[frnkeore]

If I'm getting this right, the hex of the bolt head is rounded, until a socket spins on it?

If that is the case, the way that I go about it, is to use a prick punch and a hammer to turn it. It usually works, if the bolt isn't to rusted on the threads.

Make a indentation, at the outer edge of the bolt head first. Then, with sharp, hard blows, drive it CCW, until it will turn by hand or pliers.

I'm surprised I don't hear this method mentioned on this forum. It's a old mechanic/farmer method I learned from my mechanic dad, when a teen and have used it in this way and flush, broken bolts and suds.

Sometimes, it's the only way to tighten a bolt, too.