Thread forming tap with a non-circular cross-section and radially extending cutting edges

A thread-forming tap comprising an elongated body having a first axial end section and an opposite second axial end section;

• the first end section including a connector portion;
• the second end section having a thread-forming portion for forming a thread in an interior wall of a workpiece;
• the thread-forming portion comprising at least one thread-forming thread separated by a first helical groove, said thread-forming thread having a non-circular cross section including at least three lobes adapted to physically deform the workpiece interior wall while forming an internal thread therein;
• the second end section further including a thread relief portion disposed between the thread-forming portion and a terminal end of the second axial end section;
• the thread relief portion comprising a thread in the form of a truncated ridge separated by a second helical groove, the truncated ridge defining a circular cylinder;
• wherein the thread-forming portion extends from an end of the truncated ridge remote from the terminal end, an initial plurality of turns of the thread-forming portion increasing gradually in diameter in a direction from the truncated ridge, there being at least one flute formed in an outer periphery of the body and extending generally axially through the thread-forming portion to define a discontinuity in the thread-forming portion, the at least one flute extending to the terminal end of the second end section and defining at such terminal end a cutting edge extending generally radially for cutting parts of the workpiece interior.