Abstract: Electro-chemical drilling of small diameter holes is achieved by placing an electrolyte discharge nozzle in fixed spaced apart relationship with a workpiece, heating the electrolyte passing between the discharge nozzle and the workpiece to increase the current conductivity of the electrolyte up to about 70.degree. C and forcing a jet of electrolyte across the space onto the workpiece. The electrolyte pressure and discharge nozzle orifice length are matched so as to provide an unconfined jet of electrolyte which has a constant diameter so as to obviate the necessity of relative movement between nozzle and workpiece. Increased temperature results in a fine non-conductive mist at the end of the electrolytic jet thereby providing a process for drilling holes of smaller size in the workpiece than prior procedures.A novel nozzle assembly is also disclosed adapted to produce holes in a workpiece by directing free streams of electrically charged electrolyte at the workpiece.