6344-M bearing: complete specifications & equivalents
The 6344-M is a ISO 15 radial bearing sized 220 x 460 x 88 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 220 mm |
| Outer diameter D | 460 mm |
| Width B | 88 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 410 kN |
| Basic static load rating C0 | 520 kN |
| Fatigue load limit Pu | 12 kN |
| Reference speed (thermal) | 3000 rpm |
| Limiting speed (mechanical) | 2600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 73000 g |
| Manufacturer designation | 6344 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 | 8.661 in |
|---|---|
| Outer diameter D | 18.11 in |
| Width B | 3.465 in |
| ISO bore code | 44 |
| Radial section height (D−d)/2 | 120 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) | 39 of 40 |
| Bore above smallest 6300-series size | 218 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6344 | NSK | full Dimensions and internal design equivalent — standard interchange. | NSK counterpart NSK 6344 on the same 220×460×88 mm envelope with ratings within 10 % — interchange after checking seal, cage and precision details on both pages. |
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 6344-M model number is decoded
In the 6300-series, the last two digits encode the bore: 6344 carries code 44 = 220 mm (code × 5). The envelope is 220×460×88 mm (8.661×18.11×3.465 in) with a 120.0 mm radial section height, C 410 kN, C0 520 kN and Pu 12 kN. The open 6344 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 2600 r/min, catalogue mass 73000 g.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- mill and kiln auxiliaries
- pulp and paper machinery
- marine deck machinery
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- electrical pitting in VFD-driven motors without shaft grounding
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- The fatigue load limit is 12 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
- Clearance suffixes follow the seal code in the designation stack (e.g. 6344-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
- The M suffix on 6344-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 73000 g quoted mass includes the heavier cage.
- Open 6344-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 6344-M; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- At 220 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of 6344-M?
The SKF 6344 M measures 220 mm bore × 460 mm OD × 88 mm width (8.661 × 18.11 × 3.465 in), mass about 73000 g. It is open, with no shields or seals.
How does the bore code in 6344 work?
The final two digits of 6344 are bore code 44, multiplied by 5 to give 220 mm.
What is the speed rating of 6344-M?
SKF lists a 3000 r/min thermal reference speed and a 2600 r/min mechanical limiting speed for 6344 M; real limits also depend on lubrication and fits.
What is the difference between 6344-M and a same-bore 62-series bearing?
Section height differs: 6344-M has a 120 mm radial section and C 410 kN; always match d, D and B — same bore alone never makes two bearings interchangeable.
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.