Here's how to make two different ring designs out of a brass nut!

Step 1: Materials

Brass nut
Metal files of assorted sizes
Sand paper (grit depends on the finish you want)
Drill and 5/8" bit
Grinder
Salt
Water
6v lantern battery
Copper wire
Vise

Step 2: Drill Out Threads

I don't have a picture of this but put the brass nut into the vise and drill out the threads.

Step 3: Grind Off All Corners But 2 (or 3 Depending on the Design)

Just do what the title says. The picture for this step is taken after I sanded the inside to size.

Step 4: Sand the Ring

Use your sandpaper to adjust it to your preferred size and finish. Use rough grit to shape it and gradually work through the finer grits to finish it.

Step 5: Design 1: 3 Etch Spots

Mix a good amount of salt with some water. Cover the entire ring with masking tape and cut out three circles on the faces and a small strip in the back of the ring to connect the wire to. Connect one wire to the positive of the battery and place it in the water. Connect the other wire to the negative and to the ring and place it in the water. Wait a few hours and there should be a small etch on the three spots. This isn't the best way to etch metal but it worked for me.