Fafnir2MM214WI CR DUHSuper-Precision Angular Contact Ball Bearing Duplex Set of 2 – 70 mm Bore, 125 mm OD, 24 mm Width Each, 15° Contact Angle, Open, Phenolic Machined Cage, Heavy Preload

Product Description

What this part is:

Fafnir 2MM214WICR-DUH super-precision angular contact ball bearings, 70 mm bore, 125 mm outside diameter, 24 mm width per bearing. Single row each, open both faces, machined phenolic outer-land-riding cage. ISO base number 7214. Two pieces, supplied as a duplex set.

Decoding the designation:

2MM sets a 15° contact angle in the Fafnir WI super-precision scheme, and the MM prefix carries P4S precision — ABEC 7 dimensional tolerances with ABEC 9 running accuracy. 214 is the ISO 72 medium dimension series at 70 mm bore. WI is the ground spindle-bearing execution, CR the phenolic outer-land-riding cage, and DUH a duplex arrangement at heavy preload.

What these specs mean in practice:

A 15° contact angle favours speed and radial stiffness; a 25° bearing of the same envelope trades speed for thrust capacity. An outer-land-riding phenolic cage is light and tolerant of marginal lubrication, which suits high spindle speeds on oil mist or grease. Heavy preload gives the stiffest, most repeatable spindle at the cost of higher running temperature and reduced speed limit.

Quantity and configuration:

Two bearings, 24 mm wide each, 48 mm total mounted width as a duplex stack. Faces are universally ground, so the pair mounts back-to-back, face-to-face or in tandem.

Fitting notes:

Straight bore on an interference fit to the spindle journal, with the outer rings clamped square in the housing bore. The ground faces are stacked per the chosen duplex arrangement, with the marked faces oriented together. Oil or grease lubrication, filtered, is standard for this class.

Interchange guidance:

Matching 15° heavy-preload duplex sets are the SKF 7214 CD/P4ADGC and FAG B7214-C-T-P4S-DUH; the NSK 7214CTYNDUHP4 and RHP 7214CTDUHP4 match in P4 rather than P4S class. A 7214A5 or 7214-E of the same envelope is a 25° bearing, and a single SU-ground 2MM214WI is a related item rather than a substitution for a duplex pair.