HK4020F bearing: complete specifications & equivalents
The HK4020F is a ISO 3245 radial bearing sized 40 x 47 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40 mm |
| Outer diameter D | 47 mm |
| Width B | 20 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 25.9 kN |
| Basic static load rating C0 | 52.5 kN |
| Fatigue load limit Pu | 6.4 kN |
| Limiting speed (mechanical) | 4000 rpm |
| Mass | 52 g |
| Manufacturer designation | HK4020F |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3.5 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) | 22 of 24 |
| Bore above smallest HK-series size | 37 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK4020F model number is decoded
As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK4020F is built around a thin hardened steel cup.Its printed envelope — 40 mm under-roller diameter, 47 mm outside diameter, 20 mm width — is fixed by ISO 3245; the 40 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. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. You will find this cup size inside small two-stroke crankcases, supporting the small-end of the connecting rod where the housing is split and the bearing is pressed in before the case halves close. If the shaft cannot be hardened, press the matching IR inner ring onto it first; the ring gives the rollers a hardened, ground raceway and lets you keep a soft shaft for assembly reasons.
Typical equipment & failure modes
Common applications
- printing press cylinder journals
- machine tool feed drive supports
- marine steering and linkage shafts
- lightly loaded high-speed idler positions where roller skidding must be watched
Known failure patterns
- cage wear or fracture from sustained operation near the limiting speed
- 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
Selection pitfalls — read before you substitute
- The press-fit of HK4020F at 40 mm shaft size must be done in one smooth stroke: stopping mid-way or driving at an angle leaves the cup cocked and the load on one roller row.
- The cage in HK4020F 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 40 mm.
- The 20 mm wide section of HK4020F gains rating through longer rollers at 40 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 40×47 mm narrow variant.
- The HK4020F drawn cup is a thin shell that takes the shape of its housing: the housing bore must be machined to tolerance (typically N6/N7 for steel housings) — a worn or oval seat distorts the cup and cuts life.
Frequently asked questions
What are the dimensions of a HK4020F needle roller bearing?
A HK4020F drawn-cup needle roller bearing has a 40 mm shaft diameter (Fw, under-roller diameter), 47 mm outside diameter and 20 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 HK4020F drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4020F, Fw = 40 mm, so the shaft must be machined to 40 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK4020F needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK4020F 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 HK4020F need a hardened shaft?
Either the 40 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 (IR35x40x20.5) 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.