Regular drill bits can't cut through steel, so you need a heavy-duty, hard drill bit to do the job. There are two types of drill bits that you can count on for metalworking projects: titanium and cobalt. Titanium drill bits are high-speed steel drill bits (HSS) that have a titanium oxide coating.May 18, 2011
What is the best drill bit to go through metal?
Cobalt drill bits
What type of drill bit is best for hardened steel?