Diamond setting in rock

Jewelry Discussion
21 
John, these core drills, are they ones like a petrologist would
use.  Do they drill a "circle" into the stone creating a column
[which would then be popped out]?

G’day Colleen; That’s exactly right, only the bigger cores
aren’t all that easy to pop out. Some folk make things like
vases that way - even wide mouth vessels by drilling several
cores, then cleaning up after - pretty laborious. Some find
drilling concentric holes to the same depth provides easier
break-out. And for drilling I still prefer to have the piece of
hard material just under water in a tray, and the diamond
rotating around 800 - 1000 rpm; much faster and you need a
wetsuit. I have a sturdy plastic and cloth backed mortuary type
apron and still get wet on occasion. –

        /\
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      / /      Johnb@ts.co.nz
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    (_______)  In sunny temperate Mapua NZ - clocks go back Sunday;

Done roamin’ in the gloamin’ now autumn’s here…

22 
 how do you keep the drill from jamming with the material you
have just removed?      t.lee

G’day By doing the drilling with the job just below the surface
of water and by constantly and almost continuously lifting the
drill bit up and down, with the larger bits (above 6mm) not
rotating much faster than around 800 to 1000rpm. This method
keeps the drill bit properly cool, lubricated and cleared of cut
away material. Cheers,

        /\
       / /
      / /      Johnb@ts.co.nz
     / /__|\
    (_______)  In sunny temperate Mapua NZ - now that autumn's here
23

an up and dowm method works best. The bead drill of the past
have an up and down motion with a steady water stream. The only
way to relieve the drill is to cut flutes in it to carry away the
mud. thats a job!!! Hope I’ve been some help, You could also try
some biodegradable rock cutting lubricant as it stays
longer…John the Ringman