Aspect Ratio Guide

Introduction to Aspect Ratio:

The aspect ratio (AR) is the number that represents the relationship between the wire gauge (thickness) and the inner diameter (ID) of a particular size of jump ring. The exact formula to calculate the aspect ratio is:

AR = ID / Wire Diameter OR

ID = AR x Wire Diameter

Before using the formula one must have an understanding of the thickness of a wire or the wire gauge. Wire gauges are numbered, and the smaller the number the thicker the wire. Therefore, 12 gauge wire is thicker than 14 gauge wire or any higher numbered wires. Also, 20 gauge wire is thinner than 18 gauge wire etc. To utilize the above formula, one must convert the wire gauge into millimeters. The table below gives the conversion from gauge to millimeters for the most commonly utilized sizes of jump rings for chainmaille jewelry.

Wire GaugeWire Diameter

Example:

You have just made a Byzantine bracelet out of 16 gauge - 4.5 mm ID rings. You really love it, but would like to make one that is smaller (finer) in size. Your pattern does not list any other sizes of rings that would work with the Byzantine weave. Utilizing your aspect ratio knowledge, you can figure out another size of jump ring that would the smaller bracelet you desire.

First, figure the aspect ratio of your current bracelet. AR = 4.5mm (ring diameter of rings you used) / 1.29 (16 gauge wire diameter from the table above). AR = 3.488 or 3.5. Now you want a finer bracelet so the next sized smaller gauge wire is 18 gauge. Therefore, utilizing 18 gauge wire and aspect ratio of 3.5, the ring diameter you would need would be:

ID = 3.5 (AR) x 1.02 (18 gauge wire diameter from the table above)

ID = 3.57 or 3.5 inner diameter

Suppose you wanted to utilize size 21 gauge wire for a Byzantine bracelet (I call this the micro-Byzantine size). It would be ID = 3.5 (AR) x .723 (21 gauge wire diameter from the table above) = 2.5 ID. You now know that you could make a lovely Byzantine bracelet in the following sizes: 16 gauge - 4.5 mm ID; 18 gauge - 3.5 mm ID; 21 gauge - 2.5 mm ID.

Examples to calculate:

1. Let's have you calculate one by yourself. What would the ring diamter be for a Byzantine bracelet utilizing 19 gauge wire?

2. What if you wanted to make a Half Persian bracelet and you were told the AR was 5.5. You would need to pick out the wire gauge you wanted to use, and then figure the ID. Let's pick out 16 gauge wire.

Please do the math and check for the answer to #1 and #2 at the bottom of the page.

Additional Information:

Aspect rations are generally in the range of 2.9 and 7.0. Each weave has a range of aspect rations that will work well. When one goes below the range, the rings may be too thick and the weave is either too stiff or impossible to weave. Above the correct range the rings may be weaveable, but they will be too loose to look nice.

I hope this helps you to calculate different ring sizes from which you can make your jewelry. Please email if you any questions.

Thanks,

Sue Smile

Answers: #1 - 3.2 mm: #2 - 7.0 mm