Hex Titanium Step Cone Drill Bit Hole Cutter HHSAre you tired of ordinary straight groove step drill and wants a smoother cutting? Our step drill bit is made from high speed steel which has high hardness and good wear resistance. The surface is coated with titanium which has better anti rust performance and will not fade easily. The main advantages of the spiral groove step drill compared to the ordinary straight groove step drill are its strong chip removal ability, better guidance, and smoother