Mechanical feed EDM machine for making threaded and nonthreaded bores

An electrical discharge machining device comprising:

• a generally vertically oriented base plate;
• a carriage plate vertically slidably mounted on said base plate;
• a drive shaft rotatably mounted on said carriage plate;
• an electric motor drive coupled to said drive shaft and mounted on said carriage plate for movement therewith;
• a first electrode coupling on a lower end of said drive shaft;
• means for supplying electrical power to an electrode coupled to said first electrode coupling;
• a plurality of sets of threaded lead screws, threaded guide sleeves and threaded electrodes, each said set including a threaded electrical discharge machining electrode and a threaded lead screw having matching thread pitches, and each said set including a threaded guide sleeve having a thread pitch mating with said thread pitch of said threaded lead screw, said thread pitches of each of said sets being different from thread pitches of other ones of said sets;
• and
• each said threaded lead screw being removably couplable to an upper end of said drive shaft and each said threaded guide sleeve being removably mountable on said base plate to matingly receive one of said threaded lead screws coupled to said drive shaft, whereby said sets of threaded lead screws, threaded guide sleeves and threaded electrodes are interchangeable with other ones of said sets having different thread pitches.

An electrical discharge machining device comprising:

• a normally stationary support member;
• a carriage mounted on said support member for generally longitudinal translation therealong;
• a drive shaft, having first and second ends, and being mounted on said carriage for generally axial rotation thereon;
• a motor mounted on said carriage, and operably coupled to said drive shaft for axially rotating the same;
• a threaded lead screw for translating said carriage with respect to said stationary support member;
• said lead screw having first and second ends, with the first end of said lead screw removably and interchangeably coupled to the first end of said drive shaft;
• said lead screw having a predetermined thread pitch;
• a lead screw guide removably and interchangeably mounted on said stationary support member, and having a threaded aperture therethrough in which said threaded lead screw is matingly received;
• said lead screw guide having a predetermined thread pitch corresponding to the thread pitch of said lead screw;
• means for removably coupling an electrode with one of said drive shaft second end and said lead screw second end for rotation therewith, whereby rotation of said motor both rotates the selected electrode and simultaneously translates the selected electrode longitudinally with respect to a corresponding workpiece for automatically regulating the rate of longitudinal movement of the selected electrode;
• and
• means for applying electrical energy to the electrode.