I can't believe its been about 3 years since I did lots of updates. But here's more work I've been doing. This center foot took me about 1 month to do from start (have all the parts) to painted and completed.
It don't really take that long to assemble this foot. But it was 4 years ago that I constructed my other foot on R5-D4 and the center foot shell was manufactured different and I simply forgot how the hell this thing is assembled. So I looked up past center foot build and that gave me most of my answers I needed.
Online Metals and orders a steel plat that is .125 by 5x8 inches as shown above. The cost was $4.40 and $6 bucks to ship.
So above is my solution. I went to Ace Hardware and bought a threaded rod that is 10-20 by 2 inches long. Then I screwed the bolt into the cylinder as seen above and dremeled off the bolt until it just has enuff meat for a locknut to fit on. So now the bold easily go into the center ankle and instead you need some tiny fingers to get some locknuts started. Then finish fastening them with a wrench. I don't know how other builders pulled this off, but that's how I did it.
So after both cylinders are on the center ankle you are free to attach the center ankle to the center footshell. That part is pretty easy so no photos needed.