Dismantling skills of 85 mm screws

1. Remove the broken screws and the sludge on the surface of the head first, chisel the center of the section to death with a center chisel, then mount a drill with a diameter of 6-8 mm with an electric drill, and drill holes in the center of the section to ensure that the holes are drilled through. After the hole is drilled through, remove the small drill bit and replace it with a drill bit with a diameter of 16 mm, and continue to expand and drill through the hole of the broken bolt.

2. Take covered electrode whose diameter is less than 3.2 mm, and carry out surfacing welding in the hole of the broken bolt from the inside out with medium and small current. At the beginning of surfacing welding, take half of the total length of the broken bolt. At the beginning of surfacing, the arc striking time should not be too long to avoid burning through the outer wall of the broken bolt. After surfacing to the upper end face of the broken bolt, surfacing 14- 16 mm in diameter and 8- 10 mm in height 1 cylinder.

3. After surfacing, knock the end face with a hammer to make the broken bolt vibrate along its axial direction. Due to the heat generated by the previous arc and the subsequent cooling, coupled with the vibration at this time, there will be looseness between the broken bolt and the thread of the machine body.

4, careful observation, when found traces of rust leakage from the fracture after tapping, you can take the nut sleeve of M 18 and weld them on the surfacing column head.

5. After welding, twist the nut back and forth with a ring wrench sleeve when it is hot or cold, or tap the nut end face with a small hammer while twisting back and forth, and then take out the broken bolt.

6. After taking out the broken bolt, re-process the thread in the frame with a suitable wire hammer to remove the rust and other sundries in the hole.