Hi all
After running my extrusion based router for the past year, I've decided to build a new frame using a granite surface plate as the base. I want it to cut aluminum. The one I built does a fair job, as long as you go slow. Very slow. I'm now in design paralysis when it comes to the gantry. The machine will be fixed gantry moving table layout. The base plate is a granite surface plate 24x36x4 inches. The gantry is on the long axis. I'm undecided as to the beam material, steel vs granite. If I go steel, it would be 8x8x0.5 inch square tubing. I think that would be stiff enough. I have most of the details worked out, but it will require some outside machining I would like to avoid, so I'm leaning toward granite. The thickest table top granite I can find locally is 30mm. What about laminating four slabs together with epoxy? Gantry support will be 5x5x0.375 inch sq steel tubing, with 0.5" plate welded each end. The unsupported length of the gantry will be 26 inches.

I plan on moving all the motion parts from the current machine to the new one. I have Hiwin 25mm HGH rails and carriages, 2505 screws driven by clearPath servos controlled by a Masso G2. All these parts work great, with NO issues.

ANY help you guys can give would be very much appreciated!

Ben