Marble run gate
thingiverse
This thing is designed to attach on to pipe insulation, cut in half, 1" I.D., 2" O.D. that is popularly used to create a marble run. Just print it out, put something through the holes for a pivot, and snap it onto the pipe insulation. Rest your marble behind the gate and push the lever to release!
Download Model from thingiverse
With this file you will be able to print Marble run gate with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Marble run gate.