Fafnir2MM218WIDULAngular Contact Ball Bearing — 90 mm ID, 160 mm OD, 30 mm Width, 15° Contact Angle, Light Preload, Phenolic Cage, ABEC 7/9

Product Description

What this part is

Fafnir 2MM218WICRSUL, a super-precision spindle angular contact ball bearing from Timken’s Fafnir 200WI range. Bore: 90 mm. Outside Diameter: 160 mm. Overall Width: 30 mm. Total Width: 30 mm. 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. Manufacturer Part Number: 2MM218WI SUL. World Part Number: 7218C-T-P4S-SUL.

Decoding the designation

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

218 — 200WI dimension series, bore code 18. That is the ISO 7218 envelope: 90 mm bore, 160 mm outside diameter, 30 mm width.

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.

SUL — single, universally ground, light preload. The ring faces are flush-ground to a common offset, so any two pieces clamped together arrive at the same light preload.

What these specs mean in practice

Dynamic Radial Load Rating (C1): 129,900 N (29,200 lbf). Dynamic Radial Load Rating, ISO method (C1 per row): 118,000 N (26,500 lbf). Static Radial Load Rating (C0): 97,900 N (22,000 lbf). Limiting Speed, grease: 8,900 rpm. Limiting Speed, oil: 17,800 rpm.

The 200 series is the medium section of the Fafnir spindle range, so at 90 mm bore this carries about 60 percent more dynamic load than the 9100 extra-light 2MM9118WI on the same bore, and gives up a little speed for it. The 15° contact angle holds the load path close to radial. The phenolic outer land riding cage is light, adds little to ball-set inertia and holds oil in its own porosity. Universal grinding makes the bearing stackable in any of the standard arrangements with the preload set by the grinding rather than by shims.

Quantity and configuration

Unit Quantity: 1 Pc. One universally ground single-row bearing, 30 mm total width.

Mounting data

Shaft Backing Shoulder Diameter: 102.7 mm (4.050 in). Housing Backing Shoulder Diameter: 148 mm (5.830 in). Maximum Shaft Fillet Radius: 2 mm (0.079 in). Outer Ring To-Clear Radius: 2 mm (0.079 in).

Interchange guidance

Timken’s world part number for this bearing is 7218C-T-P4S-SUL. Searchable variants of the Fafnir number: 2MM218WI-SUL, 2MM218WICRSUL, 2MM-218-WI-CR-SUL, 2MM-218-WI-CR-DUL, 2MM 218 WI CR, 7218C, 7218-C.

The 3MM218WI on the same 90 x 160 x 30 mm envelope is the 25° build: more thrust capacity, lower speed.