NX7-TN bearing: complete specifications & equivalents
The NX7-TN is a DIN 616 radial bearing sized 7 x 14 x 18 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 7 mm |
| Outer diameter D | 14 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 2.81 kN |
| Basic static load rating C0 | 2.75 kN |
| Fatigue load limit Pu | 0.29 kN |
| Reference speed (thermal) | 10000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 14 g |
| Manufacturer designation | NX 7 TN |
| 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 | 0.276 in |
|---|---|
| Outer diameter D | 0.551 in |
| Width B | 0.709 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3.5 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) | 1 of 9 |
| Bore above smallest NX-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NX7-ZTN | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 7×14×18 mm envelope and equivalent catalogue ratings; NX7-ZTN 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 NX7-TN model number is decoded
NX 7 TN packs radial and thrust capacity into 7×14×18 mm: needle rollers caged around the shaft, thrust balls packed without a cage above them, axial dynamic rating 3.45 kN (Ca). The number in NX 7 TN is the shaft diameter in millimetres; NX types differ from NKX only in the thrust part — full complement balls here, caged balls there — which changes axial capacity and speed ceiling. The thrust washer set is keyed to the housing, the ball complement to the shaft washer — assembly orientation matters, since reverse axial shocks would unload the packed ball set. Selection arithmetic for the combined unit: radial C 2.81 kN, radial C0 2.75 kN, axial dynamic 3.45 kN (Ca) and axial static 5 kN (C0a); combine them with the equivalent-load factors from the catalogue before checking L10. Check after fitting that the radial needle cage and the thrust part rotate independently where the design allows; binding between the two indicates a bent washer or a stray ball.
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
- electrical erosion on VFD-driven shafts without brush or insulated mounting
- thrust washer raceway wear from reverse axial shocks the one-direction thrust part cannot carry
Selection pitfalls — read before you substitute
- At Fw 7 mm the rolling elements are under two millimetres long — handle the NX 7 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.
- 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.
- Minimum axial load is a real requirement: below factor A 0.00013 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 2.81/2.75 kN ratings and 14 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 is the NX 7 TN designation read?
NX = needle roller radial part + full complement thrust ball part for a 7 mm shaft; the catalogue plan completes 14 mm OD and 18 mm overall height. The packed thrust set maximises axial capacity at low speed.
Can the NX 7 TN run on an unhardened shaft?
The radial needle part of the NX 7 TN runs directly on the 7 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 7 TN be mounted?
Press on the ring faces only with a fitting sleeve, keep everything square to the 7 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 7 TN?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 7 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned.
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.