HK3038ZWD bearing: complete specifications & equivalents
The HK3038ZWD is a ISO 3245 radial bearing sized 30 x 37 x 38 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 30 mm |
| Outer diameter D | 37 mm |
| Width B | 38 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 38.5 kN |
| Basic static load rating C0 | 78.5 kN |
| Fatigue load limit Pu | 9.6 kN |
| Limiting speed (mechanical) | 5500 rpm |
| Mass | 76 g |
| Manufacturer designation | HK3038ZWD |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.457 in |
| Width B | 1.496 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) | 20 of 24 |
| Bore above smallest HK-series size | 27 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK3038ZWD model number is decoded
As an open-end drawn-cup needle roller bearing in the HK-series (ISO 3245), NTN HK3038ZWD is built around a thin hardened steel cup.Its printed envelope — 30 mm under-roller diameter, 37 mm outside diameter, 38 mm width — is fixed by ISO 3245; the 30 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 ZW suffix marks two roller rows in the same cup, roughly doubling the dynamic rating of the width-equivalent single-row version at the cost of the extra width. At this shaft size the cup carries substantial radial load, but correct press-fit practice and housing rigidity become decisive for reaching the calculated life. This size is specified in printing-press folder and cutter mechanisms, where the shaft is short, the loads are cyclical, and the thin cup lets the frame plates stay close together. When replacing this size, measure the housing bore with a plug gauge before pressing the new cup: a bore worn oversize by the previous bearing will not retain the new shell.
Typical equipment & failure modes
Common applications
- rolling mill auxiliary drives
- heavy gearbox and final drive shafts
- construction equipment swing pivots
- reciprocating or oscillating motion where the rollers never complete a full revolution
Known failure patterns
- raceway spalling on a shaft that was below the required 58–64 HRC hardness
- edge loading and needle skewing under shaft misalignment or deflection
- cage wear or fracture from sustained operation near the limiting speed
Selection pitfalls — read before you substitute
- 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.
- At a 30 mm shaft diameter the press-in force for HK3038ZWD is substantial; use a press with a guided mandrel and confirm the cup seats against the housing shoulder — a cocked cup concentrates load on the outermost roller row.
- The two roller rows in HK3038ZWD share one cup: any shaft bending or housing-bore taper loads one row ahead of the other, so hold the 37 mm seat straight over the full 38 mm width and keep shaft deflection minimal.
- The 38 mm extra-wide section of HK3038ZWD (double-row or extended roller set) is the high-capacity option at 30 mm shaft; the wider cup is more sensitive to housing bore alignment, so check bore straightness over the full 38 mm width.
Frequently asked questions
Does HK3038ZWD need a hardened shaft?
Either the 30 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 (IR25x30x38.5) so a standard unhardened shaft can be used.
What are the dimensions of a HK3038ZWD needle roller bearing?
A HK3038ZWD drawn-cup needle roller bearing has a 30 mm shaft diameter (Fw, under-roller diameter), 37 mm outside diameter and 38 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 HK3038ZWD drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK3038ZWD, Fw = 30 mm, so the shaft must be machined to 30 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
Can a HK3038ZWD needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK3038ZWD 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.
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.