7 Pc TCT Stainless Steel Hole saw Kit - Contents: 16mm, 20mm, 22mm, 25mm, 32mm, 40mm, 50mm. Starrett Tungsten Carbide Tipped Stainless Steel Hole Saws are ideal for cutting high alloy and stainless steels, non ferrous light metals and reinforced fabrics. The tough tungsten carbide tipped teeth have a positive cutting angle which provides fast and efficient removal of chips and swarf. Should only be used to cut flat surfaces. Maximum material thickness of 2mm for stainless steel, mild steel and non ferrous metals. Recommended operating speed, 850 to 1200 rpm. Can be used with both hand held drills and pillar drills. Safety glasses and gloves are recommended. Do not push too hard, to avoid an impact of the TCT teeth. Once the teeth touch the material, drill with slight steady pressure.