cutting jumprings, not fingers
Here are the illustrations for my small-time jumpring manufacturing. I wind a coil on a mandrel - here it's 18 gauge copper on a 3/16" rod, which makes rings approximately 5mm ID and 7mm OD. Then I tightly wrap the coil with tape, and slide it onto my saw blade to cut from the inside out. I was concerned that the tape might gum up the sawblade but it doesn't seem to. The tape holds the coil together nicely, and keeps the rings from falling off as each is cut.
When it's all cut through, I simply open up the tape cocoon, and behold, there are my rings.
I tried using my rotary tool with a slitting disk to cut them, but thin as the disk is, it is still way thicker than a fine sawblade, and the results were not satisfactory. Guess I'll stay with hand tools.
The section of 3-in-3 chain with byzantine bits (that is byzantine, right?) was my first effort with these copper rings. On a quiet Christmas Eve with nobody around, I got it finished up into a bracelet. This is the only picture I have, because I gave it away this morning to Ellen without getting another photo. I offered her a choice of several items, and she grabbed the copper chain right away, which was fairly gratifying.
So Merry Christmas to all!