We downloaded a template and edited it to our finger size that we measured with calipers. We couldn't manufacture the rings due to the fact that the mills were not working the way we intended it to work.
F3D File: https://drive.google.com/open?id=1uEl4fE2LMAhRtsSuQAbn-vCQy7dq7uJ9
GCode File: https://drive.google.com/open?id=1BBLThEypFq-9QZO0BzfF-fVT7Nq5xM7Q