Quote Originally Posted by F1transportationserv View Post
The table will probably be 75x75x5 square tube and 50x50x5 square tube with a water tray similar to this.

Hang on a mo', stop drawing and start thinking...
You have to support the slats that support the work piece and you have to support them through the water bed. I don't see slat support. A water table 5' x 8' is 40 square feet so every inch depth weighs slightly over 200 lbs. You have to support that to, add some triangles perhaps.
When you weld this thing up it is going to bend. Suggest you do not weld the gantry supports because you will only end up trying to correct the misalignment with a THC. Best if you correct misalignment with screw adjustment or, let the gantry assembly rest on the table so it conforms.
More if you want it...