- Most popular in production machining environments, thread mill cutters allow for the interpolation of threads either on the outside diameter, or inside diameter of the part. This tool can increase production with faster cycle times and less tool breakage. For a long-lasting threading solution, choose carbide thread mills over traditional taps and dies. Threadmills give you the ablility to mill the thread, rather than the standard tapping of a hole or threading of a stud with a traditional tap or die. Unlike a traditional tap, a left-hand or right-hand thread can be produced with the same tool. Thread mills are available in metric, SAE or pipe thread sizes, uncoated or ALTiN coated. Now also availble with a through coolant option.