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 440 Cast Iron 290 Tool Steel Stainless 220 Brass 580 Aluminium 660 Wood 3000 Recommended for use with a small arbor .