Mark, Thats a good idea and good work as well. I have also always welded a support inside of my frames at the butt joint. I cut mine to fit inside of the joint and rosebud weld the piece of reinforcing plate to both frame members. Inside and outside, or two pieces per joint. Certainly nothing wrong with your "H" beam idea and it should serve you very well.

But now remember guys we are not building "Watches", there car frames. Look at any factory frame you will not find a single weld anywhere, those suckers are all riveted together.

RS