Very nice presentation! But just out of curiosity... using
this method, how do you have any idea what size the finished ring
will be? You could always hammer it up, I suppose; but if it's too
big in the first place, you'd have to start over.
Of course not every shop has one, but the standard upright ring
stretcher usually comes with a set of hemispherically shaped dies
which rotate into position under the stretcher’s anvil. A ring band
which is too large is positioned into a die slightly too small for
it, and when the handle is pulled down, the anvil presses the band
into the die, forcing it into a smaller size, without appreciably
altering the shape.
As long as the ring band being sized is annealed properly between
dies, one can size a band down many sizes without cutting the band.
–Jay Whaley UCSD Craft Center