The spindle bearing is a kind of special design of single row angular contact bearings, its contact angle, tolerance, and cage structure is different from the ordinary bearing, especially used in where high precision and high speed required. The main applications of such bearings are the spindle of the machine tool and the motorized spindle of engraving machine. Precision spindle bearing includes precision Angle contact ball bearing 70 series, 72 series, 719 series.