Hi Jim;

I had not heard of a shoe joint. Looking for an answer I found one definition meaning a cast iron "shoe" which holds the bottom of a door stud in place https://books.google.com/books?id=5lcUAQAAMAAJ or types of iron joint reinforcement in timber framing https://books.google.com/books?id=3ko1AAAAMAAJ.

Happy hunting;
Jim

The closer you look the more you see.
"Heavy timber framing is not a lost art" Fred Hodgson, 1909