I was commissioned to make some hinged hoops, so I thought I'd document the process so I could show you how I did it.
The first thing I did was hammer the end of a 20 gauge piece of silver wire into a paddle and drill a 20 gauge hole in the end. These will be the actual ear wires (the part that goes in your piercing, just in case you don't speak metal smith.) Repeat for the other ear wire.
Then I cut two lengths of 12 gauge wire the same size for the hoop part. I hammered the end flat slightly so that I could drill a hole in each one. I again used a 20 gauge drill bit, so the holes in the hoops are the same size as the hole in the ear wire.
Next, I very, very carefully sawed a slit in the end of the hoop wire. The hole I just drilled is running perpendicular to the slit.
See the slit? It goes just past the hole so that when I insert the ear wire, it'll fit just perfectly and their holes will line up.
Next I shaped the hoop (being very careful with the holes and slit that I just cut so that I don't bend them out of shape.) and I soldered a little "u" shaped latch onto the other end.
The next step is to insert the ear wire and the rivet wire. Since my holes are all 20 gauge, I used a 20 gauge wire as my rivet. I cut the rivet about 1 and 1/2 mm longer than the width of the hoop. If you cut it too long, the wire will just bend over instead of mushrooming into place, and if it's too short, then there won't be enough metal to spread out and hold it in place. I also made sure the ends of my rivet wire were filed nicely flat and and at a 90○ angle to the length of the rivet.
Usually when I rivet something, I counter sink the holes that my rivet is going through, but since my wire was so small, I omitted that step. Using the flat end of my chasing hammer I gently tapped one side of the rivet and then flipped it over and tapped the other side, repeating this carefully several times until I could see that the rivet was beginning to spread out over the hole. Then I turned my chasing hammer over to the ball side and tapped each side of the rivet alternatively in a very small circle beginning from the inside of the rivet and ending by tapping the outer circle of the rivet which eventually flattened nicely down onto the surrounding metal.
Since I wanted to make sure that my ear wire could move up and down I was very careful not to hammer the rivet too hard and smash the space in between so that the wire was too tight to move. And because I didn't counter sink the rivet, I just gently sanded it smooth. Then I bent the ear wire the way I wanted it, cut it to the correct length and finished the earring. Voila! A moving ear wire!