312 bearing: complete specifications & equivalents
The 312 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 |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 91.3 kN |
| Basic static load rating C0 | 78 kN |
| Fatigue load limit Pu | 3.35 kN |
| Reference speed (thermal) | 9500 rpm |
| Limiting speed (mechanical) | 6000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1850 g |
| Manufacturer designation | 312 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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 & 300-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 300-series | 25 mm |
| Largest outer diameter in 300-series | 190 mm |
| Width range across 300-series | 17–43 mm |
| Bore position in 300-series (smallest first) | 8 of 14 |
| Bore above smallest 300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6312-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK bearing NSK 6312VV on the same 60×130×31 mm envelope, but catalogue C/C0 differ (91.3/78 kN vs 90/52 kN) — envelope interchange only after a load check. |
| 6312-M | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 60×130×31 mm envelope as SKF 6312 M, but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match only after a load check. |
| 312-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 60×130×31 mm envelope and equivalent catalogue ratings; 312-2Z is the two non-contact shields execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 6312 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312 shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
| 6312-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312-2Z shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
| 6312-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6312-2RSH shares the 60×130×31 mm envelope but catalogue C/C0 differ (91.3/78 kN vs 85.2/52 kN) — envelope match, not a load-rating equivalent. |
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 312 model number is decoded
312 is a filling-slot (notched-ring) deep-groove bearing in the legacy 300-series: the last two digits encode the bore: 312 carries code 12 = 60 mm (code × 5). The rings carry loading slots that allow extra balls during assembly, which is what gives the 60×130×31 mm envelope its C 91.3 kN and C0 78 kN ratings (Pu 3.35 kN). The open 312 carries no shields or seals and relies on application lubrication and external sealing. Limiting speed 6000 r/min, mass 1850 g. These bearings are built for high purely-radial loads at moderate speeds.
Typical equipment & failure modes
Common applications
- slow heavy gearboxes
- farm machinery and harvesters
- construction equipment drives
- hoists and winch gear trains
Known failure patterns
- spalling of the filling-slot edge when balls are hammered through the slot under heavy thrust loading
- dirt entering through the open slot area when external sealing is neglected
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling once the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- The slots sit at one angular position: on 312, never pass the full radial load across the slot zone during mounting or the ring lip can crack.
- 312 uses the legacy SKF 200/300 numbering (light/heavy filling-slot series), not the modern 6200/6300 spelling; quote 312 exactly when ordering replacements.
- Filling-slot bearings take heavy purely-radial load at moderate speed but little thrust; the 91.3/78 kN ratings assume radial loading — use deep-groove 6xxx where axial load matters.
- Shields on 312 retain grease but do not seal against water; for wet farm duty add external lip seals rather than trusting the shield.
- The slots sit at one angular position: on 312, never pass the full radial load across the slot zone during mounting or the ring lip can crack.
- The fatigue load limit is 3.35 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
Frequently asked questions
What are the dimensions of 312?
Filling-slot bearing 312 measures 60×130×31 mm (2.362×5.118×1.22 in), about 1850 g.
What does the designation 312 mean?
It is the legacy 200/300 filling-slot numbering: series 300 and bore code 12 = 60 mm. Filling-slot bearings predate the 6xxx deep-groove spelling.
What is a filling-slot bearing?
The inner and outer rings each have a loading slot; when aligned, extra balls can be inserted, raising radial rating (C 91.3 kN for 312). The slots also make the rings separable.
Can 312 take axial load?
Very little: the filling slots interrupt the raceway shoulders, so thrust towards the open slot side can unload or jam the balls. Use a standard deep-groove 6xxx bearing for combined loads.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.