Hi,
square box profile is stronger in all directions than I profile so i suggest you make all from square or rectangular profile. Usually for a normal machine i would suggest around 80x80x3mm for all structure.


Find online the tech data of 60x60x3 , 80x80x3 and 100x100x3 and look at the moment of inertia. Compare with the respective I you have chosen and you will see what i am saying. So you will chose then what you need.

Apart from that, i believe me and some people here at the forum have come to the perfect dimensions of most popular various types of table, so better read some build logs and choose what table you like, instead of reinventing the wheel. That same is valid for the gantry.

But my direct advice for your exact drawing will be, use 80x80x3mm only and move the leg profiles inside at about 22% the length of the table, counted from edge. Cause there is where they will do most perfect job.