Tapping machine and tap die, and method of detecting overstroke of tap

A tapping tool mountable on an adapter for tapping including:

• ring gear in which the tapping tool is mountable;
• and a gear holder in which the ring gear is disposed and which is mountable on a turret of a turret punch press so as to locate the disposed ring gear at a position corresponding to a mounting section of the turret formed in advance in the turret, the tapping tool comprising:
• a cylindrical body including a cylindrical outer holder and a cylindrical gauge nut, a master screw formed on an inner circumference of the cylindrical gauge nut and being disposed in a through-hole of the ring gear and the mounting section of the turret, wherein the cylindrical gauge nut is positioned within and configured to move vertically with respect to the cylindrical outer holder;
• and
• a rotating body being configured to be capable of holding a tap, including a master screw formed on an outer circumference thereof so as to be threadedly engaged with the master screw formed on the gauge nut, the rotating body being disposed inside the cylindrical body by threadedly engaging the master screw thereof with the master screw on the cylindrical body, rotating along with rotation of the ring gear, and moving in an extending direction of a central axis of the rotation.