Neptune 4 Spool Roller Mod with Printed Bearings

The assembly is simple. Print the parts (1 off for each of the larger components and 2 off for the bearings) and assemble as in the photos. 

If you want to use a steel bearing, you can replace the printed one with an unsealed 609-9-24-7 bearing. A sealed bearing might have too much friction. 

Works well with reverse bowden setup. See link: https://www.printables.com/model/667034-neptune-4-reverse-bowden-upgrade

The other version I remixed from is flawed. The bearings are too small and the shaft is too short. I remodeled the assembly and now it all fits. I also added a printable bearing so that you don't need to buy one. The bearing I borrowed from another make as well.