"Peter W. Rowe" wrote in message
...
On Sat, 12 Sep 2009 01:06:47 -0700, in rec.crafts.jewelry "SteveB"
wrote:

I'm helping a partially blind friend. He has some small pieces of polished
Brazilian quartz he wants to drill a hole into. I have found several
suppliers on line that will sell 1/16" and 1/8" diamond bits for reasonable
prices, around $15 per. Slightly less when bought in threes.

Is this what he needs to drill these holes?

Possibly. He/you do need diamond drills, but beware of the chinese made ones
which are an ordinary twist drill coated with diamonds. Those won't do the job.
What you need are either "wire" drills (small sizes) or "core" drills, which are
tubes coated on the front edge with diamond. The wire bits are steel wire
similarly coated at the end with diamond. Better ones are not coated, but
tipped with a piece of sintered meta/diamond mix, which means the diamonds go
into the metal a bit, rather than being just a surface electroplated coating.
Make sure that the drills you get are intended for lapidary use, or drilling
glass (similar, though easier).

I know he needs to use coolant,

Generally, water is fine. If you're doing a lot of this, you'd add a corrosion
inhibitor to the water. One way to do this is to use lapidary dop wax (like
sealing wax), or a glue, to affix the stones to the bottom of a glass ashtray,
or some similar vessel you can afford to damage. The stone then can be covered
in water, so the drilling takes place submerged. And being affixed to the glass
container helps prevent chipping when the drill breaks through the back side.

and set it up in a drill press. Info on what would be the best way to do
this appreciated.

High speed, but little pressure. You bring the drill down to work for a few
seconds, then briefly lift it up a tad, to allow coolant to flush out drillings
and keep the bottom of the hole cool, then come down again. Repeat till done.

Both Crystalite and Lapcraft corporations make good quality lapidary diamond
drills, and there are no doubt others too. Like I said, try to avoid the really
cheap chinese stuff. They just don't last so long on stone.

Peter

Steve

We went to the glass shop yesterday to get some glass cut. Fred asked the
man, and he brought out a bit that cut a 1/8" hole. It looked like a core
drill, just miniature. Straight shoulders on the end of the bit. He cut
the hole with a hand drill. So, I believe what I am looking for is straight
sided core drill bits, just smaller ones. I am now researching prices, and
will look at the places you mentioned. We are going to cut holes in thin
slabs of Brazilian agate to make wind chimes.

Steve