I now have a decent abrasive cutoff saw, cuts at 90 and 45 degrees. I want to
make a frame from 2" pipe, 45'ed at the corners. I'm trying to figure out a
clever way to ensure that when I cut the second end it winds up being parallel
to the first cut end. Probably doesn't matter that much, but I've found that
proper cutting seems to really help in controlling welding distortion, and I'd
really like this frame to be flat (i.e. planar).

GWE