if you’re not going all the way through the stone, I’d avoid the
core drills. They will leave a plug and you MAY be able to break it
off… but doing so may just fracture the rest of the stone. It
really depends on what type of stone you’re drilling, what its
cleavage is, etc.
Your best bet is to use diamond cylinder bits and/or ball burs. They
do go quite a bit larger than 2mm (I have them up to 8mm, but I know
they go larger). Lasco Diamond products is my supplier of choice for
Start with the smallest one that you have, go in at an angle to get
started, then flatten it out. Work up a size at a time after you have
the hole drilled to the depth you want. That way, you end up with the
least breakage possibilities. Always work wet (I usually have the
piece I’m drilling submerged in a shallow dish. This keeps the
diamonds lubricated and makes them last longer, and also traps the
dust being created so you don’t breathe it (many stones have toxic
properties), as well as washing out the hole being drilled (makes the
drilling go faster and keeps the bur from clogging).
As for finishing the inside of the hole, it depends on what type of
stone you’re using. You can get wonderful diamond finishing papers
from dental suppliers in a variety of grits. They are flexible
strips, impregnated with diamond. The strips are about 1/4" in width
and you thread them into the hole and “thrum” them back and forth to
polish. They’re designed for shaping and finishing crowns, I believe.
That should beautifully finish any stone that you can drill with
Hope this helps!
No Limitations Designs
Hand-made, one-of-a-kind jewelry