Aleš Lombergar

buy a diamond tipped spade bit for the size hole u need. you will need to dip your bit into some spirits of turpentine ( can get at hardware store). this keeps the bit cool as it cuts. keep doing this each time you start to see grit forming. as you drill, don’t push on the glass, just let the weight of the drill do most of the work. u can hold it snuggly to the glass, but don’t push. as you work the bit into the glass, rotate it. any time you see white dust forming, your bit is getting too hot and you’re about to break the glass. for bigger holes you won’t need a spade bit. u can check out the products online at crlaurence

Also, you might want to put masking tape on the glass if you can still determine where you want to drill.