Jewelry, in the form of rings, have been made from coins for many decades; probably even centuries. You can read more about the history of coin rings here.
As is true of many crafts, or artistic endeavors; the process of creating a coin ring may range from the simplest of techniques - requiring only a few basic tools, to rather elaborate fabrication methods that involve a wide range of precise and specific jewelry making tools. Some of the more complex methods involve not only special hand-made tools, but the methods themselves may be proprietary in nature.
In order to gain some first hand knowledge about how a fine coin ring is made, I have compiled a set of instructional videos that were recently released by a single skilled coin ring maker. His name is Skyler Jenkins and his shop name is The Mint - Change You Can Wear. Although these videos go into a fair amount of detail, they really represent a good beginning. Generally, an accomplished coin ring maker will devote many hours of trial and error work before gaining all the necessary nuances of fine coin ring making.
Nevertheless, if you will watch one or more of these videos, I think you will begin to get an appreciation for the amount of time, skill and tools that are necessary to turn out a beautiful coin ring. To get a look at these videos, please sign up here and ask for the link.