I needed to make some gutters for rainwater collection on my greenhouse. I decided to use PVC Pipe. After thinking about it for a while and looking through youtube for a way to cut it straight, I came up with this simple method. Use the fence on your table saw and clamp a 2x4 on the other side of the blade. There should be an equal distance between the blade and either side. Keep the whole rig snug but not so tight it binds the pipe. This holds the pipe pretty well. If you can cut all the way through in one pass this is better. If you have to do this in two passes, you should lower the blade as far as you can. The pipe wants to close up after being cut and this will bind a blade that is exposed too high.