Thread cutting tap held in a tap wrench. This steel hand tool is used to cut a screw thread into a predrilled hole in materials such as metal and plastic. If the tool is used to recut a damaged thread the process is called chasing but if it is a new thread it is called tapping. It is often used in conjunction with a tool called a die which cuts rods into screw bolts to fit the nut. Chasing may be done with a tool made of softer metal that does not cut but rather reshapes and repairs an existing thread. This particular tap is called a bottoming tap or plug tap because it has little taper at the tip and is capable of cutting a thread into the bottom of a blind hole, that is, one that does not go through the nut.