Well did'nt get as much done as I wanted today, to many unexpected fires to put out. I finished the fixture to hold the gantry to the mill table. Since the gantry is 2" wider than the table I made 2 base plates out of 1 1/4" thick "aluminum to hold the gantry to square the ends and drill / tap all the holes.
I am using a piece of 6 x 6 aluminum angle on each end as reinforcement and a surface to mount the 1/2" side plates to. Everything will be bolted with countersink bolts. I have a nice straight piece of 3 x 12 aluminum channel and want it to stay that way so there won't be any welding. The angle will be underneath and overlap the ends of the channel.