HK0709FM bearing: complete specifications & equivalents
The HK0709FM is a ISO 3245 radial bearing sized 7 x 11 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 7 mm |
| Outer diameter D | 11 mm |
| Width B | 9 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 3.15 kN |
| Basic static load rating C0 | 2.93 kN |
| Fatigue load limit Pu | 0.355 kN |
| Limiting speed (mechanical) | 23000 rpm |
| Mass | 2 g |
| Manufacturer designation | HK0709FM |
| 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 | 0.276 in |
|---|---|
| Outer diameter D | 0.433 in |
| Width B | 0.354 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) | 5 of 24 |
| Bore above smallest HK-series size | 4 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK0709FM model number is decoded
NTN HK0709FM belongs to the HK-series of open-end drawn-cup needle roller bearings (ISO 3245).Fw = 7 mm names the shaft journal that doubles as the inner raceway; around it the drawn cup measures 11 mm outside and 9 mm across. 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 size range the drawn cup gives a far smaller radial section than any machined-ring needle bearing of the same shaft, which is why it dominates in compact transmissions. Small compressor crankshafts and refrigeration equipment fit this size on the eccentric pin, where the housing bore is finish-bored in the same setup as the main bearing seats. Where the housing is a welded fabrication, finish-bore the seat after all welding and stress-relief is complete — pressing the cup into a distorted, as-welded bore guarantees early spalling.
Typical equipment & failure modes
Common applications
- automotive accessory drives
- lawn and garden equipment spindles
- motorcycle and scooter transmissions
- dirty environments where the open ends rely entirely on the housing seals
Known failure patterns
- 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
- brinelling of the drawn cup from hammer blows during press-in mounting
Selection pitfalls — read before you substitute
- At a 7 mm shaft diameter, shaft surface finish is critical for HK0709FM: grinding marks, corrosion pits or chrome flaking on the journal will fluke the rollers within hours — polish or replace a suspect shaft.
- The cage in HK0709FM 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 7 mm.
- The 9 mm narrow section of HK0709FM is the compact option at 7 mm shaft: load capacity is limited by the short roller length, so verify the required rating before choosing it over a wider HK variant in the same 7×11 mm envelope.
- The open ends of HK0709FM retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.
Frequently asked questions
What are the dimensions of a HK0709FM needle roller bearing?
A HK0709FM drawn-cup needle roller bearing has a 7 mm shaft diameter (Fw, under-roller diameter), 11 mm outside diameter and 9 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 HK0709FM drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0709FM, Fw = 7 mm, so the shaft must be machined to 7 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK0709FM needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK0709FM 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.
How is a HK0709FM retained in the housing?
The thin-walled drawn cup of HK0709FM is press-fitted into a 11 mm housing bore (typically N6/N7 tolerance for steel housings). The press fit alone retains the cup — no snap rings or shoulders are needed, but the bore must be round and rigid.
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.