The screw cold heading machine (head punching machine) will suddenly break its head when setting, but some people can't take out the broken head screw pin very well.

1. First, remove the sludge on the surface of the broken screw head, use the central punch to punch the center of the section, and then use the electric drill to install a 6-8mm drill bit to drill the hole at the center of the section. Note that the hole must be drilled through. After the hole is drilled through, take down the small drill bit and replace it with a drill bit with a diameter of 16 mm. Continue to expand the hole for broken bolts and drill through.

2. Take the electrode with a diameter of less than 3.2 mm and use medium and small current to conduct surfacing welding in the hole of the broken bolt from the inside to the outside. Take half of the entire length of the bolt at the beginning of the surfacing welding. Do not strike the arc too long to avoid burning through the outer wall of the broken bolt. After surfacing to the upper end of the broken bolt, continue to weld a cylinder with a diameter of 14-16 mm and a height of 8-10 mm.

3. After surfacing, hammer the end face with a hammer to make the broken bolt vibrate along its axis The heat generated by the previous arc and subsequent cooling plus the vibration at this time will loosen the thread between the broken bolt and the body.

4. After careful observation, when it is found that there is a trace of rust leaking from the fracture after striking, take the M18 nut and put it on the stud of surfacing welding and weld the two.

5. After welding, it is slightly cool, while it is hot, use a box spanner to put it on the nut and twist it left and right, or twist it back and forth while striking the end face of the nut with a small hammer, so that the broken bolt can be taken out.

6. After taking out the broken bolt, use a suitable screw hammer to process the screw thread in the rack once to remove rust and other debris in the hole.