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Learn Chain Mail with Lauren Anderson, part 4

Aspect Ratio: What is it and how do you calculate it?

Facet is pleased to welcome back our guest blogger, Lauren Andersen, author of the book One Jump Ring: Endless Possibilities for Chain Mail Jewelry. Be sure to check out Lauren's other posts, teaching us everything we need to know about the art of "maille."

WEEK 1: Learn Chain Mail with Lauren Andersen

WEEK 2: Tips and Mechanics of Chain Mail

WEEK 3: Make Your Own Jump Rings

Welcome to the fourth (and final!) week of Chain Mail Month on Facet! Today, let's talk about aspect ratio (AR), something that is critical to know when you're trying to adapt a pattern, either to make a new variation, or to work with the rings that you already have!
This Double Flower Bracelet (found on p. 63 of Lauren's book) uses the European 4-in-1 weave. 

Say you made a European 4-in-1 bracelet using 18 gauge 3.5mm sterling silver chain mail jump rings and now you would like to make the same European 4-in-1 bracelet using 20 gauge wire. The first question that you must ask yourself is, what size jump rings should I buy?

To answer this question you will need to know about aspect ratio (AR). Aspect Ratio (AR) is a number that represents the relationship between the wire gauge and the inner diameter of a jump ring. The exact formula to calculate aspect ratio (AR) is inner diameter (ID) of the jump ring divided by wire diameter (WD):    AR = ID ÷ WD

wire gauges

Before using the formula, make sure to convert the wire gauge to millimeters or inches (to match the unit system used for the ring's ID). Also, be sure you know if the gauge, or thickness, of the wire you're using is measured in the American Wire Gauge (AWG) or the Standard Wire Gauge (SWG). The AWG system is generally (but not always!) used for measuring precious metals such as sterling silver, gold, and niobium. SWG is generally used for measuring base metals such as aluminum, anodized aluminum, stainless steel, copper, brass, and enamel-coated copper rings.

In my example I used 18 gauge wire with a 3.5mm inner diameter jump ring.  Since I am making my European 4-in-1 bracelets using sterling silver wire I will use the AWG measurements.  I will need to find the AWG millimeter measurement for 18 gauge wire; 1.02mm. Now I can calculate the AR:

AR = 3.5 ÷ 1.02 = 3.43

Now I need to find a 20 gauge jump ring with that same AR.  Since we know the desired AR is 3.43 and we know the AWG for 20 gauge wire is 0.81mm, we need to find out the jump ring's inside diameter. 

3.43 = ID ÷ 0.81

To get the ID, multiply both sides of the = sign by 0.81 (remember algebra!).  This will result in:

0.81 x 3.43 = ID

2.78mm = ID

You would need to purchase 20 gauge 2.75mm chainmaille jump rings. (Millimeter size jump rings do not come in 2.78mm, so I rounded to the closest size available).

Aspect ratios for chainmaille jump rings usually range between 2.9AR and 7.0AR. Each chainmaille weave will have a range of aspect ratios that will work. Below that range, the jump rings are too "thick" and the weave is either impossible to weave or so stiff that it is impractical. Above the range of appropriate ARs are rings that are probably weaveable, but the result will be a very loose weave. 

Luckily for all of us, there are several sites online that have in-depth explanations and charts that do the math for us! Several chainmaille jump ring sellers recommend sizes for common chainmaille weaves. I will leave you with a quick reference:

If the wire gauge is the same: smaller inside diameter = smaller AR; larger ID = larger AR

If the inside diameter is the same:  thicker wire = smaller AR; thinner wire = larger AR

The smaller the AR, the tighter the weave

The larger AR, the looser the weave

andersen book cover
This stunning Byzantine Four-RIng Mobius Bracelet can be found on p. 42 of Lauren's book. The earrings and bracelet shown at the top of this page are called Shaggy Loops' Big SIster Bracelet (and earrings) and they can be found on p. 51 of her book. 

Thank you so much to Facet Jewelry for allowing me to spend this month will all of you.  I love making chainmaille and I hope that I have inspired some of you to try this wonderful craft!

Editor's note: We were so pleased to have Lauren here with us throughout Chain Mail Month! 

Love Lauren's work? She is the author of the book One Jump Ring: Endless Possibilities for Chain Mail JewelryGreat for beginners, you won't have to worry about Aspect Ratio, because all the projects use the same size jump rings! Make it easy on yourself, and make it beautiful. Just pick up 3/16" jump rings, a few pair of pliers, and this fantastic book, and you'll have stunning pieces like the bracelet below in no time. 

Be sure to visit Lauren's website,, and find her under the same name all over social media: her blog, Facebook, flickr, and Twitter! There's no easier way to learn chain mail than by following Lauren. 

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