Abstract: The edge profile machine employs a centering station in which a photosensor measures a number of points on the periphery of a wafer so that the shape of the wafer and location of the geometric center can be determined in a computer. A rotatable head serves to position the geometric center of the wafer on a fixed axis and the wafer transferred to a grinding station with the geometric center located on the central axis of a rotating chuck. During grinding, a grinding wheel is moved in accordance with the differences between the detected shape of the wafer and a predetermined shape. The grinding wheel is moved on an axis perpendicular to an axis passing through the centering station and grinding station in accordance with signals received from the computer.