NK9-12-TN bearing: complete specifications & equivalents
The NK9-12-TN is a DIN 616 radial bearing sized 9 x 16 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 | 9 mm |
| Outer diameter D | 16 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 | 4.4 kN |
| Basic static load rating C0 | 5.2 kN |
| Fatigue load limit Pu | 0.57 kN |
| Reference speed (thermal) | 30000 rpm |
| Limiting speed (mechanical) | 34000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 10 g |
| Manufacturer designation | NK 9/12 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 | 0.354 in |
|---|---|
| Outer diameter D | 0.63 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) | 5 of 46 |
| Bore above smallest NK-series size | 4 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NK9-12-TN model number is decoded
In SKF catalogue PUB BU/P1 17000, NK 9/12 TN designates a flanged, machined outer ring filled with needle rollers and a cage for a 9 mm shaft — heavier section and higher accuracy than a drawn cup, with no inner ring so the journal is the raceway. In SKF nomenclature NK families drop the inner ring: the numbers after the letters give the 9 mm under-roller diameter and the 12 mm width, with the 16 mm outside diameter set by the machined-ring needle roller bearings without inner ring plan. 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. For life calculation, the 4.4/5.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 16 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.
Typical equipment & failure modes
Common applications
- guide rollers running on hardened tracks
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
- crank pins and eccentrics where the hardened journal is the raceway
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- 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
- false brinelling of standby equipment under external vibration
- rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away
Selection pitfalls — read before you substitute
- On a 9 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 16 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- The quoted 4.4/5.2 kN ratings are SKF catalogue values for this exact execution (NK 9/12 TN); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- 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.
- The 4.4/5.2 kN ratings and 10 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
Does the NK 9/12 TN need a hardened and ground shaft?
No. In this execution the 9 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.
What mounting mistakes ruin a NK 9/12 TN?
Press on the ring faces only with a fitting sleeve, keep everything square to the 9 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.
Is the NK 9/12 TN sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Which dimensions does the NK 9/12 TN have?
A NK 9/12 TN measures 9 mm bore/Fw × 16 mm outside diameter × 12 mm width (0.354 × 0.63 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 4.4 kN, static C0 5.2 kN, fatigue limit Pu 0.57 kN, limiting speed 34,000 r/min, reference speed 30,000 r/min, mass about 10 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.