The disclosure relates to a profile forming apparatus and in particular a cam grinding machine in which a cam to be ground is mounted for rotation about the axis of the cam shaft in a work-table and a drive motor rotates the cam about its axis at a speed controlled by a predetermined programme. The work-table is mounted for rocking movement about an axis parallel to the cam shaft axis to move towards and away from the rotating grinding wheel which grinds cam surfaces spaced apart along the camshaft. The work-table is driven positively about its axis by a reversible drive motor in accordance with a further programme to rock the camshaft towards and away from the axis of the grinding wheel as the camshaft rotates and thereby determine the shape and dimensions of the profile to which the cam is ground.