[brizzo]

Originally Posted by BCOrchidGuy

I've got an old plain steel one that you silicone around where you're going to drill the hole, add water and then add a cutting compound. I've drilled a bunch of holes and bought a couple more bags of cutting compound and the thing works great. You have to use a drill press though or something to stabilize the bit or it will skate around if you try it by hand.

Doug

A steel tube or brass tube drill is used with silicon carbide abrasive media. The old fashioned way to drill glass, but the most cost effective if you're doing lots of holes.

Interesting thing I learned today at work, you can actually get a 'sharpening stone' for diamond hole saws! It removes some diamond grit and bonding material exposing fresh new diamond. Apparently each holesaw can be 'refreshed' only once. Going to order one in and give it a try on some of the samona bits in my shop.