Topic The thread formation tool which is improved is offeredSolutionsThe body which the thread formation tool, the terminal area (8) with, the second end (10) the thread formation department (12) with has in the first end (6) and makes long it includes (4), the aforementioned thread formation department (12), one annular mountain (14) includes at least around the aforementioned body. According to this invention, the cross section of the aforementioned body in the center of the aforementioned mountain has non circle. Selective figure Figure 1
展开▼