Bearcar,
My first attempt at cutting the long lengths of tubing was to use an old bottle cutting set up. Essentially a glass cutting wheel set up with a vee block for the bottle, or tube in this case, to roll. The cutter wouldn't even make a scratch. I read that the mistake most people make is to make more than one score. I was able to score all the way around with a diamond file using the top of my rip fence as a way to support the tube. Thought I had it made, but the break was a mess. Tried the thermal shock method which doesn't work too well since PYREX has very low thermal expansion (that's why it works for hot stuff). The diamond tile saw worked best and probably would work better with a bit of attention to the set up. I think there's a problem on the type of saw I have in that the miter fence rides the rip fence and if you register the tube against the edge of the miter, the piece you're cutting is captive between the blade and the miter gage. Any wiggles and it can/will chip the edge. WRT the idea of using a standard glass cutter on the crossfeed I think you would have to apply so much lateral force that you would risk breaking the tubing. That and I couldn't get a regular glass cutter to touch the PYREX. Yours may be better, but it is still only meant to score the glass, not cut through it and I found a diamond file that I got at HF worked well for creating a single score line but, I was not able to convert the score line to a nice cut/break. I did try an experiment with a triangular diamond file on a piece in the lathe and using water as a lube. I could definitely cut through faster than with the cutoff wheel, but I don't think I could cut effectively to a dimension using that method so some clean up would be required anyhow. I'm sure there are a lot of ways to cut the tubing to length. My mission was more about getting the pieces I needed for the project than it was to optimize the cutting process. I got to a process that was acceptable to me, made the parts and now I'm making the metal parts that I'm more comfortable with. Hope you find a good way to make yours.
