Starrett bi-metal hole saws are constructed of hardened, heat and abrasion resisting high speed steel teeth with a tough alloy body and cap. This gives them exceptional strength, durability and shatter resistance for user safety. They will cut any wood, metal or plastic in either a hand-held drill or a drill press. Carbide tipped, carbide grit and diamond coated hole saws are specialty saws that give the Starrett hole saw line the ability to cut any material. We have yet to see a material that one of our saws can't cut.