46202. Solid Carbide Spiral Plunge 1/4 Dia x 3/4 x 1/4 Inch Shank. 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 ‘Down-Cut’ cuts from the surface down, leaving a smooth edge at the surface.