HK0306FT2 bearing: complete specifications & equivalents
The HK0306FT2 is a ISO 3245 radial bearing sized 3 x 6.5 x 6 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 3 mm |
| Outer diameter D | 6.5 mm |
| Width B | 6 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 0.925 kN |
| Basic static load rating C0 | 0.565 kN |
| Fatigue load limit Pu | 0.069 kN |
| Limiting speed (mechanical) | 33000 rpm |
| Mass | 1 g |
| Manufacturer designation | HK0306FT2 |
| 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 | 0.118 in |
|---|---|
| Outer diameter D | 0.256 in |
| Width B | 0.236 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 1.8 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) | 1 of 24 |
| Bore above smallest HK-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK0306FT2 model number is decoded
HK0306FT2 is an NTN drawn-cup needle roller bearing with open ends in the HK-series (ISO 3245 boundary dimensions).The designation encodes the shaft fit directly: Fw = 3 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 6.5 mm and the width is 6 mm. 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. At this miniature shaft size the cup wall is fractions of a millimetre thick, so handling cleanliness and housing-bore accuracy matter more than the paper load rating. Automotive steering-column and pedal-box pivots use this size, where the cup is pressed into a sheet-metal bracket and the shaft sees only slow, heavily loaded oscillation. Never re-grease through a drilled hole in the housing wall without a vent path: pressure builds behind the cup, blows grease past the rollers, and starves the bearing while the housing looks full.
Typical equipment & failure modes
Common applications
- small appliance gear drives
- instrument and meter linkages
- model and hobby drive trains
- 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 3 mm shaft diameter the cup wall of HK0306FT2 is extremely thin; inspect for transportation dents before pressing in, and deburr the housing bore edge or the cup will score and split on entry.
- The cage in HK0306FT2 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 3 mm.
- The 6 mm narrow section of HK0306FT2 is the compact option at 3 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 3×6.5 mm envelope.
- Press the drawn cup in with a mandrel bearing on the stamped face only — never hammer the cup or press through the rollers, that cracks or brinells the shell.
Frequently asked questions
What are the dimensions of a HK0306FT2 needle roller bearing?
A HK0306FT2 drawn-cup needle roller bearing has a 3 mm shaft diameter (Fw, under-roller diameter), 6.5 mm outside diameter and 6 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 HK0306FT2 drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK0306FT2, Fw = 3 mm, so the shaft must be machined to 3 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK0306FT2 needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK0306FT2 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 HK0306FT2 retained in the housing?
The thin-walled drawn cup of HK0306FT2 is press-fitted into a 6.5 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.