We use a glass cutting bit that has a hollowed center. Its especially made for drilling holes in glass and mirrors. The chuck of the drill has a hose inlet attachment that lets water flow onto the drill bit on order to keep the temperature down so as it will not crack the glass. As CAframer said in the previous post, its not a drill bit in the convetional sense, its more of a hollow tube that the cutting / grinding action is on the outside of the tublar profile of the bit. I guess that if you dont have the correct drill chuck for the hose attachment and you have the correct drill bit it will cut the holes but its inportant to take the cutting easy and dont force it with pressure, and try and pour water on the cutting bit in order to cool it down.The most important part is keeping water on the cutting head of the bit as you drill.When the hole is drilled you are left with a full cricle of glass that has been removed, not like drilling wood , where you are left with shavings and dust.
Our main business is in the manufacture of decorative glass, so we use glass cutting and drilling equipment everyday, the picture framing part just really happened as a spin off.
