Here is a pic of the X gantry under construction:
The gantry was built out of 3/4" steel L angle. Lapped over on the ends. Bolted w/ 1 bolt in the corners and a plywood insert set in to stiffen it up.
The X axis bearings were bolted to the angle iron frame with standoffs to bring them to the center of the pipe rails.
Since the base is 46" long 1" pipe would sag too much so I put them on supports and built the base strong enough support it all.
I don't have a pic of the framework under it all but there is alot pieces to the frame and it is all glued and screwed together.
The computer came from my wifes work as they had grown out of it. At some point it was state of the art. They used it for scientific imaging so it had alot of memory for it's time.
Chris