How to Drill Glass (without destroying it!)

Whether you’re planning on mounting some cutting-edge glass shelving to your spiffy new shower, or creating a spectacular indoor aquarium for the pool room—you’re going to need to drill some glass. Glass drilling is fraught with danger (glass splinters, anyone?) and is enough to send shivers down the spine of many a handyman or woman. Alas, don’t shelve your sparkly glass shelving idea just yet! With these simple tips and tools, you too can become a glass-cutting aficionado!

Tools

Your go-to tool for drilling glass (or tile, or porcelain, or any other non-wooden fragile material you need to punch a hole through) is a diamond drill bit. Diamond drill bits come in either twisted (similar in fashion to other threaded drill bits you may be familiar with) or ‘core’ drill bit varieties. Core drill bits are often much larger than their twisted brethren, are hollow in the centre and effectively cut out a ‘plug’ from the material you’re drilling. Whichever version you’re using, these drill bits are imbedded with diamond powder, which gives them their extra cutting power.

Pro-tip—don’t use a hammer drill, as this will damage the diamond drill bit, and may crack your glass!

Don’t press too hard! Increasing the pressure on the drill bit will increase the speed, increase the heat and risk cracking your glass. Let the drill bit go at its own pace—slow and steady wins the race with glass drilling.

Note—you can’t drill tempered glass!

Secure the glass

When you’re drilling something a smooth as glass, your drill bit is going to try to move around. Securing the area with a piece of tape or cardboard is a simple and effective solution to this quandary. Furthermore, you will need to secure the glass itself. How you secure your material will depend on the kind of object you’re drilling (a glass bottle isn’t as easily secured as a sheet of glass, for example). The most important thing to keep in mind is minimising the impact from the drilling. You’ll want to use a soft but sturdy material, such as rubber matting, to absorb the impact and also hold your glass still. If you’re using vice grips or the like to hold your glass steady, ensure that they’re protected with rubber or felt to absorb the impact from both the drill and the grips themselves.

Avoid cracks

To minimise the risk of cracking your entire piece of glass, try to stay at least a few centimetres away from the edges. Furthermore, as you may experience in woodworking, it is best to start with slower drill speed and a small bit, and work your way up to the desired hole size. While it may take you a little longer to move through this process, it could save your entire job by not putting unnecessary stress on the glass. Another regular technique used by glass-drilling pros is to drill a hole to approximately half-way through your sheet, and then flip and repeat on the other side. If you’re not careful (use the piece of tape, as recommended above) you can end up with an off-centre hole (nobody likes an off-centre hole!) however, with a little patience and precision, this technique can ensure that hole doesn’t turn into a giant crack!

Keep the area cool

Drilling, by nature, produces a lot of heat. This is not great for you, and it’s not great for your glass. Keep the area cool by either spraying with water, or submerging your job in water while you drill it. Some drill models incorporate this process in their mechanisms, often on a more industrial scale. Whether you’re a weekend handyperson, or a glass-cutting extraordinaire, cool glass is the key to a crack-free happy tradie and crack-free glass.

Disclaimer—always be careful when operating a power tool near water. Duh. Moving on…  

Wear appropriate safety equipment

As with any trade activities, it is important to wear the appropriate safety equipment. Recent years have seen vast improvements of the general trendiness of safety goggles and gloves—so there’s no excuse for failing to cover up those vital parts! Don’t neglect to wear a face mask as well—breathing in glass fragments is nobody’s idea of a good time! Finally, and quite obviously, ensure that your drill bit is attached securely before attempting to drill. We needn’t have mentioned that, really, as we know that you all read your operators manuals before bed each night, don’t you?