FIELD: manufacture of high-voltage insulators from ceramic mass, for example. SUBSTANCE: member molding axial cavity with bottom step is made in form of core mounted on rod with taper starting section and cylindrical calibrating section whose diameter is equal to large internal diameter of blank. Core has replaceable end-piece; diameter of rod of this end-piece is equal to diameter of smaller hole of insulator; core also has chamfer whose form corresponds to shape of groove of bottom step in axial cavity of insulator. Vacuum press for molding the bottom step in blank is provided with additional tip having constricted flow section as compared with flow section of tip. Tip is splittable in plane of axis of vacuum press. After molding this step, vacuum press is stopped and additional tip is opened. Then vacuum press is switched on again and blank of preset length id obtained through extrusion molding. EFFECT: enhanced efficiency. 3 dwg
