3307-A bearing: complete specifications & equivalents
The 3307-A is a ISO 15 radial bearing sized 35 x 80 x 34.9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 34.9 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 52 kN |
| Basic static load rating C0 | 35.5 kN |
| Fatigue load limit Pu | 1.5 kN |
| Reference speed (thermal) | 9500 rpm |
| Limiting speed (mechanical) | 8500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 740 g |
| Manufacturer designation | 3307 A |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 1.374 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 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) | 6 of 20 |
| Bore above smallest 3300-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3307-ATN9 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 35×80×34.9 mm envelope with catalogue ratings within 10 %; 3307 ATN9 is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 3307-DJ1 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 35×80×34.9 mm envelope, but catalogue C/C0 differ between executions (52/35.5 kN vs 52.7/41.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3307-A-2Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 35×80×34.9 mm envelope with catalogue ratings within 10 %; 3307 A-2Z is the stamped steel cage, shields (-2Z) execution of this size — boundary dimensions interchangeable, execution differs. |
| 3307-A-2RS1 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 35×80×34.9 mm envelope with catalogue ratings within 10 %; 3307 A-2RS1 is the stamped steel cage, contact NBR seals (-2RS1) execution of this size — boundary dimensions interchangeable, execution differs. |
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 3307-A model number is decoded
3307 A is SKF's 35 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, 35×80×34.9 mm. A on a double-row bearing means no filling slots, so both rows carry their full ball complement in both directions. with no cage suffix the double-row A execution uses the standard stamped steel ball-centred cage. Envelope 35×80×34.9 mm (1.378×3.15×1.374 in), 22.5 mm radial section height, C 52 kN, C0 35.5 kN, Pu 1.5 kN.reference speed 9,500 r/min (thermal) and limiting speed 8,500 r/min (mechanical), catalogue mass 740 g. Load balance: C0 35.5 kN against C 52 kN gives a 0.68 ratio, typical of a double-row bidirectional design; Pu 1.5 kN enters the SKF adjusted-life equation rather than the basic rating life. The 1.5 kN fatigue load limit is the equivalent-load floor for long-life adjustment; with 52/35.5 kN ratings and 740 g mass this execution carries about 1.49 kN of C per millimetre of bore. Bore-to-OD planning: OD 80 over bore 35 is a 2.29× step for this size, and the 34.9 mm width gives a bore/width ratio of 1.00; use these ratios when housing space around the 35 mm shaft is the first constraint.
Typical equipment & failure modes
Common applications
- printing and converting machinery
- gearbox input and output shafts with bidirectional thrust
- two-direction thrust positions without room for a paired single-row set
Known failure patterns
- two-direction thrust overload concentrating load on one row and spalling its raceway
- loss of controlled axial clearance (CB) after thermal growth removes residual play
- stamped steel cage noise and pocket wear in marginal-lubrication starts, where a brass-cage execution would survive
- electrical pitting on VFD-driven shafts without grounding protection
- electrical pitting on VFD-driven shafts without grounding protection
Selection pitfalls — read before you substitute
- Catalogue ratings of 52/35.5 kN apply to the A execution; the D and DNRCBM two-piece-ring executions carry their own figures on their own pages.
- Interference goes on the rotating ring (about k5 at 35 mm bore); the wide 34.9 mm ring is sensitive to tilted seats, so check squareness before clamping.
- The double-row 3307 takes thrust in both directions by itself — that is the reason to choose it over two single-row bearings: one housing bore, one fit, built-in set geometry.
- The double-row 3307 takes thrust in both directions by itself — that is the reason to choose it over two single-row bearings: one housing bore, one fit, built-in set geometry.
- Catalogue ratings are SKF PUB BU/P1 17000 figures for 3307 A as the double a steel execution; the other order numbers of the 3307 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 3307-A?
3307 A measures 35 mm bore × 80 mm OD × 34.9 mm width (1.378 × 3.15 × 1.374 in), mass about 740 g. SKF 17000 ratings: C 52 kN, C0 35.5 kN, Pu 1.5 kN, reference speed 9,500 r/min (thermal) and limiting speed 8,500 r/min (mechanical).
What does the A suffix mean?
A on a double-row bearing means no filling slots, so both rows carry their full ball complement in both directions. with no cage suffix the double-row A execution uses the standard stamped steel ball-centred cage.
Why choose the double-row 3307 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.
What does the D mean in A?
D marks a two-piece inner ring, used on the heavy 33-series executions to simplify mounting; the rest of the suffix identifies the cage (MA brass outer-ring-centred, M brass ball-centred, J1 stamped steel, TN9 PA66) and snap-ring/clearance options (NR, CB).
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.