Learning how to drill glass without breaking it is very simple if the proper tools are at hand. It is important to have the right kind of drill bit for the glass. If you do not use the right drill, then you can be sure that the glass will crack or completely break. If possible it is best to not drill through glass though sometimes it is necessary.
Step 1 - Consider the type of Glass
Ensure the glass needed is the correct thickness and size. Safety glass and tempered glass should not be used. Very special equipment is needed for safety and tempered glass. This equipment is not available at the local hardware store.
Step 2 - Use the Right Glass Bits
In order to drill through the glass, special glass drill bits are needed. These types of bits will be made of tungsten carbide and will have a point that is shaped like a spade. The tungsten carbide can stand up to the amount of friction that is created when drilling glass. It is also possible to use diamond bits but, two diamond bits will be needed for drilling where only one tungsten carbide bit is needed.
Step 3 - Measure
Once the glass is cut, measure where the holes will need to be. Do not drill holes within 3/4 of an inch from any edge. It is best to stay as far from the edges and corners as possible.
Step 4 - Support
For drilling the glass it will need to be supported. Place it on a surface that is very flat. If possible, have a type of very firm cushion material or a rubber pad underneath the glass. It is vital that the glass is properly supported and flat.
Step 5 - Drill
Use a variable speed drill for drilling. Start with a small drill bit and then place the bit so it is in the center of the hole. Start drilling and use constant pressure. It is best to drill in a slow and steady manner.
Step 6 - Reverse
Before the drill goes completely through stop drilling. Many times if the drill bit goes completely through it will chip the back side of the glass. Flip over the glass and drill through the backside to complete the hole. Drilling through the back of the glass produces a much cleaner hole.
Step 7 - Increase Size
Start small and then start using increasingly larger drill bits until the desired hole size is achieved. Make sure each new drill bit completely creates a larger hole before going up another size. Going from a small drill bit to a very large drill bit will damage the glass. As the bits get larger a lower drill pressure is needed. With too much pressure the bits will not cut through the glass.
Using a sequence of increasingly larger bits is very important because of the different pressure needed. Adding a little bit of cutting oil can help with the drilling process. For glass, water spray or even a water bath is the best.