The threaded stub is part of the casting. I can see the line where the mold came together.
There are female threads (and part of a stub) in the metal bit at the bottom of the handle. And the cross-pin which is pretty well rusted in there, since I hadn’t gotten to cleaning this one up yet.
And yeah, it’s either a 3/8 or 5/16 diameter stub. Or maybe 11/32 or something goofy.
I suspect I’ll end up passing this on to someone who has the time to repair it, rather than tackling it myself, so I’m not super keen on drilling and tapping it, only to find out I’ve made a better repair impossible. Any volunteers?