Fafnir2MM9118WI-DUHSuper Precision Angular Contact Ball Bearing Duplex Pair – 90 mm ID, 140 mm OD, 24 mm Width, 48 mm Total, 15° Contact Angle, Heavy Preload, Phenolic Cage, P4S

Product Description

What this part is

Fafnir 2MM9118WI-DUH super precision angular contact ball bearing set from Timken, supplied as a matched duplex pair. Brand: Fafnir (Timken). Bore: 90 mm. Outside Diameter: 140 mm. Overall Width: 24 mm per bearing. Total Width: 48 mm. Contact Angle: 15°. Preload: Heavy. Precision Rating: ISO P4S (ABEC 7/9). Arrangement: DU, duplex universally ground. Number Of Rows: 1 per bearing. Cage Type: CR — Phenolic Outer Land Riding Cage. Cage Material: Phenolic, Timken cage designation MBR. Ball Type: Steel. Bearing Material: Chrome steel. Closure Type: Open. Bore Type: Straight. Design Units: Metric. Series: 9100WI. Base Number: 2MM9118WI. Harmonization Code: 8482.10.50. Timken World Part Number: 7018C-T-P4S-DUH.

Published ratings and mounting data

Dynamic Load Rating (C1), duplex set, 1 million revolutions: 79,600 N / 17,900 lbf. Dynamic Load Rating per row, C1 ISO: 72,200 N / 16,200 lbf. Static Radial Load Rating (C0): 68,900 N / 15,500 lbf. Limiting Speed, grease: 9,200 rpm. Limiting Speed, oil: 18,400 rpm. Maximum Shaft Fillet Radius: 1.5 mm. Shaft Backing Shoulder Diameter: 99.7 mm. Housing Backing Shoulder Diameter: 130.9 mm. Outer Ring To-Clear Radius: 1.5 mm.

Decoding the designation

2MM: Fafnir super precision metric series, 15° contact angle. 9118: 9100WI dimension series, bore code 18, 90 mm bore, ISO 7018 envelope. WI: low shoulder on both rings. CR: phenolic outer land riding cage, Timken designation MBR. DU: duplex universally ground. H: heavy preload. The MM prefix carries ISO P4S. Searchable forms: 2MM9118WI-DUH, 2MM9118WIDUH, 2MM9118WI DUH, 2MM 9118 WI DUH, 2MM9118WICRDUH, 7018C-T-P4S-DUH, 7018C, 7018.

What these specs mean in practice

A 15° contact angle favours speed and radial rigidity over thrust capacity, which is why this execution is standard on machine tool spindles. Heavy preload raises axial and radial stiffness and holds shaft position under reversing cutting loads, at the cost of more friction and more heat than a light or medium preload set.

P4S tolerances hold bore, outside diameter and raceway runout to a few microns, giving tighter running accuracy and lower vibration. The phenolic outer land riding cage runs cool at high speed and suits oil-mist and air-oil lubrication; riding on the outer ring land lets centrifugal force stabilise the cage rather than load it.

Universal grinding means the ring faces are flush ground to a controlled offset, so the pair stacks back-to-back for maximum moment stiffness, face-to-face for tolerance of slight misalignment, or in tandem to double thrust capacity in one direction. The preload is built into the ground faces, so no shim stack or clearance setting is involved.

Quantity and configuration

Unit Quantity: 2 Pcs, one matched duplex set. Total Width: 48 mm. One row of balls per bearing.

Interchange guidance

Timken publishes the world equivalent as 7018C-T-P4S-DUH. Same-specification equivalents: FAG B7018-C-T-P4S-DUH, SKF 7018 CD/P4ADGC, SNR 7018CVDUJ94, RHP 7018CTDUHP4. A 7018 in a different contact angle, preload grade or cage material is a related size rather than an interchange, as is the 25° 3MM9118WI or 7018E.