HK1812 bearing: complete specifications & equivalents
The HK1812 is a ISO 3245 radial bearing sized 18 x 24 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 | 18 mm |
| Outer diameter D | 24 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 7.92 kN |
| Basic static load rating C0 | 11.2 kN |
| Fatigue load limit Pu | 1.27 kN |
| Reference speed (thermal) | 13000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 13 g |
| Manufacturer designation | HK 1812 |
| 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 | 0.709 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.472 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 3 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) | 15 of 26 |
| Bore above smallest HK-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HK1812FM | NTN | full Dimensions and internal design equivalent — standard interchange. | NTN counterpart on the same 18×24×12 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 HK1812 model number is decoded
In SKF catalogue PUB BU/P1 17000, HK 1812 denotes a 18×24×12 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. In HK 1812, Fw = 18 mm names the shaft that becomes the inner raceway and B = 12 mm the cup width; the shell outside diameter 24 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 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. For life calculation, the 7.92/11.2 kN ratings assume raceway geometry supplied by the shaft and housing in families without an inner ring — journal hardness, roundness and finish are part of the bearing, not of the application. 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
- auto steering gear rack supports
- clutch release mechanisms and cable pulleys
- office equipment and power tool gear trains
- steering column and pedal-box pivots in passenger cars
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
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
Selection pitfalls — read before you substitute
- On a 18 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Hardness is load capacity: in families without an inner ring the 18 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 7.92/11.2 kN ratings are SKF catalogue values for this exact execution (HK 1812); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 7.92/11.2 kN ratings and 13 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 622); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Can the HK 1812 run on an unhardened shaft?
No. In this execution the 18 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 1812 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 1812?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 18 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 3.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the HK 1812?
A HK 1812 measures 18 mm bore/Fw × 24 mm outside diameter × 12 mm width (0.709 × 0.945 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.92 kN, static C0 11.2 kN, fatigue limit Pu 1.27 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 13 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.