Abstract: An apparatus for working a workpiece comprises drive means for rotating a carrier about an axis of rotation and a tool for working the workpiece. The apparatus furthermore comprises means for moving said tool in an x-direction and a y-direction with respect to the drive means, and a control unit comprising a memory for one or more control programs. The control unit is arranged for controlling the moving means in accordance with a control program, in such a manner that the tool will follow one or more desired paths for working the workpiece. The control unit is furthermore arranged for measuring an apparatus parameter which influences the control program, such as the angle between the axis of rotation and one of the moving means and/or the tool contour and the position of said contour with respect to the axis of rotation. Said apparatus parameter(s) is (are) stored at the (each) control program in the memory.