FIELD: metallurgy.
SUBSTANCE: group of inventions relates to the processing of materials by pressure and can be used in the construction of drills. In the method, the central drill insert has a bottom surface, a top surface, and a peripheral surface extending therebetween. At least three lead drill portions protrude from the peripheral surface, each of which has a drill axis and a plurality of drill cutting edges. Further, a secondary cutting edge is adjacent each lead drill portion, extending along the intersection of the top surface and the peripheral surface, transversely to the respective drill axis. Each secondary cutting edge is spaced apart from the associated drill cutting edges along the drill axis. Also a dovetail abutment flank is formed on the peripheral surface along the intersection of the top surface and the peripheral surface, extending from each one of the lead drill portions towards the secondary cutting edge associated with another lead drill portion. Further, a cutting tool has an insert pocket for retaining the central drill insert with the operative drill axis aligned with the tool axis.
EFFECT: invention ensures use of multiple cutting zones of the drill and strong retention of the central insert.
10 cl, 11 dwg
