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 460 Cast Iron 300 Tool Steel Stainless 230 Brass 600 Aluminium 690 Wood 3000 Recommended for use with a small arbor .