HK4012V2 bearing: complete specifications & equivalents
The HK4012V2 is a ISO 3245 radial bearing sized 40 x 47 x 12 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 | 12 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 12.1 kN |
| Basic static load rating C0 | 19.5 kN |
| Fatigue load limit Pu | 2.38 kN |
| Limiting speed (mechanical) | 4000 rpm |
| Mass | 31 g |
| Manufacturer designation | HK4012V2 |
| 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 | 0.472 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 HK4012V2 model number is decoded
In the HK-series (ISO 3245), HK4012V2 is NTN's open-end drawn-cup needle roller bearing.Boundary dimensions are 40 mm under-roller diameter (Fw — the shaft journal acts as the raceway), 47 mm cup outside diameter and 12 mm width. 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 trailing code letters mark a production-variant shell or cage execution; the boundary dimensions match the base HK size, so interchange checks should rely on the printed Fw/D/C values. Larger drawn cups demand more of the housing: cast seats should be checked for roundness and rigidity before the cup is pressed in. Industrial sewing machines and textile equipment run this size on their shuttle and needle-bar drive shafts, where the compact radial section keeps the arm profile slim. Shaft tolerance for this size is h5 or j5: the roller complement needs a controlled radial clearance, and a shaft ground to general-purpose tolerances can leave the bearing either slack or pinched.
Typical equipment & failure modes
Common applications
- printing press cylinder journals
- machine tool feed drive supports
- marine steering and linkage shafts
- compact linkages where the cup doubles as both bearing and structural spacer
Known failure patterns
- grease starvation in the open-end arrangement with no relubrication path
- raceway spalling on a shaft that was below the required 58–64 HRC hardness
- edge loading and needle skewing under shaft misalignment or deflection
Selection pitfalls — read before you substitute
- The 12 mm standard width of HK4012V2 is the general-purpose section at 40 mm shaft; wider HK variants in the same 40×47 mm envelope carry more load and are not interchangeable if the housing width is fixed.
- HK4012V2 runs directly on the shaft: the 40 mm shaft journal must be hardened to 58–64 HRC and ground to Ra ≤ 0.2 µm, or fit the matching IR inner ring instead.
- The open ends of HK4012V2 retain no lubricant: grease must be supplied by the housing arrangement, and adjacent seals are needed in dirty or washdown duty.
- The press-fit of HK4012V2 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.
- HK4012V2 carries a maker-specific variant code after the size: when substituting another brand, match the printed 40×47×12 mm boundary dimensions and load ratings rather than the suffix letters, which are not standardized across makers.
Frequently asked questions
Can a HK4012V2 needle roller bearing carry axial load?
No. Drawn-cup needle roller bearings like HK4012V2 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 HK4012V2 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 (IR35x40x12.5) so a standard unhardened shaft can be used.
What duty conditions suit a HK4012V2 drawn-cup bearing?
HK4012V2 is typically specified for lightly loaded high-speed idler positions where roller skidding must be watched; match the grease/oil speed limits (4000/6000 rpm) and radial load against the actual duty before finalizing.
What are the dimensions of a HK4012V2 needle roller bearing?
A HK4012V2 drawn-cup needle roller bearing has a 40 mm shaft diameter (Fw, under-roller diameter), 47 mm outside diameter and 12 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 HK4012V2 drawn-cup bearing?
Fw is the under-roller diameter — the diameter of the shaft journal on which the needle rollers run directly. For HK4012V2, 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.
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.