| 摘要 |
The tool (10) includes a central section (12) having a left-hand drill bit section (16) at one end and an extraction section (20) at the other. The extraction section (20) tapers toward its distal end and is formed with left-hand threads (22) on the exterior of the taper. The distal end is chamfered (24) at an angle more abrupt than the taper so that the chamfer (24) intercepts the threads (22) and so that the threads (22) rise outward in a short axial distance and are able to bite into the margins of a shallow hole drilled in the bolt remnant by the bit section (16). |
