HK4020 bearing: complete specifications & equivalents
The HK4020 is a ISO 3245 radial bearing sized 40 x 47 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 47 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 24.2 kN |
| Basic static load rating C0 | 53 kN |
| Fatigue load limit Pu | 6.4 kN |
| Reference speed (thermal) | 6300 rpm |
| Limiting speed (mechanical) | 7000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 54 g |
| Manufacturer designation | HK 4020 |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.787 in |
| ISO bore code | 20 |
| 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) | 22 of 26 |
| Bore above smallest HK-series size | 37 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| HK4020-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×47×20 mm envelope, but catalogue C/C0 differ between the executions (24.2/53 vs 19/39 kN) — boundary dimensions match, not a load-rating equivalent. |
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 HK4020 model number is decoded
Ordering number HK 4020 in SKF catalogue PUB BU/P1 17000 is an open-end HK drawn cup needle roller bearing: nominal code 40 for the 40 mm under-roller diameter and 20 for the 20 mm width. Reading the code: HK marks the open-end drawn cup series, the first two digits (40) give the 40 mm under-roller diameter Fw, the last two (20) the 20 mm width; the 47 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. Drawn cups exist open (basic HK), sealed (2RS, with contact seals and grease fill) and with polymer TN cage; each is a separate order number with its own ratings, not a field conversion. For life calculation, the 24.2/53 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. 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 20 mm section.
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
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- drawn-cup shell distortion or splitting from a careless press-in without a seating mandrel
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- electrical erosion on VFD-driven shafts without brush or insulated mounting
Selection pitfalls — read before you substitute
- At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.
- Reference and limiting speeds are different limits: the 6,300 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.
- Hardness is load capacity: in families without an inner ring the 40 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 24.2/53 kN ratings and 54 g mass are SKF catalogue values transcribed from ch. 7.2 of PUB BU/P1 17000 (PDF table page 624); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Is the HK 4020 sealed?
No — the open-end HK cup has no seals: the housing must keep contamination out and grease in. The 2RS execution of the same code adds both-side contact seals with a grease fill.
Which dimensions does the HK 4020 have?
A HK 4020 measures 40 mm bore/Fw × 47 mm outside diameter × 20 mm width (1.575 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 24.2 kN, static C0 53 kN, fatigue limit Pu 6.4 kN, limiting speed 7,000 r/min, reference speed 6,300 r/min, mass about 54 g.
What does HK 4020 mean in SKF part numbering?
HK = open-end drawn cup needle roller bearing (ISO 3245); the first two digits give Fw 40 mm, the last two the width 20 mm, the shell OD 47 mm follows the plan. 2RS adds both-side contact seals, TN the polymer cage.
Does the HK 4020 need a hardened and ground shaft?
No. In this execution the 40 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.