Specially designed for speed and finish When working with solid hardwood. The combination of acute spiral flute Shear angles With face ground helix Yield High feed rates, fast plunge action, Quick direction changes, deep penetration and mirror finish. Recommended RPM 20, 000-21, 000., #46248, direction Up-cut, (D) diameter 1/4, (b) Cutting height 1, (D) shank 1/4, overall length (L) 2-1/2, flutes 2, 46248 Solid Carbide spiral plunge for solid wood 1/4 dia x 1 inch x 1/4 shank Up-cut