Jump Rings - What size do I need?

By Dave Wilson of Celtic Dreams

Byzantine Chain My Dave Wilson

Pic 0 large byzantine chain by Dave Wilson.

I am often contacted by people who have watched my YouTube videos on making Byzantine and Persian chains. Sometimes, their chains haven’t worked out or they don’t look like mine. This is because they haven’t followed the correct recipe.

When it comes to making chains and chain mail everything you make is governed by one important thing... “Aspect Ratio”. But don’t be intimidated by the name. Understanding this simple ratio is the key to mastering jump rings, chains, and chain mail. It will enable you to make any chain in the exact size and proportions you desire. Put simply, Aspect ratio is the inside diameter of a jump ring,  divided by the diameter of the wire.

Pic 1 showing aspect ratio calc.

A jump ring with a low ratio  would be quite chunky like a bagel. The center hole is small compared to the overall diameter. Whereas a larger aspect ratio will be more towards an exercise hoop, where the inside diameter is many times the thickness of the plastic part. Reducing the diameter or thickening the wire will reduce the Aspect Ratio. Conversely, thinner wire and larger diameter will increase the aspect ratio.

Pic 2 Bagel has a small aspect ratio. a Hula Hoop has a very large aspect ratio.

This ratio determines how many jump rings will fit through another one. And this is why it is so vitally important to making chains and chain mail. But to calculate this you do need to work in mm.

It is not possible to divide imperial measurements by AWG wire gauge.
All measurements need to be in the same unit, mm.

Finding the magic number.

Let us imagine that you want to make a simple round belcher chain. Just round links connected one after the other. If you think about it, every single link has ‘two’ other links going through it. And hence we need to allow for this. If the wire used is 1mm diameter then this means that the inside diameter of the jump rings must be “at least” 2mm to allow space for two rings to pass through. Any less and you would not be able to make a chain.

Pic 3. Round belcher with an Aspect ratio of 2.

But this would still be tight. Ideally, you want a little bit of space for the chain to move freely. So if we make the rings a little larger with an inside diameter of 3mm this would allow space for two jump rings and 1mm free. This will make a lovely simple chain, that looks nice, is flexible and easy to make. Hence, in this case, the inside diameter is three times the wire diameter, meaning the aspect ratio is AR 3.0

Inside diameter 3 / Wire diameter 1 = AR 3

Pic 4 Same 1mm wire but now with an aspect ratio of 3.0. Much better.

Here is the magic part. Whatever wire you use, simply select a mandrel which is three times bigger and you will get a lovely looking belcher chain every time. In this case, three really is the magic number.

Perhaps you want to make one much bigger, using 2mm thick wire. How big do you need to make the jump rings? Simple, if we stick to our original Aspect Ratio of 3, then the inside diameter is simply 3 times the diameter of the wire.
Aspect Ratio 3 X 2 mm wire = 6mm inside diameter.

Wind your wire around a 6mm mandrel and your finished chain will have the same proportions as your first one, but be bigger . How big exactly? You can calculate that too. We know the inside diameter is 6mm and we know the wire is 2mm. Imagine drawing a line across the jump ring. The outside diameter of the rings will be the inside diameter plus twice the wire diameter. In this case, 2 + 6 + 2 = 10 mm which will be the size of your fished bracelet. 1cm

Pic 5 of outer and inner diameter
Just add or subtract two wires to get the info you need.

When it comes to more complex designs such as Persian chains and Byzantine where lots of rings pass through each other, this aspect ratio becomes vital. There must be enough space inside the ring for all the others to pass through it, but too loose and the design won't look right and may even fall apart. Hence the Aspect Ratio is vitally important, and each design will have a minimum and maximum ratio (see the table at the end) and this number is the secret to success.

Persian & Byzantine

Photo 6 Persian & byzantine bracelets by Dave Wilson.

A byzantine chain, for example, requires an aspect ratio ideally between 3.5 and 4.0 Any less than 3.5 and you simply cannot make the chain. Larger than 4 will still work, but the chain is more open and loses its beauty. Whatever size you want to make a byzantine, just stick to a ratio of 3.5 and it will look perfect. Just as above choose your wire, and simply select a mandrel around 3.5 to 4 times bigger. And your Byzantine will look perfect. Whatever your chosen mandrel, add 2X the wire to get the final width of your bracelet.

Photo 7 Comparing two byzantine chains of slightly different Aspect Ratios.
In the photo above you can see two byzantine chains. Both are made from 1.2mm silver wire. The top one was made with a 5mm mandrel. 5 / 1.2 = AR 4.1 and you can see that this chain although solid is quite loose and open. The lower chain uses the same 1.2mm wire, but  was made on a 4mm mandrel. In this case, 4 / 1.2 = AR 3.4 and you can see that this chain is much tighter and denser. This is the limit. You simply cannot make it any denser than this. This photo shows how a slight change in the mandrel of just 1mm changes the aspect ratio, and in turn changes  the whole look of the chain.

To make a chain more compact and dense, reduce the aspect ratio, by using a smaller mandrel (inside diameter) or choose thicker wire. To increase the aspect ratio and make a chain more loose and open, either increase the size of the mandrel (inside diameter) or use thinner wire.

By understanding this ratio of the mandrel and the wire, you can ensure that your chain will work, be strong, and look exactly in proportion, whatever size you wish to make it.

Asorted chains
Photo 8 Using these simple calculations Dave can make a variety of beautiful chains.

Buying jump rings

I am often asked, “I want to make a Persian bracelet, what jump rings do I need to buy?”
If you want to buy pre-made jump rings from jewelry suppliers, you need to be aware that many stores list jump rings with their 'outside' diameter. But to calculate the aspect ratio you need to know the 'inside' diameter. Simple, just subtract two times the wire diameter from the outside diameter. Remember you always need to work in mm. so if the wire is listed in AWG or the size is given in inches you need to convert it to mm.

Bought rings
Pic 9 of 7mm jump rings for sale. Note the 7mm is the 'outside' diameter.

In the example above the rings are listed as heavy 7mm, which doesn’t help us much. But the description says that they are made with 1mm wire and the ‘outside’ diameter is 7mm. So if we subtract two wire diameters, this gives an inside diameter of 5 mm. we can now calculate the ratio.

Inside diameter 5mm / wire 1mm = AR 5.0

These rings are perfect for making a Full Persian bracelet, (these are actually what I use) but these would not be suitable for making a byzantine, too big.

What's the ratio of this jump ring?

You’ve got a bag of old jump rings and you want to make a nice byzantine chain out of them. But are they suitable?  Using calipers, you can measure the outside diameter of the ring for example 10 mm and measure the diameter of the wire for example 1.5 mm. Subtract two wires from the outside diameter 10 -1.5 -1.5 = 7 mm inside diameter. The aspect ratio is 7 / 1.5 = 4.6 AR

So these rings would NOT be suitable for a Byzantine. The chain would look too loose and open. Technically it would work, but the chain would not look nice.

Top tip.
The same technique can be used for repairing a chain. By measuring the outside diameter of the jump ring and subtracting two wire diameters, you know what size mandrel to use to make an identical replacement link.

So that wasn’t so hard now was it? You have now mastered jump rings. whatever you want to make, whatever the size you simply need to divide a couple of numbers and you know exactly what jump ring to use. 

Below I've given some suggestions  for AR of some popular chains. For my USA friends I've given some suggestions in AWG and imperial mandrels -  To save you converting.

Making Jump rings.

You now know exactly what jump ring you need. You’ve got your mandrel and you’ve got some wire. But what’s the simplest way to make jump rings?

The process is two-part. Firstly, you need to make a spring like coil by wrapping the wire around the mandrel. Second, you need to cut along the coil to create the jump rings.

Winding your coil by hand is simple enough but can be time-consuming. Most people prefer to use a cordless drill or screwdriver. Insert the mandrel into the chuck and bend the end of your wire 90° and pop it in the chuck between the jaws. Wind slowly with the top of the mandrel turning away from you. Apply a little tension and keep the coil uniform...

SAFETY TIP. It is vital that you only use the cordless drill very slowly, and wear eye and hand protection. Avoid the wire whipping around which may cause injury.

When you reach the desired length, slip of your coil and trim the ends with flush cutters. Continue winding coils until you have the desired number of rings. Remember that each 360° turn of the mandrel will create one jump ring.

Tip- always add a couple of extra turns to allow for any wastage at  the ends.

Having made your coil the next part is to cut it lengthwise into jump rings. This is that part that people find difficult. Many people clip the rings off by using wire cutters or flush cutters. But this creates a problem. Even the best flush cutters are only flush on one side. As you clip the jump rings off one by one, you will find that one side has a nice flush edge but the other has a beveled end. This is an unavoidable result of using any flush cutters.

Diagram of flush cutters, notice how one side of the jump ring has a bevel on the end. Only one side is flush.

Top tip.

One solution is to rotate your flush cutters and constantly trim the beveled end of the coil, before cutting the next ring. This  is fine if you just want one or two rings for a project. However, it is wasteful and time consuming, So inefficient if you require lots of rings for a chain.



Diagram showing how to correctly cut jump rings with  flush cutters. Note that  you need to trim the end of the coil flush. Rotate the cutters and cut the jump ring. Rotate back and trim the coin again before cutting the next ring. repeat.

By far the best way to cut jump rings is to always to saw them with a fine jewelers saw. But many people struggle with this. Everyone has their own method, but typically you’d place the coil near the edge of your bench pin in a manner that you can saw at a 45° angle and cut the rings one at a time. Use a fine blade and keep it lubricated. With thicker stronger wire this is ‘fairly’ easy to do with some practice. But with smaller coils or thinner wire, this can be very tricky and again time consuming.

Important safety warning...

Some people try to speed up this sawing by placing small circular saws in a Dremel or flex shaft. This is extremely dangerous and should never be attempted. An uncovered saw blade rotating at 33,000 rpm is a severe danger. I myself almost lost a finger doing this and I still bear the scars from it. Do not do it!

The Pepetools Jump Ring Maker

To make jump rings quickly, uniformly, and safely the best solution is the Pepetools Jump Ring Maker. Combined with a Foredom Flex shaft, this incredible set of tools allow you to easily wind the wire on precise mandrels creating perfect uniform coils.

The set also comes with a saw blade that is attached to a Foredom flex shaft. But it is housed within a solid aluminum housing which rides inside a specially designed coil holder. This makes the entire process simple and safe as there is no exposed blade or moving parts. The coil holder and saw cover also ensure that the rings are sawn perfectly straight every time, leaving perfect parallel edges to every ring. Using the Pepetools  Jump ring maker, you can make hundreds of perfect jump rings in a matter of a few minutes. Quickly easily, and above all else safely. All my designs you’ve seen above where all made using this tool.

For more information on this fantastic tool click the image below and follow the links to some great demos and videos. Thanks for reading. Dave.




Here is a handy chart for aspect ratios in Excel

Aspect Ratio Calculator

All Jewelry created
Written and illustrated by Dave Wilson

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