HK0509 bearing: complete specifications & equivalents
The HK0509 is a ISO 3245 radial bearing sized 5 x 9 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 5 mm |
| Outer diameter D | 9 mm |
| Width B | 9 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 2.38 kN |
| Basic static load rating C0 | 2.08 kN |
| Fatigue load limit Pu | 0.22 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 24000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2 g |
| Manufacturer designation | HK 0509 |
| 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 | 0.197 in |
|---|---|
| Outer diameter D | 0.354 in |
| Width B | 0.354 in |
| ISO bore code | 09 |
| 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) | 3 of 26 |
| Bore above smallest HK-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HK0509FM | NTN | full Dimensions and internal design equivalent — standard interchange. | NTN counterpart on the same 5×9×9 mm envelope with ratings within 10 % — interchange after checking the execution (cage/seal) details on both pages. |
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 HK0509 model number is decoded
For a 5 mm shaft in a thin housing wall, SKF catalogue execution HK 0509 offers a 9 mm wide, 9 mm diameter pressed shell with caged needle rollers — the classic minimal-section drawn cup solution. SKF's HK numbering puts the shaft size first: 05 → Fw 5 mm (the ground, hardened journal), 09 → width 9 mm, with the 9 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. Speed planning separates the two ceilings: 22,000 r/min thermal reference and 24,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 5 mm seat. 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
- idler gears and pulleys in small appliance drives
- spindle clusters of drilling and tapping units
- auto steering gear rack supports
- clutch release mechanisms and cable pulleys
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- fretting corrosion of the cup outside diameter in a soft or oversized housing bore
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- corrosion pitting from condensation in intermittently operated machinery
Selection pitfalls — read before you substitute
- At Fw 5 mm the rolling elements are under two millimetres long — handle the HK 0509 like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.
- Hardness is load capacity: in families without an inner ring the 5 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The quoted 2.38/2.08 kN ratings are SKF catalogue values for this exact execution (HK 0509); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 2.38/2.08 kN ratings and 2 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
How should the HK 0509 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 0509?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 5 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 0509?
A HK 0509 measures 5 mm bore/Fw × 9 mm outside diameter × 9 mm width (0.197 × 0.354 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 2.38 kN, static C0 2.08 kN, fatigue limit Pu 0.22 kN, limiting speed 24,000 r/min, reference speed 22,000 r/min, mass about 2 g.
How is the HK 0509 designation read?
HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 5 mm, the last two the width 9 mm, the shell OD 9 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage.
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.