-the coin is annealed (softened with a proper amount of heat)
-forced up a taper/mandrel with a soft face hammer
-filed and polished
Alot of issues can arise if these steps aren't done correctlly or rushed through,here are some issues to look for;
-when a coin has been annealed the process of hitting it with a hammer will reharden the metal to some extent,but the metal needs to be rehardened through a baking process that takes around 5 hours or the pattern on your beautiful ring will quicklly wear.
-when the coin is drilled if the hole isn't PERFECTLLY centered the ring will be prone to warping or end up larger on one side,the makers who care take the time to file the rings as true as humanly possible
-when the ring is worked up the taped there is serious force required to stretch and manipulate the metal a very small amount of warping is expected,again the better makers will take the time to correct this as much as humanly possible,another issue is hairline cracks can form under the tremendous pressure if the coin wasn't annealed properlly
-filing and polishing is what makes the ring every maker has a unique style of filing the edges for show and comfort,the edges should all be filed as uniformlly as humanly possible...not only should it be filed the edges should be smoothed to a mirror finish,this is as much for comfort as it is for beauty. Most importantly the inside of the ring should be smoothed off to the point that its free of burs,slight scratching is common on the inside due to the ring being forced up the taper. I personally do as little as possible to the inside of the ring to preserve the pattern on the inside of the coin though its not allways possible to keep the pattern on the inside.
There you have it all the technical issues to look for in a coin ring. The biggest piece of advice I can give you is these are all handmade like anything handmade there will be small imperfections every piece and every maker is going to be different,make sure you see good detailed pictures OF THE RING YOU WILL RECIEVE a stock photo of the makers finest ring likelly wont look like the one you will receive.
Like anything on Ebay there are good and there are bad,hopefully this guide will arm you with enough information to avoid a bad experience.....and hopefully some of you other makers will read this and learn something about the trade of metal working,it makes us all look bad when someone gets an ugly ring.
Good luck and happy ebaying