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How to Drill a Hole into Glass Without Breaking It

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There are many times where it may be necessary to make a hole in glass for a home project. The main thing often keeping DIY practitioners from doing it themselves is the fear of breaking the glass.

Knowing the correct way to drill a hole in glass without breaking it can expand the amount of tasks you can complete around the house.

Drill Bits for Drilling Holes in Glass

The most important thing to consider when planning to drill through glass is what type of drill bit to use. Standard steel drill bits will not be strong enough to drill a hole in glass. You will need to have (or purchase) a carbide or diamond tipped drill bit.

Various types of drill bits for drilling into glass

Carbide Drill Bits

A tungsten carbide drill bit can be an inexpensive alternative to a diamond drill bit when you plan on using it for only one, or limited, projects around the house. While they do not have the hardness of diamond, their construction helps complete a job like drilling through glass or tile more quickly.

They do break down faster, so in a situation where you will be using it multiple times, a diamond drill bit may be a better alternative.

Diamond Drill Bits

While carbide bits work fairly well in drilling a hole in glass, diamond bits are the recommended tool to keep in your arsenal. Their hardness and longevity keep the bits in good shape for long periods of time. In addition, the way the cutting edges are fabricated create fewer possibilities for cracks in materials like tile or glass.

Safety Equipment for Drilling Glass

When you drill a hole in glass, tiny glass fragments and dust particles are ejected from the material you are drilling. It is highly recommended that you protect yourself from injury using safety equipment and a little common sense.

Eye Protection

Always at the top of our list when discussing safety equipment, proper eye protection is required when you drill a hole into glass. The small shards and dust that fly out of glass when you are drilling or cutting it will easily embed themselves into your eyes, possibly causing permanent injury.

Body Protection

Most surfaces when drilled expel dust that you can easily wipe off your skin. Glass dust, on the other hand, has a sneaky way of making tiny cuts and embedding itself into your skin. Wear gloves and long sleeves to prevent skin irritation and other problems from glass slivers.

Mask

Man wearing protective glasses and mask

When released into the air and breathed into the lungs, glass dust has the possibility of causing a lung disease called silicosis. While this would normally only happen to someone who works around glass dust on a regular basis, it is recommended to wear a dust mask to protect yourself even if only drilling into glass once or twice.

Tools Needed to Drill into Glass

  • Safety Equipment
  • Glass to be Cut
  • Flat Work Area
  • Plywood or Scrap Wood
  • Table Clamps (optional, but recommended)
  • Masking or Painters Tape
  • Stiff Cardboard
  • Felt Tip Marker or Grease Pencil
  • Diamond or Carbide Drill Bits: if the hole is over 1/8”, start with a smaller drill bit than the final diameter.
  • Drill: most home drills will do well in this application. Slower speeds are needed in order not to break the glass.
  • Water or Lubricating Oil
  • Diamond File

Prepare for Drilling a Hole in Glass

The first step is to assemble every tool that you will need in the hole drilling process, and have them readily available in your work area. Always avoid going back and forth to another area when trying to get a job done.

  1. Place the glass to be cut on top of your wood work table, or if using another flat surface that is not able to be drilled into, put down a piece of plywood or other scrap wood first. If possible, try to have that plywood be larger than the glass that you are planning to drill for the best stability.
  2. It is a good idea to protect the glass by lining the plywood with some sort of cushion, whether newsprint, rubber padding, or something similar.
  3. If you have table clamps handy, stabilize the glass and plywood on the table by clamping them down. Do not clamp too tightly!

Make sure that the clamps have rubber ends, or place shop rags where the clamps will compress on the glass. This will help prevent scratching.

  1. Place cardboard on the glass where it is to be drilled, and tape it down. The cardboard will help keep the drill bit from moving around on the smooth glass surface.
  2. Mark the point to be drilled with a pen, marker, or anything you have handy.
  3. Attach a small drill bit. We recommend 1/8″ drill bit for any holes around 1/2″ or smaller, or 1/4″ drill bit for anything larger than that.
Various types of drill bits

Drill the Hole Into Glass

  1. Put on safety equipment.
  2. Begin drilling into the glass using the smaller drill bit. Keep the speed at a very low setting (under 400RPM) and let the drill do the work. At this point, we are just trying to create a pilot hole, or even just a bit guide, for the larger diameter bit.
  3. Once a hole has been drilled through the cardboard and has traveled a small bit into the glass, stop drilling. At this point the cardboard can be removed.
  4. Swap bits so you are using the larger bit that has the final diameter of the hole.
  5. Begin drilling again, still keeping a low rotational speed on the drill. 500RPM is the fastest we would recommend going, but lower is better as long as it is cutting.
  6. For thicker slabs of glass, lubricating oil or water should be used to help smooth out the cutting process and to keep the temperature of the drill bit down.
  7. When you have reached almost through to the other side, it is a good idea to flip the glass piece over and continue drilling from there. This will make for a clean edge on both sides.

After Drilling

Wipe away the dust and any shards created by the drilling process with a disposable shop rag. We would recommend throwing this rag away as glass bits can cause irritation, and they can easily embed themselves in cloth.

To clean up any rough edges, use a diamond file (around 600 grit) to smooth them out. Polishing rags may be used if any inadvertent scratches occurred, but only if there is not any type of coating on the glass surfaces.

This is especially important if you plan to route wires through the hole so the glass does not cut through the electrical insulation.

Finally, rinse the glass to remove any remaining dust.

A hole drilled into a glass without breaking it

Additional Tips for Drilling a Hole Into Glass

  • Do not attempt to drill through safety or tempered glass! These specific forms of glass construction, like you would find on the windows of a car or on large sliding glass doors, are made in such a way that any rupture may cause the entire glass panel to shatter.
  • Do not drill holes near the edge of a glass panel. The closer to the edge a cut or hole is, the easier it would be for the glass to crack.
  • Be sure your drill bit is sharp. A new bit for an application like glass drilling is recommended. This will put you in a position to finish the drilling quickly and cleanly.

Conclusion

Glass can be a temperamental material, so we often shy away from performing work on it that might make our home organization more streamlined. We hope that by showing you the right tools and techniques, you will be able to drill holes in glass and other hard materials without breaking them.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.