In the maintenance of equipment, it is often encountered that the old screw is re-screwed and reused or temporarily equipped with several screws. In the case that there is no wrench on hand, we use the following two methods. 1. After the bottom of the movable wrench or the radial section of the movable joint, drill the bottom hole at a certain distance, tap the M6mm screw hole and match the locking screw. Used to fix the positioning groove on the circular wrench,