Quote Originally Posted by magicniner View Post
Honest answer, if 9mm is good in that design you can use less, triangulate and make it lighter whilst still being stronger and more rigid.
Or triangulate and make it far stronger and more rigid for little added weight.
I might not be understanding you correctly, but I think you have in mind either gussets between the horizontal and vertical plates, or what I have been imagining, a small vertical detail that connects the horizontal plate with the Gantry, which would fully box in the ballscrew mount and ballscrew. I have been leaning away from that, because the design as is leaves that surface (the horizontal one that the ballscrew mount attaches to) fully exposed on a vertical machining center, making it easy to backside machine. In other words, I am trying to balance the design with ease of Machining these details.

If you can imagine this entire Gantry as one welded fabbed unit, then putting it on a vertical Machining Center, upside down, makes the rail Carriage surfaces easy to machine flat, and then you can back side machine the opposite side, making the ball screw Mount Services flat as well.