To prevent fluctuation in the amount of cutting agent discharged from a plurality of cutting agent discharge ports.
A taper reamer 1 is provided with cutting edges 3, 5, 7, 9 and 11 extending in the axial direction at equal intervals of the peripheral direction in a blade part 15 on the distal end side. Each of the cutting edges 3, 5, 7, 9 and 11 is provided with the three respective cutting agent discharge ports (3a, 3b, 3c), (5a, 5b, 5c), (7a, 7b, 7c), (9a, 9b, 9c) and (11a, 11b, 11c) as positions deviated in the axial direction. The hole diameters of the cutting agent discharge ports 3b, 5b, 7b, 9b and 11b at the center part of the axial direction are made larger than those of the cutting agent discharge ports 3a, 5a, 7a, 9a, 11a and 3c, 5c, 7c, 9c and 11c on both sides. As a result, fluctuation of discharge amount of the cutting agent from the plurality of cutting agent discharge ports is suppressed to improve machining efficiency.
IIIZUMI MASAHIKO
NISHIMURA KIMIO
KONDO TOMOHIRO
TAKEDA KAZUO
SEKIKAWA TAKESHI
SENDA YOSHIYUKI
Iwa Saki Kokuni
Akira Kurihara
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu