Hey Robert,
Depends on HOW hard. If it is hardened tool steel such as 0-l, W-1, A-2 etc. It may not be able to be drilled without annealing first and then re- hardened and tempered. Especially if you aren't having any luck with the carbide bit. That's about as hard as a bit can get. What specifically are you trying to drill? BTW, when to coming to Omaha??