Step 4: Finishing the Edges
OK, this is tedious part of the process. Obviously you don't want to cut your mouth every time you use the glass so you have to smooth out the rim.
Professionals who do this for a living will "flame roll" the edges of the glass making them shiny and smooth like a standard glass. Unfortunately that requires specialized tools and you'll want to carefully anneal the glasses afterwards to minimize the chances of cracking and breaking.
** You cannot simply take a propane blow torch and get the edge smooth! If you try it, it will simply crack the whole glass. If you really want to do that, you'll likely need a glass worker's torch (usually Oxygen/Propane).
Using a Dremel tool, I first rough up the sharp cut using a Silicon Carbide conical grinding tip. Oh yeah, wear a dust mask, you don't want to be breathing ground glass!
Roughly grind the inside and outside of the edges using the Dremel. I also placed a strip of aluminum tape around the rim of the glass so that my grinding comes out as even as possible.
Continue to smooth out the edge using drum sanding attachments: I used 80, 120 and 150 grit. I would have used finer grits but that is all that I could find for the Dremel.
After a while, you'll have a fairly smooth edge that although usable, it is still kind of rough. Time to sand by hand using 200 grit sandpaper or finer.
You can keep going with a finer and finer grit, but if you want to finish the glass sometime this year, you'll call it a day after 200 grit.
You can also use a wire wheel on the lip, you'll get a shiny silver edge on glass that actually looks pretty cool.