Fafnir2MM218WICRDULSuper-Precision Angular Contact Ball Bearing 90 x 160 x 30 mm, 15 Degree Contact Angle, ABEC 7, Light Preload, Phenolic Cage, Universally Ground Single

Product Description

What this part is

A Fafnir 2MM218WICR-SUL super-precision angular contact ball bearing, single row, universally ground, from the WI machine-tool spindle series. Steel rings, steel balls, phenolic cage, open on both faces.

Decoding the designation

2MM — 15° contact angle.
218 — ISO 72 dimension series, bore code 18, giving a 90 mm bore. ISO equivalent 7218C.
WI — Fafnir ground super-precision spindle series.
CR — phenolic outer-land-riding cage.
SUL — single universally ground, light preload.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity, which is the usual choice for a spindle front position. An outer-land-riding phenolic cage runs on the outer ring rather than on the balls, cutting cage wear and lubricant churn at speed. Light preload holds a lower running temperature and less frictional torque than the medium and heavy grades. Universal grinding means the faces are flush-ground, so any two rings of this designation seat together back-to-back, face-to-face or in tandem and arrive at the marked preload with no shims.

Published specifications

Bore: 90 mm (3.5433 in)
Outside diameter: 160 mm (6.2992 in)
Width: 30 mm (1.1811 in)
Contact angle: 15°
Precision class: ABEC 7 (P4S)
Preload: light
Cage: phenolic, outer-land-riding
Rolling elements: steel balls, single row
Closure: open both faces

Quantity and configuration

1 Pc, a universally ground single at light preload.

Interchange guidance

ISO base number 7218, angle-designated 7218C. Searchable forms are 2MM218WICR-SUL, 2MM218WICRSUL, 2MM-218-WI-CR-SUL and 2MM 218 WI CR SUL. A 3MM218WI ring is the 25° version of the same envelope and is a related size, not an interchange; SUM and SUH are the medium and heavy preload grades, and DU duplex sets are a different arrangement, so all are related sizes.