61868-MA bearing: complete specifications & equivalents
The 61868-MA is a ISO 15 radial bearing sized 340 x 420 x 38 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 340 mm |
| Outer diameter D | 420 mm |
| Width B | 38 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 178 kN |
| Basic static load rating C0 | 275 kN |
| Fatigue load limit Pu | 6 kN |
| Reference speed (thermal) | 2800 rpm |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 11500 g |
| Manufacturer designation | 61868 MA |
| 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 & 61800-series range
| Bore d | 13.386 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 1.496 in |
| ISO bore code | 68 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 49 of 74 |
| Bore above smallest 61800-series size | 339 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61868 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 61868 (open arrangement) shares the 340×420×38 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 61868-MA model number is decoded
In the 61800-series, the last two digits encode the bore: 61868 carries code 68 = 340 mm (code × 5). The envelope is 340×420×38 mm (13.386×16.535×1.496 in) with a 40.0 mm radial section height, C 178 kN, C0 275 kN and Pu 6 kN. The open 61868 MA carries no shields or seals and relies on application lubrication and external sealing. The MA suffix identifies the machined brass cage execution, a separate order number from the pressed-steel version. Limiting speed 2400 r/min, catalogue mass 11500 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- brinelling from static overload or hammer blows during mounting
- false brinelling from vibration while the shaft stands idle
Selection pitfalls — read before you substitute
- At 340 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.
- Clearance suffixes follow the seal code in the designation stack (e.g. 61868-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
- The MA suffix on 61868-MA 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 11500 g quoted mass includes the heavier cage.
- Open 61868-MA 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 61868-MA; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Clearance suffixes follow the seal code in the designation stack (e.g. 61868-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
Frequently asked questions
What are the dimensions of 61868-MA?
The SKF 61868 MA measures 340 mm bore × 420 mm OD × 38 mm width (13.386 × 16.535 × 1.496 in), mass about 11500 g. It is open, with no shields or seals.
How does the bore code in 61868 work?
The final two digits of 61868 are bore code 68, multiplied by 5 to give 340 mm.
What load can 61868-MA take?
Catalogue values for 61868 MA: dynamic C 178 kN, static C0 275 kN, fatigue limit Pu 6 kN. Use C in life calculation and C0 for static checks at 340 mm bore.
What is the speed rating of 61868-MA?
SKF lists a 2800 r/min thermal reference speed and a 2400 r/min mechanical limiting speed for 61868 MA; 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.