Fafnir2MM9105WIDUHSuper Precision Angular Contact Ball Bearing, Matched Duplex Pair – Straight Bore, 25 mm ID, 47 mm OD, 12 mm Width, 24 mm Total Width, Open, 15° Contact Angle, Heavy Preload, Phenolic Outer-Land-Riding Cage, ISO P4S

Product Description

What this part is

Fafnir 2MM9105WI DUH matched duplex pair of super precision angular contact ball bearings, 9100WI spindle series. Manufacturer Part Number: 2MM9105WI DUH. World Part Number: 7005C-T-P4S-DUH. Bore: 25 mm. Outside Diameter: 47 mm. Bearing Width: 12 mm per bearing. Total Width: 24 mm for the pair. Number Of Rows: 1 per bearing. Bore Type: Straight. Closure Type: Open. Rolling Elements: Steel balls. Design Units: Metric.

Decoding the designation

Contact Angle: 15°, carried by the 2MM prefix. Series: 9100WI, which maps to the ISO 70xx light section, so the 9105 is a 7005 envelope at 25 x 47 x 12 mm. WI: low shoulder on both rings. CR: phenolic outer land riding cage. DU: duplex, a factory-matched two-bearing set. H: heavy preload. Precision Class: ISO P4S, equivalent to ABEC 7/9. Preload: Heavy. Mounting Arrangement: Duplex pair.

Published ratings

Dynamic Radial Load Rating – 1M Revs (C1): 12,900 N (2,910 lbf). C1 ISO Dynamic Radial Rating, per row: 11,700 N (2,640 lbf). Static Radial Load Rating (C0): 7,400 N (1,660 lbf). Limiting Speed, grease: 30,900 rpm. Limiting Speed, oil: 61,800 rpm. Timken publishes these as bearing-level figures for the DUH execution.

Mounting dimensions

Max Shaft Fillet Radius: 0.6 mm. Outer Ring To Clear Radius: 0.6 mm. Shaft Backing Shoulder Diameter: 29.9 mm. Housing Backing Shoulder Diameter: 42.6 mm.

What these specs mean in practice

A 15° contact angle is the high-speed setting in this family. More of the load line runs radially, the ball set does less centrifugal and gyroscopic work, and the pair carries a higher limiting speed than a steeper-angle execution on the same envelope. At 30,900 rpm on grease and 61,800 rpm on oil this is a small, fast spindle position: grinding wheelheads, high-frequency heads and precision quills.

Heavy preload is the stiffest of the three duplex settings. It holds the spindle nose closest to position under a changing cut and gives the highest axial and radial rigidity of the DUL, DUM and DUH ladder, at higher running heat. Internal Clearance: N/A — a preloaded set is defined by its preload rather than by a clearance class. Lubricant: grease or oil, and Timken publishes a limiting speed for each.

Cage Type: CR, phenolic outer land riding. Cage Material: Phenolic. A machined phenolic laminate cage is light, so it loads the ball pockets very little at speed, it is self lubricating, and it damps rather than rings. Guidance on the outer ring land keeps it stable at high speed.

Quantity and configuration

Unit Quantity: 2 Pcs. A factory-matched duplex pair, ground as a set to the heavy preload. The two bearings ship together and are the sale unit, giving a 24 mm total stack width.

Interchange guidance

Base Number: 7005. MPN Variants: 2MM9105WIDUH, 2MM9105WI DUH, 2MM-9105-WI-DUH, 2 MM 9105 WI DUH, 2MM9105WICRDUH, 7005C, 7005C-T-P4S-DUH. Same-envelope 15° heavy-preload duplex equivalents are written SKF 7005 CD/P4ADGC, FAG B7005-C-T-P4S-DUH and NSK 7005CTRDUHP4. Cage material and precision class vary between makers inside those designations. The line passed from Fafnir to Torrington to Timken, and Timken lists 2MM9105WI DUH today.