Timken 2MM9305WI DUM Angular Contact Ball Bearing

Timken 2MM9305WI DUM is a factory-matched duplex set of super-precision single-row angular contact ball bearings from the Timken Fafnir 9300WI series, designed for high-speed machine tool spindles with exceptional rigidity and low runout. The DUM (medium preload) arrangement increases spindle stiffness and improves axial positioning, making it well-suited for CNC machining centers, high-speed milling, grinding machines, jig borers, and precision lathes. Each bearing features a 25 mm bore, 42 mm outside diameter, and 9 mm width, with a 15° contact angle; in duplex, the total width is 18 mm. They are ISO P4S precision (ABEC 7/9 equivalent) with static radial load 5,750 N and dynamic radial load 9,040 N per bearing, and grease-lubed limiting speed of 34,800 rpm (oil 69,600 rpm), offering reliable thermal stability for demanding spindle applications.