jump rings Aspect Ratio - The great thing about Aspect Ratio is, once you understand how it works, you'll never buy the wrong size rings. You won't have to spend "trial-and-error" time futzing with rings to see if they'll work for a particular weave; you'll already know!

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The May 2008 and October 2008 issues of our newsletter contain detailed, updated information about Aspect Ratio.


Aspect Ratio in a Nutshell

Aspect Ratio is a number that represents the relationship between the wire gauge and the inner diameter of a particular size jump ring. The exact formula to calculate aspect ratio is inner diameter divided by wire diameter, or in shorthand:

AR = ID ÷ WD

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). Note: Different metals use different gauge systems. Find out more in the Ring Sizes article.

For accurate results, use calipers to measure the ID of your rings rather than relying on the mandrel size. Two rings from different suppliers wound around the same mandrel usually yield different IDs, because each supplier uses different tension. Rings of different gauges wound around the same mandrel also yield different IDs, because springback for the gauges is different. (For more about springback, see Common Terms.)

Aspect Ratios for chainmaille jump rings generally range between 2.9 and 7.0.
Let's look at two examples:

Gauge thick compared with ID
low AR of 3.2

sterling - 16g 5/32, 16g 4.0mm
(my size F16)

Calculate AR:
ID (4.07 mm)
divided by WD (1.291 mm)
equals 3.15 AR

With an AR of about 3.15, this ring size can make Jens Pind, a tight Euro 4-in-1, and very little else. There just isn't enough space in the ID hole to fit a lot of other rings.

vs.
Gauge thin compared with ID
high AR of 5.2

sterling - 20g 5/32, 20g 4.0mm
(my size F20)

Calculate AR:
ID (4.22 mm)
divided by WD (0.812 mm)
equals 5.20 AR

With an AR of about 5.2, this ring can handle denser weaves such as Euro 6-in-1 and Full Persian. However, weaves such as Euro 4-in-1 and Half Persian 3-in-1 are not recommended with this size, because they would be too loose and airy.


So how do you use AR? Each weave has a range of ARs that will work well. 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 too loose to stay nicely put.

Once you calculate the ARs of your jump rings, you'll know what weaves they are suited for. For instance, when we make an Open Round necklace, we like the AR to be about 4.1 or 4.2. All we have to do then is look at the ARs of our jump rings to know which will work well. Anything from 4.05 - 4.25 should work, but we don't want to deviate from this range. Using jump rings with an AR less than 4.0 will create a very stiff weave; above 4.25 and the weave begins to collapse in on itself and lose durability.

We have calculated the ARs for many of the rings we sell; this information can be found by looking at the Stats and Uses charts in the supplies section. Eventually, this Aspect Ratio page will have side-by-side listings of all the ring size ARs, plus recommended ARs for a variety of weaves. In the meantime, if you are looking for suggested ARs for particular weaves, we refer you to Zlosk's Aspect Ratio Table, which is quite comprehensive.

If you live in the Chicago area and are interested in finding out more about AR (and receiving a ton of handouts that greatly minimize any calculations you need to do!), we periodically teach a Chainmaille Q&A class. Though learning about AR may seem like a daunting task, it is actually quite easy once you get the hang of it, and an invaluable tool for the serious mailler. If the class isn't currently offered, please let us know that you're interested and we'll be happy to schedule a class for the next semester or set up a private lesson.

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