Spiral flute bits combine a shearing action in cutting with an augering action in chip clearance. The shearing action yields an especially clean accurate cut, while the augering action clears chips from the cut. The “downcut” cuts from the surface down, leaving a smooth edge at the surface.Special unique grade carbide increases clearance geometry and produces razor-sharp cutting edges with polished flutes that provide a superior finish and longer tool life, especially in abrasive materials. Great for production settings and excellent for creating grooves and dado cuts in particleboard, plywood and laminate. Primarily used on CNC machines and other automatic routers. Can be used with handheld and table-mounted portable routers.