FIELD: manufacture of porcelain products, in particular, tool used for manufacture of bushing insulators from electrical porcelain. SUBSTANCE: formed blank has opening with depth of 5 cm and angle equal to self-braking angle (0 deg 30 min). Tool mandrel at side forming deep-seated part of insulator cavity has spring-loaded puncturing plunger and tip with face. Plunger and tip make entry part of tool. Air channels in plunger are oriented toward grooves in surface joined with inner surface of tip. Channels in plunger are communicated with atmosphere via tool grooves. Forming surface of tool between tip and stop is formed as one or set of sleeves manufactured from plastic or fluoroplastic. EFFECT: increased efficiency, simplified construction and provision for withdrawing tool blank without deformation. 2 cl, 1 dwg
