61948 bearing: complete specifications & equivalents
The 61948 is a ISO 15 radial bearing sized 240 x 320 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 | 240 mm |
| Outer diameter D | 320 mm |
| Width B | 38 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 | 159 kN |
| Basic static load rating C0 | 200 kN |
| Fatigue load limit Pu | 5.1 kN |
| Reference speed (thermal) | 4000 rpm |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 7300 g |
| Manufacturer designation | SKF 61948 |
| 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 | 9.449 in |
|---|---|
| Outer diameter D | 12.598 in |
| Width B | 1.496 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 40 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) | 41 of 63 |
| Bore above smallest 61900-series size | 237 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61948-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 240×320×38 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61948 | 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. |
| 61948-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61948-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 240×320×38 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61948-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 240×320×38 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61948-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF 61948 MA (machined brass cage, open arrangement) is the same-size execution on the 240×320×38 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 61948 model number is decoded
61948 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 48 by five gives the 240 mm bore; the 320 mm outside diameter and 38 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 240 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
- textile machinery
- packaging machinery
- space-constrained gearboxes
- clutch and transmission assemblies
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
- Mount this 240 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 619xx thin section at 240 mm bore (40.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- The open 61948 has no lubricant retention: grease escapes and contaminants migrate straight into the 240×320×38 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- 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 61948 units.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 320 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61948.
- The open 61948 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61948-2Z (shields) and 61948-2RSH (contact seals), not suffix-free 61948.
- The 159/200 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 61948 bearing?
A 61948 deep-groove ball bearing has a 240 mm bore, 320 mm outer diameter and 38 mm width (9.449 × 12.598 × 1.496 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
How should 61948 be mounted?
Apply the mounting force to the ring being fitted: on a 240 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 lubrication does 61948 need?
The open 61948 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
How does the 61948 bore code work?
The last two digits of 61948 are bore code 48, giving 48 × 5 = 240 mm bore. The 320 mm outside diameter and 38 mm width follow the ISO 15 diameter series, not the bore code alone.
What is the SKF designation and catalogue data for 61948?
In the SKF Rolling Bearings catalogue this size is listed as 61948 — the open (unsealed) execution, 240×320×38 mm per ISO 15. Quoted values: C 159 kN, C0 200 kN, Pu 5.1 kN, limiting speed 2400 r/min, mass 7300 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61948.
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.