Fafnir2MM9140WIDULSuper-Precision Angular Contact Ball Bearing 200x310x51 mm, 15 Degree Contact Angle, Single Universal Light Preload, Phenolic Cage

Product Description

What this part is

A Fafnir 2MM9140WI-SUL super-precision angular contact ball bearing, 200 mm bore by 310 mm outside diameter by 51 mm wide, with a phenolic cage. Fafnir is Timken’s super-precision line.

Decoding the designation

The 2MM prefix sets a 15° contact angle and carries P4S precision, equivalent to ABEC 7/9. The leading 9 in 9140 places the bearing in the ISO 70 light dimension series, giving an ISO base number of 7040, and the 40 size code gives a 200 mm bore. WI marks the super-precision angular contact family, CR the phenolic outer-land-riding cage, and SUL a single universally ground bearing at light preload.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity. The SUL grind means the faces are relieved so that any two of these bearings clamped together reach light preload, which gives the flexibility of building a pair, a triplex or a quad stack from single pieces held in stock. The phenolic cage runs quiet and cool on the outer ring land, with a lower temperature ceiling than a steel or brass cage.

Quantity and configuration

One bearing, single universally ground. Two or more may be stacked back-to-back, face-to-face or in tandem, each additional bearing adding its own light preload increment.

Fitting notes

Mounting is onto a clean straight journal against a square shoulder, with the marked ring faces oriented to the chosen arrangement. At this bore size the fit is set by measurement rather than feel, and the bearing goes on with even heat or a press rather than local blows.

Interchange guidance

Same-envelope 15° precision equivalents include the SKF 7040 CD/P4A and the FAG B7040-C-T-P4S-UL. A 7040 at a 25° contact angle, or a duplex-ground pair, is a related size rather than an interchange for a single universal bearing.