6312-ZZ bearing: complete specifications & equivalents
The 6312-ZZ is a ISO 15 radial bearing sized 60 x 130 x 31 mm (bore x OD x width) with ZZ sealing. 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 | ZZ |
| 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) | 5600 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 1800 g |
| Manufacturer designation | SKF 6312-2Z |
| 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 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting. |
| 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 (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6312-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 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 (ZZ vs RSR) — confirm sealing suits the duty. |
| 6312-ZZ-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. |
| 6312-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6312-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 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 (ZZ vs RSR) — confirm sealing suits the duty. |
| 6312-ZZ-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. |
| 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-ZZ model number is decoded
In the 6300-series (diameter series 3 of ISO 15) the last two digits encode the bore: 6312 carries bore code 12 = 60 mm. Outside diameter 130 mm and width 31 mm come from the ISO 15 boundary-dimensions general plan. Suffix -ZZ denotes two non-contact metallic shields; they retain grease and block coarse debris but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 60 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. SKF's own suffix is 2Z (this page's industry-neutral spelling is -ZZ); catalogue number 6312-2Z.
Typical equipment & failure modes
Common applications
- industrial electric motors
- centrifugal and positive-displacement pumps
- gearboxes and speed reducers
- conveyor drives
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- cage damage from operation beyond the limiting speed
- electrical pitting in VFD-driven motors without grounding protection
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.
- Do not wash 6312-ZZ in solvent before mounting: the grease inside the shielded cavity is the service fill, and solvent creeping past the shield gap strips it out.
- Shielded 6312-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- Measure the shaft, do not trust the drawing: a 60 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6312-ZZ.
- Do not quieten a noisy bearing by preloading it: the 6300-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- SKF spells the shielded version 6312-2Z (one shield: 6312-Z), not "-ZZ": the suffix language differs by brand even though the ISO envelope is identical, so quote the brand designation when ordering.
- The single-shield execution 6312-Z is a distinct order number in catalogue 17000: it suits open gears or oil-bath arrangements where the unshielded face faces the lubricant, and it is not interchangeable with the double-shield 6312-2Z for high-contamination positions.
- 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-ZZ bearing?
A 6312-ZZ 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 fitted with two non-contact metallic shields.
What internal clearance does 6312-ZZ have?
Unless a clearance suffix says otherwise, 6312-ZZ is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 6312 and verify the residual clearance after mounting.
How should 6312-ZZ be mounted?
Apply the mounting force to the ring being fitted: on a 60 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 6312-ZZ need?
6312-ZZ is greased at the factory and the shields hold the fill for the bearing's service life; relubrication is not intended, and adding grease through the shield gap usually forces dirt in with it.
What is the SKF designation and catalogue data for 6312-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 6312-2Z — two non-contact sheet-metal shields, 60×130×31 mm per ISO 15. Quoted values: C 85.2 kN, C0 52 kN, Pu 2.2 kN, limiting speed 5600 r/min, mass 1800 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6312-ZZ.
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.