The carving opening in which there was a part of a bolt can be not damaged if to execute the following.

1. Nakernite precisely on the center a bolt fragment. For simplification of a kerneniye process a break a file if it is possible.

2. Drill a bolt fragment. Diameter of a drill has to make 0,8 diameters of a carving. For example, for the threaded connection of M6 diameter of a drill has to make 4,8 mm.

3. For drilling of big bolts at first use a drill of small diameter.

4. Remove the parts of a bolt which remained after drilling and "pass" a carving a tap.