BEARINGDEXDeep groove ball
6304 bearing
20 mm bore, 52 mm outside diameter, 15 mm width (0.7874 × 2.0472 × 0.5906 in).
Dimensions
| mm | inch | |
|---|---|---|
| Bore d | 20 | 0.7874 |
| Outside diameter D | 52 | 2.0472 |
| Width B | 15 | 0.5906 |
Quick numbers
| Pitch diameter dm | 36.0 mm |
| Section height (D − d)/2 | 16.0 mm |
| n·dm at 1,800 rpm | 64,800 |
| n·dm at 3,600 rpm | 129,600 |
Compare against the maker's limiting speed. Speed calculator · L10 life
What the number means
6Deep groove ball
3Diameter series 3: medium. Width series 0 is implied and left off.
04Bore code 04 × 5 = 20 mm
How each brand writes it
Same bearing, every maker's notation| Version | SKF | FAG | NSK | NTN | Koyo | NACHI |
|---|---|---|---|---|---|---|
| Open | 6304 | 6304 | 6304 | 6304 | 6304 | 6304 |
| Shields both sides | 6304-2Z | 6304-2ZR | 6304ZZ | 6304ZZ | 6304ZZ | 6304ZZE |
| Contact seals both sides | 6304-2RSH | 6304-2RSR | 6304DDU | 6304LLU | 6304-2RS | 6304-2NSE |
| Contact seals both sides, C3 | 6304-2RSH/C3 | 6304-2RSR-C3 | 6304DDUC3 | 6304LLUC3 | 6304-2RSC3 | 6304-2NSE C3 Verify |
| Non-contact seals both sides | 6304-2RSL | 6304-2BRS Verify | 6304VV | 6304LLB | 6304-2RU Verify | 6304-2NKE Verify |
| Shields both sides, C3 | 6304-2Z/C3 | 6304-2ZR-C3 | 6304ZZC3 | 6304ZZC3 | 6304ZZC3 | 6304ZZE C3 Verify |
Same size, different bearing
These share the 20 × 52 × 15 mm envelope but carry load differently. They aren't drop-in swaps.