Fafnir2MM205WI-DULAngular Contact Ball Bearing — 25 mm ID, 52 mm OD, 15 mm Width, 15° Contact Angle, Light Preload, Phenolic Cage, ABEC 7/9

Product Description

What this part is

Fafnir 2MM205WICRDUL, a super-precision spindle angular contact ball bearing from Timken’s Fafnir 200WI range. Bore: 25 mm. Outside Diameter: 52 mm. Bearing Width: 15 mm per bearing. Total Width: 30 mm across the set. Contact Angle: 15°. Precision Class: ABEC 7/9 (ISO P4S). Preload: light. Cage Type: CR, phenolic outer land riding. Cage Material: phenolic. Rolling Elements: steel balls. Number of Rows: 1 per bearing. Manufacturer Part Number: 2MM205WI DUL. World Part Number: 7205C-T-P4S-DUL.

Decoding the designation

2MM — Fafnir super-precision spindle execution at a 15° contact angle, ground to ABEC 7/9 (ISO P4S) tolerance.

205 — 200WI dimension series, bore code 05. That is the ISO 7205 envelope: 25 mm bore, 52 mm outside diameter, 15 mm width per bearing.

WI — low shoulder on both rings, which is what allows the ball complement and the 15° angle to be ground into this section.

CR — phenolic outer land riding cage, guided on the outer ring lands.

DUL — duplex, light preload. Two universally ground bearings supplied as a matched set, faces flush-ground so they close to the same preload when clamped.

What these specs mean in practice

Dynamic Radial Load Rating (C1): 18,400 N (4,130 lbf) per bearing. Dynamic Radial Load Rating, ISO method (C1 per row): 16,700 N (3,760 lbf). Static Radial Load Rating (C0): 10,200 N (2,320 lbf) per bearing. Limiting Speed, grease: 29,800 rpm. Limiting Speed, oil: 59,600 rpm.

The 15° contact angle keeps the load path close to radial, and that is what buys the speed: 29,800 rpm on grease and 59,600 rpm under oil from a 25 mm bore. The 25° build on the same envelope trades that away for thrust capacity. The phenolic outer land riding cage is light, so it adds little to ball-set inertia at speed, and the resin holds oil in its own porosity to feed the ball pockets. Light preload fixes the stiffness while keeping the running temperature down.

Quantity and configuration

Unit Quantity: 2 Pcs. A matched duplex set of two universally ground bearings, 30 mm total width when clamped together.

Mounting data

Shaft Backing Shoulder Diameter: 30.9 mm (1.220 in). Housing Backing Shoulder Diameter: 47.1 mm (1.860 in). Maximum Shaft Fillet Radius: 1 mm (0.039 in). Outer Ring To-Clear Radius: 1 mm (0.039 in).

Interchange guidance

Timken’s world part number for this set is 7205C-T-P4S-DUL. Searchable variants of the Fafnir number: 2MM205WI-DUL, 2MM205WICRDUL, 2MM-205-WI-CR-DUL, 2MM 205 WI DUL, 7205C, 7205-C.

The 3MM205WI on the same 25 x 52 x 15 mm envelope is the 25° build: more thrust capacity, lower speed.