Essential Tips for Drilling Holes in Glass

Drilling holes in glass may seem a bit daunting at first. With the right drill bit, some preparation and careful drilling, you’ll get the hang of it quickly. Glass is a tough yet delicate material that cannot be drilled into using a regular bit. To make clean holes without the risk of cracking or broken drill bits or other issues, you need to know exactly how to drill holes into glass properly. In this guide, we’ll share some tips to help you get started.

Drilling Holes in Glass

There are a few things that you’ll need to consider when drilling holes in glass. These are the most important things to consider:

Choose the right drill bit

First, you’ll need to get the right bit. A general glass and tile bit will work for most projects involving glass. These have a spade shape, with a tungsten carbide tip. This means that they can withstand the friction that occurs during drilling. These bits are affordable and come in a few different sizes. An even better choice is a diamond core bit, however. As their name implies, these high-performance bits have a diamond cutting edge. They will drill clean, smooth, precise holes into all types of glass, from wine bottles to sea glass or glass tiles. 

Secure the glass to keep it steady

Unlike flat materials such as wood or masonry, glass pieces may be small or unevenly shaped. If you’re drilling sea glass or making holes in wine bottles, for example, you’re not going to be able to clamp the piece onto your table. One way to hold the piece in place is to place it into a small, durable plastic container or tray. Add a few layers of newspaper at the bottom to prevent drilling through the tray. Another way is to use a rubber pad or cushioning material beneath the piece. You could also tape a small piece of thick cardboard to the glass to prevent slipping. This can be used to mark the spot you want to drill. 

Start drilling at the slowest speed.

Slow speeds are best for any hard material. Going slowly allows you to get through materials without chipping the surface (or breaking your drill bit). To make the hole in the glass you’re drilling, start by making a very small dent. That bit of cardboard you taped onto the glass will make this easier. Once you’ve made the pilot hole, remove the cardboard. You can then gradually increase the speed as you get through the material. You can increase the drill bit size if you want to make a bigger hole. As the tip of the drill bit has almost broken through, you can begin to reduce speed and pressure again. This point is when the glass is at its most fragile. Going too fast or putting too much pressure can crack the glass. 

Prevent drill bit from overheating.

Coolant or lubricant is important when drilling any hard material.  As you drill your holes into your piece, add a bit of water to the area. Do this often to prevent the drill bit from overheating. If you skip this, you could end up with shattered glass, broken bits or even a damaged drill. A wet sponge placed under the glass is an easy way to keep the bit and glass cool as you work. 

Keep safety in mind at all times.

Just like any other project, safety should always be a big concern. You can drill into just about every type of glass… except for tempered or safety glass. This type of glass shatters when drilled, which can be a major safety hazard. Look at the corners of the glass to see if there are any parts etched. Other safety tips to remember include wearing protective gear and avoiding any accessories, loose clothing, long sleeves or anything else that could catch on bits as you drill. 

These tips should make it easier to get started on your project. If you’re looking for the best drill bits, Ruwag offers a range of high-quality bits for drilling holes in glass.

Photo: iStock/Grigorev_Vladimir