22 mm width; the 65 mm OD follows the dimension series, and the inner ring is a separate ground component. TN polymer cage executions run quieter and tolerate grease-lubricated pivot duty; steel cage executions remain the choice for higher temperature or oil-bath lubrication. Speed planning separates the two ceilings: 8,000 r/min thermal reference and 9,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: heat or press the inner ring onto the 40 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 22 mm assembly for free rotation before applying load.
Typical equipment & failure modes
Common applications
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
- electric motor armature shafts with ground seats
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
- 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
- At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.
- The quoted 42.9/72 kN ratings are SKF catalogue values for this exact execution (NKIS 40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
- The 42.9/72 kN ratings and 280 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 642); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Is the NKIS 40 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 NKIS 40 have?
A NKIS 40 measures 40 mm bore/Fw × 65 mm outside diameter × 22 mm width (1.575 × 2.559 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 42.9 kN, static C0 72 kN, fatigue limit Pu 8.8 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 280 g.
What does NKIS 40 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 40 mm bore, 22 mm width, 65 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NKIS 40 need a hardened and ground shaft?
Yes — that is the point of this family. The NKIS 40 carries its own hardened, ground inner ring on a 40 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
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.