so, with the 4200 nearing being finished , I stopped working on it and started to finish the thumb for the KAT .
I used a 8mm stainless tube and slid a 5mm solid shaft inside to make a fake cylinder , welded a couple of nuts on the ends.
I drilled a couple of holes in the shaft and used a clip of an old rc car to hold it in place, seems to work.
painted and done.
and because I had some paint left over , I decided to paint the cylinders and the 4200, two more to go.
cheers andy