Automatically controllable projecting contour grinding machines

An automatically controllable projecting contour grinding machine comprising a grinding disc, a workpiece supported for contour machining by said grinding disc, cross slide means displacing said grinding disc and said workpiece relative to each other along two mutually perpendicular axes, manual actuator means for displacing said cross slide means along said axes, numerical control means for automatically displacing said cross slide means along said axes, an optical projection device forming on a projection surface a magnified image of said grinding disc and of said workpiece to be machined thereby in accordance with a predetermined contour line, a transparent carrier on said projection surface having said predetermined contour line and a marking in the form of an enlarged outline of the grinding disc, wherein said marking defines a starting position for said grinding disc programmed in said numerical control means for effecting machining of the workpiece along said predetermined contour line by said numerical control means after placing the image of said grinding disc at said marking by way of said manual actuator means.