Working on the middle cross member. It has to provide rigidity in several planes for the radius arm mounts, support the transmission, and be removable. I went with rectangular tubing over bent round tube to match the rest of the frame so far.
The frame is boxed with 0.25 plate and ties the RA mount to the X-mem. The RA mounts are offset inboard for tire max clearance, so the X-mem also has to be to clear the arm heims.
Since the frame bends at the mount point, I used a strip of 1" with a bend to match. Then ground down the ends to allow a flat contact surface to the 45* lower mount tab.
I used my Evo chop to make nice miter cuts. The lower fasteners have captive nuts welded inside. I contemplated boxing the ends fully but it provides little benefit for the weight added.
After some math and verification measurements, I was able to cut the big piece only once and it fit nicely. Trying to get everything within ~1/16" and 1* so everything fits well enough as the pieces come together.
With trans at *nominal* height, I left 1.25" below front yolk. Plan to run a 1350 double cardan shaft. Can notch if needed later for full droop case.
Fully welded on the bench
X-mem is a tight fit getting in but all 8 bolts line up. The holes are not over-sized (right at 0.500) for the 1/2-13 bolts. The fact they fit perfectly even after welding is a miracle for me.
Next step is to fab the transmission mount, which will be adjustable front/rear and be shim-able up/down.
