Hi Marcio, this is silversmithing use a mandrel and a rawhide mallet.
Anneal the wire and immediately quench in water.
File ends true gives clean metal as well.
Hammer into a U shape round the mandrel.
Put mandrel into holder (hole in bench) and place wire with middle
on mandrel and hammer close to mandrel until it bends down, turn round
You now have a U. Hammer U ends until you have a ring shape.
Now WATCH YOUR FINGERS!
Hammer on the join until it is a D shape
Gently bend with pliers into a perfect D with the ends on the flat
of the D.
Cut through join to make it light tight tight. Hold up to light you
should not see any light through join.
Solder and quench in pickle.
Slide up mandrel put in holder or on a Solid bench. Now the first
hits are on the corners of the D.
Hit one side hard, turn round and repeat.
Now hammer round mandrel with the rawhide mallet.
The ring should be round.
Anneal and quench in pickle.
Check ring is “level” on flat wood surface hammer flat.
NOTE THE INSIDE OF THE RING NOW HAS A DIFFERENT PROFILE FROM THE
Now with a little sanding you have a beautiful comfort fit ring,
ready to sell or to set gems into.
This is good for ring bands, but if you need giant jump rings, i. e.
a band with uniform profile, follow Ted’s post.
This is what is GREAT about Orchid. 2 solutions to a problem but
with slightly different final pieces.
Now for my production version.
I use a PEPE ring bender to bend the shank. 30 secs.
Hammer into D 30 secs.
Put D into a bench mate to saw through join. 30 secs.
Solder 30 secs, pickle, etc.
Hammer D out on mandrel. 30 secs.
Put on ring stretcher, hammer true 30 secs.
Anneal and quench in pickle 30 secs.
Check for level and true.
Say 5 mins hands on to this point
Clean up and polish.