Fafnir3MMC9113WICRDUHSuper-Precision Angular Contact Ball Bearing – 65 mm ID, 100 mm OD, 18 mm Width, Open, 25° Contact Angle, Phenolic Outer-Ring-Guided Cage, Heavy Preload, Duplex Pair

Product Description

What this part is

Fafnir 3MMC9113WICR-DUH super-precision angular contact ball bearing, 65 mm bore, 100 mm outside diameter, 18 mm width, in the 9100WI spindle series. Steel rings and balls in a phenolic cage guided on the outer ring land, open on both faces, supplied as a universally ground duplex pair set to heavy preload.

Decoding the designation

3MM is the Fafnir super-precision prefix at a 25° contact angle, built to P4S tolerances. In the 9100WI series the last two digits are the bore code, so 13 is 65 mm and the envelope corresponds to an ISO 7013. CR is the phenolic cage riding on the outer ring land. DUH breaks down as D for duplex, U for universally ground and H for heavy preload, which is why two bearings make one set.

What these specs mean in practice

A 25° contact angle carries more thrust and less speed than a 15° bearing in the same envelope, and it raises axial stiffness for a given preload. Heavy preload takes that further: shaft position holds tighter under changing load and the bearing runs quieter at low speed, at the cost of higher internal friction and more heat. The phenolic outer-land-guided cage is light, damps well and tolerates momentary oil starvation, which is what supports the 21,000 rpm limiting speed. Dynamic radial rating is 45.3 kN (10,184 lbf) and static radial rating 32 kN (7,194 lbf) per bearing. P4S tolerances hold bore, outside diameter, width and runout to machine tool spindle grade.

Quantity and configuration

Two bearings, one duplex pair, 36 mm across the pair. Universal grinding lets them be mounted back to back, face to face or in tandem and reach the ground heavy preload when clamped solid. Sale unit is 2 Pcs.

Installation and setup notes

Preload is ground into the ring faces, so the pair clamps against square shoulders with no shims between the rings. Ring faces carry the match marking and the stack orientation follows the chosen arrangement. Oil lubrication suits the phenolic cage and the speed range. This bearing has no relubrication feature.

Interchange guidance

SKF 7013 ACD/P4ADGC and NSK 7013A5SNTRDUHP4 share the 65 x 100 x 18 mm envelope, the 25° angle and heavy-preload duplex grinding. The 2MM version of this number is a 15° bearing in the same envelope, a related size rather than a substitution, and a 71913 is a different envelope at 65 x 90 x 13 mm.