Fafnir2MM309WICRDULSuper-Precision Angular Contact Ball Bearing — 45 mm Bore, 100 mm OD, 25 mm Wide, 15° Contact Angle, Light Preload, Phenolic Cage, Universally Ground

Product Description

What this part is

Fafnir 2MM309WI-CR-SUL super-precision angular contact ball bearing, single universally ground. Bore Diameter: 45 mm. Outside Diameter: 100 mm. Overall Width: 25 mm. Item Weight: 0.809 kg (1.78 lb). Series: 300WI. Base Number: 309. Rolling Elements: Ball. Bore Type: Straight. Closure Type: Open. The 309 size code is the ISO 7309 envelope.

Decoding the designation

2MM — Contact Angle: 15°, in Timken’s MM super-precision spindle range.

MM — Precision Class: ABEC 7/9 (P4S).

309 — the 45 mm bore size in the 300 heavy series, on ISO 7309 boundary dimensions.

WI — low shoulder on both rings.

CR — Cage Material: Phenolic.

SU — Mounting Arrangement: single universally ground, so any number of these bearings can be stacked back-to-back, face-to-face or in tandem.

L — Preload: Light.

What these specs mean in practice

Dynamic Load Rating: 66,500 N. Static Load Rating: 38,700 N. The 300 heavy series carries a larger ball complement in a deeper section than the 9100 light series at the same bore, which is where those ratings come from.

Limiting Speed: 15,100 rpm grease; 30,200 rpm oil. Contact Angle: 15°, favouring speed and radial stiffness. Preload: Light. Precision Class: ABEC 7/9. Cage Material: Phenolic, light, self-lubricating and quiet at high surface speeds.

Mounting data

Shaft backing shoulder diameter 55.4 mm. Housing backing shoulder diameter 90.2 mm. Maximum housing fillet radius 1.5 mm. The straight bore seats on a ground spindle journal, and the universally ground faces take up the light preload when the clamp nut is tightened.

Quantity and configuration

Unit Quantity: 1 Pc. Number Of Rows: 1. One single universally ground bearing, which pairs with any other SU bearing of the same designation and preload class.

Interchange guidance

The 45 x 100 x 25 mm envelope at 15° is the ISO 7309 C size, so a 15° super-precision 7309 universally ground single at light preload from another maker fits the same seat. The Fafnir 3MM309WI-CR-SUL shares the envelope at 25° and is listed as a related angle rather than an interchange.