We’ve been refining the art of driving wooden pegs.  By the way, if you get a high end cordless drill, I recommend Hitachi over  Porter Cable.  The proter cable (18V Lithium) didn’t have the power, or battery life to drill these holes, and the gear box eventually stripped out.

The Hitachi drill powers right through and keeps going.  Even it’s drill setting will “slip” if subject to too much torque, but it seems to be a reasonable point that is adequate for heavy duty drilling.