Dormer Pramet R7131 6.80 mm CARBIDE TIALN 140 DEG CHAMFER DRILL140 degree pilot and 90 degree chamfer recommended for creating chamfered holes for standard metric threads; Titanium Aluminium Nitride coating increases service life of the drill, improved performance when drilling harder materials; Specific pilot diameter and length designed to create the correct hole size and depth for standard threads; Premium carbide material can be used for drilling many materials including steel, aluminium, stainless steel;