7304-BECBPH bearing: complete specifications & equivalents
The 7304-BECBPH is a ISO 15 radial bearing sized 20 x 52 x 15 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer |
| Basic dynamic load rating C | 19 kN |
| Basic static load rating C0 | 10 kN |
| Fatigue load limit Pu | 0.425 kN |
| Reference speed (thermal) | 17000 rpm |
| Limiting speed (mechanical) | 18000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 140 g |
| Manufacturer designation | 7304 BECBPH |
| 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 & 7300-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.591 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in 7300-series | 10 mm |
| Largest outer diameter in 7300-series | 420 mm |
| Width range across 7300-series | 11–80 mm |
| Bore position in 7300-series (smallest first) | 5 of 31 |
| Bore above smallest 7300-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7304-BE-2RZP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×15 mm envelope with catalogue ratings within 10 %; 7304 BE-2RZP is the glass-fibre PA66 cage, non-contact NBR seals (-2RZ) execution of this size — boundary dimensions interchangeable, execution differs. |
| 7304-BEP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×15 mm envelope with catalogue ratings within 10 %; 7304 BEP is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 7304-BECBP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×15 mm envelope with catalogue ratings within 10 %; 7304 BECBP is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 7304-BECBM | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×15 mm envelope with catalogue ratings within 10 %; 7304 BECBM is the brass cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 7304-BECBY | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 20×52×15 mm envelope, but catalogue C/C0 differ between executions (19/10 kN vs 20.4/11.2 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7304-ACCBM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 20×52×15 mm envelope, but catalogue C/C0 differ between executions (19/10 kN vs 20.8/11.2 kN) — boundary dimensions match, not a load-rating equivalent. |
| QJ-304-N2MA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 20×52×15 mm envelope, but catalogue C/C0 differ between executions (19/10 kN vs 32/21.6 kN) — boundary dimensions match, not a load-rating equivalent. |
| QJ-304-MA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 20×52×15 mm envelope, but catalogue C/C0 differ between executions (19/10 kN vs 32/21.6 kN) — boundary dimensions match, not a load-rating equivalent. |
| QJ-304-N2PHAS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 20×52×15 mm envelope, but catalogue C/C0 differ between executions (19/10 kN vs 32/21.6 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7304 | SKF | full Dimensions and internal design equivalent — standard interchange. | SKF SKF 7304 BEP is the basic 20×52×15 mm angular-contact page with ratings within 10 % of this execution — same boundary dimensions, verify execution details. |
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 7304-BECBPH model number is decoded
7304 BECBPH is SKF's 20 mm-bore single-row angular-contact ball bearing in the 7300 series, nominal 40° (B) contact angle, 20×52×15 mm to the ISO dimension plan. 40° contact angle (suffix B): the steep standard single-row angle, giving the highest axial capacity at the cost of speed, with a recommended load ratio Fa/Fr ≥ 1. E marks the optimized internal design with an enhanced ball complement and race geometry. glass-fibre reinforced PA66 cage, ball-centred (suffix P), with a 120 °C continuous-temperature ceiling. CB means universally matchable with Normal axial internal clearance: the two side faces are ground so any two units form DB (back-to-back), DF (face-to-face) or DT (tandem) sets without regrinding. BECBPH combines CB universal clearance with a PEEK ball-centred cage for hot, high-speed positions where PA66 is unsuitable. Envelope 20×52×15 mm (0.787×2.047×0.591 in), 16.0 mm radial section height, C 19 kN, C0 10 kN, Pu 0.425 kN.reference speed 17,000 r/min (thermal) and limiting speed 18,000 r/min (mechanical), catalogue mass 140 g. Speed planning distinguishes the two published ceilings mechanically: the cage and balls tolerate 18,000 r/min while thermal balance under catalogue load sets the 17,000 r/min reference; at dm ≈ 36.0 mm the corresponding dn is approximately 648k mm·r/min. At the printed limiting speed of 18,000 r/min the mean pitch diameter dm ≈ 36.0 mm implies a dn value around 648k mm·r/min; the 17,000 r/min reference speed is the thermal-planning figure under catalogue load. Bore-to-OD planning: OD 52 over bore 20 is a 2.60× step for this size, and the 15 mm width gives a bore/width ratio of 1.33; use these ratios when housing space around the 20 mm shaft is the first constraint. PEEK cage note: the PH cage is moulded from glass-fibre reinforced polyetheretherketone, ball-centred, aimed at high-speed oil-air and grease positions where PA66 would approach its thermal and speed limits; it needs clean lubricant (PEEK cages are sensitive to hard-particle cage-wear) and is a separate order number from the brass BECBM.
Typical equipment & failure modes
Common applications
- servo and stepper motor shafts
- textile and wire-guide spindles
- small gear and metering pumps
Known failure patterns
- preload loss as a loosely clamped set runs slack and the balls smear the raceways
- thermal preload runaway in a back-to-back pair when inner-ring heat cannot expand away
- ball skidding when Fa/Fr stays below the 1,0 (40°) or 0,55 (25°) ratio and the contact ellipse is unloaded
- PEEK cage wear from hard particles in the lubricant, which abrade the moulded pocket surfaces
- mounting score marks when the bearing is cocked over a burr or keyway
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- Fillet radii must clear the chamfer so the 15 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
- Mount by induction-heating the inner ring to max 120 °C — the PA66 cage sets the ceiling, not the steel; driving the bearing home through the outer ring or balls brinells the asymmetric raceway.
- Keep the load ratio in the SKF design range: Fa/Fr ≥ 1 for this angle; below it the balls unload the contact ellipse and skid, which is why the catalogue insists on a minimum axial load (Fam ≈ A·(n·dm/1000)²) at high speed.
- One 7304-BECBPH locates the shaft in one axial direction only; reversing-thrust positions need a DB or DF pair — or a double-row bearing — with preload set from the load diagram, never from assembly feel.
- The steep 40° angle of 7304-BECBPH favours thrust-heavy combined loads; for a predominantly radial high-speed position the 25° ACCBM execution of the same size is the alternative order number.
- Universally matchable BECBPH bearings arrive ready for set mounting, not preloaded sets: preload results from how the set is clamped, so follow the SKF stand-off-ring and nut-torque procedure.
Frequently asked questions
What are the dimensions and catalogue data of 7304-BECBPH?
7304 BECBPH measures 20 mm bore × 52 mm OD × 15 mm width (0.787 × 2.047 × 0.591 in), mass about 140 g. SKF 17000 ratings: C 19 kN, C0 10 kN, Pu 0.425 kN, reference speed 17,000 r/min (thermal) and limiting speed 18,000 r/min (mechanical).
What does the BECBPH suffix mean?
40° contact angle (suffix B): the steep standard single-row angle, giving the highest axial capacity at the cost of speed, with a recommended load ratio Fa/Fr ≥ 1. E marks the optimized internal design with an enhanced ball complement and race geometry. glass-fibre reinforced PA66 cage, ball-centred (suffix P), with a 120 °C continuous-temperature ceiling. CB means universally matchable with Normal axial internal clearance: the two side faces are ground so any two units form DB (back-to-back), DF (face-to-face) or DT (tandem) sets without regrinding. BECBPH combines CB universal clearance with a PEEK ball-centred cage for hot, high-speed positions where PA66 is unsuitable.
What do the reference and limiting speeds mean for 7304-BECBPH?
The 17,000 r/min reference (thermal) and 18,000 r/min limiting (mechanical) speeds are catalogue conditions; preload, lubrication and heat removal move the permissible value, so re-calculate for the actual arrangement.
Can one 7304-BECBPH take thrust in both directions?
No. A single-row angular-contact bearing reacts axial load in one direction; reversing thrust needs a DB/DF matched pair (use a universally matchable CB/GA execution) or a double-row bearing. Under radial load the 40° angle induces an axial force that the arrangement must balance.
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.