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.
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.
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.
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."
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.
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.
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