In my insanity, I decided to get rid of the rust between the plates, and restore the jack properly. Yes, I know, the jacks were dipped, then the jack screw was inserted, and crimped in place. The few clean jacks I've seen with a phosphatized screw had a pin in them, rather than the original crimps. I pulled the screw to do the jack frame itself, and one thing lead to another . . . Having a lathe to play with can be a dangerous distraction.
I pulled apart the 9K jack that came with the car, went to put it back together by holding it up against a different jack to make sure I put the pieces in the right places, and noticed the difference in the sizes of the jacks, which started me on the quest for knowledge.
Carl