DRILL TOOL

摘要

PROBLEM TO BE SOLVED: To remarkably decrease possibility of that a drill head is restricted by reinforcing iron bars regardless of diameter of the drill head even when drilling work is applied on an reinforced concrete. SOLUTION: At least three pieces of cutters 7-9 made of a rigid alloy are provided on a drill head and these cutters are arranged on the outer periphery of the drill head 5 in such an arrangement that they are at least partly close to a guide region 14 connected with the axial direction of the drill head 5. At least two mutually adjoining cutters positioned on the outer periphery of the drill head 5 forms each other an angleβof approximately 100 deg.-approximately 150 deg. and are mutually divided by at least one head waste channel 10-12 in the outer peripheral direction and the head waste channel is connected with at least one discharge channel provided spirally on a shaft 2.