HK0808 bearing: complete specifications & equivalents
The HK0808 is a ISO 3245 radial bearing sized 8 x 12 x 8 mm (bore x OD x width). 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 | 8 mm |
| Material | GCr15 |
| Seal / shield | open |
| 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 |
| Reference speed (thermal) | 19000 rpm |
| Limiting speed (mechanical) | 22000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2.7 g |
| Manufacturer designation | HK 0808 |
| 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 | 0.315 in |
| ISO bore code | 08 |
| 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 HK0808 model number is decoded
HK 0808 is the standard caged drawn cup execution for a 8 mm shaft: ISO 3245 boundary dimensions (8×12×8 mm), open at both ends so the shaft can be pushed through, and rated 2.7 kN dynamic. In HK 0808, Fw = 8 mm names the shaft that becomes the inner raceway and B = 8 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. 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. The shell is intentionally thin: seat it square with a slow press stroke, support the housing wall behind the bore, and stop the moment the cup face meets the shoulder — hammer blows split drawn cups.
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
- false brinelling of standby equipment under external vibration
Selection pitfalls — read before you substitute
- At Fw 8 mm the rolling elements are under two millimetres long — handle the HK 0808 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 0808 shares its 8×12×8 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 19,000 r/min reference is the thermal criterion under load, 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 2.7 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
What limits the service life of a HK 0808?
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 0808?
A HK 0808 measures 8 mm bore/Fw × 12 mm outside diameter × 8 mm width (0.315 × 0.472 × 0.315 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 22,000 r/min, reference speed 19,000 r/min, mass about 2.7 g.
How is the HK 0808 designation read?
HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 8 mm, the last two the width 8 mm, the shell OD 12 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage.
Can the HK 0808 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.
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.