Proxxon HSS Tungsten Vanadium Micro Drills HSS drill bits made from specially selected steel. Method of manufacture ensures high concentricity and accuracy. The shank and bit are made from a one-piece blank. A high degree of hardness for the longest possible life expectancy. For drilling metal, non-ferrous metals, plastic, PC cards and wood. Work speeds: hard materials approx. 3,000rpm, soft materials approx. 8 000rpm. All shafts are 2.35mm, supplied in packs of 3 per size.