3310-DMA bearing: complete specifications & equivalents
The 3310-DMA is a ISO 15 radial bearing sized 50 x 110 x 44.4 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 44.4 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 93.6 kN |
| Basic static load rating C0 | 85 kN |
| Fatigue load limit Pu | 3.6 kN |
| Reference speed (thermal) | 6700 rpm |
| Limiting speed (mechanical) | 5600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2200 g |
| Manufacturer designation | 3310 DMA |
| 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 & 3300-series range
| Bore d | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 1.748 in |
| ISO bore code | 10 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 3300-series | 15 mm |
| Largest outer diameter in 3300-series | 240 mm |
| Width range across 3300-series | 19–92.1 mm |
| Bore position in 3300-series (smallest first) | 9 of 20 |
| Bore above smallest 3300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3310-DNRCBM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×44.4 mm envelope, but catalogue C/C0 differ between executions (93.6/85 kN vs 81.9/69.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3310-A | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×44.4 mm envelope, but catalogue C/C0 differ between executions (93.6/85 kN vs 90/64 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3310-ATN9 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×44.4 mm envelope, but catalogue C/C0 differ between executions (93.6/85 kN vs 90/64 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3310-A-2Z | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×44.4 mm envelope, but catalogue C/C0 differ between executions (93.6/85 kN vs 90/64 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3310-A-2RS1 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 50×110×44.4 mm envelope, but catalogue C/C0 differ between executions (93.6/85 kN vs 90/64 kN) — boundary dimensions match, not a load-rating equivalent. |
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 3310-DMA model number is decoded
3310 DMA is SKF's 50 mm-bore double-row angular-contact ball bearing of the 3300 series — two ball rows back-to-back for two-direction axial location in one unit, 50×110×44.4 mm. A on a double-row bearing means no filling slots, so both rows carry their full ball complement in both directions. D marks a two-piece (split) inner ring that simplifies mounting of the heavy 33-series section. DMA pairs the split inner ring with a machined brass outer-ring-centred MA cage. Envelope 50×110×44.4 mm (1.969×4.331×1.748 in), 30.0 mm radial section height, C 93.6 kN, C0 85 kN, Pu 3.6 kN.reference speed 6,700 r/min (thermal) and limiting speed 5,600 r/min (mechanical), catalogue mass 2200 g. At the printed limiting speed of 5,600 r/min the mean pitch diameter dm ≈ 80.0 mm implies a dn value around 448k mm·r/min; the 6,700 r/min reference speed is the thermal-planning figure under catalogue load. Speed planning distinguishes the two published ceilings mechanically: the cage and balls tolerate 5,600 r/min while thermal balance under catalogue load sets the 6,700 r/min reference; at dm ≈ 80.0 mm the corresponding dn is approximately 448k mm·r/min. Speed-ratio note for this exact unit: the reference speed is 6,700 r/min against a 5,600 r/min limiting speed, i.e. a reference-to-limit ratio of 1.20. Split-ring execution note: DMA combines the two-piece inner ring (used to simplify mounting of the wide 33-series section) with a machined brass cage guided on the outer ring (MA rather than ball-centred M); outer-ring guidance steadies the cage in the heavy section at the cost of a different lubrication requirement at the guide land.
Typical equipment & failure modes
Common applications
- two-direction thrust positions without room for a paired single-row set
- centrifugal pump shafts
- elevator and hoist machinery
Known failure patterns
- snap-ring groove or two-piece-ring damage when the D execution is pressed home through the wrong ring
- two-direction thrust overload concentrating load on one row and spalling its raceway
- uneven loading of the split inner-ring halves if the MA cage guide land runs dry
- edge loading from shaft deflection or housing misalignment
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- Interference goes on the rotating ring (about k5 at 50 mm bore); the wide 44.4 mm ring is sensitive to tilted seats, so check squareness before clamping.
- The D executions have a two-piece inner ring: mount both halves square to each other, never press on the outer ring, and keep the split faces clean during fitting.
- A capped 3310-2Z/-2RS1 execution of this envelope exists for sealed-for-life duty; an open double-row bearing needs application sealing and a defined lubricant supply.
- A capped 3310-2Z/-2RS1 execution of this envelope exists for sealed-for-life duty; an open double-row bearing needs application sealing and a defined lubricant supply.
- The D executions have a two-piece inner ring: mount both halves square to each other, never press on the outer ring, and keep the split faces clean during fitting.
- Catalogue ratings are SKF PUB BU/P1 17000 figures for 3310 DMA as the double d ma execution; the other order numbers of the 3310 size are different products and may carry different ratings — always quote the full designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 3310-DMA?
3310 DMA measures 50 mm bore × 110 mm OD × 44.4 mm width (1.969 × 4.331 × 1.748 in), mass about 2200 g. SKF 17000 ratings: C 93.6 kN, C0 85 kN, Pu 3.6 kN, reference speed 6,700 r/min (thermal) and limiting speed 5,600 r/min (mechanical).
What does the DMA suffix mean?
A on a double-row bearing means no filling slots, so both rows carry their full ball complement in both directions. D marks a two-piece (split) inner ring that simplifies mounting of the heavy 33-series section. DMA pairs the split inner ring with a machined brass outer-ring-centred MA cage.
Which fits should I use?
With a rotating inner ring use roughly k5 on the 50 mm shaft and H7 in the 110 mm housing; check the wide ring seats square because the 44.4 mm width is sensitive to tilt.
Why choose the double-row 3310 instead of two single-row bearings?
The double-row bearing locates the shaft in both axial directions in one unit, in one housing bore and with factory-controlled axial clearance — a more compact arrangement than a pair, with no field matching of ground faces. A single-row pair offers adjustable preload instead.
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.