Quote Originally Posted by JAZZCNC View Post
Cheaper yes but it's not better unless it's prepped correctly and even then it's much more resonant. The profile is generally much flatter than box steel which isn't flat in any direction and it's less resonant, it's a lot easier to work with and does the job fine.

Torsion isn't an issue until gantry width gets wide and even then if sized correctly profile works fine for routers.
I was meaning box section aluminium, not steel, I'm aware of the problems with that. The stuff I got was pretty straight, the only error from square was a very slight (0.3mm) but even dip along the middle of the long sides, obviously the die designer didn't get his shrinkage allowance quite right