The Iron Ring is a ring worn by many Canadian-trained engineers, as a symbol and reminder of the obligations and ethics associated with their profession. (https://en.wikipedia.org/wiki/Iron_Ring)

I decided to replicate mine for one of my first prints. This one is ring size 7.5 (17.7mm ID) which can be changed in the .ipt file attached (originally from https://grabcad.com/library/engineering-ring-1). This version is much thicker than the actual ring but I plan on scaling it down to match.