I broke up my original model into to seperate parts, the base and the arms. This wasn't because of model functionality, but to simply cut down on the number of supports and make the model much cleaner. As far as the functionality of the Newton's Cradle, it works...(for 3 to 4 hits). The balls simply don't have enough weight to continue to swing. Its looks cool on your desk though.
The base takes a while to print (11 hours on an SLA printer at .050µm). If attempting with an FDM printer, you might want to cut down on the in fill of the base. Other than that, this is a fun, clean print.