I started by casting a block of Plaster of Paris and allowing it to dry about 2 weeks. I designed the shape and letters in Adobe Illustrator, chopped it into G code with http://www.JSCut.com and set the files to my Shapeoko 2 with http://www.JSCut.com I used a 1/8" straight 2 fluted bit to do the cutting. I didn't know how it was going to work but it came out perfect. I melted down some scrap aluminum, poured it into the mold and stuck the entire mold into the oven to make sure it was properly liquified. I cleaned it up on the belt sander after knocking it out of the mold.
The laws in Canada are very clear about this sort of thing. Anything made of metal that goes around the knuckles is considered a prohibited weapon. I had no intention of using these, it was just a cool proof of concept so I filled 3 of the 4 holes with epoxy so I am able to hang it up. Its basically an ugly, poorly designed ring no so its 100% legal.