On mine I'll cut a slot 1/2-3/4 of an inch into the end of the threaded rod, and grind the end of the tang to barely fit in it. Heat it with the torch and apply the filler to one side so you can tell when it wicks all the way through. I use a bolt a thicker than the tang, so you have to make sure you remember to put the guard in first. No prizes for guessing how I figured that out....
This way has plenty of contact area, and I've beat the crap out of one with a hammer and had absolutely no luck getting the bolt anywhere close to breaking or coming loose.
I'm sure there are many other ways to do it, this just happens to be my approach