what size hole and how deep?
drilling a tang hole is actually challenging in the sense that the depth is many times the diameter. a 1/4" hole 3.5" deep is 14X the diameter
the challenge is to clear the chips from the hole, you have to dump the chips out of the hole constantly.
also the flutes tend to get clogged with packed wood and you have to relieve the flutes of the loaded chips.
I haven't found various drill bits to really make a difference in wood...but have you tried a brad-point drill bit for wood?
also I wonder if this will clear chips better -
http://www.rockler.com/fisch-hss-pen-making-drill-bits-millimeters
this is more designed for a lathe which is generally horizontal