Strong, rigid overall length. Heavy duty 135§ split point for self-centering and quick penetration. Heavy duty web geometry provides added rigidity. The three flatted shank design ensures positive grip in keyless drill chucks. Applications: Ideal for the aircraft industry. Used for the drilling of high tensile martensitic stainless steels, titanium alloys and hard steel. Diameter: 0.421875" Decimal Equivalent: 0.4219" Flute Length: 2.875" Overall Length: 4 7/16"