I will insert my 2 cents worth at this point. A major concern using
either a tailstock chuck or morse taper drills is the taper slipping.
Drilling larger diameters in steel requires a lot of torque. Most
tailstocks are not keyed and so the taper can slip. You need to
axially lock the drill or the drill chuck when doing this (some sort
of clamp/bar locked to the drill/chuck and supported by the tool
post/topslide.) That having been said I support those who recommend
step drilling as far as you can then going to the biggest/most rigid
boring bar you can fit. Set the boring bar no further extended than
necessary.
Regards
Bob


Unfortunately, step drilling and Morse tapers do not go hand in hand. The feed
pressure helps keep the taper from slipping, and when step drilling you don't
have much feed pressure - unless you are taking large steps.

Seating the taper quickly will help, and the extra mass of a chuck will help
the taper seat even tighter. Sometimes, however, the only solution is a dog
clamped on the drill shank.

John Martin