Mandrel (I used a pry bar)
80 Grit sand paper
400 Grit sand paper
2000 Grit sand paper
Step 1: Mark the center
Clamp the ring. Starting with a small drill bit, drill through the premarked center. Progressively drill a bigger hole until it will fit on the mandrel your using. I used a pry bar as the mandrel.
Step 2: Start Hammering
As you hammer rotate the mandrel and apply slight pressure towards the anvil. This hammering and pressure helps elongate the coin as it moves down the mandrel. As the coin stretches, check it against the measurement you want.
In other words the bigger you want the ring, the more you have to hammer. View the pictures of how the hole gets bigger measured against my pinky.
Step 3: Keep Hammering
As you hammer the ring will expand. I find it easier to use increasingly bigger socket bits to serve as an anvil. From my pry bar I went to a 12mm socket and ended up at a 7/8 socket.
Every so often hammer the edge of the ring as shown. This helps keep thickness to the ring as opposed to becoming a ribbon.
Step 4: Mount The Ring
After you press the ring on the socket (or brass fitting), use a nut and bolt and secure it through the female end. The protruding end of the bolt will be used for mounting in the drill press. Mount the assembly in the drill press and spin it round. Use a 80 grit to shape it. You will shape the bottom side first.
Now you have to start being careful not to mar the ring. Use a piece of wood to tap the ring on and off the mount.
With the assembly spinning in the drill press, use progressively finner sand paper to make the ring it's final shape. I start with 80 grit, then 400, then 2000. Spray the 400 and 2000 grit sand paper with water. This prevents the sand paper from getting clogged with metal particles. Again, this gets HOT! And don't breathe the metal dust.
Flip the ring as needed. Use polishing compound to buff it to a shine.
Step 5: Cut It In Half
Score a line with a razor blade. Minimal pressure is needed to mark a line. Once the line is marked, remove the assembly from the drill press and move it to a scroll saw.
Slowly and carefully cut the hoop in half with the saw at it's lowest speed setting.
Use caution and work within your experience.
Step 6: Micro Hammer
Remove the tip of the engraver and flip it around to the flat side. Turn it on it's highest setting and use your new micro hammer to remove burs.
Finally, repolish the hoops in your drill press.