https://www.youtube.com/watch?v=hBvgi7P-TLY "Marblevator Air" is the latest in my "Marblevator Series" of marble machines. Many fans of the Marblevators Series have sent me links to videos of marble machines that are truly quite amazing. A couple of the videos included designs incorporating "drums", where the marble bounces off a drum surface and into a catch bin. Some of the Marblevator fans went even further and challenged me to design a 3D printed Marblevator that included drums and, well, I was hesitant. However, when my wife and I recently visited the "Paul Boyer Museum of Animated Carvings" (http://www.kansastravel.org/boyergallery.htm), I finally became convinced that I should except the challenge. Mr. Boyer has created some absolutely stunning automata, one of which is an almost unbelievable marble machine incorporating 6 drum heads! We thoroughly enjoyed our visit to the museum, and highly recommend taking the slight detour north of I-70 in Kansas to visit this small yet wonderful museum displaying his extraordinary craftsmanship. If you wish to experiment with different drum head diameters (the included drum head is 50mm) and drum surface thicknesses (the included drum head is .4mm), I have included the file "Marblevator Air Drumhead v0.f3d" which is an Autodesk Fusion 360 export of the drum head design. A few notes about my experience designing, assembling and testing Marblevator Air. A marble machine incorporating drums is challenging to align, operate and maintain; one this small, printed in PLA, is even more challenging. This marble machine works best on a smooth, solid, level surface, such as granite or marble. I found that granite and marble suppliers were happy to give me scrap pieces at no cost (especially after I showed them the prototype Marblevator Air video), and small squares of either are available for purchase online. Completing a Marblevator Air requires a few non-3D printed items as described in the next step, and the 3D printed parts can be a challenge to print (the drum head surface is only .4mm thick and requires a .1mm first layer thickness). Assembly is fairly easy (installing the motor into the tower can be tricky), but alignment requires time and a lot of patience. As usual, I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make mistakes in plenty. Designed using Autodesk Fusion 360, sliced using Cura 2.6.2, and printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended.