Effect of Forces on Gantry Cross-Sections?

[Iwant1]

How come you didn't make a drawing of how JAZZCNC quoted in your build log.

The 45x90 will be better but I'd put it top & bottom and have the wide bit flat.
This way it ties into the sides better and gives more resistance to bending in lateral cutting directions.,

I've knocked up a drawing of this and also think this is a great way to go.

1. It gives a nice straight guide to fix the profiled rails onto.
2. Using the BK/BF blocks as spacers between the top and bottom extrusions, will help the profile rails being parallel with each other.
3. Makes a nice void for the ball screw to hide in and keeping the z axis close to the extrusion.
4. Better fixing to the gantry side plates by having 4 bolts in both extrusion ends, 8 for both ends.

Cheers