Parts need turning

[corkcnc]

Sliding head is all well and good for the OD but I'd agree with RH that a gun drill is needed for the ID for any bit of accuracy. If you started off with a tube with the ID already close enough to the required finished dims then the bore of the tube might keep you in line (with a new drill - symmetrical point angle and both lips even) but not for tight tolerances. You would need a long travel to accomodate the long drill or a gun drill at starting point and the material held either with the rear in the chuck and front on a fixed steady or else the front of the job in the chuck and the rear in a custom collet at the "back" of the chuck, i.e. left side of the machine.
It's quite specialised but for those with the correct tooling it shouldn't be overly complicated. Cylindrical grinding as mentioned previously would be the most cost effective method of achieving the final ODs on the smaller shafts.
Best of luck with it.
Noel.

(Edit: Looks like Irving said what I was trying to say about 2 minutes ago :) )