FafnirMM212WISuper Precision Angular Contact Ball Bearing 60x110x22 mm, 15° Contact Angle, Phenolic Cage, ABEC 7, Universally Ground

Product Description

What this part is

A Fafnir 2MM212WI super-precision angular contact ball bearing, 60 mm bore x 110 mm outside diameter x 22 mm wide — the 7212 envelope. The outer ring is counterbored on one side so the full ball complement can be loaded and so the bearing develops a contact angle. It carries radial load plus thrust in one direction, and the high shoulder must face the thrust.

Decoding the designation

2 – in Timken/Fafnir super-precision numbering the numeric prefix names the contact angle: 2MM = 15°, 3MM = 25°.
MM – Fafnir super-precision tolerance, ABEC 7, and the MM prefix implies the P4S tolerance package. A single M would be ABEC 3, so the doubled letter matters.
212 – 200 series, bore code 12, so 60 mm bore.
WI – maximum-capacity (filling-slot) type with a counterbored outer ring, which is what makes it angular contact rather than deep groove.
CR – composition retainer: a phenolic laminated-fabric, outer-land-riding cage. Fafnir stamps CR on the carton, not the ring.

What these specs mean in practice

A 15° contact angle is the high-speed end of the range. The shallow angle keeps the ball load path closer to radial, so centrifugal ball loading and heat generation stay low and the bearing tolerates a higher DN value than a 25° or 40° equivalent. What you trade away is thrust capacity and axial stiffness, so 15° suits grinding spindles and high-speed milling heads while thrust-dominant boring and drilling positions want 25° or steeper.

ABEC 7 controls bore, outside diameter, width and above all radial and axial runout, so the ring can be fitted in any rotational orientation without hunting a high spot. The phenolic cage is the matching high-speed choice: light, self-lubricating, and soft enough that a ball skid polishes the pocket instead of galling it. Its limits are sustained heat much above roughly 120 °C and attack by some synthetic lubricants and solvents — check your lubricant before fitting.

Published dimensions

Bore (d): 60 mm
Outside diameter (D): 110 mm
Width (B): 22 mm
Contact angle: 15°
Rows: 1
Cage: phenolic laminated fabric, outer-land riding (CR)
Precision: ABEC 7
Closure: open, no seals or shields
Outer ring: counterbored one side

Quantity and configuration

Sold as one bearing. This is a single, not a factory-matched duplex set, so there is no supplied preload. The WI series is universally ground, so two of these can be clamped face-to-face, back-to-back or in tandem and will develop a repeatable preload; where a drawing calls for a matched pair to a named preload class, order a DUL, DUM or DUH set.

Fitting notes

Orient the counterbored (low shoulder) side away from the thrust load — fitted backwards the balls climb the raceway shoulder and the bearing fails quickly. Press or induction-heat against the inner ring only; never hammer an ABEC 7 bearing and never drive force through a phenolic cage. Grease sparingly, roughly a quarter to a third fill, or run the oil-air system the spindle was built around. A single angular contact locates the shaft in one direction only and needs an opposing bearing in the arrangement.

Interchange guidance

Fafnir is now sold by Timken, so Timken 2MM212WI and Fafnir 2MM212WI are the same part. Direct 60 x 110 x 22 mm super-precision 15° equivalents: NSK 7212CTYNSULP4, SKF 7212 CD/P4A, NTN 7212CT1P4, RHP 7212CTP4 — C and CD are the 15° codes in those schemes. Carried as dimensionally-correct cross-references with the difference named: SKF 7212 ACD/P4A and NSK 7212A5TYNP4 are the same envelope at 25°, RHP 7212ETP4 is 25° in RHP nomenclature, and FAG 7212-B-TVP-P4 is the same envelope at 40°. All fit the same bore and housing but change speed and thrust behaviour, so match the angle your spindle was designed around. Within Fafnir, 3MM212WI is this bearing at 25°.