I've been studying for a while now and I'm taking the plunge. I've got my rail and Z axis. SBR16 1,150mm Y and 800mm X. I'm going to build a torsion box gantry...hopefully very stiff. Here's an overview of what I want to do...
The 800mm gantry torsion box was just a little to large to cut out on my current CNC machine, a Shapeoko2, so a friend cut the pieces out on his very large machine..
Torsion box under construction...
I'm going to cut the torsion box ribs out on my machine and finish the structure. I was tempted to go without the ribs as the box is very rigid like it is, but I'll go ahead. The box is made out of 3/4" MDF and it might be on the heavy side. I have two NEMA23 270oz motors to move the Y Axis.
I'm not an engineer so I don't have a rigidity analysis on the structure, but a lot of the advice I saw here was to go for it, learn a lot, then modify if necessary. That's my plan. The box is alreay more rigid than the Shapeoko2 X axis and my hope was to built a rigid machine capable of aiding me in building electric guitars.