Each Irwin® hole saw is crafted from the highest quality bi-metal. The high speed steel teeth are welded to a carbon steel body for bi-metal construction that allows a hole saw to stay sharper longer. Because Irwin® hole saws are engineered and manufactured for exceptional sharpness and durability, they will cut a variety of materials. These saws will cut holes in wood, aluminum, copper, iron, stainless steel and zinc. Irwin® 373338BX Linear Edge Hole Saw, 3-3/8 in dia, HSS Cutting Edge