The eighteen gauge steel is armour grade, barely. You don't want much heavier on your arms in any case....but eighteen gauge will dent rather quickly under the stress of combat unless you stiffen it up. Still, it would be a bit of a shame to have these bits smashed in. (and they would be the very devil to pop them back out...though of course, not impossible.)
I did not bother to install a bale inside the rolled edges. I figure these are more decorative than otherwise, so a bale would just add needlessly to the price. The top edges (the big end) are a large outside roll that needed a special tool to enable me to roll it neatly. Special tool, hah! Just a heel dolly mounted on the workbench. Seems to have done the trick though. The english wheel cleaned up the inside edges pretty neatly.
So these bracers would be just fine for archery, and of course, would stand up to most any form of combat. If you wanted to use them for live steel, well then, we would need to do something a little different...I suspect two of these would need to "clamshell" together to make a proper vambrace. Traditionally, a hinge would be installed on the outside edge to make this work, although we tried a tricky bit t'other day with Bengt's armour where we were in an ungodly hurry, and used four of these vambraces which were already made up, (two per arm of course) and installed a couple of pivot rivets at the top. They opened up like a post hole digger so he could get his hands in, then clicked neatly closed. A simple strap kept it closed. A neat trick, and probably not period. But...a neat trick.