FIELD: cutting metals and electrically conductive materials, working articles in universal and special machine tools at all levels of automatization in different conditions of production process organization, investigation of strength properties of cutting tools. SUBSTANCE: apparatus includes electric circuit and cutter. In seat of cutter body head cutting tip is placed onto supporting electrically conductive plate; tip is electrically insulated relative to electrically conductive plate, relative to cutter body and mounting members. Insulator is applied onto surface of supporting plate engaging with cutting tip, onto head of cutter body, onto bearing surface of seat of cutter body head and onto surfaces of mounting members engaging with cutting tip and extending outside cutter body. Apparatus is provided with electronic signaling device for registering time moment of admissible wear degree of cutting tip. Said device is connected to electric circuit between spindle and housing of machine tool. Body of cutter is not insulated relative to mass of machine tool. Electronic signaling device may include connected in series integrator, threshold unit, switching unit and indicator connected to electric power system of machine tool, circuit for charging integrator having resistor and capacitor grounded through connection wire to housing of machine tool. Signaling wire conductor of spindle of machine tool is connected with discharging circuit of integrator through additional resistor and said capacitor connected with outlet of integrator. Control inlet of switching unit serves as inhibition inlet for indication. EFFECT: enhanced strength of tool, improved rigidity of technological system, high- quality controlling system. 2 cl, 7 dwg
