Marble Run 5 by Jim Larsen

Marble Run 5 stands 570mm (22.5") tall and has two auger lifts taking the marbles to the top of the four towers and three tracks to get them down the run. 

Only basic printing skills are required. All of the parts can be printed on a Bambu A1 or similar printer. Everything snaps into place and very little adjustment is required. 

Marble Run 5 was designed around standard children's 5/8" (15.8mm) glass marbles.  About 30 marbles are required to operate the marble run. It is powered by two TT Motors and an optional Speed Controller.

It is a fun and challenging project.  Detailed, illustrated assembly instructions are posted here with the model. Be sure to download a copy before you start your project.