现在提供一种在厚度达2.5mm的板材上加工大量M3～M5细牙螺纹的新方法(苏联发明证No.944829),该方法只需1～1.5秒钟便可同时在零件的所有孔内切削螺纹。方法是,先在板材上预钻或冲孔,预制孔d(见图1)的直径略大于所加工螺孔的内径,丝锥前端带有穿孔齿(见图2 K-K剖面),所以加工的第一个工序为冲出三条呈120°均布的纵槽。三条纵槽形成后,进行攻丝。这时丝锥旋转120°即停止转动,并把丝锥从工件纵槽中取出。螺孔上的三条窄槽,虽然使螺纹减弱15～20%,但一般情况下,这些螺纹仍有足够的安全系数。纵槽对螺钉的拧入条件没有影响,但在高硬度钢制零件上切削螺纹不宜采用这种方法。丝锥上分穿孔齿和螺纹切削齿两段,分别见图2 Now a new method of processing a large number of M3 to M5 fine threads on boards of up to 2.5 mm in thickness (USSR No.944829) is provided, which takes only 1 to 1.5 seconds in all holes of the part Thread cutting. The method is to pre-drill or puncture the plate, the diameter of the prefabricated hole d (see Figure 1) is slightly larger than the inner diameter of the screw hole to be machined, and the perforated tooth is provided at the front end of the tap (see KK section in Figure 2) One process is to punch three 120 ° evenly distributed longitudinal grooves. After three longitudinal grooves are formed, tapping is performed. At this time, the tap rotates 120 ° to stop rotating and remove the tap from the longitudinal groove of the workpiece. Three narrow slots on the screw hole, although the thread weakened 15 ~ 20%, but in general, these threads still have sufficient safety factor. Longitudinal grooves have no effect on screwing conditions, but cutting threads on high-hardness steel parts should not be used in this way. Tap on the sub-perforated teeth and thread cutting teeth two sections, respectively, see Figure 2