絲錐在卧式車床或鏜床上使用时,容易挤坏螺孔、折断絲錐。这是因为: ①在鉆制螺紋底孔时,由于鉆刃不对称、工件材質不均匀等,引起底孔中心偏移,使得絲錐不易切入,可能挤坏螺紋孔口。②把絲錐装在車床尾座上,靠摇动手柄来实现絲錐軸向运动,难于实现軸向配合;如把絲锥装在刀架上 Tap in the horizontal lathe or boring machine used, easily squeezed screw holes, broken tap. This is because: ① In the drilling of the bottom hole, due to asymmetric drilling edge, uneven workpiece material, etc., causing the bottom hole center offset, making the tap is not easy to cut, may squeeze the threaded orifice. ② The tap mounted on the lathe tailstock, by shaking the handle to achieve axial movement of the tap, it is difficult to achieve axial coordination; such as the tap mounted on the turret