FAGB7205CBTPAP4DULSuper Precision Spindle Bearing – 25 mm Bore, 52 mm OD, 15 mm Width, 15° Contact Angle, P4 Class, Light Preload, Universally Matchable

Product Description

What this part is

A FAG B7205-C-TPA-P4-UL super-precision spindle bearing: a single-row angular contact ball bearing, 25 mm bore by 52 mm outside diameter by 15 mm wide, open on both faces, with a 15° contact angle, P4 accuracy and a machined phenolic window cage. It is universally ground with light preload, so any two pieces of the same designation form a matched set.

Decoding the designation

The leading B denotes the standard-size steel ball complement. 72 is the light dimension series and 05 gives the 25 mm bore. C is the 15° contact angle. TPA is the fabric-base laminate phenolic cage. P4 is ISO accuracy class 4, equivalent to ABEC 7. UL is single universal grinding with light preload.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness, giving a reference speed of 43,000 rpm and a limiting speed of 28,000 rpm at this size. Dynamic load rating is 14.8 kN, static 6.1 kN, and the fatigue limit load 0.63 kN. A 25° design in the same envelope would carry more thrust and turn slower; the 15° trade is the one made for spindle duty.

Cage material and its effect

The phenolic cage is machined from fabric-reinforced laminate and rides on the outer-ring land. It weighs a fraction of a brass cage, holds oil in its porous structure, and runs quietly at high speed, which is why it remains the classic choice for grinding and milling spindles. Continuous operating temperature runs to about 100 °C.

Quantity and configuration

One bearing, universally ground. Sets are assembled from individual pieces of this designation, back-to-back, face-to-face or in tandem, and the light preload is established by the grinding of the ring faces.

Fitting notes

Mounting force is applied only to the ring being fitted. The rings are marked so that the high sides of the outer rings face each other in an O arrangement. Cleanliness governs the life of a P4 spindle bearing more than load does, so the bearing goes to the shaft straight from its wrapper.

Interchange guidance

The Timken/Fafnir 2MM205WI CR SUL is a direct interchange — same angle, same phenolic land-riding cage, same single universal light-preload grinding. B7205-C-T-P4S-UL is the current Schaeffler designation for this bearing at the tighter P4S accuracy class. The B7205-E variant uses larger balls for higher capacity and the 7205-B-TVP-P5-UL is a 40° polyamide-cage bearing, so both are related sizes rather than substitutions.