On Sun, 13 Mar 2011 15:55:57 +0000, David Billington
wrote:

Larry Jaques wrote:
On Sun, 13 Mar 2011 12:48:39 +0000, David Billington
wrote:


Karl Townsend wrote:

The new way would be to use a diamond hole saw but still have the dam to
retain water to keep the glass cool. You can probably buy them on eBay
for a few dollars in the size you want.


Carbide bits are available for under ten bucks and they work extremely
well for tile, glass (not tempered), and ceramics. No cooling
necessary at all. http://tinyurl.com/48c32js HF apparently doesn't
carry them any more.

Back up the drilling point so the glass doesn't break out the back
side. Cold clay works well to provide a solid backing. Use a light
touch and immediately stop the drill upon exiting. Quick-stopping
cordless drill motors work best for this.

Cooling may not be required but it does help prevent the glass cracking
due to thermally induced stress.

I haven't noticed warmth above body temp in drillings I've done with
the carbide "spade" style drills I use. I know the powdered diamond
style gets hotter and can require coolant.

--
You create your opportunities by asking for them.
-- Patty Hansen