HK0912F bearing: complete specifications & equivalents
The HK0912F is a ISO 3245 radial bearing sized 9 x 13 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 9 mm |
| Outer diameter D | 13 mm |
| Width B | 12 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 5.4 kN |
| Basic static load rating C0 | 6.25 kN |
| Fatigue load limit Pu | 0.765 kN |
| Limiting speed (mechanical) | 18000 rpm |
| Mass | 4 g |
| Manufacturer designation | HK0912F |
| Standard | ISO 3245 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & HK-series range
| Bore d | 0.354 in |
|---|---|
| Outer diameter D | 0.512 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 2 mm |
| Smallest bore in HK-series | 3 mm |
| Largest outer diameter in HK-series | 58 mm |
| Width range across HK-series | 6–38 mm |
| Bore position in HK-series (smallest first) | 7 of 24 |
| Bore above smallest HK-series size | 6 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK0912F model number is decoded
As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK0912F is built around a thin hardened steel cup.Its printed envelope — 9 mm under-roller diameter, 13 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 9 mm figure is the shaft journal itself, which carries the rollers directly. There is no separate inner ring — the thin-walled cup is drawn from sheet steel, hardened, and press-fitted into the housing, giving the smallest radial section of any rolling bearing at this shaft size. The F suffix marks NTN's caged drawn-cup execution: a formed steel cage spaces the rollers, lowering friction versus full-complement drawn cups. This is the classic two-wheeler and small-engine size class: the cup replaces a bulky machined bearing and lets the gearbox casing shrink around it. This size is frequently specified in motorcycle gear-selector mechanisms, where the shaft is short, the housing is cast around the bearing, and the roller set must survive repeated shock from shift forks. Grease for this size should be a soft NLGI 1 or 2 lithium-complex grade: the open cup lets the housing supply the lubricant, and a stiff grease will not flow back through the roller set after standstill.
Typical equipment & failure modes
Common applications
- power tool gear reduction stages
- small hydraulic pump drives
- automotive accessory drives
- continuous high-speed rotation where grease redistribution is the limiting factor
Known failure patterns
- cup cracking from an oval or tapered housing bore distorting the thin shell
- fretting of the cup outer surface in a soft or worn housing seat
- scoring of the needle rollers from abrasive contamination past the open ends
Selection pitfalls — read before you substitute
- The open ends of HK0912F retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.
- With no inner ring, HK0912F reads the 9 mm shaft surface as its raceway: hardness 58–64 HRC and a ground finish are prerequisites, not recommendations.
- The cage in HK0912F guides the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 9 mm.
- The 12 mm standard width of HK0912F is the general-purpose section at 9 mm shaft; wider HK variants in the same 9×13 mm envelope carry more load and are not interchangeable if the housing width is fixed.
- HK0912F runs directly on the shaft: the 9 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.
Frequently asked questions
What duty conditions suit a HK0912F drawn-cup bearing?
HK0912F is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (18000/27000 rpm) and radial load against the actual duty before finalizing.
What are the dimensions of a HK0912F needle roller bearing?
A HK0912F drawn-cup needle roller bearing has a 9 mm shaft diameter (Fw, under-roller diameter), 13 mm outside diameter and 12 mm width, per ISO 3245 boundary dimensions. It has no inner ring — the shaft journal serves as the raceway.
What does Fw mean on a HK0912F drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0912F, Fw = 9 mm, so the shaft must be machined to 9 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK0912F needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK0912F carry radial load only and provide no axial shaft location. Axial forces must be carried by separate thrust washers or a locating bearing in the arrangement.
Does HK0912F need a hardened shaft?
Either the 9 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or you can fit the matching inner ring (IR6x9x12) so a standard unhardened shaft can be used.
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.