Fafnir3MM9114WIDULSuper-Precision Angular Contact Ball Bearing – 70 mm Bore, 110 mm OD, 20 mm Width, 25° Contact Angle, Light Preload, Universally Ground, Open

Product Description

What this part is

Fafnir 3MM9114WI-SUL super-precision angular contact ball bearing, a single bearing ground for universal matching. Bore 70 mm, outside diameter 110 mm, width 20 mm. Open on both faces, one row of balls, phenolic outer-land-riding cage. This is a machine tool spindle bearing held to super-precision tolerances rather than general-purpose bearing tolerances.

Decoding the designation

The leading 3MM gives a 25° contact angle and the MM prefix places the bearing in the P4S super-precision class, equivalent to ABEC 7/9. The 9114 maps to the ISO 7014 base number in the 70 light dimension series. WI is the angular contact spindle configuration with the phenolic outer-land-riding cage. SU means a single bearing, universally ground, and the closing L sets light preload.

What these specs mean in practice

A 25° contact angle carries more thrust and less speed than a 15° bearing in the same envelope, which makes it the choice where axial cutting load dominates. Light preload keeps running friction and heat generation low, favouring speed and bearing life over maximum axial rigidity. The phenolic outer-land-riding cage is light and tolerates oil and oil-mist lubrication at spindle speeds.

Universal grinding

Universal grinding means the ring faces are finished so that any two bearings from the series clamp up to the stated light preload with no shims and no measurement. A single bearing can therefore run alone, or be stacked with further universally ground bearings of the same designation to build a duplex, triplex or quad set.

Preload rather than clearance

Light preload is built into the ground ring faces, so it is established as soon as the bearing is clamped against a matching face. A radial internal clearance grade does not apply to a preloaded bearing, and none is published here.

Quantity and configuration

One bearing. Single row, single universally ground bearing at light preload.

Interchange guidance

The NSK 7014A5TYNSULP4 is the same single universally ground 25° light-preload bearing, with a polyamide cage in place of phenolic. The SKF 7014 ACDGA/P4A is a single universally matchable 25° bearing at extra light preload rather than light. The SKF 7014 ACD/P4A shares the envelope and contact angle but is not universally ground. The Fafnir 3MM9114WI-SUM is the medium-preload version, and the Fafnir 3MM9114WI-DUL is a matched pair of two bearings ground as a set.