Joe's 1000x600x200 steel and aluminium router started

[Sterob]

I have been thinking about this. I like the idea of placing the rails on the side of the extrusion( for simplicity), but I would like the wider spacing top and bottom mounting gives.( for ridgidity )

How about using 2 smaller extrusions, spaced apart so the ball screw will fit in between them, and use a say a 10mm Ali backing plate to stiffen the extrusions?
That could bolt to the Gantry arms as well?

I guess aligning 2 extrusions may be a bit of work?

Been thought of already?...lol