公开(公告)号：US20190201993A1

公开(公告)日：2019-07-04

申请号：US16075712

申请日：2016-03-08

申请人： OSG CORPORATION

发明人： Takayuki NAKAJIMA ,  Kohichi SAITOH

IPC分类号： B23G5/06 ,  B23G1/52

摘要： A pipe-tapered-thread machining tap has a thread, four spiral flutes and four cutting edges that include a plurality of thread intersection portions at each of which a corresponding one of the four cutting edges intersects with the thread. The thread intersection portions of the cutting edges have four groups, such that each of the four groups has ones of the thread intersection portions that are portions of a corresponding one of the four cutting edges. Every two of the thread intersection portions of each of the four groups is removed, such that, in each of the four groups, at least one of the thread intersection portions that is removed and at least another one of the thread intersection portions that is not removed are alternately arranged in a direction in which a corresponding one of the four cutting edges extends.