新型中心钻中心钻的种类较少．但却是不可缺少的预加工孔用工具。图１所示为普通中心钻。我厂采用普通中心钻在某零件的球头上（钻孔前）打中心孔时，发现出现较大的们移．经分析造成这种现象的主要原因有以下两点：图１（１）中心钻为２个切削刃．两刀的径向跳动量不同．... There are fewer types of new center drills. But it is indispensable pre-hole tool. Figure 1 shows a typical center drill. I plant ordinary center drill in the ball of a part of the hole (before drilling) hit the center hole, we found a larger shift. Analysis of the main causes of this phenomenon has the following two points: Figure 1 (1) Center drill is two cutting edges. Two knife radial runout different. ...