Drilling out a broken bolt (Focus 2)

The threaded hole in which part of the bolt remains can be left undamaged if you do the following.

1. Punch the bolt fragment exactly in the center. To make punching easier, file the fracture if possible.

2. Drill out the bolt fragment. The drill diameter should be 0.8 of the thread diameter. For example, for an M6 threaded connection, the drill diameter should be 4.8 mm.

3. To drill out large bolts, use a small diameter drill bit first.

4. Remove the remaining parts of the bolt after drilling and "run" the thread with a tap.