I’m making bangle bracelets from copper, and didn’t care for the solder seam from just cutting a strip, bending it round and soldering the ends. So I decided to try to form them from sheet using a hammer & mandrel. I cut a piece of sheet that looks roughly like a 45-rpm record (anybody here old enough to remember those?), slip it over my tapered mandrel and hammer/anneal/hammer/anneal/hammer until I get a mostly-straight-sided bracelet-sized cylinder.
Here’s my problem: I’m having trouble figuring out how to get that last bit of the edge – the one that was formerly the outside edge of the disk – hammered down to match the size of the edge that started out as the inside circle. Does that make sense? That last bit of flare. I can’t figure out how to get rid of it. Hammering against the mandrel doesn’t work. It just shifts the metal around.
I think I need something to confine the metal while I hammer. I’m thinking something like an inverse mandrel. Like a big, really stout funnel I can hammer the wide side of the bracelet down into.
Does anyone have any ideas? My tools are limited. No stakes, no hydraulic press. I’m willing to acquire the right tools, if they fit in my budget, or make them if possible.
How would you guys approach this?