Variable tooth unique variable tooth geometry for consistent cutting ability in a wide range of materials Manufactured to strict Alpha specifications to suit demanding Australian conditions 8% cobalt Bi-metal gives ultimate performance and superior welding technology prevents tooth strippage 38mm cutting depth Recommended Speeds Mild Steel 325 Cast Iron 215 Tool Steel Stainless 160 Brass 435 Aluminium 480 Wood 2700 Recommended for use with a small arbor .