NX20-Z bearing: complete specifications & equivalents
The NX20-Z is a DIN 616 radial bearing sized 20 x 30 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 | 20 mm |
| Outer diameter D | 30 mm |
| Width B | 28 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 13.2 kN |
| Basic static load rating C0 | 19.3 kN |
| Fatigue load limit Pu | 2.28 kN |
| Reference speed (thermal) | 6300 rpm |
| Limiting speed (mechanical) | 4500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 68 g |
| Manufacturer designation | NX 20 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 | 0.787 in |
|---|---|
| Outer diameter D | 1.181 in |
| Width B | 1.102 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 5 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) | 6 of 9 |
| Bore above smallest NX-series size | 13 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NX20 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×30×28 mm envelope and equivalent catalogue ratings; NX20 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 NX20-Z model number is decoded
Where a 20 mm shaft needs radial support plus one-direction axial location in minimal length, NX 20 Z from the combined needle roller / full complement thrust ball bearings stacks both functions: 30 mm OD, thrust part 7.8 kN (Ca) dynamic. The NX 20 Z code gives only the 20 mm Fw — the construction is fixed by the letters: caged radial needles below, packed thrust balls above, 28 mm total height. Full complement thrust parts run slower than caged ones: observe the 4,500 r/min limiting speed, and expect the thrust part to govern the thermal ceiling. The minimum load factor A 0.0016 applies to the thrust part: below that axial load the rolling elements of the thrust set skid, so springs or preload washers are part of the arrangement, not an afterthought. 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
- valve and dosing pump stems with slow axial push
- light rotary tables under axial load
- oscillating pivots with steady axial preload
- small hoisting and winch drums
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- corrosion pitting from condensation in intermittently operated machinery
- thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry
Selection pitfalls — read before you substitute
- On a 20 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 30 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Hardness is load capacity: in families without an inner ring the 20 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 13.2/19.3 kN ratings are SKF catalogue values for this exact execution (NX 20 Z); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- 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 20 Z facing the working thrust.
- Minimum axial load is a real requirement: below factor A 0.0016 the thrust elements skid, polish their raceways and lose them — springs or preload washers belong in the arrangement drawing, not the troubleshooting notes.
- The 13.2/19.3 kN ratings and 68 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
How should the NX 20 Z be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 20 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 20 Z?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 20 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 5.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NX 20 Z?
A NX 20 Z measures 20 mm bore/Fw × 30 mm outside diameter × 28 mm width (0.787 × 1.181 × 1.102 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 13.2 kN, static C0 19.3 kN, fatigue limit Pu 2.28 kN, limiting speed 4,500 r/min, reference speed 6,300 r/min, mass about 68 g. Axial ratings of the thrust part: dynamic Ca 7.8 kN (Ca), static C0a 17.3 kN (C0a), minimum load factor A 0.0016; the thrust set carries load in one direction only.
How is the NX 20 Z designation read?
NX = needle roller radial part + full complement thrust ball part for a 20 mm shaft; the catalogue plan completes 30 mm OD and 28 mm overall height. The packed thrust set maximises axial capacity at low speed.
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.