NKS65 bearing: complete specifications & equivalents
The NKS65 is a DIN 616 radial bearing sized 65 x 85 x 28 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 65 mm |
| Outer diameter D | 85 mm |
| Width B | 28 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 66 kN |
| Basic static load rating C0 | 114 kN |
| Fatigue load limit Pu | 14.6 kN |
| Reference speed (thermal) | 6000 rpm |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 360 g |
| Manufacturer designation | NKS 65 |
| 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 & NKS-series range
| Bore d | 2.559 in |
|---|---|
| Outer diameter D | 3.346 in |
| Width B | 1.102 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 10 mm |
| Smallest bore in NKS-series | 20 mm |
| Largest outer diameter in NKS-series | 95 mm |
| Width range across NKS-series | 20–28 mm |
| Bore position in NKS-series (smallest first) | 15 of 17 |
| Bore above smallest NKS-series size | 45 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NKS65 model number is decoded
In SKF catalogue PUB BU/P1 17000, NKS 65 designates a flanged, machined outer ring filled with needle rollers and a cage for a 65 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NKS families drop the inner ring: the numbers after the letters give the 65 mm under-roller diameter and the 28 mm width, with the 85 mm outside diameter set by the wide-section machined-ring needle roller bearings without inner ring plan. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.
Typical equipment & failure modes
Common applications
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
- crank pins and eccentrics where the hardened journal is the raceway
- gearbox planetary and idler gears on hardened pins
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- 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
- corrosion pitting from condensation in intermittently operated machinery
- 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 65 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.
- 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: NKS 65 shares its 65×85×28 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 66/114 kN ratings and 360 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 632); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Which dimensions does the NKS 65 have?
A NKS 65 measures 65 mm bore/Fw × 85 mm outside diameter × 28 mm width (2.559 × 3.346 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 66 kN, static C0 114 kN, fatigue limit Pu 14.6 kN, limiting speed 6,700 r/min, reference speed 6,000 r/min, mass about 360 g.
What does NKS 65 mean in SKF part numbering?
NKS names a machined-ring needle roller bearing without inner ring: the figures give Fw 65 mm and width 28 mm, OD 85 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Does the NKS 65 need a hardened and ground shaft?
No. In this execution the 65 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.
What mounting mistakes ruin a NKS 65?
Press on the ring faces only with a fitting sleeve, keep everything square to the 65 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.
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.