NKXR40 bearing: complete specifications & equivalents
The NKXR40 is a DIN 616 radial bearing sized 40 x 52 x 32 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 52 mm |
| Width B | 32 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 26.4 kN |
| Basic static load rating C0 | 51 kN |
| Fatigue load limit Pu | 6.3 kN |
| Reference speed (thermal) | 2400 rpm |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 200 g |
| Manufacturer designation | NKXR 40 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.10 needle roller / cylindrical-needle thrust); 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 & NKXR-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 1.26 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NKXR-series | 15 mm |
| Largest outer diameter in NKXR-series | 62 mm |
| Width range across NKXR-series | 23–35 mm |
| Bore position in NKXR-series (smallest first) | 7 of 9 |
| Bore above smallest NKXR-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKXR40-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 40×52×32 mm envelope and equivalent catalogue ratings; NKXR40-Z is the combined needle/thrust needle execution — boundary-dimension interchangeable, execution differences (seals, shields, cage) apply. |
| NKX40-Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (40×52×32 mm) combined needle/thrust ball execution with ratings within 10 % — substitution possible after checking ring/flange construction. |
| NKX40 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (40×52×32 mm) combined needle/thrust ball 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 NKXR40 model number is decoded
The combined needle roller / full complement needle thrust bearings execution NKXR 40 measures 40×52×32 mm: radial dynamic 26.4 kN, axial dynamic 43 kN (Ca) — the thrust needle complement gives roughly twice the axial rating of a same-size thrust ball part. The code NKXR 40 identifies the construction exactly — needle radial part, needle thrust part — for a 40 mm shaft; the thrust set is one-directional and must face the working axial load. Execution notes: the Z suffix shields the thrust needle set; the full complement part delivers the highest axial rating in the family but needs the minimum axial load (factor A 0.0015) to prevent needle skidding. Selection arithmetic for the combined unit: radial C 26.4 kN, radial C0 51 kN, axial dynamic 43 kN (Ca) and axial static 137 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Fit with a press against the washer faces only — needles packed without a cage will skew if the assembly is dropped or driven sideways onto the 40 mm seat.
Typical equipment & failure modes
Common applications
- turntables and slewing pivots with shock loads
- press-fit die set guide positions
- heavy screw presses and clamping spindles
- crane slew rings and kingposts at low speed
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
- false brinelling of standby equipment under external vibration
- thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry
Selection pitfalls — read before you substitute
- At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.
- Hardness is load capacity: in families without an inner ring the 40 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 26.4/51 kN ratings are SKF catalogue values for this exact execution (NKXR 40); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- Minimum axial load is a real requirement: below factor A 0.0015 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 26.4/51 kN ratings and 200 g mass are SKF catalogue values transcribed from ch. 7.10 of PUB BU/P1 17000 (PDF table page 660); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the NKXR 40 run on an unhardened shaft?
The radial needle part of the NKXR 40 runs directly on the 40 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 NKXR 40 be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 40 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 NKXR 40?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 40 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 NKXR 40?
A NKXR 40 measures 40 mm bore/Fw × 52 mm outside diameter × 32 mm width (1.575 × 2.047 × 1.26 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 26.4 kN, static C0 51 kN, fatigue limit Pu 6.3 kN, limiting speed 5,000 r/min, reference speed 2,400 r/min, mass about 200 g. Axial ratings of the thrust part: dynamic Ca 43 kN (Ca), static C0a 137 kN (C0a), minimum load factor A 0.0015; 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. 7.10 needle roller / cylindrical-needle thrust on 2026-09-26. Read our editorial & correction policy.