I just know them for joining readyrod/all thread lengths...
A long nut..
https://www.mcmaster.com/threaded-rod-coupling-nuts
Ah, I got you. Duh! Yeah, that would be an easier way to build a hub and make it stronger too. Thank you!
At this point we are leaning towards, if possible, to go with the double flanged hub I linked to with a replacement axle that is longer because that hub is just over a 1/2" wider. We like this idea because it avoids any welding which I've never done and we're tryin' to get this thing rollin' asap. We'll have to also find a suitable hub for the other side with the same bolt circle.
So, that brings up another possible issue. We measured the distance the front wheels stick out relative to the rear wheels and also the difference between each of the rears and found that the front wheels sit more inward and also the left rear drive wheel sits more outward than the right.
What is the optimal arrangement of wheel distances relative to each other, all 4 in line or maybe the fronts a bit inward?