The Scientific Cutting Tools 4PDT1 thread mill is a carbide thread mill designed for cutting internal threads in steel, stainless steel, cast iron, aluminum, and other metals. It has a 1/2" shank diameter, can cut threads from #10-24 to 1/2"-13, and has a TiAlN coating for increased tool life and heat resistance. The 4-flute design provides efficient chip evacuation. Overall, this thread mill is well-suited for cutting a wide range of internal thread sizes in most common metals.