To make the base for the ball of my prototype trackball I went to Homedpot and got 3″ to 1.5″ PVC bushing and a 3mm Teflon rod from McMaster.com (Damn that’s an awesome site) and assembled them like you see in the picture. This was a complete failure. There is some serous resistance when moving the billiard ball. I tried flat and pointed Teflon nubs with the same result. I am not sure what I am going to use in its place but I am thinking a hard smooth metal of some sorts. Its funtional so i am leaving it the way it is for now.
It never occurred to me to check the pitch of the ADNS-9500, which is a problem since its 1.78mm and almost most everything development or prototype related is 2.54 mm.