One of the issues nearly everyone has is cutting the appropriate length of ring stock needed to make a particular size. Let’s see, there is the wrap a string/paper/tape around your finger method. And that can work pretty well if the ring is for you. But what if you want to make a standard size 7 set of stack rings, or a wide band for someone who wears that size? Each of those situations would require a slightly different length even though they are both for the same size. A wider band needs more length or it will not fit the finger properly. Yeah, I know, it feels complicated.
A long time ago I saved a chart and some information that would help me with just this issue so I am posting it here so everyone will be able to use this guide to help them when they want to make a ring. As is often the case when we are making rings it is also good to remember that you are likely (99.9%) going to have to put it on a ring mandrel and round it up with a mallet. In doing so it is going to make the ring a smidgen larger – a lot larger. It is an easy fix to make something a tad larger than smaller after all your soldering and hard work, so keep that in mind as you are creating your shank. I have had to recreate many a ring when I neglected to take this and the width of the band into account when I was cutting a shank.
Ring Sizing Chart
Getting ring sizes right:The easiest way to get a ring sized right is to cut the stock or wire to the right size to begin with! It's easy once you know the size you are targeting. The formula is :
(Inner Diameter Of Ring + width of shank) X PI. PI is a constant 3.142.
The width of 18 ga wire or flat stock is 1mm. The following chart shows the inner diameter of the various ring sizes:
5 -- 15.7mm
6 -- 16.5mm
7 -- 17.3mm
8 -- 18.2mm
9 -- 18.9mm
10 -- 19.8mm
11 -- 20.6mm
12 -- 21.3mm
13 -- 22.2mm
So -- if you wanted to make a size 8 ring with 18ga round wire you would cut (18.2mm + 1mm X 3.14 or 60.3mm of wire and make a circle and solder.