SNFAE250-7CE3TUMSuper Precision Angular Contact Ball Bearing Triplex Set – Straight Bore, 50 mm ID, 90 mm OD, 20 mm Width, Open, 25 Degree Contact Angle, Universal Medium Preload

Product Description

What this part is

SNFA E250-7CE3TUM super-precision angular contact ball bearing set. Bore: 50 mm. Outside diameter: 90 mm. Width per bearing: 20 mm. Open on both faces, straight bore. Three bearings, factory matched and universally ground as a triplex set. Country of origin: Italy.

Decoding the designation

E — SNFA’s E series, the 72-dimension super-precision spindle range. 250 — bore code: 50 mm. 7 — Precision Class: ABEC 7 (P4). CE3 — Contact Angle: 25°. TUM — triplex, universally matchable, medium preload. The carton also carries the Fafnir designation 3MM210WI TUM and the equivalent 7210-A P4 TUM, both of which read 25° and triplex medium preload. Searchable forms: E250-7CE3TUM, E 250-7-CE-3-TUM, E-250-7-CE-3-TUM, E250 7CE3 TUM.

What these specs mean in practice

A 25° contact angle carries more thrust and less speed than a 15°, which suits a spindle that has to hold axial position under cutting load. Dynamic Load Rating: 42.3 kN per bearing. Static Load Rating: 32.5 kN per bearing. Limiting Speed: 16,000 rpm on grease. Operating temperature range: -30 to 120 °C. The machined phenolic cage is outer-ring-land-riding, which is what allows the high speed at this precision class.

Quantity and configuration

Three pieces, a complete factory triplex set. Universal grinding means the three bearings stack in any combination of back-to-back, face-to-face and tandem, and medium preload is set by the ring faces clamping directly against one another.

Fitting notes

Bore form: straight cylindrical, 50 mm, for an interference fit on a ground spindle seat. Total set width across the triplex stack: 60 mm. Lubrication: oil or grease. Item weight 1.10 lb per bearing.

Interchange guidance

SKF 7210 ACD/P4 and FAG B7210-E-T-P4S-TUM are the equivalent 25° medium-preload super-precision executions on the same 50 x 90 x 20 mm envelope. Fafnir 3MM210WITUM is the Timken/Fafnir equivalent. SNFA E250-7CE1 is the same envelope at a 15° contact angle, so it is a related size rather than a substitution.