My vambraces have a lip on the top side that goes over the inside of the bottom.
"Standard" piano hinges won't work on this one. When you open the shell, it creates a gap. I _might_ just cut it off, seal the edge and go the piano hinge route. Sigh, what a pain. Did my first, complete top end suit up and discovered my shoulder armor velcro is about 1" too low. Soooo... spent an hour cutting all the seams of the sleeve and removing the velcro. Now I have to resew velcro after the reposition. I knew I should have put it on while it was pinned in place, before the final stitching.