61938-MA (brass cage) bearing: complete specifications & equivalents
The 61938-MA is a ISO 15 radial bearing sized 190 x 260 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 190 mm |
| Outer diameter D | 260 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 117 kN |
| Basic static load rating C0 | 134 kN |
| Fatigue load limit Pu | 3.8 kN |
| Reference speed (thermal) | 5000 rpm |
| Limiting speed (mechanical) | 4300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5200 g |
| Manufacturer designation | 61938 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 & 61900-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 1.299 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 35 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) | 38 of 63 |
| Bore above smallest 61900-series size | 187 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61938-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | FAG bearing FAG 61938 on the same 190×260×33 mm envelope, but catalogue C/C0 differ (117/134 kN vs 140/146 kN) — envelope interchange only after a load check. |
| 61938-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | NSK counterpart NSK 6938 on the same 190×260×33 mm envelope with ratings within 10 % — interchange after checking seal, cage and precision details on both pages. |
| 61938-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | NTN counterpart 6938 on the same 190×260×33 mm envelope with ratings within 10 % — interchange after checking seal, cage and precision details on both pages. |
| 61938 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 61938 (open arrangement) shares the 190×260×33 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 61938-MA model number is decoded
In the 61900-series, the last two digits encode the bore: 61938 carries code 38 = 190 mm (code × 5). The envelope is 190×260×33 mm (7.48×10.236×1.299 in) with a 35.0 mm radial section height, C 117 kN, C0 134 kN and Pu 3.8 kN. The open 61938 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 4300 r/min, catalogue mass 5200 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- marine deck machinery
- crusher auxiliary drives
- space-constrained gearboxes
- clutch and transmission assemblies
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling once the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- Catalogue ratings for 61938-MA (C 117 kN, C0 134 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
- At 190 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.
- The MA suffix on 61938-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 5200 g quoted mass includes the heavier cage.
- Open 61938-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 61938-MA; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Do not preload 61938-MA to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- SKF Explorer deep-groove bearings of this size are produced to tight internal-geometry control; rating revisions between catalogue years do not change the designation, so keep the catalogue edition with the machine documentation.
- Sealed SKF units are filled with a lithium-based grease for general service; food-grade, low-temperature and high-temperature fills are order options and are not field-interchangeable once the unit is sealed.
Frequently asked questions
What are the dimensions of 61938-MA?
The SKF 61938 MA measures 190 mm bore × 260 mm OD × 33 mm width (7.48 × 10.236 × 1.299 in), mass about 5200 g. It is open, with no shields or seals.
How does the bore code in 61938 work?
The final two digits of 61938 are bore code 38, multiplied by 5 to give 190 mm.
What internal clearance does 61938-MA have?
Standard supply is normal CN radial clearance unless a suffix states otherwise; for tight fits or hot shafts SKF lists the C3 execution of the same size — the residual clearance left after mounting is what governs running life.
How long can a greased 61938-MA be stored?
Sealed and shielded SKF units carry a finite grease shelf life: SKF recommends first-in-first-out stock rotation and dry, cool, vibration-free storage. Open units ship with rust preventive only and are greased at assembly.
What load can 61938-MA take?
Catalogue values for 61938 MA: dynamic C 117 kN, static C0 134 kN, fatigue limit Pu 3.8 kN. Use C in life calculation and C0 for static checks at 190 mm bore.
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.