Thread repairing tool

A tool for repairing damaged spark plug threads within a bore of a head that may be attached to an engine block, which comprises:

• (a) a generally cylindrically shaped tool body including:
• (i) a threaded section for rethreading the bore at its bottom end having an over-all diameter less than the diameter of the adjacent section of the tool body,
• (ii) a cylindrically shaped axial bore for conveying particulate waste, said bore extending from said disk-shaped wall at the bottom end of the tool body to an upper terminal point in a higher portion of the tool body, and means for controlling movement of the particulate waste at the bottom end of the tool body that restricts radial and axial movement of the particulate waste through the bottom end of the tool body comprising a disk-shaped wall disposed within the axial bore at the end of the tool body transverse to its central axis,
• (iii) at least one particulate waste entry aperture in the wall surrounding said axial bore, which provides communication between the space external to the tool body and the bore interior, said at least one entry aperture being elongated in shape and located immediately adjacent said disk-shaped wall, said at least one particulate waste entry aperture being bounded on one end by said disk-shaped wall, with its longitudinal axis at approximately 15.degree. to the longitudinal axis of the tool body,
• the height of the threads in the portion of said threaded section extending from (a.sup.1) a point that is intermediate the ends of said at least one elongated particulate waste entry aperture to (b.sup.1) the bottom end of the tool body progressively decreases, from the standard height of the threads at said intermediate point to substantially zero at the bottom end of the tool body,
• (iv) a groove in the wall surrounding said axial bore that extends upward, with its longitudinal axis at approximately 15.degree. to the longitudinal axis of the tool body, from (a.sup.1) the outer surface of said disk-shaped wall to (b.sup.1) a point on the inner surface of said axial bore wall, at the upper end of said at least one elongated entry aperture, to (c.sup.1) a point, at the crest of the threads comprising said threaded section, that is spaced from the bottom end of the tool body by a distance approximately two-thirds the length of said threaded section,
• (v) at least one particulate waste exit aperture in the wall surrounding said axial bore, which provides communication between the bore interior and the space external to the generally cylindrical tool body, said exit aperture being located adjacent said upper terminal point of the axial bore, and
• (vi) drive-receiving means proximate to the upper end of the tool body, said means having the form of a non-circular hole extending into the tool body from the upper end thereof and terminating short of said terminal point of the axial bore;
• and
• (b) a housing fully enclosing, with an airtight seal, the portion of said generally cylindrical tool body in which said at least one exit aperture is located, to provide an enclosed space that completely encircles the tool body and is in communication with said at least one exit aperture at all times,
• said housing having an outlet opening,
• whereby, the disk-shaped wall defines a border of the at least one particulate waste entry aperture thereby restricting radial movement of the particulate waste passing through the at least one particulate waste entry aperture and axial movement of the particulate waste through the bottom end of the tool body, and
• the tool body being rotatable within the housing.