Drill bits are made from high-speed steel (HSS) and are the hardest working from 62–65 HRC, thus can drill through aluminum, mild steel, and even thermoplastics. These bits are manufactured to a diameter that is from 0.1 mm to 30 mm range and have a spiral angle of 118 to 140 degree which is best for chip removal. Moreover, their coating of titanium nitride (TiN) and titanium aluminum nitride (TiAlN) also improves the bits surface hardness of 2500 HV hence increases their working life by 30% in hot condition like automobile parts manufacturing. Also these HSS bits conform to ISO 3479.
