All jump rings start off as a coil of wire, but there are several different ways of cutting that coil into the separate rings. The simplest is to snip them off one at a time with wire cutters, but this takes a while. You also have to remember that one side of the cutters results in a sharp rather than a flush end to the wire so you need to keep turning the cutters round and snipping off the sharp end. I find it a lot quicker to use a blade, and the trick with this is to find a way of keeping the coil together so that you have something to hold onto while you're cutting. This is the method that I prefer and teach my students.
Wire can be coiled round almost anything round - pencils, knitting needles, wooden dowels. I make so many jump rings in various sizes that I invested in a set of mandrels that came with a drill chuck on a stand with a handle. It makes turning the coils much quicker. Whether you use a similar set up or wrap the wire round the coil by hand make sure that you keep each turn as close and neat to the previous as possible to make it easier to cut later on. Keeping your thumb on the wire close to the mandrel helps with this.
Trim off the excess wire.
I wrap masking tape around the coil to help it keep together when I cut it. Without the masking tape the coil would get smaller as I cut through it and the separate rings fell off and it would get very fiddly to hold onto.
Thread the blade through the middle of the coil, making sure that the blade is taut in the frame.
Place the coil on the bench peg so that most of the coil is on the wood with a small place for the blade to run through the V cut in the peg. The mandrels I use have a slot at the end to hold the wire as I start turning the coils. The results in a piece of wire that sticks into the middle of the coil, and I place the blade in the bend of this wire to prevent the blade from slipping as I start sawing.
Holding the blade at an angle so that you are cutting the top rings first, start sawing! Make sure that you use nice long cuts and don't put too much pressure on the blade. This will help make sure that you cut smoothly. By the way, this is the only time that I hold my blade at an angle - I keep it upright for all other sawing work as this makes cutting curves easier.
While sawing the coil, hold it at the top with your free hand to help hold the coil together. I was taking the photo with my free hand!
Once you have cut all the way through, unwrap your new jump rings! There is always a short piece of wire from the top and bottom of the coil that ends up in the scrap pot.
Lots of lovely rings ready for tumbling to get rid of the burrs!