Abstract: A floating rotary drive device sequentially holding a workpiece of a series of workpieces to be supported with slack while each workpiece is machined by grinding while the workpiece is rotated about a slack axis of rotation, comprising a motor having n output shaft, a chuck (2) rotatable about an axis of rotation which chuck is attached to the output shaft of the motor (9), by a flexible control (30) and positioning means for positioning the machined workpiece after it has been ground, characterized in that the device comprises: coupling means (14, 39; 15, 40) for automatic coupling of the workpiece to be ground with the chuck; the coupling means being actuatable at the end of a machining operation to bear against the chuck to center the chuck with its axis of rotation coincident with the specific axis of rotation of the machined workpiece in a final position and to immobilize the chuck in the final position during the removal of the machined workpiece and during the fitting of a sequential workpiece to be ma

Abstract: A grinding device is provided for machining and facing workpieces made of resilient or semi-resilient materials. Said device comprises means (31) for holding the workpiece being processed after the machining operation to allow facing thereof. Machining can be improved by allowing limited drift of the workpiece, providing a flexible rotational drive, applying back pressure and using a recessed grinding wheel. This device can be used particularly for machining and facing drive rollers for office machines.