Abstract: A slotted inverse tap, compressible for insertion past damaged entry threads in blind holes. (FIG. 1 thru FIG. 5) The tool can be made to smaller sizes than that of prior art. An elongate slot (23) proceeds through a first threaded end (21), then well into a reduced diameter cylindrical body (25). After insertion to the hole bottom, a tabbed shim (28) is inserted to the slot from its side, then pressed down until stopped. The shim (28) enforces mating engagement with undamaged internal threads. A second end of hex and/or squared or other configuration facilitates use of a tap wrench or other tool for rotational extraction. Damaged threads are reformed/re-cut upon rotational withdrawal.

Abstract: The invention provides a chasing tool for repairing damaged internal threads, including a body provided with a bore; a handle retained in the bore with one degree of freedom in rotation, the handle being provided over at least part of its length with an internal thread; a cylindrical component having an external thread matching the internal thread of the handle; a tubular member fixedly attached to the body perpendicular to the axis of rotation of the handle and opening into the bore of the body and a lever tiltable about a pivot providing the lever with one degree of freedom in rotation, the cylindrical component being articulated to the lever and a cutter articulated to the other end of the lever, the cutter projecting from the tubular member.

Abstract: A thread cutting tool which can be configured to cut threads in a variety of bore sizes using universal thread cutting chasers mounted in select radial extension such as by using variable length tool blocks which are themselves interfit within retaining slots in the head portion of the tool, or by providing alternate radial position notches an the head portion for mounting the cutting chasers. By using variable tool blocks mounted to the head portion of the tool, universal thread cutting chasers having a preselected thread pitch can be utilized for multiple bore sizes, thus saving the expense of providing chasers or head portions corresponding to each bore size. Alternately, by providing alternate radial position notches in the head portion for mounting the cutting chasers, a single tool can be used for different bore sizes, such as for undertaking a start thread cut in a bore and then undertaking a finish thread cut in the pre-cut bore using an alternate radial position for the chasers.