My father cut down a glass cylinder once, taking off about an inch. We used masking tape to create the line location. Then we used a thin cutting wheel on a angle die grinder, figured we had nothing to lose right since the cylinder was cracked? We went around in a circle taking a little off at a time, slow going. I thought he was crazy at the time, but it worked just fine. The edge was a little rough but it didnt crack and once it was mounted you couldnt tell the edge was perfectly smooth. Im not necessarily recomending this approach as we've only done it once but it did work.
When you cut glass for stained glass, they usually use water with an abrasive cutter, we did the above dry.
Last edited by Paul Bell; Sun Jan 18 2015 06:51 PM.