While in the throw away tip/chip and the drill

摘要

PROBLEM TO BE SOLVED: To provide a throwaway tip 1 for a drill of one tip type with two similar tips having an inner blade 11 cutting a center portion of a hole and an outer blade 12 cutting a circumferential edge of the hole which are arranged across the drilling hole at a tip in which the chip discharging property is further improved, and a drill holder forming a throwaway drill combined therewith. ;SOLUTION: The tip 1 connects a step between a first face 13a and a second bearing surface 1c by a curved surface 15 for guide which guides chips cut by the inner blade 11. In the holder, a connection surface adjacent to the first face of a flute groove is inclined in the same direction as the inclination of a spiral of the flute groove.;COPYRIGHT: (C)2001,JPO