I've been turning pens...well, for almost a year, although there have been some largish gaps. The last couple of months I've really gotten into turning pens more, after watching some of the presentations at a pen turners virtual conference in May. Learned a LOT from that conference (sadly, all the content seems to be locked out and is no longer accessible for re-review, I'm sure I could learn so much more), which lead me to switch from boring blanks on the lathe to buying a new Jet free-standing drill press, pen blank vise, and using a more refined technique there. Also started painting my tubes when doing acrylic/poly pens to avoid coloration issues. These have helped refine the quality of my pens a lot.
Another change I made was to move from a shafted mandrel, to a turn-between-centers mandrel from PSI. This too, has helped a lot. The TBC mandrel is really great, and even though I can't turn a pair of blanks at once, applying some of the tips and techniques from the conference (such as marking the inside of the tubes on the sides of each half of the pen blanks that are supposed to match grain/design wise, and also drawing arrows and labeling each blank as to whether it is the top or bottom half, or pen or cap half, etc. has made the ability to turn only one at a time a non-issue.)
I am still struggling, however, to achieve that "perfect seam" where the blank is turned down to just exactly the right size at the bushings to seamlessly fit the pen kit parts. I've spent weeks recently trying to hone my skills there, and I think I've pretty much got it down. Sadly, I still have out of round issues, and it doesn't seem as though any amount of trying has resolved it so far.
I started to pay closer attention to the tools, the lathe, and the mandrel...and I am beginning to think that the mandrel I received from PSI may in fact not be entirely true. The shaft from the mandrel that fits into the head stock seems to be quite true, however the shaft from the free-spinning mandrel that fits into the tail stock, seems like it may be very slightly bent...ever so slightly. I think this is causing a vibration in the bushing, which is keeping me from turning that side of any given blank down properly. I seem to be able to turn it down just right on one side of the blank, but on the other I'm unable to turn it all the way down to the bushing.
It may also be partly the lathe as well. I have two lathes, a Wen 14x20 and a Laguna Revo 1524. The Wen is pretty nice, was a replacement for my original lathe, a Nova Comet 14DR (horrible lathe, started exhibiting problems within 6 months, if even, and took another 4+ months to get Teknatool to actually accept an RMA, fix it, and when they sent it back it still had problems...very souring experience!), and I've turned the majority of my pens on it. Its size just kind of fit pen turning better than the much larger Laguna. I did try turning some pens on the Laguna recently, however, and while I still had out of round issues, they seemed to be much less. Laguna has their Precise Point technology in the tailstock which allows you to very precisely align the headstock and tailstock/quill centering, and I think that may have helped as well. Despite dialing that in as perfectly as I could, it still seems as though there is a vibration in the tailstock side of the TBC mandrel.
Finally, I've occasionally had vibration in the bushing at the headstock side of things. Not in all cases, but sometimes I think some bushings don't perfectly fit the bushing shaft on the mandrel, and I'm wondering if that may also be allowing for some vibration...
Anyway. I guess my question is...has anyone else encountered vibration issues like this? If so, are there any tips or techniques I could follow to try and minimize these issues, so I can get that more-perfect turn and ideal fit at the seams when assembling my pens?
