Two single row annular ball bearings selected dimensionally to be a matched pair or set. The ring faces have been specially ground to specified offsets that will produce predetermined preload when mounted. May include a single row angular contact bearing with faces specially ground for duplex mounting.
c28 calibration designator, 0.0003 inches minimum radial and 0.0008 inches maximum radial internal clearance, 7.5 pounds nominal bearing preload rating, radial load direction, 0.8748 inches minimum and 0.8750 inches maximum bore diameter