6312 bearing: complete specifications & equivalents
The 6312 is a ISO 15 radial bearing sized 60 x 130 x 31 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 60 mm |
| Outer diameter D | 130 mm |
| Width B | 31 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 85.2 kN |
| Basic static load rating C0 | 52 kN |
| Fatigue load limit Pu | 2.2 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 7000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 1700 g |
| Manufacturer designation | SKF 6312 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
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 & 6300-series range
| Bore d | 2.362 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 1.22 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 6300-series | 2 mm |
| Largest outer diameter in 6300-series | 500 mm |
| Width range across 6300-series | 3–95 mm |
| Bore position in 6300-series (smallest first) | 19 of 40 |
| Bore above smallest 6300-series size | 58 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6312 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 6312-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6312-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6312-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6312-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6312-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6312-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6312-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6312-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 7312 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| NU312 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| 21312 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| 6312-M | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 6312 M (machined brass cage, open arrangement) is the same-size execution on the 60×130×31 mm envelope with ratings within 10 % — boundary dimensions interchangeable. |
| 312 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 312 shares the 60×130×31 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
| 312-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 312-2Z shares the 60×130×31 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
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 6312 model number is decoded
6312 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 12 by five gives the 60 mm bore; the 130 mm outside diameter and 31 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 60 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- industrial electric motors
- centrifugal and positive-displacement pumps
- gearboxes and speed reducers
- conveyor drives
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Temperature rise and interference fits consume internal clearance on this 60 mm bore: a CN bearing on a tight, hot shaft can lose all residual clearance — size 6312 with C3 for those conditions.
- The 63xx medium section at 60 mm bore gains dynamic rating through larger rolling elements on a 130 mm OD; the penalty is mass and a lower limiting speed than the 6212 — do not specify it for speed-critical shafts.
- Storage matters for open bearings: 6312 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Open bearings tolerate the highest speeds in the 6300-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6312 units.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- Never mix components between two 6312 units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- The open 6312 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6312-2Z (shields) and 6312-2RSH (contact seals), not suffix-free 6312.
- The 85.2/52 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 6312 bearing?
A 6312 deep-groove ball bearing has a 60 mm bore, 130 mm outer diameter and 31 mm width (2.362 × 5.118 × 1.22 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
What lubrication does 6312 need?
The open 6312 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
How does the 6312 bore code work?
The last two digits of 6312 are bore code 12, giving 12 × 5 = 60 mm bore. The 130 mm outside diameter and 31 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6312 mean?
A bare 6312 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
What is the SKF designation and catalogue data for 6312?
In the SKF Rolling Bearings catalogue this size is listed as 6312 — the open (unsealed) execution, 60×130×31 mm per ISO 15. Quoted values: C 85.2 kN, C0 52 kN, Pu 2.2 kN, limiting speed 7000 r/min, mass 1700 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6312.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.