Fafnir2MM218WICRAngular Contact Ball Bearing — 90 mm ID, 160 mm OD, 30 mm Width, 15° Contact Angle, Phenolic Cage, ABEC 7/9

Product Description

What this part is

Fafnir 2MM218WICR, 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. Contact Angle: 15°. Precision Class: ABEC 7/9 (ISO P4S). Cage Type: CR, phenolic outer land riding. Cage Material: phenolic. Rolling Elements: steel balls. Number of Rows: 1. Design Units: Metric. Manufacturer Part Number: 2MM218WICR.

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.

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: at 90 mm bore it runs a 160 mm outside diameter and a 30 mm width, so it carries substantially more load than the extra-light 9100 section on the same bore and gives up a little speed for it. The 15° contact angle holds the load path close to radial, which is what keeps that speed limit high. The phenolic outer land riding cage is light, adds little to ball-set inertia and holds oil in its own porosity to feed the ball pockets.

Quantity and configuration

Unit Quantity: 1 Pc. One single-row bearing.

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. Searchable variants of the Fafnir number: 2MM218WI, 2MM218WICR, 2MM-218-WI-CR, 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. The MM218WIMBR is the same size with a machined bronze cage in place of the phenolic one.