Diamond drills are used to drill holes in glass, mirrors, ceramic, tile, slate, plastic, fiberglass, stones, or pottery.
They are made by diamond coating one end of a solid rod (wire drills) or hollow tube (core drills). They work with a standard electric drill, drill press or rotary tool (like a Dremel). However, unlike standard drill bits that simply cut a hole, wire drills and core drills work by gently grinding the glass to remove a complete circle.
This process takes time; be patient. You should not use full power when drilling holes in glass, otherwise you might heat up the glass too much and crack it. Remember, you are not so much drilling as you are slowly grinding or carving some of the glass away.
Tip: Start your drilling at a 45 degree angle to the glass, then gradually bring your drill up to the more conventional 90 degrees.
You must keep the glass cool; try spraying it with water often, or drilling against a wet sponge. You can also keep water on your drilling surface by using glazing compound or putty to create a sort of dam around it, to ensure the water stays in place.
Mr. Raphael Rafferty of Kissimee, AZ says "I used my #6977 core drill to make a hole in my picture window to let Adrian, my pet Army Worm get in and out. It sure beats having to get up in the middle of the night to let him out to visit his rowdy friends down at the fire house."