Editing Tap and die (section)

===Tap sequence===

With soft or average hardness materials, such as [[plastic]], [[aluminum]] or [[mild steel]], common practice is to use an intermediate (plug) tap to cut the threads.  If the threads must extend to the bottom of a blind hole, the machinist uses an intermediate (plug) tap to cut threads until the point of the tap reaches bottom, and then switches to a bottoming tap to finish. The machinist must frequently eject chips to avoid jamming or breaking the tap. With hard materials, the machinist may start with a taper tap, whose less severe diameter transition reduces the torque required to cut threads. To threads to the bottom of a blind hole, the machinist follows the taper tap with an intermediate (plug) tap, and then a bottoming tap to finish.