After a bit of trial and error, this is the best I have come up with for an easy, cheap, and quite way to stretch a coin ring. I hope to come up with a more effective method in the future. Trying to google how to hammer without making lots of noise was quite an experience.
Let’s just say the quite hammer is a running joke. Since I was not able to find any real answers I had to improvise. This method does reduce the noise of hammering. The coin stretching tool I use in this video is linked below, it is called a Rathburn ring stretch. I would like to get a more expensive ring stretcher but this is what I have for now.
Hope this video helped you out! After making this video I noticed that the inside detail of the rings was getting mildly scratched by the ring stretcher. Wrapping the rings in PTFE Thread seal tape fixes this problem.