6312 bearing dimensions
A 6312 bearing is 60 mm bore × 130 mm outside diameter × 31 mm wide (2.362 × 5.118 × 1.220 in). The sealed version is 6312-2RS; the shielded version is 6312-ZZ.
6312 at a glance
Boundary dimensions in millimetres and inches, and the common closure designations.
- Bore, d
- 60 mm 2.3622"
- Outside diameter, D
- 130 mm 5.1181"
- Width, B
- 31 mm 1.2205"
- Section height, (D − d)/2
- 35 mm 1.3780"
- Series
- 63 series medium
- Bore code
- 12 12 × 5 = 60 mm
- Sealed, both sides
- 6312-2RS
- Shielded, both sides
- 6312-ZZ
- Open
- 6312 no closures; any version may add C3 for extra internal clearance
Reading the number 6312
Every deep groove ball bearing number follows the same pattern: type, dimension series and bore code, then suffixes.
Seals, shields and suffixes
Suffixes add closures and internal clearance. They do not change the boundary dimensions: a sealed and an open bearing of the same number are interchangeable in size.
| Suffix | Meaning | 6312 example |
|---|---|---|
| Open (no suffix) | No seals or shields. Can be relubricated, or run in an oil bath; the housing needs its own seal against dirt. | 6312 |
| Z | One metal shield, on one side only. | 6312-Z |
| ZZ, 2Z | Metal shields on both sides. Non-contact, so low friction; keeps out larger dirt. Usually greased for life. | 6312-ZZ |
| RS | One rubber contact seal, on one side only. | 6312-RS |
| 2RS, 2RS1, 2RSH, 2RSR, DDU, LLU | Rubber contact seals on both sides. Better than shields against fine dirt and splashing water, with a little more friction. Usually greased for life. | 6312-2RS |
| C3 | Radial internal clearance greater than normal (CN). Used with tight shaft or housing fits, or where the inner ring runs hotter than the outer ring. | 6312-2RS C3 |
6312 in other brands
The sealed and shielded versions as each maker writes them. All share the same boundary dimensions.
| Maker | Sealed both sides | Shielded both sides |
|---|---|---|
| SKF | 6312-2RSH | 6312-2Z |
| FAG (Schaeffler) | 6312-2RSR | 6312-2ZR |
| NSK | 6312DDU | 6312ZZ |
| NTN | 6312LLU | 6312ZZ |
| Koyo (JTEKT) | 6312-2RS | 6312ZZ |
| Timken | 6312-2RS | see catalogue |
Seal designs and suffixes vary by maker, size range and product generation, for example contact versus low-friction seals. Confirm the exact designation in the maker's catalogue before ordering.
Same 60 mm bore, other series
Bearings that fit the same shaft. A heavier series carries more load in a bigger housing bore; a thin-section series saves space and weight.
63 series
Common questions
What size is a 6312 bearing?
60 mm bore, 130 mm outside diameter and 31 mm wide, which is 2.362 × 5.118 × 1.220 in.
What does 2RS mean on a 6312 bearing?
6312-2RS has rubber contact seals on both sides. 6312-ZZ (also written 6312-2Z) has metal shields on both sides. Both have the same 60 × 130 × 31 mm dimensions.
Is 6312-2RS the same as 6312-ZZ?
They are the same size and interchangeable in a housing. The sealed 6312-2RS keeps out fine dirt and water better; the shielded 6312-ZZ runs with less friction.
What is the SKF equivalent of 6312-2RS?
SKF writes it 6312-2RSH; FAG 6312-2RSR, NSK 6312DDU, NTN 6312LLU and Koyo 6312-2RS. Check the maker's catalogue for the exact seal type.
What does the number 6312 mean?
6 is the deep groove ball bearing type, 3 is the medium dimension series, and 12 × 5 = 60 mm (from 04 up, multiply by 5).
Which bearings have the same bore as 6312?
6012, 6212 also have a 60 mm bore, with different outside diameters and widths.