6304 Bearing — Cross-Reference & Equivalents
The 6304 is a deep groove ball bearing with ISO 15 boundary dimensions 20×52×15 mm. The table below lists how 8 major brands designate it, with catalog links and interchange notes.
Specifications
| Bore (d) | 20 mm |
|---|---|
| Outer Diameter (D) | 52 mm |
| Width (B) | 15 mm |
| Type | Deep Groove Ball Bearing |
| Standard | ISO 15 |
Cross-Reference by Brand
| Brand | Part No. | Contact seal | Shield | Boundary dims | Catalog |
|---|---|---|---|---|---|
| SKF | 6304 | 2RSH | 2Z | match | SKF catalog ↗ |
| NSK | 6304 | DDU | ZZ | match | NSK catalog ↗ |
| FAG | 6304 | 2RSR | 2ZR | match | FAG catalog ↗ |
| NTN | 6304 | LLU | ZZ | match | NTN catalog ↗ |
| KOYO | 6304 | 2RS | ZZ | match | KOYO catalog ↗ |
| NACHI | 6304 | 2NSE | ZE | match | NACHI catalog ↗ |
| Timken | 6304 | 2RS | ZZ | match | Timken catalog ↗ |
| INA | 6304 | 2RSR | 2ZR | match | INA catalog ↗ |
Interchange notes
All brands listed build this designation to the same ISO 15 boundary dimensions, so they share the same mounting envelope. Before substituting, match these brand-specific attributes: (1) internal radial clearance (CN/C3/C4); (2) precision class (P0/P6/P5); (3) seal/shield suffix — naming differs by brand (see table); (4) cage material and factory grease. Open and sealed (2RS/ZZ) variants usually share width B. Load ratings (dynamic Cr, static C0r) are intentionally NOT listed here: they vary by brand and internal design and are a safety-critical selection parameter — read them directly from the manufacturer catalog linked in the table above.
FAQ
What bearings are equivalent to a 6304?
The 6304 is built to ISO 15 boundary dimensions 20×52×15 mm by SKF, NSK, FAG, NTN, KOYO, NACHI, Timken, INA. All share the same mounting envelope; match clearance, precision class and (where applicable) seal suffix before substituting.
What are the dimensions of a 6304 bearing?
Bore 20 mm, outer diameter 52 mm, B 15 mm (ISO 15).
Is an SKF 6304 interchangeable with an NSK 6304?
Dimensionally yes — both follow ISO 15 (20×52×15 mm). Note the contact-seal suffix differs: SKF uses 2RSH, NSK uses DDU. Confirm internal clearance (e.g. C3) and precision class match.
Related sizes
Boundary-dimension cross-reference only. Per the applicable ISO standard (ISO 15 for ball, ISO 355 for tapered), the boundary dimensions are common across brands, so the mounting envelope is interchangeable. This is NOT a drop-in part equivalence. Internal clearance, precision class, seal/shield type (where applicable), cage material and factory lubrication are encoded in brand-specific suffixes and must be matched separately. Always verify against the manufacturer's catalog before substituting.