FAGB7028CAP4ULSuper Precision Spindle Bearing – 140 mm ID, 210 mm OD, 33 mm Width, Open, 15° Contact Angle, Light Preload, Phenolic Cage

Product Description

What this part is

FAG B7028CA.P4.UL super precision radial spindle bearing. Single-row angular contact ball bearing, B70 high-speed spindle series, 140 mm bore x 210 mm outside diameter x 33 mm width. Open on both faces. Carton designations: B7028CA.P4.UL, B7028C, B-7028-C-A-P4-UL, and the Fafnir equivalent 2MM9128.

Decoding the designation

Series: B70, Schaeffler’s high-speed spindle bearing range. Contact Angle: 15°. Cage Material: fabric-base laminate phenolic. Cage Type: machined. Precision Class: P4, equivalent to ABEC 7. Preload: light. Universally matchable, so any two rings of this designation pair into a light-preload set in back-to-back, face-to-face or tandem order.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity, which is why the B70 range is the standard choice for machine tool spindles running at high rpm. Radial dynamic load rating: 153,000 N. Radial static load rating: 114,000 N. Limiting speed with grease: 6,300 rpm. Limiting speed with oil: 10,000 rpm. Fatigue load limit, radial: 9,100 N. Maximum operating temperature: 100 °C. Minimum operating temperature: -30 °C.

Stiffness and preload figures

Axial rigidity: 142 N/µm at light preload, 237 N/µm at medium, 335 N/µm at heavy. Preload force: 866 N light, 2,724 N medium, 5,429 N heavy. Lift-off force: 2,661 N light, 9,007 N medium, 19,129 N heavy. Distance between the apexes of the pressure cones: 39.9 mm.

Quantity and configuration

One bearing. Supplied as a universally matchable single ring set, ready to be combined with further pieces of the same designation.

Fitting notes

Straight cylindrical bore, interference fit on the shaft. Shaft shoulder diameter: 152 mm. Outer ring shoulder diameter: 199 mm. Maximum fillet radius: 1 mm. Minimum chamfer dimension: 2 mm. Lubrication pitch diameter range for oil injection: 161.6 mm to 169.2 mm.

Interchange guidance

Dimensionally and functionally equivalent 15° light-preload spindle bearings in this envelope: SKF 7028 CDGA/P4A, NSK 7028CTYNDULP4, Timken/Fafnir 2MM9128WI. The 25° execution of the same envelope is a related size and carries different thrust capacity and stiffness.