Ian, I’ve never tried this but I’m going to offer it as a possible
solution anyway. Maybe it will work. Try taking a piece of masonite
and drill a hole through it only slightly larger in diameter than
the hemisphere you are trying to make. I’m thinking desired diameter
plus 2 times the thickness of the metal. Make sure that the masonite
is at least as thick as the depth you are wanting to attain. Then
place your metal on top of the masonite and follow that with a layer
of rubber as thick as the desired depth. Take that whole sandwich,
put it in your vise and squeeze down tight like you have been. In
theory, the rubber will press into the hole in the masonite taking
the metal in with it. The rubber should form the metal with less
likelihood of causing it to stretch and split like it does with a
hard steel bearing. As before, make sure the metal is annealed. You
probably shouldn’t have to go to 26 ga. I think Charles Lewton-brain
wrote about something like this in the archives but off the top of
my head I can’t be sure. Check the archives out though. I hope this
helps some. Like I said, I’ve never tried it myself but I’d feel
confident that someone else here in Orchidland has. Any
confirmations or denials out there? I’d like to hear them myself.
Mike