Specifically designed for hand held operations in materials up to 3/8" thick, these carbide tipped Steel Plate Cutters stay sharper longer than High Speed Steel or Bi-Metal Hole Saws. They produce Drill Press quality holes even in hand held operations. For cutting materials over 3/8" up to a depth of 1/2", a drill press is recommended. When cutting depth is over 1/4", use Hawg Wash cutting fluid to keep cutting surface cool and lubricated. Hawg Wash fluid is available in 16 ounce bottles (49-32-0081). One bottle makes one gallon of lubricating solution.