Revisit problem drilling on lathe.

[TurtleTom]

My Rikon mini won't drill straight holes either but no problem. I just did an extreme test to confirm my belief on drilling straight holes.
I cut some dry red oak on the diagonal, put it in the lathe in my pin chuck for Barracuda C chuck and marked center with a pencil.
I then removed the entire chuck and took it to the drill press and proceeded to drill with my smallest center drill a short hole 3/16 off center. I then put the chuck back on the lathe and with a #8 drill (0.199 inch) chucked in a keyless chuck on a MT2 taper, I drilled by hand, no tailstock,(wobble and all) a hole all the way through the blank. Imagine if you will my hand wobbling 3/8 inch from side to side as I do this. I then mounted the 7mm drill bit from PSI into the same chuck and ran that through the blank as well using the same hand technique. For the initial entry I shut the lathe off and put the bit in the hole, turned the lathe on and pushed the bit into the wood. I removed the drill about 5 times to remove shavings and these subsequent entries were on the fly. The lathe was at 400 rpm, don't try this at speed with a wobbling blank.
After removing the blank from the chuck I ran the 7 mm drill bit half way through the blank and checked for eccentricity. There was none. The bit wouldn't move one way or the other one iota. The hole was perfectly round and the perfect size for a pen tube.
Maybe this will help make better pens for those with tailstocks that make oval holes. My Rikon mini won't drill straight holes either but no problem.
If you attempt this technique I advise not drilling off center as I did for testing, but right in the center after a center drill. I've seen many wood turners on You Tube videos perform the same trick without using the tailstock. If I'm using the tailstock with smallish drill bits I don't even use the hand crank, I loosen the tailstock once I've drilled a half inch and shove tailstock and all forward to drill the hole, pulling it back to clear shavings. (I don't do this with forstner bits.)
Your safety is your responsibility, so be safe and do not exceed your personal limitations.

 

[Wildman]

If you have a 5" or 6" blank cut to rough size before attempting to drill verus trying to drill entire blank whether need single or double barrel pen. Will get less out of round holes or drill bits wandering off center.

You need to concentrate more on what is happening while drilling on a lathe. Have to watch what the bit is doing as you turn the hand wheel. Make adjustments based upon what is going on.

I think problems with drilling on the lathe comes from dull bits, forcing the bits (bit actually flexes) by not clearing chips often enough, and run out at the head & tailstock.
Most lathes have minimal run out at the head stock but maybe more at the tailstock because of play in quill. Most of us cannot see or detect drill bit flex any quill movement when drilling. Take that back pretty apparent when bit breaks. When you combine those things with dull bits, forcing bits and not clearing chips often get out of round holes.

Using correct speed, let drill bit cut clear chips more often will let you see straighter holes. If bits wander and not getting straight holes most of what already said applies.

Only problem have with out of round holes, you need the best gap filling glue to compensate. You can try using thick CA glue, I prefer to use epoxy or polyurethane glue tubes. If so out of round none of those glues work you need to change technique or equipment.