6303 bearing: complete specifications & equivalents
The 6303 is a ISO 15 radial bearing sized 17 x 47 x 14 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 17 mm |
| Outer diameter D | 47 mm |
| Width B | 14 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 | 14.3 kN |
| Basic static load rating C0 | 6.55 kN |
| Fatigue load limit Pu | 0.275 kN |
| Reference speed (thermal) | 34000 rpm |
| Limiting speed (mechanical) | 22000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 110 g |
| Manufacturer designation | SKF 6303 |
| 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 | 0.669 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.551 in |
| ISO bore code | 03 |
| Radial section height (D−d)/2 | 15 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) | 8 of 40 |
| Bore above smallest 6300-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6303-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6303-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. |
| 6303-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6303-2RS | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6303-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. |
| 6303-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6303-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6303-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 6303-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. |
| 6303-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 6303-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 7303 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| W6303-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303-2RS1 shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — not a load-rating equivalent. |
| W6303-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303-2Z shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — not a load-rating equivalent. |
| W6303 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303 shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — 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 6303 model number is decoded
6303 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), its bore code 03 comes from the 10/12/15/17 mm exception table, giving a 17 mm bore; the 47 mm outside diameter and 14 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 17 mm shaft under normal load, catalogue practice seats it on a j5 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
- power tools
- small fans and blowers
- garden equipment
- instrument drives
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- electrical pitting in VFD-driven motors without grounding protection
- raceway smearing under marginal lubrication at start-up
Selection pitfalls — read before you substitute
- Bore codes 00–03 use the exception table: 6303 fits a 17 mm shaft — the code × 5 mnemonic does not apply below code 04 (it would imply 0 mm for code 00).
- The 63xx medium series gains rating at 17 mm bore through a 47 mm OD and 14 mm width; the heavier rolling elements also trade away some speed versus a 6203.
- The open 6303 has no lubricant retention: grease escapes and contaminants migrate straight into the 17×47×14 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Storage matters for open bearings: 6303 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.
- The housing bore for the 47 mm OD should be round within IT7; an oval bore pinches the outer ring of 6303 and shows up later as two-point loaded raceway wear.
- Shaft and housing fillets must clear the bearing chamfer so the 14 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
- The open 6303 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6303-2Z (shields) and 6303-2RSH (contact seals), not suffix-free 6303.
- The 14.3/6.55 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 6303 bearing?
A 6303 deep-groove ball bearing has a 17 mm bore, 47 mm outer diameter and 14 mm width (0.669 × 1.85 × 0.551 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How should 6303 be mounted?
Apply the mounting force to the ring being fitted: on a 17 mm shaft seat the press load must pass through the inner-ring face only. A fitting sleeve and an arbor press are normally sufficient at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 6303 need?
The open 6303 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.
Why does 6303 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 6303 with code 03 has a 17 mm bore. The code × 5 convention starts at code 04 (20 mm).
What is the SKF designation and catalogue data for 6303?
In the SKF Rolling Bearings catalogue this size is listed as 6303 — the open (unsealed) execution, 17×47×14 mm per ISO 15. Quoted values: C 14.3 kN, C0 6.55 kN, Pu 0.275 kN, limiting speed 22000 r/min, mass 110 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6303.
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.