I spent most of today working on the machine, just like yesterday. Got a lot done.
I got the Y-axis carriages built and mounted, and most of the X-axis rail built. I also got the X-axis carriage assembled, but not yet mounted, as the glue was still drying.
The carriages are all assembled out of MDF, secured with 12" pieces of threaded rod. The threaded rod keeps the entire carriage assembly under tension, which makes it very rigid.
Assembly of the X gantry is not yet complete. There dosn't seem to be any way to get the T nuts into the 8020 to support the bolts that should go in the empty holes in the upper picture (blue circles). The other snag I ran into was that the bolts highlighted in the lower picture (red circle) were nearly impossible to tighten due to the very small space they are in. I spent probably 20 minutes on each of the four of them getting them to snug up, turning them about 10 degrees at a time.