TIP END STRUCTURE OF DRILLING MACHINE

摘要

PROBLEM TO BE SOLVED: To enhance a grinding efficiency by further improving a structure of a tip end of a drilling machine and to enhance the efficiency of supplying a coolant in a drilling machine used to drill a small diameter hole. SOLUTION: A leading end of a rotary shaft 1 of the drilling machine for punching 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 closed except a coolant jet hole 3. Then, a superabrasive segment 4 having an inner space opened at a part of a circumferential direction in a horizontal section is mounted on an outer surface of a closed part 2 to constitute the drill. The hole 3 for ejecting the coolant in an oblique direction from a position deviated from a center of the end of a hollow part 6 of the shaft 1 toward a peripheral edge position of the outer surface of the closed part 2 is formed at the part 2.