Here are the directions we provide with our cermet drill bits.
GLASS
Glass should be drilled with a cutting lubricant. An oil-based lubricant is best. Water can be used, but not recommended. Make a small reservoir out of a piece of string or bit of clay to hold lubricant around drilling area. Drill pilot hole if possible, you will get better results for your efforts. Never apply excessive pressure to glass. Be sure you are drilling on a flat surface and do not let the body of the drill (not drill bit) slide into and hit the glass when the bit exits the hole. Glass should be drilled at speeds of 300 - 600 RPM. NO FASTER! Remember friction creates heat - the enemy when drilling glass.
Especially important is to keep the glass pwoder out of the hole while dirlling.
Glass is very easy to machine with an abrasive jet machining center. It cuts faster than aluminum and can be machined into very intricate shapes. Have a look at
