7304-BECBM bearing: complete specifications & equivalents

Specification table

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.

Cross references & equivalents

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-BECBM model number is decoded

7304 BECBM 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. machined brass cage, ball-centred (suffix M), the choice for high speed, marginal lubrication and shock duty. 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. 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 22,000 r/min (mechanical), catalogue mass 140 g. Mass and section check: 140 g inside the 20×52×15 mm outline leaves a 16.0 mm radial section, and the 10 kN static rating is 0.53× the dynamic rating — plan static safety and minimum load against those numbers rather than against sister executions. The 0.425 kN fatigue load limit is the equivalent-load floor for long-life adjustment; with 19/10 kN ratings and 140 g mass this execution carries about 0.95 kN of C per millimetre of bore. 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. Cage detail specific to this order number: the M cage is a one-piece machined brass window cage centred on the balls, chosen for high speeds, thin-film lubrication and shock loads; it is heavier and stiffer than the stamped Y-cage execution and tolerates interrupted oil supply far better than the PA66 or PEEK alternatives. Do not substitute the stamped-brass BECBY order number expecting identical cage behaviour.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Mount by induction-heating the inner ring to max 120 °C; driving the bearing home through the outer ring or balls brinells the asymmetric raceway.
• DB pairs give the highest moment stiffness, DF pairs tolerate misalignment and thermal expansion better, DT shares heavy one-direction thrust; choose from the shaft thermal calculation rather than by habit.
• One 7304-BECBM 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.
• 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.
• The steep 40° angle of 7304-BECBM 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 BECBM 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.