6307 bearing: complete specifications & equivalents
The 6307 is a ISO 15 radial bearing sized 35 x 80 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 21 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 | 35.1 kN |
| Basic static load rating C0 | 19 kN |
| Fatigue load limit Pu | 0.815 kN |
| Reference speed (thermal) | 19000 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 460 g |
| Manufacturer designation | SKF 6307 |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.827 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 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) | 14 of 40 |
| Bore above smallest 6300-series size | 33 mm |
Mounting, lubrication & life for 6307
Recommended fits & mounting
- Rotating inner ring on a 35 mm shaft: k5; housing bore H7 for normal stationary-load outer rings. Reverse the logic if the outer ring rotates.
- Fit by induction heating (max 120 °C) where practical — never drive the ring home through the rolling elements.
- Keep shaft and housing fillet radii below the bearing chamfer so the 21 mm-wide ring seats square on its shoulder.
Lubrication strategy
Open execution: the application supplies lubrication. Use the grease relubrication chart for this bearing — pitch diameter dm = 57.5 mm, so the speed factor at the 12,000 r/min limiting speed is 690,000 mm·r/min. Intervals shorten steeply as that factor rises.
Worked L10 life example (illustrative duty)
For ball bearings, L10h = (C/P)3 · 106 / (60·n). Taking an example radial equivalent load P = 3 kN at n = 1,500 r/min (a small belted motor duty — substitute the real equivalent load from the application calculation):
C = 35.1 kN → L10h ≈ 17,796 hours
Choosing a section at the same 35 mm bore
| Series | Open execution | OD × width | C (kN) | Limiting speed (r/min) |
|---|---|---|---|---|
| 60xx | 6007-FAG | 62 × 14 | 17.5 | 17,700 |
| 62xx | 6207-FAG | 72 × 17 | 28.0 | 15,000 |
| 63xx | 6307-FAG | 80 × 21 | 37.0 | 13,600 |
| 64xx | 6407-FAG | 100 × 25 | 56.0 | 9,500 |
| 618xx | 61807-FAG | 47 × 7 | 4.7 | 21,600 |
| 619xx | 61907-FAG | 55 × 10 | 10.9 | 17,800 |
| 160xx | 16007 | 62 × 9 | 12.3 | 16,700 |
A larger section is not a drop-in swap — OD and width change — and same-envelope seal variants are compared on the 35×80×21 envelope page. Match meaning, not the size chart alone: see what the cross-reference levels mean.
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6307-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6307-FAG | FAG | 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. |
| 6307-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6307 | 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. |
| 6307-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6307-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. |
| 6307-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6307-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6307-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6307-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. |
| 6307-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6307-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×21 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 7307 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| NU307 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| 1726307-2RS1 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 1726307-2RS1 is a standard-inner-ring insert on the same 35x80x21 mm ISO 15 envelope with ratings within 10 %, but its outer surface is sphered for a Y-housing whereas this page is the cylindrical-OD deep-groove bearing — not interchangeable mounts. |
| 6307-M | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 6307 M (machined brass cage, open arrangement) is the same-size execution on the 35×80×21 mm envelope with ratings within 10 % — boundary dimensions interchangeable. |
| W6307-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6307-2RS1 shares the 35×80×21 mm envelope but rates differently (35.1/19 kN vs 28.6/19 kN) — not a load-rating equivalent. |
| 307 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 307 shares the 35×80×21 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
| 307-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 307-2Z shares the 35×80×21 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 6307 model number is decoded
In the 6300-series (diameter series 3 of ISO 15) the last two digits encode the bore: 6307 carries bore code 07 = 35 mm. Outside diameter 80 mm and width 21 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 35 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. 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
- centrifugal pumps
- small gearboxes
- conveyors and drives
- agricultural equipment
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- Sizes around 35 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 6307.
- The 63xx medium section at 35 mm bore gains dynamic rating through larger rolling elements on a 80 mm OD; the penalty is mass and a lower limiting speed than the 6207 — do not specify it for speed-critical shafts.
- Storage matters for open bearings: 6307 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 6307 units.
- The housing bore for the 80 mm OD should be round within IT7; an oval bore pinches the outer ring of 6307 and shows up later as two-point loaded raceway wear.
- Shaft and housing fillets must clear the bearing chamfer so the 21 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
- The open 6307 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6307-2Z (shields) and 6307-2RSH (contact seals), not suffix-free 6307.
- The 35.1/19 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 6307 bearing?
A 6307 deep-groove ball bearing has a 35 mm bore, 80 mm outer diameter and 21 mm width (1.378 × 3.15 × 0.827 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How does the 6300 compare with other series at the same 35 mm bore?
The '3' is the medium diameter series: 80×21 mm, 22.5 mm radial section at 35 mm bore, carrying more load than a 6207 but needing a larger housing bore and giving up some speed.
Are 6307 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 6307 uses the same ISO 15 envelope (35×80×21 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
What internal clearance does 6307 have?
Unless a clearance suffix says otherwise, 6307 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 6307 and verify the residual clearance after mounting.
What is the SKF designation and catalogue data for 6307?
In the SKF Rolling Bearings catalogue this size is listed as 6307 — the open (unsealed) execution, 35×80×21 mm per ISO 15. Quoted values: C 35.1 kN, C0 19 kN, Pu 0.815 kN, limiting speed 12000 r/min, mass 460 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6307.
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.