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 360 Cast Iron 240 Tool Steel Stainless 180 Brass 480 Aluminium 540 Wood 2700 Recommended for use with a small arbor .