Reddit reviews SE Diamond Hole Saw Set with 80 Grit and 1/4" Shank Size (6 PC.) - DH6HS

diamond drill bits are useful for that, here

Based on this frequently bought together item that comes up with it, I don't think most people are using this tool to make glasses.

Buy one of these.

Attach it to a drill, and bore through the glass by letting the drill bit do all the work.
Run water on the drillbit while it's grinding through the glass, it prevent cracks from forming.

I'm gunna be a dick and say I told you so. But anyway... Here's a cheap set of bits that will last a long time if you take care of them properly.
SE DH6HS Diamond Hole Saw, 5/32-Inch by 1/2-Inch
http://amzn.com/B000SJ2TL6
You can cut an array of different sized holes with these.
As for the gravity bong idea you should take a look at the product called the kinkajou. It's basically a mounted glass cutter for bottles. If you've got some carpentry skills you can make a brace with your glass cutting tool to cut bottles perfectly. Honestly if you get the bits all you'll need is a hole. Here's a link to a homemade bottle cutter you can make with your glass cutter: https://homemade-modern.com/ep01-diy-herb-garden/

Thanks man :D and I used a 1/2 inch diamond drill bit and the rubber grommet is also 1/2 inch that I got at my local hardware store. Diamond Drill Bit Link

that one seems a bit big, possibly smaller ones are cheaper?

hole saw set - says diamond tipped
http://www.amazon.com/SE-Diamond-Hole-Saw-Set/dp/B000SJ2TL6/ref=sr_1_6?s=hi&ie=UTF8&qid=1334198775&sr=1-6

hole saw - 1 bit 3/4 inch
http://www.amazon.com/DEWALT-DW5582-4-Inch-Diamond-Drill/dp/B000VRBENO/ref=sr_1_1?s=hi&ie=UTF8&qid=1334198775&sr=1-1

dremel kit - must have a dremel for sufficiENT speeds
http://www.amazon.com/Pro-Quality-20-Piece-Diamond-Point-Rotary-Tool/dp/B000MOI9G6/ref=sr_1_4?s=hi&ie=UTF8&qid=1334198775&sr=1-4


ALWAYS MEASURE TWICE and CUT ONCE
I used a half inch spade bit and it kinda cracked my first one

http://i.imgur.com/T9w9t.jpg

Has slide to bottom and then removable bowl
stuff at neck is hot glue for a air tight seal, glass was to thick for gromit that came with the slide


bottle cutter - for other fun things
http://www.amazon.com/Generation-Green-g2-Bottle-Cutter/dp/B004ZRV3AU/ref=pd_bxgy_hi_text_b

Glass Drill Bit

would any drill bit fit a standard drill? i don't have a personal drill, but i'm looking to buy a glass drill bit and borrow a friend's for a diy project with a huge belvedere bottle

i was thinking about getting these http://www.amazon.com/SE-Diamond-Hole-Saw-Set/dp/B000SJ2TL6/ref=sr_1_3?s=industrial&ie=UTF8&qid=1324616893&sr=1-3