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How can I drill a hole in tempered glass without shattering it? Is it even possible? The hole only needs to be around 1/4" in diameter, nothing crazy huge.

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    Tempered glass can be cut with industrial lasers (at least the thin stuff; this is how they make those tempered glass screen protectors for phones), but nothing you would be able to do DIY, or even something your local glass shop would likely have. Large tempered glass products are usually cut before the tempering process.
    – QuantumRipple
    May 6, 2016 at 20:30
  • What if you use a laser cutter, a high pressure water cutter, or a hot steel rod and melt a hole through it? What if you epoxy the surface of both sides and drill through the epoxy and glass, so the epoxy will keep it intact?
    – Chloe
    May 6, 2016 at 21:04
  • I wonder if any type of cutting/drilling would increase the risk of breaking the glass regardless of whether or not the cutting was successful. Or at least reducing it's strength properties.
    – Programmer
    May 6, 2016 at 21:17
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    This guy tries carefully, see what happens: youtube.com/watch?v=qvRgklsm6so
    – Aaron Hall
    May 7, 2016 at 1:45

6 Answers 6

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You can't. The tempered glass will completely shatter if this is even attempted. If you absolutely must have tempered glass with a hole in it, the hole or any other shaping must be done before the tempering process.

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  • I kinda had a feeling this would be the answer...thanks for clarifying!
    – Programmer
    May 6, 2016 at 18:21
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    Tempered glass is treated such that the inner layer of glass is compressed by the hardened outer layers. High powered lasers can simultaneously vaporize and harden at the vapor surface, keeping the inner layer of glass compressed (at least for thin sheets of glass); but, any technique likely available to you will release the pressure of the inner glass. That release of pressure will be fast, causing a fracture; and, as the rest of the glass releases its pressure, the fracture will propagate until the entire inner layer is shattered.
    – Edwin Buck
    May 7, 2016 at 5:05
  • This would have been very helpful three hours ago...
    – George Mauer
    Oct 6, 2018 at 21:57
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You cannot cut or drill heat tempered glass. Not waterjet, not laser, not hot needle, not under water. Physics, not technique. There is no secret formula for cutting or drilling tempered glass.

You can do edge work if you are careful, but you are weakening the edge substantially in doing so. IF you don't remove too much glass it may not break.

If you think that you have cut or drilled tempered glass, you are mistaken, you have not.

Tempered glass is made by heating the glass to near melting point and then rapidly cooling the glass surface. When the glass is hot it expands, when you cool the surface it contracts while the hot center remains in an expanded state. This results in a surface compression layer and a center layer in tension. If you pierce the boundary between the layers you will have a pile of little glass cubes where the solid sheet used to be.

I test tempered and laminated glass for a living. In fact, there is a high-speed tempering line manufacturing tempered glass as I type this, less than 150 feet from where I am currently sitting.

The ultra thin glass used in cell phones (and so on) is chemically tempered in a very shallow surface ion exchange process (replacing the surface sodium ions in the glass with potassium ions is one example of ion exchange) and that glass can be cut unlike heat tempered glass.

Chemical tempered glass is not used in normal windows, cars, etc. It's used in specialty applications.

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    Chemically strengthened glass obtained by ionization is not considered tempered by ASTM because it will break similarly to annealed glass, where the stress is evenly distributed throughout thermally tempered glass causing the finer break patterns.
    – Steve Buzonas
    Aug 13, 2016 at 21:02
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Yes, you can. You can't exactly CUT a hole, but you can GRIND a hole, if you're gentle and patient.

This feller demonstrates grinding tempered glass.

About half-way down this page, "sammiesoo" claims to have sand-blasted and ground tempered glass before.

This forum also discusses methods for grinding tempered automotive glass.

So the answer is hardly "no," but rather "it might not be worth it."

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    Grinding an edge is not the same as drilling a hole.
    – mustaccio
    May 7, 2016 at 1:26
  • While that's certainly true, I don't have any reason to believe that those differences are relevant.
    – mHurley
    May 9, 2016 at 13:41
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    @mHurley: do some reading and you'll see there are plenty of reasons that the differences are relevant: en.wikipedia.org/wiki/Prince_Rupert's_Drop
    – whatsisname
    May 9, 2016 at 19:19
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I'm going to go with the first comment and say that it's not possible. Tempered glass can not be cut, scored or sandblasted. Doing so will result in the glass shattering. Laminate glass can be cut, tempered can not.

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Glass that has undergone thermal tempering cannot be cut; however, it can become annealed once again.

Tempered glass can be annealed in a kiln around 900F, varying depending on type of glass. Once slowly lowered to room temperature (~8 hrs+), annealed glass can then be cut and tempered if desired.

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  • What you've described is to 'un-temper' the glass in order to cut or drill it - but then what? You're not going to be able to re-temper it...
    – brhans
    Aug 14, 2016 at 2:44
  • If you have a kiln capable of annealing, you may be able to temper again as well
    – Steve Buzonas
    Aug 15, 2016 at 8:21
  • @Steve Buzonas It takes a lot more than a kiln! You would have to support and air-cool an extremely hot sheet of glass.
    – Technophile
    Dec 4, 2018 at 5:20
  • @Technophile when using a kiln in a home setting, it's common to do the cooling via heat transfer to some sort of stone. Generally by placing the glass on room temperature stone once removing from the kiln.
    – Steve Buzonas
    Dec 4, 2018 at 20:43
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You can. Yes, the tempered glass will completely shatter if this is even attempted. But if you can use a steel needle or stylus absolutely thin and spikes, you can. Then placing a hard wood behind the glass you must use the stylus very gently tapping with a hammer. After a long time, you can drill a hole. Necdet Ekin

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    You said "You Can" immediately followed by "the tempered glass will completely shatter if this is even attempted". This answer contradicts itself as currently written.
    – Programmer
    May 6, 2016 at 20:30

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