Subject: Re: drilling granite
From: dwilkins@orion.polaristel.net (Don Wilkins)
Date: Aug 18 1996
Newsgroups: rec.woodworking

On 16 Aug 1996 19:27:52 GMT, king@lvld.hp.com (Phil King) wrote:

>I would guess that a carbide tipped drill bit run slowly with water would
>do the trick, BUT before I tried it I would stop by a tile or floor
>covering store and ask for advice.  Most places are very helpful.

The method we used to drill holes in glass was to use a piece of
copper pipe as the drill bit and silicon carbide in a water suspension
(valve grinding compound). Very low RPM, not too much pressure, and
frequent lifting of the "bit" to allow carbide into the groove. The
"bit" of course wears away fast but is not expensive. With this method
you do not grind out the entire hole but just a slice the thickness of
the pipe. I suspect copper was used because it would be better in
conducting the heat away from the glass.