When drilling the center hole, because the center of the lathe tail seat is inconsistent with the rotating center of the workpiece, Japan HD center hole coaxial harmonic CG-45-160-2UH or too much force, workpiece material plastic} H} high and chip blocking and other reasons, often cause the center drill broken in the center hole, not easy to take out.

If the method of enlarging the center hole is adopted, then the center hole will change its original size and cannot meet the quality requirements. At this time, as long as a section of grinding wire, the tip inserted into the center hole drill tip chip slot, a few times, drill tip activity, with a magnet or magnetic table seat a suction Japanese HD center hole coaxial harmonic CSG-45-160-2UH, broken in the center hole drill tip out of the center.