Sizing a ring smaller - maths?

[SteveCairney]

Hi all, I've had a question I've always meant to ask but I've never needed the answer till now.

I've heard and seen on a few videos that you can work out the exact amount of material to cut out of a ring in order to bring it down in size to resolder. However I've never seen the formula for this or read about it in any books. One video. Saw the chap had the steps etched into his bench so he could caliper the excess right away.

I'd assume that the method would involve the hight of the material and pi, but how would you work out the difference inbetween sizes? I'd love to know as I've got a little restoration project in progress that needs bringing down a couple of (UK) sizes.

Any help would be great

[Dennis]

You can work it out from this table, by calculating the difference between the existing ring and the new size. The top row gives the width of the band, and the vertical row the English sizes.

This was a labour of love, by our treasured member Wallace. However, maths can let you down, so bearing in mind that one mm is roughly equivalent to one size, I would get to one size above and then slowly file until the ring stick says you are there.

However if you have a ring stretcher, you can afford to overdo it slightly and stretch up to size. Dennis.

http://www.sleepingdragon.co.uk/uplo...1-3mm_a-z6.pdf

[SteveCairney]

Amazing, that's absolutely brilliant thanks. A mystery no more!