628 Bearing
Bore (d) 8 mm
Outside diameter (D) 24 mm
Width (B) 8 mm
Inches (bore × OD × width) 0.3150 × 0.9449 × 0.3150″
Deep-groove ball bearing, miniature (62x) series. Seal/shield suffixes (ZZ, 2RS, …) change the closures, never these dimensions — a 628-ZZ and 628-2RS are the same size.
What the number means
- 6 — deep-groove ball bearing
- 2 — miniature (62x) series
- 8 — bore in mm (8 mm)
Neighboring sizes (miniature (62x) series)
| Designation | Bore | OD | Width |
|---|---|---|---|
| 626 | 6 mm | 19 mm | 6 mm |
| 627 | 7 mm | 22 mm | 7 mm |
| 628 | 8 mm | 24 mm | 8 mm |
| 629 | 9 mm | 26 mm | 8 mm |
Same bore, other series
Fits the same 8 mm shaft with a different OD/width envelope and load capacity.
- 608 — 8 × 22 × 7 mm (miniature (60x))
Common suffixes on a 628
| Suffix | Meaning |
|---|---|
| ZZ / 2Z | steel shields both sides (metal, non-contact) |
| Z | steel shield, one side |
| 2RS | contact rubber seals both sides (SKF 2RS1, NSK DDU, NTN LLU) |
| RS | contact rubber seal, one side |
| 2RZ | low-friction non-contact seals both sides (NSK VV, NTN LLB) |
| C3 | radial internal clearance greater than Normal (common in motors) |
| C2 | radial internal clearance smaller than Normal |
| NR | snap ring groove in the outer ring, with snap ring |
| P6 / P5 / P4 | ISO precision classes (≈ ABEC 3 / 5 / 7) |