61956 bearing: complete specifications & equivalents
The 61956 is a ISO 15 radial bearing sized 280 x 380 x 46 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 280 mm |
| Outer diameter D | 380 mm |
| Width B | 46 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 | 216 kN |
| Basic static load rating C0 | 285 kN |
| Fatigue load limit Pu | 6.7 kN |
| Reference speed (thermal) | 3200 rpm |
| Limiting speed (mechanical) | 2000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 12000 g |
| Manufacturer designation | SKF 61956 |
| 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 & 61900-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 14.961 in |
| Width B | 1.811 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 43 of 63 |
| Bore above smallest 61900-series size | 277 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61956 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 61956-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 280×380×46 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61956-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 61956 MA (machined brass cage, open arrangement) is the same-size execution on the 280×380×46 mm envelope with ratings within 10 % — 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 61956 model number is decoded
61956 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the thin 619xx section (diameter series 9 of ISO 15), multiplying bore code 56 by five gives the 280 mm bore; the 380 mm outside diameter and 46 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 280 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. 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
- robotics and automation joints
- lay shafts and idler shafts
- textile machinery
- packaging machinery
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- raceway smearing under marginal lubrication at start-up
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- At 280 mm bore the ring mass is significant: heat 61956 on an induction heater (max 120 °C), never over an open flame, and plan puller access or a withdrawal sleeve now for the day it has to come off again.
- The 619xx thin section (50.0 mm section height at 280 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
- Storage matters for open bearings: 61956 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Open bearings tolerate the highest speeds in the 61900-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61956 units.
- Vibration during standstill brinells the raceways of a 280 mm bearing at ball spacing; if the machine sits idle next to running equipment, turn the shaft over periodically or isolate the arrangement.
- Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 61900-series position can soften the mixture and leak — clean out the old fill before switching grease types.
- The open 61956 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61956-2Z (shields) and 61956-2RSH (contact seals), not suffix-free 61956.
- The 216/285 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 61956 bearing?
A 61956 deep-groove ball bearing has a 280 mm bore, 380 mm outer diameter and 46 mm width (11.024 × 14.961 × 1.811 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
Are 61956 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 61956 uses the same ISO 15 envelope (280×380×46 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
What internal clearance does 61956 have?
Unless a clearance suffix says otherwise, 61956 is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 61956 and verify the residual clearance after mounting.
How should 61956 be mounted?
Apply the mounting force to the ring being fitted: on a 280 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What is the SKF designation and catalogue data for 61956?
In the SKF Rolling Bearings catalogue this size is listed as 61956 — the open (unsealed) execution, 280×380×46 mm per ISO 15. Quoted values: C 216 kN, C0 285 kN, Pu 6.7 kN, limiting speed 2000 r/min, mass 12000 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61956.
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.