We can take out the broken screws or break the bolts according to the following steps.

1. First, the sludge of cutting the broken head surface of the broken screw is killed by the center of the center, and then the drill is drilled with an electric drill with a diameter of 6-8 millimeters in the center hole of the cross section. After drilling, the small drill is removed and replaced by a drill bit with a diameter of 16 millimeters. The hole of the bolt is expanded and drilled through.

2. The welding rod with a diameter of less than 3.2 millimeters uses medium and small electric current in the hole of the broken bolt from the inside to the outside to remove the whole length of the bolt at the beginning of the surfacing welding. At the beginning of the surfacing, the arc should not be too long to burn the outer wall of the bolt. After surfacing to the end of the bolt, 1 diameters of 14-16 mm will be surfacing. A cylinder with a height of 8-10 millimeters.

3. After the surfacing is good, the head bolt of the hammer is used to make the end bolt vibration along its axis. Since the heat generated by the arc and the subsequent cooling, then the vibration will cause the loosening between the broken bolt and the thread of the body.

4. Observe carefully that when there is trace of rust after knocking, the M18 nut can be placed on the stigma of the build-up welding and the two can be welded when the rust leaks from the fracture.

5. After welding, it is cool to use a plum blossom wrench to wrench back and forth on the nut. It can be wriggled back and forth, and then the end of the nut can be taken out with a small hand hammering on the end of the nut.

6. After removing the bolts, use the appropriate tap to process the threads in the frame to remove rust and other impurities in the hole.