FIELD: plastic metal working, namely manufacture of fastening members in cold upsetting automatic machines. SUBSTANCE: tool assembly includes body and working members mounted in it. Said tool assembly is provided with fastening bolt whose head is designed for engaging with flat of said body. On outer surface of said body there are single-side axial slit and grooves whose depth values are no less than 0.5 of thickness of body wall. Said grooves are arranged radially relative to axis of body and equally spaced by angle 120 degrees relative to said axial slit. EFFECT: improved design. 2 dwg
