I thought this might help someone looking for the blank plastic ball transition piece for a Williams/Bally EM. Since I couldn't find someone that makes them, I made my own.
A jig saw and a new straight fine tooth blade are a must for this.
I remade part #C-434-4 (incomplete part number) for a triple action machine.
Menards or home depot for the acrilyc/Plexi. $6.
I made a cardboard template by tracing the old part and then transferred that to the Plexi.
A piece of 220 grit sandpaper for smoothing and shaping to the exact profile of the old part.
I hope this helps someone.