What you’ll need:

• – Printer: Ultimaker 2
• – Rafts: No
• – Resolution: 0.15 mm layer height
• – Infill: 25%
• – One elevator and four tracks
• – Printable without any support

Instructions:

• – Once you’ve printed the STL files place the screw like item through the hole at the top of the marble machine.
• – Place the item that looks like a wheel on top of the hole.
• – Place the last piece on top, tip side down (the dent is for your finger to turn in a circular motion).
• – Place the marbles on the four tracks and watch them roll.
• – Using your finger to turn the top allows the marbles to automatically filter through the machine.
• – Takes 9.5 mm (3/8 in.) steel ball bearings.

Refer to this YouTube video if needed: The 3D Printed Marble Machine #3