628-ZZ bearing: complete specifications & equivalents
The 628-ZZ is a ISO 15 radial bearing sized 8 x 24 x 8 mm (bore x OD x width) with ZZ sealing. 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 | ZZ |
| 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) | 32000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 18 g |
| Manufacturer designation | 628-2Z |
| 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 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 8×24×8 mm envelope and equivalent catalogue ratings; 628 is the open arrangement execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 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. |
| 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-ZZ 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. SKF spells the double shield 628-2Z (suffix 2Z); the shields are non-contact, retain grease and block coarse debris but are not liquid-tight. Limiting speed 32000 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
- model-making and hobby mechanics
- small pumps
- office equipment
- fractional-horsepower motors
Known failure patterns
- fine-particle abrasion when non-contact shields let dust through in a dirty environment
- grease aging inside the shielded cavity with no relubrication path
- fretting corrosion on a creeping shaft or housing seat
- cage damage from running beyond the limiting speed
Selection pitfalls — read before you substitute
- Assign interference to the rotating ring: on a conventional shaft-mounted 8 mm position the inner ring rotates, so use a k5/m6 shaft seat with an H7 housing — reverse the logic if the outer ring rotates.
- Mount by heating the inner ring (max 120 °C) — driving 628-ZZ home through the outer ring or balls brinells the raceways.
- Shields on 628-ZZ are non-contact: chips and coarse dust stay out, but water passes straight through — specify the sealed 628-2RS for washdown duty.
- Do not pry the caps off 628-ZZ to repack it; shield/seal damage leaves a gap that throws grease and admits dirt.
- Do not preload 628-ZZ to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- Clearance suffixes follow the seal code in the designation stack (e.g. 628-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
Frequently asked questions
What are the dimensions of 628-ZZ?
The SKF 628-2Z measures 8 mm bore × 24 mm OD × 8 mm width (0.315 × 0.945 × 0.315 in), mass about 18 g. It has two non-contact sheet-metal shields.
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 load can 628-ZZ take?
Catalogue values for 628-2Z: dynamic C 3.9 kN, static C0 1.66 kN, fatigue limit Pu 0.071 kN. Use C in life calculation and C0 for static checks at 8 mm bore.
What is the speed rating of 628-ZZ?
SKF lists a 63000 r/min thermal reference speed and a 32000 r/min mechanical limiting speed for 628-2Z; real limits also depend on lubrication and fits.
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.