I must bore and hone a 6061 6.125" cylinder 15" long on my 14x40 lathe.

It must be smooth and round, but the actual i.d. is not important (except
to document on the drawings).

I have no experience boring long, large tubes, and figure tool flex is
going to be the primary problem.

Any hints on what size boring bar and cuts I'm going to have to take to
make this work? (none of the local machine shops, including a marine
diesel shop, will take it on).

LLoyd