Drilling glass is a relatively easy process as long as time is taken when drilling the glass. Whilst it is very easy to drill normal plate glass it is much more difficult to drill tempered or hardened glass as it has a tendency to shatter into thousands of pieces.
In this tutorial we are going to drill a hole in a piece of decorative 4mm thick plate glass using a spear shaped drill bit, these types of drill bit are also very effective when drilling ceramic tiles.
This is the piece of glass which is going to be drilled. Glass is difficult to clamp so here it is held between two pieces of timber which will prevent the glass from rotating.
It is essential to use a coolant/lubricant when drilling glass. Without the coolant you are much more likely to break the glass!
Here a well has been made around the hole to be drilled which can be filled with paraffin or other suitable lubricant, if no paraffin is available you could even use water but paraffin is best.
This well has been made with some off cuts of plastic shims and some insulation tape, you can make a well from almost anything at hand including silicone, plumbers mait or putty.
Now the glass is firmly in position and the well is filled with some paraffin we can begin to drill the hole. These spear drill bits are normally easy to get started as they have a sharp point but pulsing the trigger can often help to start the hole in the correct place.
Use a medium speed on the drill and do not press on too much or the glass will break!
You can see here that the well is full of paraffin which is cooling the glass and lubricating the drill bit.
As soon as the point of the drill bit breaks through the surface of the glass you need to stop drilling and then turn the glass over to drill it from the other side, this will guarantee that you get the best possible hole in the glass.
Once you have drilled the hole through the glass you can wipe off any paraffin using a clean cloth.
As well as spear point glass drilling bits you can also use multipurpose drill bits to drill glass.
For making larger holes in glass you can use diamond coated hole saws or for really large holes you can use a circle glass cutter.