These carbide tipped sheet metal cutters produce fine, burr-free holes in a variety of materials up to 3/16" thick. Designed for for stainless steel, structural steel studs and electrical boxes. They also improve your production in cast iron, brass, aluminum and other thin non-ferrous metals. These cutters are designed to be used in hand held drills to achieve drill press quality holes. The carbide tips stay sharper longer than high-speed steel or bi-metal cutters giving these cutters longer life. Lubrication during drilling extends the life of the carbide cutter. Arbors 49-57-0035 or 49-57-0037 are needed for these cutters.