On Feb 13, 1:17*am, Peter W. Rowe
wrote:
On Thu, 12 Feb 2009 22:06:52 -0800, in rec.crafts.jewelry Jeweller

wrote:
If you do decide to resize by cutting and putting a piece in, one
finger size is equal to 1.1mm

In Australian ring sizes (assumed by your addy), that's correct (I assume. *but
didn't look it up...) * But in U.S. sizes, one full size is 2.5 millimeters. If
one is being very precise, I think it's actually 2.54 mm... *And then, since you
cut the shank open to insert the piece, you can add another .25 mm to make up
for the width of the saw cut. * Again, for real precision, remember that this
length of stock is most accurately measured on the inside of the ring, at the
finger or mandrel surface. *But actually measuring it on the inside is a pain in
the backside. *Most people mark the ring, and the stock, on the outside surface.
For fractions of a size, or a size or even two, the result is the stock is very
slightly shorter, so the ring ends up a little bit tighter than the desired
size. *That's perfect, since it allows you to clean up the solder and the
addition, and mallet the ring properly round again, and the slight stretching
that causes then gives you the desired end size. *But if you're making a ring
more than maybe a size and a half, or two sizes, larger, you start to need to
measure longer than that theoretical 2.5 mm per size, or the ring will end up
significantly too small. *Practice will teach you how much to adjust. * The
other way to do this which avoids the math is simply to cut the shank, slide it
up a ring mandrel to the desired size, making sure the shank stays flush to the
madrel while doing this. *Then use a divider to measure the resulting gap and
mark your sizing stock to cut the needed insert piece.

Peter







From looking at the picture you've posted, the bezel surounding the
agate is not holding the stone in place. I can see gaps on the outer
edges which means you could probably soak the ring in a product called
" Atack " and that will release the stone without hurting the agate at
all. Agates are around 71/2 on the hardness scale so you wont hurt the
the polish in any way. This would be the easiest way to approach this
job as anyone not familiar with soldering the ring in wet sand or
water most often overheats the shank and makes more problems then
they'd like.



Mark