我厂加工的主轴如图１所示，螺孔Ｍ６均布在直径为ｄ１的圆周上。ｄ１与轴径ｄ２仅差１１ｍｍ，而主轴２长达８００ｍｍ，加工该孔难度很大。图１我们采用的方法是，先从主轴左侧加工，加工出４个大螺孔（底孔）Ⅰ，然后将该四孔底部锪平，再钻好４个工艺孔（图２中７），然 I plant machining spindle shown in Figure 1, M6 screw holes are evenly distributed on the circumference of the diameter d1. d1 and shaft diameter d2 difference of only 11mm, while the spindle 2 up to 800mm, processing the hole is very difficult. Figure 1 Our approach is to first machined from the left side of the spindle, machining four large screw holes (bottom hole) Ⅰ, and then the bottom of the four-hole flattening, and then drilled a good four holes (Figure 2  7 ), However