Progress report:
After a couple of hints from
@derf I found solutions to both the compound angle lock and the compound lead screw nut.
The compound lock was a case of a broken off set screw jamming up the threads. I
thought that was where it would be but couldn't get it to work. Chased it with a bottoming tap to get the broken bits out of the threads and all is well.
The lead screw nut for the compound I had to fabricate, but it also went right where I thought it must.
Conveniently enough, the lead screw is a common 7/16-14 thread so I was able to TIG a post to an ordinary hex nut and fix that issue as well.
Now all I need to do is get the 3 jaw chuck tuned up a little better and learn to grind HSS tools (I have printed out
@mikey 's excellent instructions) and I should be able to start making chips.