HSS Drill Bit. These drill bits have short flutes and a short overall length for maximum rigidity when drilling in sheet metal. Now made with cobalt blend for longer life. Features: Drills more holes, faster. Ideal split point for fast drilling in sheet metal. Short length for maximum breakage resistance. Special bronze SST surface treatment. Materials: mild steel, non-ferrous metal, sheet metal, stainless steel. #30 tip.