ok, first attempt using sketchup 8

[JAZZCNC]

Also now confused after reading comments on the other post about the "effect of forces on gantry cross sections" and the following was mentioned-

Am i going round in circles

Dean don't worry about it your only cutting wood the box section will easily handle it. The box can resonate but cutting wood it won't really matter or show.
There are also ways around this if it does by filling with sand. So long has the resonance doesn't affect the motors then you won't have problem and because your using belts then this won't happen and why it's good idea to use belts.