in 2021 I purchased a "Turn between Centers Mandrel" from PSI - I had been using a Mandrel Saver exclusively for years, and occasionally saw some incidents of poor concentricity. With the PSI TBD mandrel, you can only turn one item at a time - so a 2 barrel pen is two steps. No big deal. But it seems to me that my concentricity issues have become more frequent, and more pronounced. I do not over tighten the tail stock, or apply much pressure to the bushings. But I am not terribly happy with the mandrel. I may explore this colleted mandrel, or the Wood Turning Store option, to see if I see any improvement.
Thanks for bringing up this topic.
Kevin