HSS Cobalt Twist Drill Bits 0.5mm – 14mm HSS-Co For Hard Metal Stainless Steel. Material: HSS M35 contains 5% cobalt. The 135° split point makes center punching unnecessary and avoids slippage. 4mm 4.2mm 4.5mm. 5mm 5.2mm 5.5mm 5.8mm. 6mm 6.2mm 6.5mm 6.8mm. (410mm): Maroon black yellow. (28mm) :Fuchsia black yellow. (310mm):Fluorescent yellow black yellow. (1.56.5mm):Fluorescent green black yellow. 13 sticks pack(small). (28mm):Emerald green black yellow. 13 sticks pack(Big). (110mm):Turmeric black yellow. (1.56.5mm):Bright yellow black yellow. 13 sticks pack /. Ideal for drilling in extremely hard or abrasive materials. Most suitable for drilling light metal, high carbon steel, aluminum and alloy steel, cast iron and stainless steel (thickness less than 2mm). M2 high-speed steel is treated with yellowing, high-quality cobalt has high machinability, high-performance high-speed steel. Large quantity accepts various sizes and can be customized. If you can’t find the relevant series of goods, you can ask us. We will be happy to help. The pictures are for reference only, please choose your requirements (size, quantity).