Interior cooling

[Seymour Snerd]

I did this due to the fact that when re-threading the mandrel, I must have ground it down too much and the threads toward the end of the mandrel would slip when expanding the rivet nut, thus using washers didn't work.

One thing that I did but got away with it was inadvertently threading die on a little crooked (it kinda goes with threading a hand-ground shaft). If you did the same thing it might cause the threads to be no good at the upper end. I wish there were a better way....

Well, there probably is, for example, cutting off the original thread and brazing on the desired thread which now I could do (at the time I didn't haved my whole silver-brazing setup). Or permanently install the desired male thread into the mandrel with epoxy or nuts on either side. HF is pretty good about selling spare parts for cheap so probably one could call them up and buy a handful for a few bucks.