攻制两同轴度要求较高的两个相距间隔较大的螺孔时(见图1),采用标准丝锥,分别从外侧攻制,因手攻难以控制丝锥,往往丝锥对孔口产生一些歪斜,故很难保证攻制的两螺孔的同轴度的要求,零件的不合格率高。对此我们设计了图2所示的同心丝锥,解决了上述攻制的偏斜问题。本丝锥主要是采用前、后导柱,分别以螺纹底孔为引导,其长度都应大于两孔外侧距离。使用时,只需将前导柱1插入 Attack two coaxial requirements higher clearance between the two large screw holes (see Figure 1), the standard tap, respectively, from the outside attack, because of hand control is difficult to control the tap, the tap often have some of the orifice Askew, it is difficult to ensure the attack of the two coaxial screw hole requirements, the high rate of failure of parts. In this regard, we designed the concentric tap shown in Figure 2, to solve the problem of deflection of the above-mentioned attack. The taps are mainly used before and after the guide column, respectively, to guide the bottom of the screw thread, the length should be greater than the distance between the two holes outside. When in use, simply insert the Pole 1