Grigg,

Thanks for the numbers. It's a place to start.

I am even considering making some, cut from .250 or .188 wall thickness box or rectangle. This allows cutting the exact size hole for the axle and then using the desired section height when halving the box material. I wish the material came in 5" width though.

4" box minus 1/4" wall each side leaves 3-1/2" in theory....
U-bolt is 2" ID plus two 5/8" shafts = 3-1/4" so it fits inside.

Now that doesn't leave much at the edges, but the clamp force WILL be directly over the 1/4" thick vertical wall. The u-bolt nut contact area could easily be built up with some plate laminated to the outside edges and the ends could be boxed off for strength.

For now, I will hunt for more elusive parts like yours. LOL

Larry W.

1953 3800 Dually Flatbed