NK100-26 bearing: complete specifications & equivalents
The NK100-26 is a DIN 616 radial bearing sized 100 x 120 x 26 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 120 mm |
| Width B | 26 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 76.5 kN |
| Basic static load rating C0 | 156 kN |
| Fatigue load limit Pu | 19.6 kN |
| Reference speed (thermal) | 4000 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 520 g |
| Manufacturer designation | NK 100/26 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without 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. 7.3 machined rings with flanges, without 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 & NK-series range
| Bore d | 3.937 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.024 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 10 mm |
| Smallest bore in NK-series | 5 mm |
| Largest outer diameter in NK-series | 130 mm |
| Width range across NK-series | 10–40 mm |
| Bore position in NK-series (smallest first) | 44 of 46 |
| Bore above smallest NK-series size | 95 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NK100-26 model number is decoded
In SKF catalogue PUB BU/P1 17000, NK 100/26 designates a flanged, machined outer ring filled with needle rollers and a cage for a 100 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. The letters identify a flanged machined outer ring without inner ring; the figures give 100 mm Fw and 26 mm B — dimensionally identical envelopes exist with an inner ring under the NA/NKI names, which changes the shaft seat entirely. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 520 g catalogue mass and 10.0 mm radial section ((120−100)/2) frame a rating of about 0.77 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 120 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.
Typical equipment & failure modes
Common applications
- piston-pin style pivots in hydraulic pumps
- guide rollers running on hardened tracks
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
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
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- false brinelling of standby equipment under external vibration
- rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 100 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.
- Hardness is load capacity: in families without an inner ring the 100 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The quoted 76.5/156 kN ratings are SKF catalogue values for this exact execution (NK 100/26); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 76.5/156 kN ratings and 520 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 634); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the NK 100/26 run on an unhardened shaft?
No. In this execution the 100 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
How should the NK 100/26 be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 100 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs.
What limits the service life of a NK 100/26?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 100 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 10.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NK 100/26?
A NK 100/26 measures 100 mm bore/Fw × 120 mm outside diameter × 26 mm width (3.937 × 4.724 × 1.024 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 76.5 kN, static C0 156 kN, fatigue limit Pu 19.6 kN, limiting speed 4,500 r/min, reference speed 4,000 r/min, mass about 520 g.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring on 2026-09-26. Read our editorial & correction policy.