Fafnir2MM216WIDULSuper Precision Angular Contact Ball Bearing 80x140x26mm 15 Degree ABEC 7 Phenolic Cage Light Preload Single Universally Ground

Product Description

What this part is

A single Fafnir 2MM216WI super-precision angular contact ball bearing on the 7216 envelope: 80 mm bore, 140 mm OD, 26 mm wide. It is universally ground for light preload (SUL), so it can be run on its own or stacked with identical bearings to build a duplex, triplex or quad set without spacers. This is high-speed machine tool spindle hardware — milling and grinding spindles, precision gearboxes, rotary tables.

Decoding the designation

2MM — Fafnir super-precision series, 15° contact angleThe MM prefix implies ABEC 7/9 (P4S) tolerance class, not plain P4216 — ISO 7216 envelope, 80 x 140 x 26 mmWI — super-precision spindle bearing designCR — phenolic outer-land-riding cageSUL — single, universally ground, light preload

Correcting the source data

Earlier copy carried both SUL and DUL on the same bearing. Those are mutually exclusive: SU is a single universally ground bearing, DU is a matched duplex pair. This listing is the single, SUL — one bearing, not a pair. Order two if the spindle takes a pair.

What these specs mean in practice

A 15° contact angle favours speed and radial capacity over thrust; it is the usual choice for the high-speed end of a spindle where axial load is modest. Light preload keeps friction and heat low, which is what allows those speeds. The phenolic outer-land-riding cage is light and quiet at speed but should be kept away from solvents, steam and sustained high temperature.

Published specifications

Bore: 80 mmOutside diameter: 140 mmWidth: 26 mmContact angle: 15°Tolerance class: ABEC 7/9 (P4S)Preload: lightCage: phenolic, outer-land ridingRows: singleClosure: open

Quantity and configuration

One bearing. Because the rings are universally ground, any number of these can be assembled back-to-back, face-to-face or in tandem and the ground offsets produce the intended light preload automatically.

Fitting notes

Mount clean and handle by the rings, not the cage. Shaft and housing seats should be ground to a comparable precision class or the bearing’s accuracy is lost in the fit. Where two or more are stacked, orient them per the spindle design and mark faces before any future removal. Lubricate sparingly with a spindle grease or an oil-air system matched to the speed.

Interchange guidance

Equivalent parts are 7216-envelope 15° ABEC 7 light-preload universally ground singles, and the 2MM216WISUL / 2MM-216-WI-CR-SUL forms of this number. Related but NOT interchangeable: 3MM216WI is the same envelope at 25°, and SUM/SUH are medium and heavy preload. Contact angle and preload both have to match the spindle design.