Our factory produces JNP type condensate automatic pump. The pump body (Fig. 1) has tapped pipe threaded holes of R_o2 and R_o3. Due to the high workpiece, the rotating radius is too large, which makes it difficult to process. To this end, we placed on the C630 lathe, the workpiece is not rotating, the main drive shaft with the model of the car cone pipe thread device, as follows: