Isn't a blind rivet sort of what I was thinking of? Expanding metal into the scale? Correct me if I'm wrong, but putting the male end into a female end spreads the female end, creating a press fit right?

That seems cur tand argumentative, but I am really curious about flush pins... which is why I started this thread.

And what if instead of flexing scales you had friction washers at the hinge? I know this need s aspecial straight not tapered tang, but worth it?