Re: Cup-cutting machines
I know exactly what you are talking about.
Last year our state lapidary exhibition in Victoria Australia had a set of lovely nested Agate bowls as one of their prizes, possibly even made by the Italian factory. There was considerable speculation about how they were made, I was surprised that I was the only one with any idea how it was done. There was a photo published in the Gem clubs association magazine just before the exhibition which I may be able to track down if you think a picture could help as it looks like you and I may be the only ones in the know.
To other interested people, the machine uses steel hemispherical cutters (think half a tennis ball on a shaft) with diamond grit, the cut is started and the cutter is gradually angled down while the stone is rotated to cut out the complete hemispherical bowl center piece. (think icecream scoop)A slightly larger cutter is then used to cut out the first very thin bowl, then larger cutters are used to cut a series of ever larger nested bowls.
These bowls are quite thin and really beautiful.
From Paul - September 19, 2012 at 21:47:09