HK3012 bearing: complete specifications & equivalents
The HK3012 is a ISO 3245 radial bearing sized 30 x 37 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 | 30 mm |
| Outer diameter D | 37 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 11.7 kN |
| Basic static load rating C0 | 18.3 kN |
| Fatigue load limit Pu | 2.12 kN |
| Reference speed (thermal) | 8000 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 23 g |
| Manufacturer designation | HK 3012 |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.457 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) | 20 of 26 |
| Bore above smallest HK-series size | 27 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HK3012CT | NTN | full Dimensions and internal design equivalent — standard interchange. | NTN counterpart on the same 30×37×12 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 HK3012 model number is decoded
SKF supplies HK 3012 for housings where machining an outer-ring pocket is uneconomical: the 37 mm shell broached from sheet steel press-fits into a plain bore and runs a 30 mm hardened shaft. Reading the code: HK marks the open-end drawn cup series, the first two digits (30) give the 30 mm under-roller diameter Fw, the last two (12) the 12 mm width; the 37 mm OD follows the ISO 3245 plan. Open caged execution: the standard HK drawn cup with steel cage, relubricable through the shaft where the housing allows. Caged HK bearings space the rollers for lower friction than full complement HK types; the cage is not a seal — 2RS executions are the sealed members of the family. 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
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- fretting corrosion of the cup outside diameter in a soft or oversized housing bore
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- hard-particle indentation in unfiltered lubricant
Selection pitfalls — read before you substitute
- At 30 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 30 mm seats can bend past the compensation range long before the load rating is exhausted.
- The quoted 11.7/18.3 kN ratings are SKF catalogue values for this exact execution (HK 3012); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- 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.
- The 11.7/18.3 kN ratings and 23 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
Which dimensions does the HK 3012 have?
A HK 3012 measures 30 mm bore/Fw × 37 mm outside diameter × 12 mm width (1.181 × 1.457 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.7 kN, static C0 18.3 kN, fatigue limit Pu 2.12 kN, limiting speed 9,000 r/min, reference speed 8,000 r/min, mass about 23 g.
What does HK 3012 mean in SKF part numbering?
HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 30 mm, the last two the width 12 mm, the shell OD 37 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage.
Does the HK 3012 need a hardened and ground shaft?
No. In this execution the 30 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.
What mounting mistakes ruin a HK 3012?
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.
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.