With this simple jig, you will be able to make perfectly square cuts for your PVC projects. It is made for use with a standard hacksaw. When solvent welding PVC pipes, square cuts are the key to creating a strong joint which will hold pressure. This jig was made for cutting schedule 40 2'' diameter PVC (2.375'' outside diameter). I will create jigs for other sizes as I need them, but I'll be happy to add any sizes from requests.

UPDATE: added jigs for schedule 40 pipes in the sizes 1'' and 4''. The large 4'' jig is designed to just fit the build plate of a replicator 1. I tightened the tolerances a bit, but have not tested the new sizes, please report any issues.

I printed in PLA with 2 layers and 10% infill. Just about any structural configuration should do. Reorient the model so the base is on the bottom (duh) so you don't need support. To use, measure where you want to cut, hold the pipe firmly in the jig, and saw away.
UPDATE: If you are having trouble keeping your pipe in place while cutting, printing a second jig will allow you to keep the pipe level with the jig while you cut.