Forking to a new thread... Here is my current design. I think it is finally almost complete. I just need to align all the parts to make sure all of the measurements are good and there aren't any critical clearance issues. For those that saw the earlier design, I moved the extruders to the gantry to minimize bowden tubed length. This will also add to inertial mass which will further offset/limit gantry movement inertial response. The other greatest change was moving from double to triple v-slot rails on the gantry and on the vertical braces. This change will also add significant inertial mass while also adding stiffness to both the gantry and frame. It also dispensed with 4 triple hole joining straps, 4 angle brackets, and four double angle brackets (which will be replaced by less expensive, non-OB single brackets). So all-in-all the change was actually a wash cost-wise and it simplifies the structure. It also allows the top frame rails to be turned flat, further enhancing frame stiffness and racking resistance. In the front and rear, the triple rail also allows for an enclosure to be implemented by simply sliding a sheet of your desired material (lexan, etc.) into the v-slot! As you can see it also allowed me to place the Z-steppers back on the bottom, lowering the CG and ultimately placing them to be hidden and below a to-be insulated and closed off bottom area where the power supply will be (a single 24V supply as I will be using a 120V heater). I also changed the gantry to a single rail, reducing mass (for added speed) and optimizing the CG. This also let me switch to a standard 20mm v-slot gantry plate which, with only minor modification can be used with mini wheels and will allow the e3d chimera (cyclops pictured - need to find a model) to be directly mounted underneath - reducing wasted build-able area! This will also allow a PLA cooling fan to be mounted underneath without impact build area - double win! Finally, I moved the filament holders on the top so that they can either be inside or outside of an enclosed cube (as desired). Their placement also allows the filament to be fed from the spool through a very short piece of 2x4mm PTFE tube directly into the vertical rail! Another small section of PTFE (which is perfectly sized for the center hole in a v-slot rail) will be used at the bottom rail exit (this one will need to be chamfered at the opening to allow easy filament insertion) and up through the bottom board. As noted previously, this build allows simple expansion to quad extruders with no modification and no impact to build area!!! Any thoughts on the new model???