Timken2MMC9107WI DULHybrid Ceramic Super Precision Angular Contact Spindle Bearing Matched Pair, 35 x 62 x 14 mm each (28 mm set), 15 Degree, ABEC 7/9, Light Preload, Phenolic Cage

Product Description

What this part is

Timken Fafnir 2MMC9107WI DUL hybrid ceramic super-precision angular contact ball bearings, factory matched and universally ground to a light preload. Bore: 35 mm. Outside Diameter: 62 mm (2.441 in). Width: 14 mm (0.551 in) per bearing. Total Width: 28 mm (1.102 in) as a mounted set. Contact Angle: 15°. Preload: Light. Precision Class: ABEC 7/9 (ISO P4S). Rolling Elements: Silicon nitride ceramic balls in steel rings. Cage Type: Outer-ring land-riding. Cage Material: Phenolic, Timken MBR. Closure: open. Design Units: Metric. Series: 9100WI. Base Number: 2MMC9107WI. Timken World Part Number: C7007C-T-P4S-DUL.

Published performance data

Dynamic Load Rating (C1): 21,200 N (4,760 lbf) per bearing. Dynamic Load Rating (C1 ISO, per row): 19,300 N (4,340 lbf). Static Load Rating (C0): 12,190 N (2,730 lbf) per bearing. Limiting Speed: 27,100 rpm grease lubrication, 54,240 rpm oil lubrication.

Mounting data

Shaft Backing Shoulder Diameter: 40.6 mm (1.600 in). Housing Backing Shoulder Diameter: 56.6 mm (2.230 in). Maximum Fillet Radius on the mating shaft: 1 mm (0.039 in). Outer Ring To-Clear Radius: 1 mm (0.039 in).

Decoding the designation

2MM — Fafnir super-precision spindle bearing, 15° contact angle, ISO P4S tolerance.

C — hybrid ceramic ball complement.

9107 — 9100WI series, bore code 07, giving a 35 mm bore and the ISO 7007 envelope.

WI — Fafnir spindle bearing series.

CR — phenolic outer-ring land-riding cage.

DU — duplex, universally ground.

L — light preload.

What these specs mean in practice

Silicon nitride balls run at roughly 40 per cent the density of steel. Lower ball mass means lower centrifugal force at speed, so contact stress against the outer race falls, heat generation falls, and preload grows less as the spindle warms through. That is what carries the 27,100 rpm grease and 54,240 rpm oil ratings on a 35 mm bore. Ceramic balls are also electrically insulating, which matters on motorised spindles and anywhere stray shaft current runs.

The 15° contact angle keeps ball spin and cage load down, so the set runs faster and cooler than a 25° execution in the same envelope. Light preload works the same way: lowest friction, least heat, highest speed capability of the three preload grades. This is a set specified for speed and thermal stability. The 25° steel-ball execution in this envelope is the 3MM9107WI.

Universal grinding means the ring faces are flush ground to a controlled offset, so either bearing takes either position and the pair mounts back-to-back for moment stiffness, face-to-face for tolerance of slight misalignment, or in tandem to double thrust capacity in one direction, all without shims.

Quantity and configuration

Unit Quantity: 2 Pcs. One complete factory-matched pair. The carton is marked 2MMC9107WI DUL with bore and outside diameter grade marks d-2 and D-5 and lot number 2011747, and the two bearings are sealed together in the original factory wrap. The THRUST direction marking on the outer ring band faces the direction of the thrust load; on a back-to-back set the two marked faces go outward.

Interchange guidance

The ISO world part number is C7007C-T-P4S-DUL. Parts matching the envelope, angle, cage, class and preload include SKF 7007 CD/HCP4ADGA, where HC is hybrid ceramic, CD is 15° and DGA is universally matched, and FAG HCB7007-C-T-P4S-DUL. The steel-ball counterpart is 2MM9107WI DUL: same size, lower speed capability and no electrical insulation. A plain 7007 industrial-class bearing shares the boundary dimensions only.