A cross slide contour forming box tool which can be applied to automatic screw machines for contour forming desired contours on the outside of a workpiece. The contour forming tool is positioned to a transverse slide perpendicular to the drive axis. The transverse slide is driven by a pin and cam groove in the face of a cam so that the contour forming tool is positioned in accordance with the shape of the cam groove. The workpiece is rotated relative to the contour forming tool and the desired contour is formed on the surface of the workpiece.