Todd,
Do you put the brass tube only in the head and tail stock? Or some type of bushing?
My mandrel has been giving me issues keeping the roundness of the blank.
I tried only the brass tube, but was worried it would split or flair or something.
Yes, just the tube glued into the blank between 60 degree centers. It doesn't take too much pressure from the tailstock to keep it turninng, and in the event of a catch, the blank will often stop spinning rather than self destruct (HUGE benefit, not that I'VE EVER had that problem...:biggrin
You do get some ever so slight flairing on the end of the brass, but it has NEVER been anything that would affect the kit or parts fitting, and because of this you need to slightly tighten the tailstock as you turn a bit, because the flairing will loosen the fit a bit... As with everything, SHARP tools help, as the harder you press, the more you have to tighten the tailstock which will eventually cause the blank to crack...
I finish ALL my pens straight between centers, and for kits that I don't have TBC bushings I go from square to done 100% this way. TBC bushings for me just make rounding from square and getting close to size easier and quicker.
If you want to give it a shot, I would suggest grabbing a few extra tubes (most of us have several dozen of these hanging around...) and glue them in some scrap wood (again, most of us have some sort of supply of this type) and give it a whirl. Kits with a lot of meat on them (like Cigars & Sierra Vistas) are probably the easiest to start on. Slims, because they are so small, take some getting used to, and kits with very little material left after the tube (like the El Grande) take a bit of care when you get near the end and you have to be careful the pressure doesn't crack the thin material...