NK7-12-TN bearing: complete specifications & equivalents
The NK7-12-TN is a DIN 616 radial bearing sized 7 x 14 x 12 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 | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 3.58 kN |
| Basic static load rating C0 | 3.75 kN |
| Fatigue load limit Pu | 0.415 kN |
| Reference speed (thermal) | 32000 rpm |
| Limiting speed (mechanical) | 36000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 8.200000000000001 g |
| Manufacturer designation | NK 7/12 TN |
| 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 | 0.276 in |
|---|---|
| Outer diameter D | 0.551 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3.5 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) | 3 of 46 |
| Bore above smallest NK-series size | 2 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NK7-12-TN model number is decoded
Where the shaft can be hardened and ground, SKF offers NK 7/12 TN in the machined-ring needle roller bearings without inner ring: outer ring only, needle rollers caged between integral flanges, 7 mm bore seat and 14 mm OD. The NK 7/12 TN code states Fw 7 and width 12 mm directly; because the family has no inner ring, the 7 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. SKF offers this family open as standard; a matching IR inner ring can be added separately when the shaft cannot be hardened, which converts the envelope into the NKI/NA equivalent. The 8.200000000000001 g catalogue mass and 3.5 mm radial section ((14−7)/2) frame a rating of about 0.51 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: the flanged outer ring presses into the H7 housing bore against its flange face; the shaft (hardened to 58–64 HRC, ground) enters afterwards, and axial retention is by the housing wall plus a cover washer.
Typical equipment & failure modes
Common applications
- piston-pin style pivots in hydraulic pumps
- guide rollers running on hardened tracks
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
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
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- rolling-contact fatigue spalling after the rated L10 life
- rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away
Selection pitfalls — read before you substitute
- At Fw 7 mm the rolling elements are under two millimetres long — handle the NK 7/12 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.
- The 3.58/3.75 kN ratings and 8.200000000000001 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the NK 7/12 TN run on an unhardened shaft?
No. In this execution the 7 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.
How should the NK 7/12 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 NK 7/12 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.
What are the dimensions and ratings of the NK 7/12 TN?
A NK 7/12 TN measures 7 mm bore/Fw × 14 mm outside diameter × 12 mm width (0.276 × 0.551 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 3.58 kN, static C0 3.75 kN, fatigue limit Pu 0.415 kN, limiting speed 36,000 r/min, reference speed 32,000 r/min, mass about 8.200000000000001 g.
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.