Titanium nitride coating is just a way to get a couple of good holes drilled with a piece of crap soft Chinese drill bit. Once the coating wears away, most of the drill bits sold by Harbor Freight have a hard time cutting soft butter. Resharpening doesn't help if the metal underneath the plating is too soft to hold an edge. I mix up a spritz bottle of water and soluble cutting oil and mist the solution onto the drill bit to keep it cool and also lubricate the cutting flutes.
Jerry
