slightly OT-drilling glass

[Jim Cunningham]

I am trying to drill a 3/8 diameter hole in the side of a glass block like the ones you see used in construction. Any help on drill bits (carbide?) drill speeds( I will be using drill press with variable speed) and the need for lubricant. Ypour collective comments, advice and experiences will be greatly appreciated.

Happy Holidays

Jim Cunningham

[Gary Jacuk]

Jim,
In my old glazier days we did all of our hole drilling with diamond tube bits. It's the only way to get a good clean hole. You could use one of those lance tipped carbide bits if quality of the hole is not a concern. You want to use a real slow speed (200 - 300rpm), lots of lubricant and don't force it as the hole will break out on the inside. Sometimes we just used glass cleaner for the lubricant, although there is a lubricant available for drilling. Two companies I can remember are C R Laurence and Somaca for supplies.

Gary

[Andy Fox]

You probably already know this: if the glass is tempered, it will shatter if drilled.

Andy

[Joe Pelonio]

Jim,

There are bits made specially for glass. As a stained glass artist I have tried lots of them for making things like windchimes, and stained glass clocks. Diamond is the best, and unfortunately for 3/8" it won't be cheap, I'd guess $20+.

They come as blunt nose, which is either like a dremmel stone tool, or the diamond grit is on the end of a steel shaft (I use these mostly) or as core drills. You can use water for lubrication though I have a lubricant made for glass drilling, cutting, and grinding that I use. I'd recommend 700-900 rpms for the core bits, 5,000 rpms on the blunt nose. I doubt you will find the 3/8" diamond bits at your local home improvement store, more likely a power tool repair shop. If you have time search on "diamond drill bits". There's also a "paddle type" glass bit that looks like a pointed metal canoe oar, I found those to be useless. If you are not going to do a lot of these you might even contact a local stained glass store and they might do it for less than the price of a bit.

[Reg Mitchell]

there is an alternative way to drill the hole. It is a solid drill bit that will drill a 3/8 hole also. Then there is a tube bit that can be used with a subtance carbarumdim. If i were you and you didn't have too many to drill I would take them to a glass shop and have them drilled. You would probly save money by paying someone and getting it right the first time instead of breaking a bunch and not getting the desired results and haveing to have it done anyway.
I worked in a mirror shop in Fla. did many yatchts. glass is another animal completely. It isn't very forgiveing at all. :)

[Richard Wolf]

I have drilled hundereds of these for my wife's craft business. I purchased a diamond hole saw, 3/4", for $10.00. You can find them in a good tool store buy the dremel stuff, but it wasn't dremel. I used painters putty to make a dam for water. Use your drill press at a slow speed. Take your time.

Richard

[Perry Holbrook]

We drill a lot of holes in glass in my studio, including 1 1/2" holes in 3/4" glass sinks. For these holes we use a special water feed set up on the DP. It feeds water through the bit as you are drilling.

For the occassional hole you might want to look up hisglassworks.com . They have a full range of bits and set ups.

Another approach is to sand blast the holes. Works fine but the hole will be a little ragged.
Perry

[John Stevens]

...I purchased a diamond hole saw, 3/4", for $10.00. You can find them in a good tool store buy the dremel stuff, but it wasn't dremel. I used painters putty to make a dam for water...

Same procedure here. Got the bit years ago at a store that sold lapidary supplies.