Fafnir2MM214WIDUHSuper Precision Angular Contact Ball Bearing 70 x 125 x 24 mm 15 Degree ABEC 7 Heavy Preload Phenolic Cage

Product Description

What this part is

A single-row super-precision angular contact ball bearing in the Fafnir 200WI spindle series, 70 mm bore × 125 mm outside diameter × 24 mm width. The ISO equivalent designation is 7214 C.

Decoding the designation

2MM — 15° contact angle, Fafnir super-precision spindle bearing.
214 — 200 dimension series, bore code 14, giving a 70 mm bore.
WI — spindle angular contact ball bearing, universally ground faces.
SU — single bearing, universally ground for matching.
H — heavy preload.

The MM prefix on a Fafnir spindle bearing carries P4S tolerances — ABEC 7 dimensional accuracy with ABEC 9 running accuracy.

What these specs mean in practice

A 15° contact angle biases the bearing toward speed and radial rigidity, and carries less thrust than a 25° bearing in the same envelope. Heavy preload raises axial and radial stiffness and holds the ball complement in a fixed contact path under load reversal, at the cost of extra running friction and heat, so it belongs on rigid, well-cooled spindles rather than long unsupported shafts.

Published specifications

Bore: 70 mm (2.7559 in)
Outside diameter: 125 mm (4.9213 in)
Width: 24 mm (0.9449 in)
Contact angle: 15°
Precision class: ABEC 7 / ISO P4S
Preload: heavy (H)
Rows: 1
Cage: phenolic, outer-land-riding
Rolling elements: steel balls
Closure: open, both faces
ISO equivalent: 7214 C

Quantity and configuration

Single bearing, 1 Pc. Universal grinding allows it to be stacked back-to-back, face-to-face or in tandem with matching bearings of the same designation.

Fitting notes

Mounting is an interference fit on the shaft and a close fit in the housing bore, both held to super-precision spindle limits. Faces seat against square ground shoulders, and heavy preload makes shoulder squareness more consequential because the stiffer stack has less compliance to absorb a cocked seat.

Interchange guidance

Same-spec 15° P4 equivalents in other schemes are the SKF 7214 CD/P4A, FAG B7214-C-T-P4S and NSK 7214CTR, matched for heavy preload. The 3MM214WI is a 25° bearing in the same envelope, and the SUL and SUM variants differ in preload — those are related sizes rather than interchanges.