Looks like we are headed to ambiguity. [

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IMO, "Don't care and other" don't know what they are missing. I get the feeling that pen turning, beside being fun is subtly stressing.
This "subtly stressing" part - I read between the lines that when someone gets things working right, but it was a struggle to get there, they don't want to mess with success. For a person who has success immediately in something - they will usually experiment with options more easily.
A couple of people on Lee's (Firefyter's) poll said that they tried it and didn't like it. I would like to know what they did that made them not like it. What is the downside to it other than not doing _both_ parts of a pen at the same time. To me, all of the other advantages out weigh the disadvantages. Plus, if one is just starting off, not having to buy a mandrel or two is cheaper. The bushings bought for any pen except slimlines will work.
It is sooo simple, a lot less frustrating and much more accurate. I have a full Beall compliment, but even with a Beall driven mandrel setup, they are subject to many of the problems associated with mandrels - too tight, out or round/bent, 2 different sizes, 4 different nuts needed.