Reddit mentions of Diamond Tile Black Oxide Drill Bit Porcelain 1/2 " Dia

Sorry, this is becoming a bit of a copypasta from me to people, but:

I use this bit, and so far it's worked great, 15 bottles and still going strong.
I constantly spray a stream of water onto the glass at drill point while I work, I find it keeps the glass smoother and less cracking and helps control glass flakes. Key is to take your time and not overpush, but to be firm as well. Balance. Be extra careful when it breaks through, the more controlled you can be when it suddenly gives way, the less it will chip.

Follow the directions on the drillbits, they do help. I also put my bottles into a vise (with padding, so it doesn't scratch or crack them), that way they don't suddenly move while I'm drilling.

I usually find it helps to have a friend hold the water thing for you, either a hose or the sink sprayer or whatever you end up using, because that way you can focus on drilling straight.

After I drill them I always use a little bit of standard pumice to smooth down the edges of the hole and to prevent flaking and cuts.

Good luck friend, I'm sure you'll do fine!

noooo, use this, it will be sooooooooooooooooo much faster than the carbide arrow tips