The general drill is HSS high-speed steel, and if a good point is high-speed cobalt containing steel, black should be treated by blackening! Black Brown should be TIALN coated!! This drill is usually not custom-made, at most, take the standard drill bit to make a TIALN coating!!
Material is 6542, even better, it contains cobalt... Then coated TiAIN pure blackThe effect is better than your black brownI have a punch hereOrdinary processing around 3WAfter coating processing can do 25-30W or soThe effect is very strongThe drill you want, I can do for you. I'm from the tool factory
The drill bits are of high speed steel, of which 439365 are cobalt and cobalt is the best
