Aspect RatioWhat the heck is aspect ratio anyway, and why do I need to know about it? The answer is that all chain maille patterns have a certain ring size/wire diameter combination that is optimal for creating a strong, flexible and good looking chain. Some weaves are more ring size critical than others. For example, the Byzantine chain has a range of ring sizes that will work for the weave - depending on how tight or loose you would like the finished product to look. A Full Persian weave, on the other hand, has a smaller range of sizes that will work. Too small, and you will find yourself trying to cram rings together after just a few links, with the chain getting tighter and tighter until you can't physically join any more links. Too large, and the chain will quickly collapse and look like just a big mess of jump rings.
There are many books, web sites, and chain maille tutorials that you can easily access for information on jump ring sizes for numerous weaves. It is very handy to know how to convert a given size jump ring to one that will accommodate a larger or smaller wire diameter for any particular weave. As you might expect, there is a mathematical formula for this. Don't let the math scare you - once you know the formula, it is not difficult to convert any pattern to accommodate a different size of wire.
Here's the formula:
Divide the inside diameter of the jump ring by the diameter of the wire, and you will get the number for the aspect ratio of the weave. For example, suppose you want to make a Byzantine bracelet, and the directions you have say that you need an eighteen gauge jump ring with an inside diameter of 3.5mm. You want to make something a little more delicate than that, and would like to use twenty gauge wire. What size should the inside diameter of the jump rings be for the 20 gauge wire? Before you can successfully use the formula, you will need to know the diameter of the wire you want to use in millimeters. Eighteen gauge wire is usually 1.02mm., and twenty gauge wire is usually 0.813mm. Divide the 3.5mm (jump ring inside diameter) by the 1.02mm (eighteen gauge wire diameter). Your answer should be 3.43... Now use the 3.43 number and multiply it by the diameter of the twenty gauge wire. 3.43 x 0.813 = 2.78mm In this case, you will most likely have to round up a little bit, and use a 3mm jump ring for the twenty gauge wire.
Below is a chart, listing some of the more common wire gauges and their diameter in millimeters.
Bear in mind that the thinner the wire gauge, the smaller the jump ring inner diameter needs to be. Very thin wire is not strong enough to use for large size diameter rings. On the other hand, heavy, thick wire will be very difficult to manipulate if the ring size is very small. In the long run, experimentation and experience is the only real way to know what will work and what will not. I usually use copper or bronze wire for learning a new weave. Both are inexpensive and soft enough to be easy to manipulate, and either one will make a beautiful and unusual piece of jewelry.