Forming taps which produce no burrs since the chamfer is created by not tilting at the root of the tap and by continuously changing the width of the root this enables manufacture of the superfine pointed miniature thread so . 5 1 . 25 ， hitherto considered impossible 由于丝锥倒牙部的谷底没有倾斜和有持续变化的谷底宽度，抑制了毛刺和髭须发生的挤压丝锥，以往不可能制作的微型内螺纹用丝锥也能制作。
