Abstract: An expansion tap having a body (20) with a head (22) on one end and angularly tapered threads (26) on the other, with a bore (24) running therethrough. The body (20) has a shoulder stop (38) in the middle and a plurality of flutes (28) through the threaded portion. A capscrew (46) penetrates the bore (24) and is threadably engaged to a forcing cone (40) contiguous with the bore on the threaded end. A plurality of aligning ribs (44) engage the flutes (28), preventing rotation when the capscrew is tightened. The tap is inserted into a damaged threaded hole engaging the original threads in the middle and subsequently expanded by tightening the capscrew (46), thus straightening the tapered thread portion until the lands are parallel. Removal of the tap straightens and recuts the damaged threads.