Sandra, In the automotive industry, when the gear that the starter
engages to turn the flywheel is mounted on the flywheel, it is not
welded or bolted or fastened in any other way, but rather “shrunk to
fit”. They make the ring gear slightly too small to fit around the
flywheel, then the flywheel is cooled and the ring gear is heated to
the point where it has expanded enough to fit. This is also the way
the old wheelwrights put the iron bands around the wooden wheels for
carriages, heating the band til it was large enough, then cooling it
as soon as it is in place.
I don’t know for sure if the amount of expansion would be sufficient,
but if you were to make the inner ring just barely too big to fit,
then use a combination of heating (carefully! of course the
original ring and cooling the inner one, then force them together and
cross your fingers, it might work.
It might also work to just force them together without worrying about
the heat, as fine silver is pretty malleable. That might be better
anyway, since heating the stones might be a problem.
Here’s another thought: make the inner ring just a smidgen wider,
then flare the edges and work them to a larger diameter, just like a
rivet. You don’t have to have a lot of material projecting beyond the
original ring’s width, just the slightest bit of it worked over the
edge of the outer ring. In fact, you could bevel the original ring
just a bit and fill that space with the flare from the inner, and
burnish over the line between them to the point where it would just