The downside of that is that if the pipe dries out from extended periods of no smoking, you end up with a loose stem. Beeswax lubricates it long enough to find a proper fit with no material loss.very light sanding of the tenon
Problem is, you can take off material with sandpaper, but you can't put it back on. If there are other options, use other options first.Not really sure why people are afraid of sandpaper... Have done it to several pipes and they are fine. It isn't hard to remove .0005"-.001" from the O.D. of the tenon.
As far as the pipe drying out and becoming loose, by that line of thinking, all properly fitting stems(non-insanely tight) from the manufacturer would eventually become loose from non-smoking... which I haven't experienced. But then, I don't have any 30 year old unsmoked pipes on my shelf either.
Graphite is a good lubricant without the drawbacks of oils or waxes, which tend to change in consistency over time, and become sticky. Also first choice to lubricate any locks or hinges.I have always used graphite quite successfully on tight tendons. A number two pencil or softer works very well. I run it up and down the tendon and even in the mortise. Even super tight stems will work very nicely with a little graphite.
It's the only thing that should be used for locks - anything else (oil, silicon, spray grease, WD40, etc.) will eventually gum up and f-up the tumblers...Graphite is a good lubricant without the drawbacks of oils or waxes, which tend to change in consistency over time, and become sticky. Also first choice to lubricate any locks or hinges.
A used Scotch-Brite (tm) pad out of the kitchen...I give it a light sand with very fine paper.
As long as you try it as you go it's safe.