Drilling Through Tempered Glass: Is It Possible?

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Cutting and drilling glass can be intimidating, but many artisans embark on projects that require the correct techniques. But before you start drilling, you’ll need to know which types of glass you can pierce.

Unfortunately, it’s not possible to cut or drill through tempered glass. It is compressed on the exterior and compacted in the center, causing it to shatter into tiny, round shards with a lower chance of injury. It’s possible to drill through annealed and laminated glass with the proper techniques.

Don’t worry if you’ve never cut or drilled glass before. There’s a lot to consider and learn ahead of time. Thankfully, we cover everything you need to know and safety instructions in the article below. Read on for more information.

What is Tempered Glass?

Sheets of Factory manufacturing tempered clear float glass panels cut to size

Tempered glass, often called safety glass, is heat-treated and engineered glass four to five times stronger than standard options. The reason it’s called safety glass is because of its durability and how it breaks.

Tempered glass is compressed on the exterior and compacted in the center, causing it to shatter into tiny, round shards with a lower chance of injury.

The material is often used in commercial interiors, like museums, stores, offices, and restaurants.

Can You Drill Tempered Glass?

Unfortunately, it’s impossible to drill holes into glass after it’s gone through the tempering process.

Tempered glass is incredibly durable and designed to break into tiny, granular pieces instead of sharp shards. So if you decide to drill into the glass, it won’t break easily and will create web-like cracks if pierced.

Because of its durability and safety, tempered glass is often used in car windows, showers, glass doors, and screen protectors.

Which Glass Types are Drill-Proof?

There are different types of glass, like tempered, annealed, and laminated. Some of these materials cannot be cut or drilled, even with the correct drill bits and equipment.

You Cannot Drill Tempered Glass

It’s impossible to drill through tempered glass, as it’s stronger than standard glass and designed to shatter into tiny, granular pieces.

If you decide to drill into the glass, it won’t break easily and will create web-like cracks if pierced.

You Can Drill Annealed Glass

Annealed glass, or float glass, is a common material softer than tempered glass. The material can be edged, polished, drilled, and cut for various projects. When annealed glass breaks, it shatters into large, sharp pieces with a higher risk of injury.

Annealed glass is typically used for tabletops, cabinet doors, basement windows, or applications where safety isn’t a significant concern.

You Can Drill Laminated Glass

Laminated glass is another variety of safety glass that stays intact when broken. The material remains intact thanks to the plastic interlayer between two sheets of glass.

It’s possible to drill or cut laminated glass with the right tools and equipment. However, the material can create web-like cracks under pressure, so proper drilling techniques are essential. Laminated glass is typically used in auto windshields, skylights, and hurricane-prone areas.

How to Choose the Right Drill Bit

Although you can’t drill tempered glass, you can cut holes into annealed and laminated glass with the right tools. Drill bits suited for boring glass have spear-shaped carbide or diamond tips.

Spear-shaped drill bits (on Amazon) are sharp enough to pierce the glass without harming it. Carbide and diamond-tipped bits are sharper and have a higher risk of breaking and chipping the glass.

You can find glass-boring bits in various sizes at most hardware stores or online. You’ll want to use smaller drill bits, around ⅛ inch or 3/32 inch, for creating pilot holes. Larger bits are best-suited for drilling the finished opening you wish to make.

How to Prevent Your Glass from Shattering

Man working at factory manufacturing tempered clear float glass

It’s impossible to cut through tempered glass, but you can drill and cut other glass types. However, several considerations must be considered before drilling to ensure your glass doesn’t shatter or cause injury. Here’s what you need to know:

Use a New Drill Bit

Avoid old, dull drill bits when working with glass. The glass is more likely to shatter or break when you use an older drill bit.

Not only will this set your project back, but it can increase the chances of injury. Instead, consider a new, sharper drill bit for your glass projects.

Support the Glass While Drilling

Ensure the glass is supported on a flat surface before you start. Glass will almost always shatter if the surface isn’t flat.

Be sure the glass is secure beforehand with a cushion or towel underneath to reduce the chances of breakage.

You can also use a wet towel underneath the glass to reduce heat and the chance of shattering.

Avoid the Edges

Avoid drilling near the edge of the glass to prevent shattering and breakage. It’s advised to maintain ¾ inches from the border. If you drill too close to the border, you won’t have enough support, increasing the shattering chances.  

Avoid High Temperatures

Glass heats up when it’s drilled, which can cause safety hazards if you aren’t careful. To avoid breakage or injury, you’ll want to be conscious of the temperature. Use water or lubricants to maintain the temperature.

Alternatively, you can place a wet cloth under the glass to support it and keep it cool. Be sure also to spray water over the glass when drilling.

Safety Tips

Drilling through glass is possible and necessary for some projects. However, it can be dangerous if you aren’t careful or practicing proper safety measures. Here are some safety tips to avoid breakage and injury.

Wear Safety Equipment!

Glass can easily shatter into sharp, jagged pieces when drilling or cutting it. So ensure you wear safety equipment, gloves, and goggles before starting. You should also consider wearing a mask, as it’s possible to inhale glass dust.

Start with a Small Hole

Start your glass project with a smaller hole and drill bit. You may want to use a smaller drill bit around ⅛ inch or 3/32 inch.

Afterward, you can use a larger drill bit to finish the final hole. Not only will this reduce the chances of breakage, but injury as well.

Increase Drill Speed Slowly

There is no need to rush when drilling a hole through the glass. Going too fast can cause the glass to break and increase the likelihood of injury.

First, create a small dent in the location of the final hole. Afterward, you can remove the cardboard or rubber pad used to stabilize the glass from underneath the glass. Then, proceed to drill a bit faster at around 350rpm.

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