How to Drill Glass Without Breaking It
To drill glass you need two fundamental elements: precise techniques and tools suitable for the type of operation. You cannot drill the material with just any drill bit, this is the rule you must always keep in mind.
Actually, for drilling iron, metal, wood and building materials you also need specific tools but for drilling glass this reasoning is even more important. The reason? Its fragility: it is a hard surface but capable of cracking and breaking in an instant, with inadequate pressure. And not all glasses to be drilled are the same. There can be specific needs such as drilling in crystal or tempered glass. Let's see which tools to use and how to proceed in these cases.
Useful tools for drilling glass
Let's start with a minimal inventory in the workshop to understand what we need to drill a sheet of glass or a vase, a window, a bottle. First of all you need a comfortable work surface, capable of keeping the piece to be drilled well stable.
Then you need to get the appropriate PPE. You can't drill glass without safety glasses and gloves, they are the basis for avoiding dangerous splinters. Then you need a drill: a standard model is fine, the important thing is to be able to use it with rotary movement, not percussive. Having drilling oil available can help you in more demanding work and finally you need suitable drill bits.
For wider holes you can use diamond mills while if you need to make a hole in a window for a ventilation fan or the air conditioning tube and dehumidifier you need a circular glass saw with suction cup. So you can proceed with maximum precision.
Which bits for a hole in glass?
The use of bits for glass is the secret to drilling smoothly. Especially to minimize the risk of breaking or chipping it. Sure, there are different technical aspects of the procedure that help but having a good bit on your side is essential.
How should it be? Diamond coated ones are exceptional, they can drill glass with ease. Those in tungsten carbide are reliable and allow you to operate excellently. You recognize glass bits from their shape: they have a lance-shaped tip, just like the model in the Krino catalog. This is a solution for glass and ceramics, to be used at low speed with coolant.
How to drill glass, the technique
First of all you must carefully clean the surface to be drilled. Fix the glass sheet at a stable point of the work bench, perhaps with clamps being careful not to apply too much pressure to avoid breakage. Insert a layer of sacrificial material (like a wooden board) between glass and bench so you have the ability to pass through the glass. Then mount the bit you have chosen on the drill.
The bit - in addition to having a specific shape - must be of the diameter required for the hole. Never as in this case is any forcing to enlarge the hole in the glass banned. Mark the point to be drilled and position the drill perpendicular. Now, if you need to drill a bottle or a balloon this operation requires maximum attention because the surface is curved.
Work at low, stable speed. Add drilling oil or water: the reduced temperature and friction reduction allows you to drill with precision and without risks. High temperatures lead to glass breaking, use the coolant before and during the operation. The stability of drilling is important, so you can also use a column drill for precision operations.
How to drill tempered or netted glass?
The first point to consider: tempered glass cannot be either drilled or cut. The moment you try to handle it it breaks into a thousand pieces with relative danger to your safety. So, how to proceed in these cases?
If you have a suspicion, check that at the corners of the sheet there is no recognition symbol. If instead it is glass with embedded net it is not certain that it is also tempered but the machining is difficult: it is better to ask a glazier for help.
