Today, I fabricated the front rolling frame assembly. The cross beam is thicker wall that the rear one - it is heavy. I didn't measure it, but the wall is about 3/16" - definitely thicker than the rear one which looks to be about 1/8" wall. When welding the square post to it, I had my little Miller Mig 90 maxed out. While welding, I would sit the end of the nozzle on top of the cross beam and wait and wait, and then kiss the edge of the square tubing and then back over the cross beam... and wait and wait, and then kiss the upright square tubing again. Easily spent 4 to 5 times as long trying to put heat into the cross beam to get penetration. The plates that mount to the car are nearly 3/16" thick. Though the welds could be prettier, I am confident they have good strength.
It will be an exciting time when I get to use these as the car will be really close to being ready for paint. 😍