I have hunted and hunted for this and I know that IF it
exists, the wonderful people here will know where it is. I have
added chain weaving to my addictions of metal clay and fine beads. I
am cutting my own rings with the Koil Kutter and have tried to keep
track of how many rings I can get from sterling silver wire. Does
anyone know where there is a chart showing how many rings one gets
from a given quantity of wire? I’m interested in the sizes most
common to chain weaving–2.5mm ID to 14mm ID. The number doesn’t
have to be precise, but the will go a long way in helping
me calculate the price of some of my chains. I’ve tried to keep track
when I cut rings, but age has taken hold of my brain and scatters
the numbers around so I can’t seem to get them all together.

An approximation can be made by taking the diameter of the coil you
are making and multiply it by the number of coils. For example, a
1/4" coil x 12 coils would take a wire that is 3" long. Allow a
little extra when actually cutting.

I think it would be much easier to just weigh the wire of the
finished piece then figure your cost based on the amount of metal you
used.

If you must figure the length of wire used in each jump ring you
could use the mathematical calculation of the inside diameter plus
the thickness of the wire x 3.1416.

Determining the length of wire required to make a given number of
jump rings isn’t hard. Here’s one way to do it. It helps to have a
calculator with a Pi button on it.

Add the diameter of the wire to the diameter of the rings to be
made. e.g…6 mm ring from 18 ga (.040", 1 mm) = 7 mm.

Multiply the diameter + wire thickness by Pi (3.14). 7 mm x 3.14 =
21.98 Round up to next whole number 22. Each ring requires 22 mm of
wire.

Multiply the number of rings required by the length of 1 ring.
e.g. 450 x 22 = 9900 mm. If you want to convert this number to
inches, divide the 9900 by 25.4 9900/25.4= 389.76. Round up to 390.

The reason to add the thickness of the wire to the diameter of the
ring is to give the average diameter (the diameter of the ring
measured at the center of the wire the ring is made of) of the ring
itself. The mandrel the ring is wound on is 6 mm, but the diameter of
the wire will enlarge the diameter of the finished ring.