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 300 Cast Iron 200 Tool Steel Stainless 150 Brass 400 Aluminium 450 Wood 2700 Recommended for use with a small arbor .