What tube size do i need for my settings?

[FacetNation]

hello all,
wonder if you could help at all with a quick question?

i have some 5mm & 3mm round peridots which i am going to set in a rubover style in tube.

which size silver tube would be best to purchase for these settings?

thanks,

amy

[Dennis]

Hi Amy,
When you have prepared your tube, you should aim for a rim of about 0.5mm (or a little less, but not more) remaining all the way round. So for a 5.0mm stone you would get 6.0mm outside diameter tubing and for a 3.0mm stone, 4.0mm o/s diameter tubing.

Now come the iffy bits. The stones you will receive can vary by plus or minus 0.25mm, so the rims left on your tubes can turn out to be too thin and fragile, or too thick and tough to rub over.

My remedy is to have in stock a selection of short pieces of tubing so that I can choose an ideal size by sitting the stone on the end and judging by eye. Alternatively you can ask your dealer for exact sizes, or pay them a visit and choose for yourself.

I find it useful to have some six inch electronic callipers to hand. They are not essential, but I like to know what's going on. There are often good bargains in these in discount shops such as Liddle and Maplin. You just have to get used to returning them to zero before use, rather like you do with kitchen scales.

Kind regards, Dennis.

[FacetNation]

Thanks Dennis, can always count on your wisdom!