The floating grinding head follows automatically any run-outs of the work piece with constant pressure. The weight of the floating part of the grinding head was reduced to a minimum by mounting the driving motor to the basic part. The power is transmitted by a cardan drive. The precise adjustment of the grinding pressure with a pneumatic control system and a belt oscillation ensures an optimal 0utilization of the grinding belts. The belt change requires only a few manipulations. Pneumatic belt tension and belt running correction. The MS-400 can be equipped with grinding belts as well as polishing rings, wire brushes, flap wheels, Scotch-Brite-discs and belts.