FIELD: electro-spark formation of working surfaces of abrasive tools, formation of surfaces with high friction properties. SUBSTANCE: passed between tool and part are pulses of current with periodic variation of their polarity. Period of polarity variation of pulses is established equalling 10-20 periods of supply of current pulses. When positive potential is applied to instrument, its material is transferred to the part in the form of hard alloy grains. When negative potential is applied to tool, material is removed from the part. As a result, the surface with high abrasive properties is formed. EFFECT: higher efficiency. 2 dwg
