NK42-30 bearing: complete specifications & equivalents
The NK42-30 is a DIN 616 radial bearing sized 42 x 52 x 30 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 42 mm |
| Outer diameter D | 52 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 39.1 kN |
| Basic static load rating C0 | 86.5 kN |
| Fatigue load limit Pu | 10.8 kN |
| Reference speed (thermal) | 9500 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 130 g |
| Manufacturer designation | NK 42/30 |
| 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 | 1.654 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 1.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 5 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) | 28 of 46 |
| Bore above smallest NK-series size | 37 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NK42-30 model number is decoded
NK 42/30 belongs to the machined-ring needle roller family: an outer ring turned and ground to 52 mm with two retaining flanges, a roller-and-cage set inside, and envelope 42×52×30 mm on a hardened 42 mm shaft. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 42 mm under-roller diameter and the 30 mm width, with the 52 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. The wide NKS/NKIS siblings share the Fw and OD but add width for higher ratings — check both when the radial space allows a wider seat. For life calculation, the 39.1/86.5 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Grease through the housing groove before fitting the shaft; the integral flanges hold the grease film at the roller ends, which is where these bearings first starve.
Typical equipment & failure modes
Common applications
- guide rollers running on hardened tracks
- 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
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
- electrical erosion on VFD-driven shafts without brush or insulated mounting
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- At 42 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 42 mm seats can bend past the compensation range long before the load rating is exhausted.
- Reference and limiting speeds are different limits: the 9,500 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.
- Hardness is load capacity: in families without an inner ring the 42 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 39.1/86.5 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 630); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Is the NK 42/30 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 NK 42/30 have?
A NK 42/30 measures 42 mm bore/Fw × 52 mm outside diameter × 30 mm width (1.654 × 2.047 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 39.1 kN, static C0 86.5 kN, fatigue limit Pu 10.8 kN, limiting speed 11,000 r/min, reference speed 9,500 r/min, mass about 130 g.
What does NK 42/30 mean in SKF part numbering?
NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 42 mm and width 30 mm, OD 52 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Does the NK 42/30 need a hardened and ground shaft?
No. In this execution the 42 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.
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.