6401 bearing: complete specifications & equivalents
The 6401 is a ISO 15 radial bearing sized 12 x 48 x 14 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 12 mm |
| Outer diameter D | 48 mm |
| Width B | 14 mm |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Mass (geometry estimate) | 121 g |
| Standard | ISO 15 |
| Catalog version | iso15-ed4-geometry |
| Last verified | 2026-09-24 |
Source: ISO 15 boundary-dimensions standard · extracted 2026-09-24
Standard-interchange bearing: dimensions per ISO 15; CN clearance, P0 tolerance and a stamped-steel cage are catalogue defaults unless the supplier states otherwise, and mass is a geometry-derived estimate. Brand catalogue load ratings and limiting speeds for 6401 are being backfilled — use the inquiry form for certified values.
Dimensions in inches & 6400-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 1.89 in |
| Width B | 0.551 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 18 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) | 2 of 21 |
| Bore above smallest 6400-series size | 2 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6401 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 6401 model number is decoded
In the 6400-series (ISO 15 diameter series 4) the last two digits encode the bore: 6401 carries bore code 01 = 12 mm. Codes 00–03 follow the 10/12/15/17 mm exception table rather than code × 5. Outside diameter 48 mm and width 14 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 12 mm shaft, typical catalogue practice is a j5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude.
Typical equipment & failure modes
Common applications
- domestic appliances
- power tools
- small fans and blowers
- garden equipment
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- cage damage from operation beyond the limiting speed
- electrical pitting in VFD-driven motors without grounding protection
Selection pitfalls — read before you substitute
- Bore codes 00–03 use the exception table: 6401 fits a 12 mm shaft — the code × 5 mnemonic does not apply below code 04 (it would imply 0 mm for code 00).
- The 64xx heavy section at 12 mm bore (48 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 6401 has no lubricant retention: grease escapes and contaminants migrate straight into the 12×48×14 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 6401 units.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 6401-C3. No clearance suffix means normal CN clearance.
Frequently asked questions
What are the dimensions of a 6401 bearing?
A 6401 deep-groove ball bearing has a 12 mm bore, 48 mm outer diameter and 14 mm width (0.472 × 1.89 × 0.551 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields. Geometry-based estimated mass is about 121 g for a steel-cage unit; catalogue masses vary slightly with seal and cage design.
Why does 6401 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 6401 with code 01 has a 12 mm bore. The code × 5 convention starts at code 04 (20 mm).
What does no suffix on 6401 mean?
A bare 6401 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 12 mm bore?
The '4' is the heavy diameter series: 48×14 mm, 18.0 mm radial section at 12 mm bore — the highest-capacity single-row 6xx option here, aimed at lower-speed, high-load shafts.
Are 6401 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 6401 uses the same ISO 15 envelope (12×48×14 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
Reviewed & verified by the MPN Base engineering desk against source catalog iso15-ed4-geometry on 2026-09-24. Read our editorial & correction policy.