NX30-Z bearing: complete specifications & equivalents
The NX30-Z is a DIN 616 radial bearing sized 30 x 42 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 | 30 mm |
| Outer diameter D | 42 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 22.9 kN |
| Basic static load rating C0 | 38 kN |
| Fatigue load limit Pu | 4.8 kN |
| Reference speed (thermal) | 5300 rpm |
| Limiting speed (mechanical) | 3600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 130 g |
| Manufacturer designation | NX 30 Z |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement 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. 7.8 needle roller / thrust ball, full complement 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 & NX-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 1.654 in |
| Width B | 1.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NX-series | 7 mm |
| Largest outer diameter in NX-series | 47 mm |
| Width range across NX-series | 18–30 mm |
| Bore position in NX-series (smallest first) | 8 of 9 |
| Bore above smallest NX-series size | 23 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NX30 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 30×42×30 mm envelope and equivalent catalogue ratings; NX30 is the combined needle/thrust ball execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply. |
| RNA6905 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×42×30 mm envelope, but catalogue C/C0 differ between the executions (22.9/38 vs 38/62 kN) — boundary dimensions match, not a load-rating equivalent. |
| NKX30-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
| NKX30 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (30×42×30 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
| NKXR30 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
| NKXR30-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (30×42×30 mm) combined needle/thrust needle execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
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 NX30-Z model number is decoded
Where a 30 mm shaft needs radial support plus one-direction axial location in minimal length, NX 30 Z from the combined needle roller / full complement thrust ball bearings stacks both functions: 42 mm OD, thrust part 12.7 kN (Ca) dynamic. The NX 30 Z code gives only the 30 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 30 mm total height. Full complement thrust parts run slower than caged ones: observe the 3,600 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. Selection arithmetic for the combined unit: radial C 22.9 kN, radial C0 38 kN, axial dynamic 12.7 kN (Ca) and axial static 32.5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Mounting: assemble the thrust washer set with the keyed washer in the housing, fill the packed ball complement with grease so the balls adhere during fitting, and orient the thrust part toward the working axial load.
Typical equipment & failure modes
Common applications
- screw jack and lifting screw spindles
- valve and dosing pump stems with slow axial push
- light rotary tables under axial load
- oscillating pivots with steady axial preload
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
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry
Selection pitfalls — read before you substitute
- At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.
- 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.
- 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 treat the axial rating 12.7 kN (Ca) as independent of radial load: the combined equivalent load formulas couple them, and a unit sized on radial life alone will spall the ball raceway first under real thrust.
- The thrust part is one-direction: reverse axial events — however brief — lift the rolling elements off the raceway, and the subsequent re-entry impact dents the washer face; mount the NX 30 Z facing the working thrust.
- The 22.9/38 kN ratings and 130 g mass are SKF catalogue values transcribed from ch. 7.8 of PUB BU/P1 17000 (PDF table page 656); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the NX 30 Z run on an unhardened shaft?
The radial needle part of the NX 30 Z runs directly on the 30 mm journal — harden to 58–64 HRC and grind it. The thrust washers are integral, so no separate inner ring exists; size the shaft for the raceway tolerances in the catalogue table.
How should the NX 30 Z be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 30 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 NX 30 Z?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 30 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 6.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NX 30 Z?
A NX 30 Z measures 30 mm bore/Fw × 42 mm outside diameter × 30 mm width (1.181 × 1.654 × 1.181 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 3,600 r/min, reference speed 5,300 r/min, mass about 130 g. Axial ratings of the thrust part: dynamic Ca 12.7 kN (Ca), static C0a 32.5 kN (C0a), minimum load factor A 0.0055; the thrust set carries load in one direction only.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.8 needle roller / thrust ball, full complement thrust part on 2026-09-26. Read our editorial & correction policy.