HK4520 bearing: complete specifications & equivalents
The HK4520 is a ISO 3245 radial bearing sized 45 x 52 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 | 45 mm |
| Outer diameter D | 52 mm |
| Width B | 20 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 27.6 kN |
| Basic static load rating C0 | 59 kN |
| Fatigue load limit Pu | 7.2 kN |
| Limiting speed (mechanical) | 3700 rpm |
| Mass | 58 g |
| Manufacturer designation | HK4520 |
| 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 | 1.772 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.787 in |
| ISO bore code | 20 |
| 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) | 23 of 24 |
| Bore above smallest HK-series size | 42 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK4520 model number is decoded
HK4520 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 = 45 mm is the under-roller diameter, i.e. the shaft journal that serves as the inner raceway; the cup outside diameter is 52 mm and the width is 20 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. No suffix letters follow the size code: this is the basic caged drawn-cup execution in the HK range. In this class the limiting factor is rarely the rating table — a poorly supported or out-of-round seat will end the bearing long before fatigue does. This cup size is common in power-tool intermediate shafts — drills, saws, grinders — where the gearbox casing is magnesium or aluminium and the cup is pressed into a steel insert. If the shaft sees axial float, allow for it in the housing width — the cup cannot guide the shaft axially, and a shaft that walks will eventually hammer the open end of the shell.
Typical equipment & failure modes
Common applications
- construction equipment swing pivots
- printing press cylinder journals
- machine tool feed drive supports
- continuous high-speed rotation where grease redistribution is the limiting factor
Known failure patterns
- 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
- scoring of the needle rollers from abrasive contamination past the open ends
Selection pitfalls — read before you substitute
- The 20 mm wide section of HK4520 gains rating through longer rollers at 45 mm shaft; confirm the housing width accepts 20 mm — it will not drop into a seat machined for the 45×52 mm narrow variant.
- Needle rollers tolerate almost no misalignment; if the 52 mm housing seat cannot be held square to the shaft, expect edge loading and early spalling.
- 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.
- Pressing HK4520 (45 mm shaft) home needs real force: keep the cup square with a guided mandrel, because a tilted cup overloads the roller row nearest the shoulder.
- With no suffix letters, HK4520 is the base caged execution: when replacing a branded equivalent, confirm the boundary dimensions 45×52×20 mm match exactly — suffix conventions for cage and shell variants differ between makers.
Frequently asked questions
Can a HK4520 needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK4520 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 HK4520 need a hardened shaft?
Either the 45 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 (IR40x45x20.5) so a standard unhardened shaft can be used.
What duty conditions suit a HK4520 drawn-cup bearing?
HK4520 is typically specified for intermittent duty with long standstill periods that invite false brinelling; match the grease/oil speed limits (3700/5500 rpm) and radial load against the actual duty before finalizing.
What are the dimensions of a HK4520 needle roller bearing?
A HK4520 drawn-cup needle roller bearing has a 45 mm shaft diameter (Fw, under-roller diameter), 52 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 HK4520 drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4520, Fw = 45 mm, so the shaft must be machined to 45 mm, hardened to 58–64 HRC and ground, unless a separate IR inner ring is fitted.
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.