HK4512 bearing: complete specifications & equivalents
The HK4512 is a ISO 3245 radial bearing sized 45 x 52 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 45 mm |
| Outer diameter D | 52 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 14.2 kN |
| Basic static load rating C0 | 27.5 kN |
| Fatigue load limit Pu | 3.2 kN |
| Reference speed (thermal) | 5600 rpm |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 33 g |
| Manufacturer designation | HK 4512 |
| Standard | ISO 3245 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & HK-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.472 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 3.5 mm |
| Smallest bore in HK-series | 3 mm |
| Largest outer diameter in HK-series | 68 mm |
| Width range across HK-series | 6–38 mm |
| Bore position in HK-series (smallest first) | 23 of 26 |
| Bore above smallest HK-series size | 42 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HK4512 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the HK4512 model number is decoded
In SKF catalogue PUB BU/P1 17000, HK 4512 denotes a 45×52×12 mm drawn cup needle roller bearing with open ends — the shaft journal is the inner raceway, the pressed shell the outer, and the cage keeps the rollers parallel. SKF's HK numbering puts the shaft size first: 45 → Fw 45 mm (the ground, hardened journal), 12 → width 12 mm, with the 52 mm shell OD from the ISO 3245 dimension table. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. The suffix TN denotes the glass fibre reinforced PA66 cage; the 2RS execution adds rubber contact seals on both faces, retaining factory grease for life-lubricated pivots. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. Open ends mean the housing must do the sealing; where that is impossible, the 2RS execution with its integrated seals and grease fill replaces sealing rings that would not fit the 12 mm section.
Typical equipment & failure modes
Common applications
- clutch release mechanisms and cable pulleys
- office equipment and power tool gear trains
- steering column and pedal-box pivots in passenger cars
- idler gears and pulleys in small appliance drives
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- electrical erosion on VFD-driven shafts without brush or insulated mounting
Selection pitfalls — read before you substitute
- At 45 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 45 mm seats can bend past the compensation range long before the load rating is exhausted.
- Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- The 14.2/27.5 kN ratings and 33 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
How is the HK 4512 designation read?
HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 45 mm, the last two the width 12 mm, the shell OD 52 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage.
Can the HK 4512 run on an unhardened shaft?
No. In this execution the 45 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
How should the HK 4512 be mounted?
Press the cup in with a shouldered mandrel bearing on the stamped face, into a housing bore sized for a firm press fit; never hammer it or press through the rollers. Then slide the hardened shaft in. For 2RS executions the seals and grease are already in place — no additional sealing is needed.
What limits the service life of a HK 4512?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 45 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.5 mm radial section leaves no reserve once a raceway is dented or ribboned.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.2 drawn cup needle roller bearings on 2026-09-26. Read our editorial & correction policy.