NKX70 bearing: complete specifications & equivalents
The NKX70 is a DIN 616 radial bearing sized 70 x 85 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 70 mm |
| Outer diameter D | 85 mm |
| Width B | 40 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 44.6 kN |
| Basic static load rating C0 | 98 kN |
| Fatigue load limit Pu | 12.2 kN |
| Reference speed (thermal) | 3400 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 500 g |
| Manufacturer designation | NKX 70 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part); 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 & NKX-series range
| Bore d | 2.756 in |
|---|---|
| Outer diameter D | 3.346 in |
| Width B | 1.575 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 7.5 mm |
| Smallest bore in NKX-series | 10 mm |
| Largest outer diameter in NKX-series | 85 mm |
| Width range across NKX-series | 23–40 mm |
| Bore position in NKX-series (smallest first) | 13 of 13 |
| Bore above smallest NKX-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKX70-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 70×85×40 mm envelope and equivalent catalogue ratings; NKX70-Z is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the NKX70 model number is decoded
In SKF catalogue PUB BU/P1 17000, NKX 70 designates a combined bearing with needle roller radial part and caged thrust ball part: 70 mm shaft seat, 85 mm OD, thrust dynamic rating 43.6 kN (Ca). Reading the designation: NKX marks needle roller + caged thrust ball, the number the 70 mm shaft seat; the 85 mm OD and 40 mm overall height come from the series plan. The thrust part takes axial load in one direction only; mount it facing the working load and provide a separate locating bearing for reverse events. Axial capability is one-direction: size the arrangement so working thrust pushes the thrust-washer face, and provide a mirrored unit or separate bearing for load reversals. The caged thrust part survives moderate speed only with the Z shield intact — damaged shields admit grit straight into the ball raceways, and the narrow section leaves no margin.
Typical equipment & failure modes
Common applications
- turntable and swivel mounts
- machine tool feed spindles with one-direction thrust
- pump impeller shafts with steady axial pull
- gear pairs generating one-direction axial force
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
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- false brinelling of standby equipment under external vibration
- thrust-part ball or roller skidding and smearing when the axial load falls below the minimum factor
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 70 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: NKX 70 shares its 70×85×40 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Minimum axial load is a real requirement: below factor A 0.097 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.
- Height stack-up is easy to mis-check: the thrust-washer part adds height beyond a plain needle bearing, and clamping the stack solid over it preloads the thrust set beyond its rating.
- The 44.6/98 kN ratings and 500 g mass are SKF catalogue values transcribed from ch. 7.9 of PUB BU/P1 17000 (PDF table page 658); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What mounting mistakes ruin a NKX 70?
Press on the ring faces only with a fitting sleeve, keep everything square to the 70 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.
Is the NKX 70 sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Which dimensions does the NKX 70 have?
A NKX 70 measures 70 mm bore/Fw × 85 mm outside diameter × 40 mm width (2.756 × 3.346 × 1.575 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 44.6 kN, static C0 98 kN, fatigue limit Pu 12.2 kN, limiting speed 4,500 r/min, reference speed 3,400 r/min, mass about 500 g. Axial ratings of the thrust part: dynamic Ca 43.6 kN (Ca), static C0a 137 kN (C0a), minimum load factor A 0.097; the thrust set carries load in one direction only.
What does NKX 70 mean in SKF part numbering?
NKX = needle roller radial part + caged thrust ball part for a 70 mm shaft: 85 mm OD, 40 mm overall height. The caged thrust part trades some axial capacity for higher permissible speed versus NX.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.9 needle roller / thrust ball, caged thrust part on 2026-09-26. Read our editorial & correction policy.