For minimum material thickness of 1/8", minimum metal thickness of .120". These are the only metal cutting blades made specifically for power scroll saws. Jewelers or metal piercing blades are for use in hand held frames due to inherent brittleness. These premium blades are made of hardened and tempered steel and have more teeth per inch required for cutting thin metal and other hard materials. Blades have regular style teeth. Metal Cutting Scroll Saw Blades Univ.No.9 25TPI 5" long plain end For cutting non-ferrous or mild steel.120" or thicker.