628 bearing: complete specifications & equivalents
The 628 is a ISO 15 radial bearing sized 8 x 24 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 | 24 mm |
| Width B | 8 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 3.9 kN |
| Basic static load rating C0 | 1.66 kN |
| Fatigue load limit Pu | 0.071 kN |
| Reference speed (thermal) | 63000 rpm |
| Limiting speed (mechanical) | 40000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 18 g |
| Manufacturer designation | 628 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 62800-series range
| Bore d | 0.315 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.315 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 8 mm |
| Smallest bore in 62800-series | 5 mm |
| Largest outer diameter in 62800-series | 24 mm |
| Width range across 62800-series | 4–8 mm |
| Bore position in 62800-series (smallest first) | 4 of 5 |
| Bore above smallest 62800-series size | 3 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 628-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 8×24×8 mm envelope and equivalent catalogue ratings; 628-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 628-RSR | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 8×24×8 mm envelope and equivalent catalogue ratings; 628-2RZ is the low-friction non-contact seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 628-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 8×24×8 mm envelope and equivalent catalogue ratings; 628-2Z is the two non-contact shields execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| W628-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 8×24×8 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (3.9/1.66 kN vs 2.47/1.12 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
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 628 model number is decoded
In the 62800-series, the final digit is the bore in millimetres: 628 fits a 8 mm shaft (direct-number miniature spelling). The envelope is 8×24×8 mm (0.315×0.945×0.315 in) with a 8.0 mm radial section height, C 3.9 kN, C0 1.66 kN and Pu 0.071 kN. The open 628 carries no shields or seals and relies on application lubrication and external sealing. Limiting speed 40000 r/min, catalogue mass 18 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- hand-held power tools
- domestic appliances
- instrument and encoder drives
- model-making and hobby mechanics
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- brinelling from static overload or hammer blows during mounting
- false brinelling from vibration while the shaft stands idle
Selection pitfalls — read before you substitute
- Mount by heating the inner ring (max 120 °C) — driving 628 home through the outer ring or balls brinells the raceways.
- Deep-groove geometry tolerates only minutes of misalignment; if the 24 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming 628.
- Open 628 needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 628; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Deep-groove geometry tolerates only minutes of misalignment; if the 24 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming 628.
- Do not preload 628 to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
Frequently asked questions
What are the dimensions of 628?
The SKF 628 measures 8 mm bore × 24 mm OD × 8 mm width (0.315 × 0.945 × 0.315 in), mass about 18 g. It is open, with no shields or seals.
How do I read the 628 designation?
Small miniature bearings print the bore as the final digit, so 628 is a 8 mm bearing; the series digits in front give the section (OD/width family).
What is the speed rating of 628?
SKF lists a 63000 r/min thermal reference speed and a 40000 r/min mechanical limiting speed for 628; real limits also depend on lubrication and fits.
What is the difference between 628 and a same-bore 62-series bearing?
Section height differs: 628 has a 8 mm radial section and C 3.9 kN; always match d, D and B — same bore alone never makes two bearings interchangeable.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.