HK0812-2RS bearing: complete specifications & equivalents
The HK0812-2RS is a ISO 3245 radial bearing sized 8 x 12 x 12 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 8 mm |
| Outer diameter D | 12 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 2.7 kN |
| Basic static load rating C0 | 2.75 kN |
| Fatigue load limit Pu | 0.285 kN |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3.3 g |
| Manufacturer designation | HK 0812.2RS |
| 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 | 0.315 in |
|---|---|
| Outer diameter D | 0.472 in |
| Width B | 0.472 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 2 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) | 6 of 26 |
| Bore above smallest HK-series size | 5 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the HK0812-2RS model number is decoded
HK 0812.2RS is the standard caged drawn cup execution for a 8 mm shaft: ISO 3245 boundary dimensions (8×12×12 mm), open at both ends so the shaft can be pushed through, and rated 2.7 kN dynamic. In HK 0812, Fw = 8 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 12 mm is fixed by the boundary plan, so the housing bore needs only a press-fit tolerance. Sealed 2RS execution: rubber contact seals on both cup faces, factory grease fill, and the slightly lower ratings of a sealed drawn cup — 2.7 kN C against the open bearing of the same code. The shell itself is the outer ring: hardened sheet steel, closed at neither end (open type), so the shaft can pass through and lubricant can be fed axially along the journal. The 3.3 g catalogue mass and 2.0 mm radial section ((12−8)/2) frame a rating of about 0.34 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: press the cup in with a shouldered mandrel against the stamped end face only — through-the-rollers pressing brinells both raceways; the housing bore takes a firm press fit and the shaft slides in after.
Typical equipment & failure modes
Common applications
- spindle clusters of drilling and tapping units
- auto steering gear rack supports
- clutch release mechanisms and cable pulleys
- office equipment and power tool gear trains
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
- rolling-contact fatigue spalling after the rated L10 life
Selection pitfalls — read before you substitute
- At Fw 8 mm the rolling elements are under two millimetres long — handle the HK 0812.2RS like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.
- Do not interchange envelope-identical needle families blindly: HK 0812.2RS shares its 8×12×12 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- Reference and limiting speeds are different limits: the catalogue lists no reference speed for this execution, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- The 2.7/2.75 kN ratings and 3.3 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 620); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the HK 0812.2RS run on an unhardened shaft?
No. In this execution the 8 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 0812.2RS 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 0812.2RS?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 8 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 2.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the HK 0812.2RS?
A HK 0812.2RS measures 8 mm bore/Fw × 12 mm outside diameter × 12 mm width (0.315 × 0.472 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.7 kN, static C0 2.75 kN, fatigue limit Pu 0.285 kN, limiting speed 13,000 r/min, mass about 3.3 g.
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.