DRILL STRUCTURE OF DRILLING MACHINE

摘要

PROBLEM TO BE SOLVED: To enhance breaking capability and dischargeability for cut chips by further improving a drill structure in a drilling machine used to punch a small diameter hole. SOLUTION: A leading end of a rotary shaft 1 of the drilling machine for drilling while ejecting the coolant supplied via a channel in the shaft toward the end of the drill by mounting the drill at the leading end of the rotary shaft is formed with a circular flat surface 2 closed except a coolant jet port 3. The drill constituted of a superabrasive segment 10 having a crushing surface 11 in a radial direction of the surface 2 is mounted on the surface 2, and an oblique surface 11a of a direction for reducing a sectional area at the end side of the segment is formed on the surface 11.