Abstract: A pair of orthogonal drive shafts carry cams which are coupled to a platform for orbital movement of the platform. The platform supports a workpiece below an electrode in an electrical discharge machining operation. The cams are cylindrical segments which extend axially at an acute angle to their respective drive shafts so as to present a changing throw along the axial extent of the cams and the coupling means is selectively adjustable along the axial extent of the cams to enable selection of the amplitude of the orbit. In another embodiment, a single drive shaft carries cams each having a throw extending perpendicular to the drive shaft and a further cam having a throw parallel to the drive shaft. The cams are coupled to a platform for orbital movement of the platform and have changing throws in the respective directions of the throws to enable selection of the amplitude of the orbit.

Abstract: A method of making toothed lock washers from sheet material wherein the lock washer bodies are blanked from the sheet material with adjacent outline configurations of the lock washers in close proximity within the sheet material, whereby the unused portions of sheet material between the outline configurations is minimized and sheet material is conserved.