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 425 Cast Iron 280 Tool Steel Stainless 210 Brass 560 Aluminium 635 Wood 3000 Recommended for use with a small arbor .