Die cutters and wrench handle. This steel hand tool is used to cut a screw thread onto a rod of metal or 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 threading. It is often used in conjunction with a tool called a tap which cuts a screw thread into a predrilled hole. Chasing may be done with a tool made of softer metal that does not cut but rather reshapes and repairs an existing thread. These solid dies cannot be adjusted, so their accuracy is dependant on the condition of the die cutting teeth, but there are adjustable dies.