To my knowledge there is no standard for square ring sizes.
Why wouldn't we use the same dimensions? The ID remains the same,
right? We could use the same diameter as a round ring but build a
square around it - technically its the circle inscribed in the
Finelt Casting of NYC offered a line of 'Anatomical Rings' in the
late 1960's. The key issue we faced was how the corner radius would
'grow' as the finger size (ID) increased. We didn't attack the
problem and dropped the project because everyone questioned how we
would offer sizing after sale - there was no ring stick. My Dad,
Aron, didn't want to invest in a product retailers / contractors
But... I'll provide to anyone what I think is a reasonable standard.
All you need is Adobe Acrobat to read the file!