Looking at mine the pin hole is somewhat oblong almost as if it was stretched before if broke. I would suspect that if you over tightened the set screw that holds the pin in place that you could easily stretch that hole out, especially if those set screws were installed at the factory with a electric driver. That set screw only needs to tight enough to hold the pin in place.

What I am thinking about doing in chucking it up in a lathe with the ball end inside the head. I want to cut the necked down part of the shaft off flush with the bearing race that would hold the 2 bearings inside the GS010 hub. Then drill and tap the largest threads I can safely fit inside the race. After that find the appropriate shoulder bolt and drill the hole for the 3 * 19 pin that holds the hex in place. Thread the shoulder bolt (with red lock tight) into the stub shaft and voila. I may not be describing it correctly. I'll try to get a few pics up as I am doing it to show what I am talking about.

If I could find a way to secure the hex to the shoulder bolt without drilling a hole for the pin that would be the ultimate in strength. I could TIG weld it on... If I chucked the hex up and cut a small chamfer on the inside diameter I could use that as my point to add some filler. Brazing I guess would even be an option. Hmmmmmm....