对于一个折断的M20螺栓,我们先用φ14钻头对正螺栓中心钻一孔,并钻透,再用3～4毫米宽的油槽凿子,在直径方向上两边各凿半月形沟,沟深将近螺栓丝底,然后用凿轻打,即能打成二块,分别取出。这种方法不但效率高,而且不损坏螺孔。 For a broken M20 bolt, we first use a φ14 drill bit to drill a hole in the center of the bolt and drill through, and then use a 3 to 4 mm wide oil groove chisel, chisel semicircle grooves on both sides in the diameter direction, Silk bottom, then tap with a chisel, which can be labeled as two, were removed. This method is not only efficient, but does not damage the screw hole.