Timken 2MM9305WI DUM Spindle & Precision Machine Tool Angular Contact Bearing

Description:

The Timken 2MM9305WIDUM (Manufacturing Part Number: 2MM9305WI DUM, World Part Number: 71905C-T-P4S-DUM) is a matched duplex set of super precision single-row angular contact ball bearings from the Timken Fafnir® 9300WI series. Factory matched with DUM (medium preload), this bearing set is designed for high-speed machine tool spindles requiring exceptional rigidity, low runout, and precise shaft positioning. It is commonly used in CNC machining centers, milling machines, grinding machines, jig borers, precision lathes, and other high-accuracy manufacturing equipment.

Applications:

The Timken 2MM9305WIDUM bearing set is engineered for high-speed spindle applications where accuracy, rigidity, and thermal stability are critical. Its duplex medium preload arrangement increases spindle stiffness, improves rotational accuracy, and minimizes vibration, making it ideal for CNC machining centers, high-speed milling machines, grinding machines, machining spindles, routers, and other industrial machine tools requiring super precision bearings.

Technical Specifications:

• Manufacturer Part Number (MPN): 2MM9305WIDUM (Manufacturing Part Number: 2MM9305WI DUM)
• World Part Number: 71905C-T-P4S-DUM
• Manufacturer: Timken Fafnir
• Product Type: Super precision angular contact ball bearing set
• Bearing Type: Duplex matched single-row angular contact ball bearings
• Series: 9300WI (ISO 71905C)
• Bore Diameter (ID): 25 mm
• Outside Diameter (OD): 42 mm (1.654 in)
• Bearing Width (Single): 9 mm (0.354 in)
• Total Width (Duplex Set): 18 mm (0.709 in)
• Contact Angle: 15°
• Arrangement: Duplex matched pair
• Preload: DUM (Medium preload)
• Ball Material: Steel
• Cage Type: CR outer land riding cage
• Cage Material: MBR phenolic cage
• Precision Rating: ISO P4S (ABEC 7/9 equivalent)
• Static Radial Load Rating (C0): 5,750 N (1,290 lbf) per bearing
• Dynamic Radial Load Rating (Ce): 9,040 N (2,030 lbf) per bearing
• ISO Dynamic Radial Load Rating (C1): 8,220 N (1,840 lbf) per bearing
• Limiting Speed (Grease): 34,800 rpm
• Limiting Speed (Oil): 69,600 rpm
• Maximum Shaft Fillet Radius: 0.30 mm (0.012 in)
• Maximum Housing Fillet Radius: 0.30 mm (0.012 in)
• Function: Supports combined radial and axial loads in high-speed precision spindle applications.
• Features: Factory-matched duplex set, medium preload, super precision construction, low runout, high rigidity, optimized for high-speed machine tool spindles, and excellent thermal stability.

Common Replacements:

• Timken 2MM9305WIDUM super precision bearing set
• SKF 71905 CD/P4A duplex bearing set
• NSK 71905CTYNSULP4 duplex bearing set