HK2212FM bearing: complete specifications & equivalents
The HK2212FM is a ISO 3245 radial bearing sized 22 x 28 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 | 22 mm |
| Outer diameter D | 28 mm |
| Width B | 12 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 9.2 kN |
| Basic static load rating C0 | 13.4 kN |
| Fatigue load limit Pu | 1.63 kN |
| Limiting speed (mechanical) | 7500 rpm |
| Mass | 13 g |
| Manufacturer designation | HK2212FM |
| 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 | 0.866 in |
|---|---|
| Outer diameter D | 1.102 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3 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) | 17 of 24 |
| Bore above smallest HK-series size | 19 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK2212FM model number is decoded
As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK2212FM is built around a thin hardened steel cup.Its printed envelope — 22 mm under-roller diameter, 28 mm outside diameter, 12 mm width — is fixed by ISO 3245; the 22 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 FM/FT2 suffix marks NTN's caged drawn-cup execution: a formed steel cage keeps the rollers evenly spaced, lowering friction and noise versus full-complement drawn cups. In this mid size range the HK cup is the standard compact radial bearing choice across automotive and industrial gearboxes. Compact hydraulic gear pumps use this size on their drive shafts: the pump housing is machined once, the cup is pressed home, and the shaft runs directly on the rollers for the life of the unit. For oscillating service, pack this size with a high-tackiness grease and re-lubricate at short intervals: the rollers do not complete a full revolution, so the same contact patch carries the load cycle after cycle.
Typical equipment & failure modes
Common applications
- hydraulic pump and motor shafts
- compressor crankshaft supports
- agricultural machinery PTO drives
- compact linkages where the cup doubles as both bearing and structural spacer
Known failure patterns
- grease starvation in the open-end arrangement with no relubrication path
- raceway spalling on a shaft that was below the required 58–64 HRC hardness
- edge loading and needle skewing under shaft misalignment or deflection
Selection pitfalls — read before you substitute
- The open ends of HK2212FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.
- At a 22 mm shaft diameter, check housing bore roundness after previous bearing removal for HK2212FM; a pulled or scored seat must be re-machined or sleeved before the new cup goes in.
- The cage in HK2212FM spaces the rollers but is not a seal: it retains nothing against dust or washdown, so the housing still needs its own sealing arrangement at 22 mm.
- The 12 mm standard width of HK2212FM is the general-purpose section at 22 mm shaft; wider HK variants in the same 22×28 mm envelope carry more load and are not interchangeable if the housing width is fixed.
- HK2212FM runs directly on the shaft: the 22 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 HK2212FM drawn-cup bearing?
HK2212FM is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (7500/11000 rpm) and radial load against the actual duty before finalizing.
What are the dimensions of a HK2212FM needle roller bearing?
A HK2212FM drawn-cup needle roller bearing has a 22 mm shaft diameter (Fw, under-roller diameter), 28 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 HK2212FM drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK2212FM, Fw = 22 mm, so the shaft must be machined to 22 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK2212FM needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK2212FM 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 HK2212FM need a hardened shaft?
Either the 22 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 (IR17x22x13) 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.