May I introduce you to the Whaley Ring Gauge? Mine came in a monthly subscription box (the company is now closed), otherwise I might never have purchased this amazing tool. My epiphany moment was adding a ring clamp to the mix and then BOOM! I was off like a rocket. It is so nice to be able to make the ring shank the right size the first time.

Before starting, make sure you have flush cut at the end of your wire or sheet metal.

First, loosen the black knob on the right side of the Whaley Ring Gauge and slide your wire or sheet into the slot at the bottom (this adds the thickness of the wire/sheet to the ring size). Slide the middle part down and then tighten the knob. The wire should be snug in the slot and you should be able to wiggle it out without marring your wire.

Then align your wire or sheet with the left edge of the gauge and select your ring size. The ring size is indicated by the lines and numbers in the middle of the gauge.

You will get a lovely flush cut, with little filing, if any needed, before soldering. You are ready for soldering and to finish your ring.
You won't regret adding this little tool to your bench, it is truly a time saver!