Lapadary question? & a comment on Granulation

Greetings, I was doing a project yesterday & ran into a problem that
may stop the product from being commercially viable product for my
historical recreation market. I was at the Lapidary shop & cut some
whetstones to sell at SCA events. Cutting went fine but when I was
drilling the holes to hang them by I wore off all the cutting surface
of a diamond drill bit. I was drilling at a medium speed using a
Fordham with the stone in a bowl of coolant & frequently dipping the
bit in fresh coolant. I don’t think I over heated the bit, I was
being careful. Anyone have any suggestions? On the subject of
Granulation. Some of the greatest examples of granulation were done
in silver by the Norse a thousand years ago. I will be working on a
granulation project tomorrow in class if the fine silver comes in.
Pax, Jim Revells Olaf’s Plunder who when he finishes school will offer
reproductions of Norse artifacts & jewelry inspired by Viking Art.

The whetstone probably wore away the sintering metal, usually
nickel, taking the diamond particles with it The metal of the bit
needs to be harder than the whetstone (silcon carbide? carborundum?)
and I would suggest the use of a titanium nitride coated bit with the
proper coolant oil at the correct cutting speed And I have no idea of
the correct sutt ing speed Usually, when boring holes, a hole cutter
is used rather than a drill nit Also, you might want to look
into having a large lapidary house drill your holes for you using an
ultrasonic drill Probably cheaper, too

Wayne Emery
Jewelry Design Service
3D CAD services for the Trade