Good to see you up here c_kelly!
I too am 57 but can only say that for about 4 more hours.
Would agree with Clam71s diagnosis and remedy. Could very well be wrong but I don’t remember any Illinois movement that would have the stem as an integral part of the movement. This is called a male stem and can be found on some 1883 Walthams and some Elgin movements and it would make sense that Illinois also made them. My minds just drawing a blank right now. I’ll check around to see what I can find out about it. How does the end of the stem look under magnification? Could be a broken off stem or someone may have jammed something in there to wind it while out of its case. Would be interested to know what you find out upon disassembly. Also those stereo microscopes are really nice to work with once you get used to them. I still haven’t tried the one that John has yet but from what he has said about it in earlier posts it sure sounds like a great buy.
Please keep us posted and let us know what you find out about that stem…and Welcome to the forum!