6408 bearing: complete specifications & equivalents
The 6408 is a ISO 15 radial bearing sized 40 x 110 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 40 mm |
| Outer diameter D | 110 mm |
| Width B | 27 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 | 63.7 kN |
| Basic static load rating C0 | 36.5 kN |
| Fatigue load limit Pu | 1.53 kN |
| Reference speed (thermal) | 14000 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 1250 g |
| Manufacturer designation | SKF 6408 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
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 & 6400-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.063 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 6400-series | 10 mm |
| Largest outer diameter in 6400-series | 250 mm |
| Width range across 6400-series | 12–58 mm |
| Bore position in 6400-series (smallest first) | 9 of 21 |
| Bore above smallest 6400-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6408-ZZ | GENERIC-ISO | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×110×27 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 6408-2RS | GENERIC-ISO | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×110×27 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
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 6408 model number is decoded
In the 6400-series (ISO 15 diameter series 4) the last two digits encode the bore: 6408 carries bore code 08 = 40 mm. Outside diameter 110 mm and width 27 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 40 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
- small gearboxes
- conveyors and drives
- agricultural equipment
- fans and blowers
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- fretting corrosion on a loose shaft seat
- cage damage from operation beyond the limiting speed
Selection pitfalls — read before you substitute
- At a 40 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 6408; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
- The 64xx heavy section at 40 mm bore (110 mm OD) is built for high-load, lower-speed duty; specifying it in a high-rpm motor gives excess heat and short grease life — use 62/63 there.
- The open 6408 has no lubricant retention: grease escapes and contaminants migrate straight into the 40×110×27 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 6400-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 6408 units.
- A 40 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
- The open 6408 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 6408-2Z (shields) and 6408-2RSH (contact seals), not suffix-free 6408.
- The 63.7/36.5 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 6408 bearing?
A 6408 deep-groove ball bearing has a 40 mm bore, 110 mm outer diameter and 27 mm width (1.575 × 4.331 × 1.063 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields. Geometry-based estimated mass is about 1136 g for a steel-cage unit; catalogue masses vary slightly with seal and cage design.
How does the 6408 bore code work?
The last two digits of 6408 are bore code 08, giving 08 × 5 = 40 mm bore. The 110 mm outside diameter and 27 mm width follow the ISO 15 diameter series, not the bore code alone.
What does no suffix on 6408 mean?
A bare 6408 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.
How does the 6400 compare with other series at the same 40 mm bore?
The '4' is the heavy diameter series: 110×27 mm, 35.0 mm radial section at 40 mm bore — the highest-capacity single-row 6xx option here, aimed at lower-speed, high-load shafts.
What is the SKF designation and catalogue data for 6408?
In the SKF Rolling Bearings catalogue this size is listed as 6408 — the open (unsealed) execution, 40×110×27 mm per ISO 15. Quoted values: C 63.7 kN, C0 36.5 kN, Pu 1.53 kN, limiting speed 9000 r/min, mass 1250 g. Brand suffixes (2Z, 2RSH) differ from the industry-neutral spelling 6408.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.