After the end face of the one-way thrust ball bearing of the power head is broken, it is often repaired by bonding and butt welding. I have a set of vertical boring, the one-way thrust ball bearing end of the power head is positioned as shown in Figure 1. After the break at A, it is repaired by bonding method. The adhesive is epoxy resin, and it will not be cracked for a long time. Bonding does not help, it is repaired by butt welding. Due to thermal deformation, the perpendicularity error between the A end surface and the central axis increases. The mast circle jumps beyond the tolerance range. Although it is barely used, it cannot guarantee the machining accuracy and the wear of each component. Fast, for this purpose, use the bearing sleeve positioning (Figure 2).