Quote Originally Posted by CaptainBarnacles View Post
My original arrangement was 2 off 80x80, one above the other without any bracing. On the feedback I've had so far I think that any of these new arrangements should outperform my original.
Your orginal would been ok if the profiles where bolted together without the gap. The gap wasn't required so bolted together the profiles are stronger.


Quote Originally Posted by CaptainBarnacles View Post
I like A, B and C as they allow the ballscrew to sit in the gap but I know that strength and stiffness are more important.
The gap would just fill up with crap and shorten the screws life. Like wise being exposed to chips is why I don't like open gantry's along with being weaker. The L shape gantry helps protect the screw as it's behind and is also stiffer.

Quote Originally Posted by CaptainBarnacles View Post
E: 1 off 40x160, 1 off 40x80 'L' arrangement with lower linear rail front mounted

E is my current favourite. The only thing I don't like is that the Z axis will protrude out further from the gantry but I think I can live with it.
This would be my choice with the profiles you have.