How do i cut glass?

I don't want to cut a sheet of glass i want to cut the mouth end off of a glass bottle. What are the best ways of going about it?

lemonie8 years ago
In addition to kelseymh's good advice:
You need to do this in one go, firm hard scoring. going over the line repeatedly doesn't help and can make things worse.
Also, people do use thermal-shock instead of mechanical stress (not the best link but gives you a general idea)
If you are physically breaking it, take a bit of time to imagine the transition from bottle to broken glass: where are your hands, what protection do you have against being slashed? Think first and you'll find a way to do it safely.

azice (author) 8 years ago
Mucho gracias senior.
kelseymh8 years ago
Use a glass cutter, just as you would for a flat sheet. However, you will need to make a wooden or plastic jig to guide the cutter. Get a small block or board, larger than the neck of your bottle. measure the diameter of the bottle at (or 1/8" below) the point where you want to cut it, and also the diameter as far below that line as the thickness of your board. Drill a small (1/16") pilot hole through the board. Using that as a center, draw a circle the diameter of the top level on one side, and of the bottom level on the other side. Using a hole cutter and a coping saw, you can make a bevelled (conical) hole so the guide fits over the mouth of the bottle and sets securely. Now drop the guide over the mouth of the bottle, and use it like a ruler as you run the glass cutter around and around. Treat the cut edge carefully until you polish it smooth.