structure for and method of electrical discharge machining with a wire electrode to produce small holes including completely controlling electrical discharge machining parameters such as voltage , reactance , current and servo speed with a programmable microprocessor , central processing unit sensing first sparking between the wire electrode and the workpiece and controlling depth of cut from the position of the electrode on spark initiation electrode feeding to replenish eroded electrode through clamping sequencing between an electrical discharge machine head and an electrode carrying slide thereon . in accordance with the invention there is also provided ultrasonic vibration of at least one of the workpiece , a wire electrode guide and the electrode during machining . also , the slide is driven by a screw and nut combination including a plastic extruded between the screw and nut to remove backlash therefrom and the tapered end of the wire electrode is removed prior to electrical discharge machining therewith by machining with the tapered end of the electrode with a reverse polarity , that is with a high wear polarity , between the electrode and workpiece , and splitting of the wire electrode is substantially eliminated by increasing the pulse time of the cutting parameters and lowering the current thereof while flushing at a low velocity .