Circumference of a 9mm gemstone
To get the circumference of a circle, multiply the diameter by pi (3.14).
Hi,
circumference= diameter x pi (3.14)
so, 9 x 3.14 = 28.26
if trying to figure this out for a bezel, then you need to add metal thickness to the diameter
ie: imagine you have a piece of 1mm thick metal strip wrapped around the 9mm stone…
including the strip,
the outside diameter would be 1+9+1= 11
the inside diameter would still be 9
lets say you want a bezel where you would be cutting a seat….that was half the thickness of the strip…say .5mm…
then the outside diameter would be .5 + 9 + .5= 10
inside diameter (of metal) would be
9 - .5 - .5= 8
then multiply by 3.14
if you draw circles out, based on above, it is easy to visualize…
julie
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Assuming that it is round: 28.26 mm (9.0X3.14). The trouble is that, if you are making a bezel, you have to add something for the thickness to the diameter of the bezel. Otherwise, when you form the bezel, the inside diameter will be smaller than 9.0 mm. Theoretically, you are adding the thickness of the bezel to the diameter before you multiply by 3.14. Then you have to add a bit for the loss from filing down the ends before you solder them. I get it right maybe 1 time out of 10. The rest of the time it is either too short or too long. Too long is better than too short, but too long can become too short quickly. Good luck…Rob
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