The set up for drilling in glass is to have a pan of water (with enough water deep enough to cover the piece being drilled) sitting on your drill press. (You can also use a handheld rotary tool. But it's best to have it set up for ninety degree drilling.) I also used a thin piece of wood to place my glass on. This way I wasn't going to drill into the bottom of my pan. Also, it's a good idea to have a towel handy to dry your hands...... electrocution is not something I want to experience.
The procedure is to coat the drill bit with some type of lubricant. I used Bur-life (a liquid oil) but I could have used Pepe lube (a stick lubricant..... this is probably what I should have used in the first place and saved myself some money since I already had some of it.) I use the stick lubricant on my jeweler's saw and Flex-shaft saw. Lubricating the drill bit cuts down on friction and increases the life of the drill bit. I did keep adding the oil every so often which I'm not sure I needed to do.
As I mentioned in my previous post, I got conflicting information on the drilling process. I chose to use high speed as was mentioned in the one video. But next time I will try a low speed as this is also supposed to increase the life of the drill bit.
The glass is held in place (on the wood and under the water) with the fingers. Start up the drill, lower the arm being sure to use a gentle pressure......... (which I did until I started to get frustrated.) I'm ashamed I gave into a little fit of temper and really tried to force the drill bit on my last couple of pieces.
In the videos I noticed that they were using a pumping action when they were drilling, although I did not know why. So, every so often I would raise the lever and lower it again.
The first pieces drilled like butter. A little cloudy swirl would rotate out from the glass and before I knew it, I was through.
One video said to drill half way through, turn the piece over and drill from the other side. First, that only works on clear pieces of glass and secondly it's not all that easy to line it up correctly. The other video said not to bother turning it over; just drill all the way through. This can cause the back of the glass to "break out" a little. This can be remedied by using a different type of drill to clean up the back.
(I think it was a diamond core drill.) I did notice the back breaking out on my test pieces but it really was not that noticeable.
What frustrated me about the whole process was how fast my drill bit burned up. So I did some more research to see how long they are supposed to last. I got about 12 drills in before mine was not working like butter anymore. Of course, there is no definitive answer. I saw one article that said between 100-200 quarter inch thick pieces can be drilled. Other articles were far, far less (but more than my experience.)
What I did find out.
Lower speed means longer bit life.
The pumping action serves a very good purpose, allowing water to fill the drilled hole and thus keeping the bit cooled. Next time I will raise and lower the bit continually to allow this to happen.
Light pressure is essential.
If the drill bit starts to turn a color or black...... it's burning up.
Luckily my father has a tool for sharpening drill bits. (Another new tool for me to learn to use..... Yay!)
I was just doing test pieces this time so it was meant to be a learning experience. Next I'll move onto drilling into stone. Will let you know how that goes. (And I'll be sure to stay calm.)