How to make a coin ring
Find the coin you want to use. Quarters are probably the easiest to do.
Find some way to make sure you get the hole perfectly centered. If it's off center, it makes for a difficult ring.
Make your hole.
Check to see that your hole is centered. Use calipers if possible.
Anneal the metal so that it's easy to work with.
It should now look like a black washer when it's cool.
Begin hammering on a mandrel.
Hammering is the hardest and most tedious part of the process, it can take hundreds of rings to get this technique just right.
After awhile, you should end up with something like this.
Continue to apply heat and hammer until you get the size/shape that you want. The top edge in this one has already begun to be polished.
Second hardest part of the process, polishing it without losing all the detail.
The finished product!