How to Drill a Hole in Glass

From drilling a hole into a pot to passing an electric wire in and out of a window, drilling is imperative when it comes to glass. After all, glass is very fragile, and drilling through it is a real dilemma and a challenge on its own.

How to drill a hole in glass? To drill a hole in the glass, use tungsten carbide or diamond coated drill bit. Never use the hammering feature while drilling a hole in the glass. Refrain from applying pressure on the drill while making a hole. Try to stay away from the edges of the glass. To avoid cracks while drilling a hole in the glass, drill with slow speed, use water cooling, start with smaller drill bits and place a rubber cushion under the glass.

In unprofessional hands, drilling a hole in a glass block can be quite difficult. I will share my personal experience and experimentations in the blog below, With a proper practice that will transform your DIY project into a joyful one.

Types of Glass

Every glass is not suitable for drilling therefore, it is important to briefly discuss types of glass. Glass can be broadly classified into 4 major types,

  1. Annealed Glass: This is the most basic type of glass that is further processed into fine types. It has low strength and thermal tolerance. Drilling through annealed glass is not suitable due to its low strength.
  2. Heat Strengthened Glass: This glass is semi-processed. As the name suggests, it is heat-treated and has got an improved heat tolerance and stability. Mechanical strength is also good. Drilling can be carried out easily but with added reserve.
  3. Toughened Glass: Intense heat and immediate cooling transformers annealed glass into an industrial-strength glass. This is ideal for drilling.
  4. Laminated Glass: Any of the above types of glass can be laminated. Lamination does provide some added strength ( lamination can prevent intense shatter).
Types of glass drilling

Why Does Glass Break While Drilling a Hole?

If carried out with conscious desire, drilling a hole through glass is usually a win situation, but glass is an amorphous solid that usually cracks under stress. This is because glass has microscopic cracks (that are not visible to the human eye) that act as seeds for larger cracks and eventual shatter.

Glass shattered while drilling - Drill a hole in glass block

Here I will be listing the main causes of glass breakage when it comes to drilling.

1. Using the wrong drill machine to make a hole in glass

Drills can be broadly classified as hammered and non-hammered drill. Hammering produces micro burst of forces that shatters the glass into pieces drills hence are considered lethal for glass.

2. Using wrong drill bit for drilling a hole in glass

Drilling on glass requires special drill bits. Not only the bit-type matter, but the bit diameter is also of utmost importance. Moreover, the thickness of glass also plays a pivotal role in selecting the appropriate drill bit.

3. Applying Pressure.

As mentioned earlier, glass has micro cracks; therefore, if excessive pressure is applied while drilling, it can prove disastrous.

4. Drilling on the Edge.

The glass’s edge has the least support from interconnected layers, which predisposes the class to fracture.

5. Heat

The frictional heat produced during the drilling process through the glass produces simultaneous cold and hot temperature areas, which destabilizes the glass structure, resulting in cracks.

6. High Speed

High RPM Drilling has the disadvantage of instability due to the brittle nature of glass. This can prove havoc to the operation.

Methods to Drill a Hole in Glass

Glass can be drilled using either a tungsten carbide drill bit or a diamond bit. Both have got some pros and cons. We will be discussing both methods separately.

A. Using a Diamond Drill Bit to Drill a Hole in Glass

Diamond drill bits are the cornerstones of drilling into the glass. They come in different sizes and shapes. Selecting a proper drill bit is crucial. There are two basic types of diamond drill bits 1) Core Drill Bits 2) Blunt Nose Bit. They can range from 6mm/0.23″ to 32mm/1.26″. You will find many diamond drill bits online, but I will be mentioning my personal favorite below.

Diamond drill bits for glass drilling

1. Baban 10Pcs Hole Saw Diamond Drill Bit

They have a hollow center and diamond-coated edges. They are ideal for drilling through the glass but can be used on marble and porcelain as well. The body is made out of everlasting steel. They are intended for 1/2 inch depth.

2. Norske Vacuum Brazed Diamond Drill Bit

Norske offers individual drill bits in a separate package, so you don’t have to buy the whole set. Size range from 10mm to 24mm. The best thing about it is its heat dispersing capability. The best thing about it is its ability to mount on an impact wrench.

Procedure

  1. Safety: Before you embark on drilling, personal safety should be your top priority. There are chances that the glass may shatter during the drill, giving rise to flying fragments. Therefore always wear proper safety goggles and gloves.
  2. Identifying the type of glass is important because all glasses are not of the same strength. Some are good candidates for drilling, and others poor. Wine bottles, mirrors, and window glass can be drilled, whereas tempered glass usually shatters.
  3. Selecting the appropriate drill bit is crucial. The selection depends on individual preferences. I prefer using smaller diameter drill bits at the start of the procedure and then jumping to larger ones. This helps prevent excessive heat build-up. Moreover, when buying drill bits, keep in mind that bits are different for impact wrenches and conventional ones.
  4. Securing the glass means placing the glass in the position that is ideal for drilling. Drilling on erect glass is not a good position. If you are drilling a wine glass, try securing it with duct tape. For drilling flat glass, using a wooden jig is an excellent option. It will prevent drill wobbling.
  5. Setting up the drill speed is as necessary as selecting the appropriate bit. Always opt for slow speed. It is preferred to flip the side when drilling a hole ( bi-end approach).
  6. Intermittent cooling is necessary to avoid glass breakage. The coolant will also act as a lubricant, thus keeping the heat to a minimum. The best coolant is nothing other than plain water. Use a sponge or a spray bottle for sprinkling water.
  7. Polishing the hole will prevent secondary splintering. This can be done using fine-grit sandpaper.
drilling a large hole in glass using a diamond drill bit

B. Using a Tungsten Carbide Drill Bit to Drill a Hole in Glass

Although tungsten carbide-tipped bits can drill a hole into any glass, they are better to be used on untempered glass. The real problem with them is that they tend to chip the surfaces leaving a poor finish.

If you are interested in using tungsten drill bits then follow these steps;

  • Select an appropriate sized drill bit
  • Mark the glass’s surface with duct tape where the hole is to be drilled.
  • Stabilize the glass with cardboard placed underneath.
  • Keeping the speed slow, aim at the right spot, and start the drill.
  • Intermittent cooling with water is a must.

I will recommend only one tungsten drill bit, this is more efficient.

YUFUTOL Carbide Burr Set

They have got excellent quality and affordable price. The set comes with different shapes and double grooved layers that work better than the conventional single grooved bits. Besides using on glass, they can also be used to drill metal, porcelain, and concrete.

Preventing Glass Breakage During Drilling

Although drilling through the glass has the chances that you may end up shattering it, but if precautions are followed, you can easily minimize it. Below I will be briefly discussing general precautions that apply to all the glass irrespective of the type.

  • Never use a hammer drill. The microburst shatters the glass into pieces.
  • I prefer diamond drill bits over tungsten carbide when drilling through glass.
  • Before moving on to a larger bit, always start with a smaller diameter than the intended hole.
  • Always use coolant when drilling glass. Water or WD40 will do the job nicely.
  • Refrain from applying pressure. Never force the drill. Allow the bit to do its job.
  • When possible, refrain from drilling on edge. Instead, opt for the center because it has a strong resilience.
  • Always drill with slow speed. Drilling at a faster speed is more likely to build up heat and eventual shatter.
  • Use a shock absorber under the glass. The shock absorber can be a rubber pad, cardboard, or even a folded towel.

Can you drill a hole in glass with a regular bit?

Yes! Theoretically, you can drill a hole in the glass with a regular bit, but it requires a lot of work and dedication. Moreover, the results are mainly poor. When drilling into the glass, I prefer using diamond drill bits.

Can you cut glass with a soldering iron?

Yes! You can cut the glass with soldering iron, but most likely, it will crack. Moreover, it also requires a lot of patience and experience.

Can you melt glass with a torch?

N0! You can not melt the glass with a torch, but you can mold it easily. This is because the torch can only reach the temperature to 900-degree Celsius, whereas glass melts at 1400-degree Celsius.