Hi all, first post here. I have been reading up on this exciting open source product for a few weeks now since I have discovered the capabilities. I am going to be working on a design here soon based on the awesome designs that I have seen (my hopes probably exceed what is "cheaply" possible, but I can expand on that later). First I had a couple questions about strengthened beams. I saw some people using 2 c-beams back to back to create an I-beam to vastly strengthen unsupported spans which seems great for the Z axis where the force is more of a cantilever and the forces from the router are more linear in the X and Y directions. Vertical deflection is just as important on the X&Y axes as well, but there are also more torsional forces involved from the router, the gantry in my head would be the biggest one since the (I think we are calling the bottom axis Y) axis rails are sort of tied together and the cutting forces would be turned into more of a linear horiztonal force. For these cases, wouldn't it make more sense to tie the C-beams together to make a box beam? This may be done elsewhere, but I have not been able to find anyone else doing it this way in my searches. Even for lateral forces, the moment of inertia is 46% higher than a dual C-Beam I-Beam (Sketchup is telling me 703,646.9 mm^4 vs 1,031,956.1 mm^4). Granted, this does assume full rigidity between the pieces in both cases. Unfortunately, it has been a few years since I have graduated and have not been using my engineering degree enough to remember how to calculate the torsional constant, but from "eye-balling it" calculations it definitely would be stronger torsionally. I wish I could put a number to this though. Granted, the downside is you can't use the recess of the C-beam for v-slot wheels, so it makes the machine a bit bigger. And adding onto this tangent, to add even more strength to the dual C-Beam Box-Beam, why not slide a 40x40 channel in the useless void in the middle to stiffen up the beam even more? Granted, Sketchup is telling me the moment of inertia increase is only 7-8% in each direction since all of the added support is so close to the centroid, but added stiffness is added stiffness provided that it doesn't increase the weight too much for the motors to push! At this point, I think we are approaching the size of a 3030 piece of 8020, and that is used on aluminum cutting routers with 48" gantries. Anyways, these are just some questions/thoughts I have had trying to implement the design I am looking to create. I look forward to your comments!