Can You Drill Tempered Glass

Can You Drill Tempered Glass? A Comprehensive Guide to the Process

Tempered glass is not like your average annealed glass. It is known for its strength and durability. However, people often wonder if making a hole in tempered glass is possible without causing it to shatter.

From experience, tempered glass is stronger than standard glass and is designed to shatter into tiny, granular pieces when broken. Unfortunately, this strength makes it nearly impossible to drill through tempered glass without causing it to crack or shatter completely. Some edge work may be possible only with special diamond drill bits and correct techniques.

Understanding the properties of tempered glass can help individuals determine whether or not drilling a hole in it is a feasible option. As we move forward in this article, we will discuss tempered glass, how to identify it, and how it compares to other types of glass in drilling. So, stick around if you want to learn more on the topic!

Can You Drill Tempered Glass?

As someone with experience with various glass types, I want to clarify the common question: You cannot drill into tempered glass. Even though it is stronger than standard glass, drilling through it will cause the glass to completely shatter into tiny pieces or create web-like cracks.

Tempered glass is specifically manufactured to resist breakage and withstand higher temperatures. When subjected to stress, it shatters into small, relatively harmless fragments instead of large, sharp shards, making it a popular choice for safety applications.

The only downside to tempered glass is that you cannot drill holes in it - it is impossible without breaking the glass. Annealed glass can be drilled, but proper tools and methods will be needed. Here is how you can drill into regular glass safely:

  1. Add a piece of tape over the area you plan to drill to help prevent cracking and guide the drill bit.
  2. Use a carbide or diamond-tipped bit specifically designed for glass.
  3. Start slowly and cautiously increase the force, ensuring that you do not press too hard or drill too fast, which could lead to the glass cracking.

This technique works well for annealed glass, as tempered glass will still shatter when subjected to the stress of the drill. It is best to make the needed holes before the glass is tempered.

Potential Risks in Drilling Tempered Glass

milwakie drill

There are many potential risks to drilling into tempered or safety glass. Tempered glass is toughened glass, making drilling through it a considerable challenge.

One of the primary concerns when working with tempered glass is the likelihood of shattering. Due to its manufacturing process, tempered glass is designed to shatter into small pieces instead of large shards when stressed. Drilling into this type of glass may cause web-like cracks to form as it's being pierced. These cracks can ultimately compromise the piece's structural integrity, resulting in the glass shattering before the hole can be completed.

Personal injury is another risk associated with making holes in tempered glass. The shattered glass presents a hazard, increasing the chances of getting cut by the fragments. Drilling can generate considerable heat, which increases the risk of burns. However, using appropriate safety gear, such as gloves and eye protection, is also essential when drilling into tempered glass.

Lastly, creating a hole in tempered glass may weaken the overall structure of the glass. This compromise might lead to further breakage over time, especially if the glass is subjected to temperature changes or additional stress. While it may be technically possible to drill through tempered glass, these potential risks should be weighed against the benefits to determine if they are necessary for your project.

Preparation Steps for Drilling

Before attempting to drill tempered glass, it's crucial to be well-prepared. Here are the necessary steps to ensure a successful drilling process:

  1. Gather the right tools for the job. Since tempered glass is dense and difficult to drill through, you need a special diamond or carbide bit. Additionally, you will need a drill with adjustable speeds, as different glass types and drill bits necessitate varying drilling speeds.
  2. Secure the glass piece to prevent any movement. Use clamps to hold the glass firmly in place to do this. It's essential to be gentle when clamping the glass to avoid causing any cracks or breaks.
  3. Apply a strip of masking tape to the area where you plan to drill the hole. The tape will provide a surface to mark the precise location for drilling and help prevent the glass from chipping when the bit penetrates it.
  4. Keep the diamond drill bit cool and well-lubricated at all times. Regularly dipping it into water will prevent the bit from overheating and ensure a smoother drilling process.
  5. Use appropriate safety gear, such as safety goggles and gloves. Drilling through tempered glass can be risky, so taking necessary precautions to protect your eyes and hands from potential harm is essential.

After taking the necessary preparation steps, you can begin drilling the tempered glass carefully and attentively.

Actual Drilling Process

I must stress again that making holes in glass is not recommended after the tempering process. However, if you want to try the procedure on a scrap piece of tempered glass, here is what you will need to do:

Choosing the Right Drill

In my experience, drilling into tempered glass requires special diamond drill bits to cut through the dense material. It's essential to choose the right drill bit size depending on the thickness of the glass. I recommend starting with a small bit of about ⅛-3/32-inch to initiate the procedure and gradually move to the desired hole size.

Drilling Technique

Regarding the drilling technique, I've learned that lubrication is crucial for the drill bits. To start, I usually mark where the hole needs to be drilled and surround it with clay. That helps to create a small pool for the lubricant to prevent it from spreading.

I then set my drill to a low speed and positioned it perpendicular to the glass. Applying gentle pressure, I start drilling slowly while adding the lubricant to keep the bit cool and reduce friction. During the process, I often stop to check the progress and add more lubricant as needed.

However, it's important to note that drilling through tempered glass is nearly impossible. Drilling into annealed glass is better, as it's less prone to breaking during the process.

Managing Micro Cracks

Actual Drilling Process

You can do a few things if you want to manage micro-cracks while drilling into chemical tempered glass.

First, proper preparation is crucial. Ensure the glass is clean and debris-free to prevent undesired scratching or cracking. Use a high-quality glass drill bit, and maintain a slow, steady drilling speed. Applying lubricating oil to the glass surface will help reduce heat and dust build-up, which can contribute to cracking. When working on a vertical surface, a bit of plumber's putty or modeling clay can keep the lubricating oil in place.

You will want to gently press the bit onto the glass at a low speed, using a small piece of masking tape to help prevent skidding. Gradually increase speed and pressure as you go, but avoid excessive force, as this can increase the likelihood of micro-cracks or even severe cracking.

Using a hybrid micromachining process that combines thermal ablation with chemical machining could also help decrease the chances of surface cracks in the micro-drilling of glass. This process involves using heat to soften the glass. At the same time, a chemical agent simultaneously breaks down and removes the softened material, thus significantly reducing the risk of built-up edges and surface cracks.

While managing micro-cracks during the drilling process may be feasible for certain types of glass, it is not advisable to attempt drilling through tempered glass. Tempered glass is not shatter-resistant, and attempting to drill through it may result in unpredictable cracks or complete breakage.


As you can see, tempered glass has many purposes. There are tempered glass doors, shower doors, car windows, screen protectors for cell phones, table tops, and various other things made from this material. But whatever it is used for, you will not find anyone drilling into it after it has gone through the tempering process.

Attempting to drill through tempered glass will almost certainly lead to glass shattering unless done with industrial lasers. In a DIY context, it is not recommended due to the inherent risks and high likelihood of failure. You should rethink your project or use regular glass to make holes.

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