rotating base 33 is in turn attached to a positioning motor 37 either directly or indirectly through a transmission or direct drive the positioning motor 37 positions or rotates the fixture 34 containing the workpiece while the translational movement mechanism 30 moves the workpiece 22 through the rotating abrasive brush 20 a controller such as controller 200 controls the positioning motor 37 to vary the rotation of the fixture 34 in accordance with a predetermined program such as a numerical control program which accurately rotates positions or stops the rotation of the positioning motor 37 alternately the controller permits an operator to provide positioning commands to the motor 37 as shown in fig1 a vertical movement mechanism 28 is employed which adjusts the vertical position of the motor 20 relative to the base in one embodiment the vertical movement mechanism 28 includes a screw driven actuator that is controlled either manually as by a handle 46 fig1 or by a control motor 80 fig6 if a control motor 80 is utilized the motor 24 is preferably engaged to one or more guide rails 84 through linear bearings 86 a screw 82 turned by the control motor 80 passes through a threaded fitting on the motor 24 such that rotation of the screw 82 causes the motor 24 to move up or down it is contemplated that the movement of the motor 24 and abrasive brush 20 may be pre programmed into.