公开(公告)号：EP3427881A1

公开(公告)日：2019-01-16

申请号：EP16893453.7

申请日：2016-03-08

申请人： OSG Corporation

发明人： NAKAJIMA, Takayuki ,  SAITOH, Kohichi

IPC分类号： B23G5/06

摘要： Provided is a taper thread-cutting spiral pipe tap for which the occurrence, in the female thread, of gouges and cutting edge marks when tap rotation is stopped is limited. The taper thread-cutting spiral pipe tap 10 has four helical grooves 20. The cutting edge 24 located every specified number of the multiple cutting edges 24, which are located successively along the succession of thread crests 18 of the complete thread portion 14, is removed. As a result, it is possible to obtain a taper thread-cutting spiral pipe tap 10 for which the occurrence of gouges of the inner circumferential surface of a tapered female pipe thread, the occurrence of chip clogging, and the occurrence of cutting edge 24 marks when tap rotation is stopped are limited.