Quote Originally Posted by Voicecoil View Post
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
That is interesting, if the box is square to its corners then it is much simpler to skim it flat on the mill.I would need to buy a length in order to check it in the mill with a DTI, Aluminium warehouse if out of stock.

I'm still interested in looking into constructing the gantry from all this spare plate I have.