Things You'll Need
Diamond-tipped drill bit for glass
Any number of projects can require drilling a hole in glass block. Glass block is a piece of hollow glass and special tools and procedures are required to drill through it without shattering the glass. Still, with proper technique, drilling holes in a glass block should be relatively easy.
Choose the right diamond-tipped bit for the project. Diamond is the hardest substance on earth and is used for drilling into materials where conventional bits will not do. Diamond bits used for glass are not tapered on the end as most imagine, but are actually flat cylinders. They are available in a variety of shapes and sizes.
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Position the block on the working surface of the drill press. Lower the press with the power off, matching the desired spot on the block. Position the block so you can maintain a firm grip to keep the block from spinning as you drill.
Drill a guide hole. Wearing the safety goggles, turn on the drill press and lower the bit onto the glass block to create a small dimple-like guide hole. Carefully retract the press and verify the location is correct. Cool the bit and the glass surface with some running water.
Complete the hole. Slowly lower the drill press and move it evenly and steadily through the glass block until it emerges into the hollow center. Without moving the block, carefully remove the press and shut down the drill.
Repeat if necessary. If more holes are necessary, repeat the entire process, being careful to leave adequate space between holes to prevent breakage.
If running water is not available at your drill press site, spray water, olive oil or mineral spirits intermittently to keep the bit cool during longer projects. A drill press in not absolutely necessary. A handheld drill can work with the proper bit but has increased risk of creating sudden torque that can crack or shatter the glass.
The glass dust and bits produced from drilling into glass blocks can be dangerous. A dust mask can be used to protect your lungs when working on large projects. Be sure to carefully remove all glass debris from the work area with a vacuum or running water, and avoid contact with skin and eyes.