BORDO REDUCED SHANK HSS DRILLS118 notched point 30 helixDRILL BIT SURFACE TREATMENTBordo reduced shank HSS drills are ground and then a black finish is achieved by steam tempering, a thermal process resulting in a porous tool coating. This surface aids chip flow and heat dissipation. The drill is then ground a second time to achieve a bright finish on the shank and cutting edges.