6338-M bearing: complete specifications & equivalents
The 6338-M is a ISO 15 radial bearing sized 190 x 400 x 78 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 190 mm |
| Outer diameter D | 400 mm |
| Width B | 78 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 371 kN |
| Basic static load rating C0 | 430 kN |
| Fatigue load limit Pu | 10.8 kN |
| Reference speed (thermal) | 3400 rpm |
| Limiting speed (mechanical) | 3000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 47500 g |
| Manufacturer designation | 6338 M |
| 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 & 6300-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 15.748 in |
| Width B | 3.071 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 105 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) | 37 of 40 |
| Bore above smallest 6300-series size | 188 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6338 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 6338 (open arrangement) shares the 190×400×78 mm envelope with ratings within 10 % — execution variant of the same size; boundary dimensions interchangeable. |
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 6338-M model number is decoded
In the 6300-series, the last two digits encode the bore: 6338 carries code 38 = 190 mm (code × 5). The envelope is 190×400×78 mm (7.48×15.748×3.071 in) with a 105.0 mm radial section height, C 371 kN, C0 430 kN and Pu 10.8 kN. The open 6338 M carries no shields or seals and relies on application lubrication and external sealing. The M suffix identifies the machined brass cage execution, a separate order number from the pressed-steel version. Limiting speed 3000 r/min, catalogue mass 47500 g.
Typical equipment & failure modes
Common applications
- large industrial gearboxes
- heavy conveyor drives
- hoists and winches
- industrial fans and blowers
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- raceway smearing under marginal lubrication at start-up
- electrical pitting in VFD-driven motors without shaft grounding
Selection pitfalls — read before you substitute
- Do not preload 6338-M to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- Do not preload 6338-M to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- The M suffix on 6338-M denotes a machined brass cage: it is the choice for high speeds, marginal lubrication and shock/vibration duty, and it is temperature-tolerant where polymer cages are not — the 47500 g quoted mass includes the heavier cage.
- Open 6338-M needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 6338-M; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Catalogue ratings for 6338-M (C 371 kN, C0 430 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
Frequently asked questions
What are the dimensions of 6338-M?
The SKF 6338 M measures 190 mm bore × 400 mm OD × 78 mm width (7.48 × 15.748 × 3.071 in), mass about 47500 g. It is open, with no shields or seals.
How does the bore code in 6338 work?
The final two digits of 6338 are bore code 38, multiplied by 5 to give 190 mm.
What load can 6338-M take?
Catalogue values for 6338 M: dynamic C 371 kN, static C0 430 kN, fatigue limit Pu 10.8 kN. Use C in life calculation and C0 for static checks at 190 mm bore.
What is the speed rating of 6338-M?
SKF lists a 3400 r/min thermal reference speed and a 3000 r/min mechanical limiting speed for 6338 M; real limits also depend on lubrication and fits.
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.