Inspired by my favorite artist Arthur Ganson's "Machine with Concrete", see: http://blog.makezine.com/2012/04/25/arthur-gansons-machine-with-concrete
This is a printable version of Machine with Concrete. The sculpture is a series of twelve 50:1 worm gears, with each gear reducing 1/50th of the previous gear. With 12 gears, the final gear ratio is a mind boggling 244,140,625,000,000,000,000 : 1 (244.14 quintillion to 1). With the first gear spinning at 200RPM it would take over 2 TRILLION years for a single revolution at the end of the machine, so the final drive shaft can be embedded in concrete or plaster.
I emailed Arthur Ganson a link to this page and he replied "looks FANTASTIC!". For a great introduction to Arthur Ganson and his work please see: http://www.ted.com/talks/arthur_ganson_makes_moving_sculpture.html
Video of this thing at: http://youtu.be/E7Pw2sD2dHg
Thanks for the article hack-a-day! http://hackaday.com/2013/03/08/printed-machine-does-nothing-until-the-heat-death-of-the-universe/ and Boing Boing http://boingboing.net/2013/03/09/print-your-own-machine-with.html
NOTE: Most of the provided STL files are specific to the bearings and motor I used. If you use different bearings or motor you will need use Customizer.
I used 6202-2RS bearings which are 15x35x11mm. If I had more time for the contest deadline I would have printed the bearings instead. In addition to customizing the size, you may choose between a round or hex shaft, making it possible to use Emmett's Gear Bearing http://www.thingiverse.com/thing:53451
The motor stand can also be customized; just enter in the dimensions for your motor. Note that all dimensions are in millimeters.
The bearing stands are available to print as sets of two or as an individual stand. The sets are nice because it assures the gears are at a perfect 90 degrees to each other. If your print bed isn't big enough to print the combined stand, then choose "Separate Stand A" and "Separate Stand B" instead. If you choose the combined stands, you will need both A and B, as B is a mirror configuration of A.
Print the following:
6 @ Gear A
6 @ Gear B
12 @ Worm Gear
1 @ Motor Stand
1 @ Motor Worm
12 @ Shaft bushings
1 @ Concrete form
3 @ Combined Stands 1
3 @ Combined Stands 2
6 @ Separate A Stand
6 @ Separate B Stand
Then arrange the parts per the assembly diagram. The diagram only shows 2 sets, but the remainder of the sets are installed in the same way.
For me, the worm gears came out best when I turned off my heated build platform (using PLA) and printed on tape instead. Also, I printed them slowly and turned the heat down (~195C).
The motor I used was from a fan. It has 3 speed settings, and I am guessing the slow speed is somewhere around 200-300RPM.
I printed all of the parts to have enough tight fits so that no glue was required. After a light sanding I was able to tap the parts together with a hammer. The tightness of the fit can be adjusted with the "Fit Buffer" parameter. The higher the number, the looser the fit.
A well-calibrated machine will be required to successfully print this machine.
The concrete form size can be customized. I would recommend getting the entire machine mounted, then putting a few screws on your mounting board inside the form area, then poking a hole where the final shaft is. Tape around the bottom parameter. You may also want to place some books or something around the form so that it won't flex from the weight of the concrete. Then pour in place. This is to ensure a perfect fit as the placement of the final shaft in the concrete is absolutely critical. I think a good alternative to concrete is plaster. It's up to you!
I printed all the gears at 100% fill, the stands at 60% fill and the motor stand at 100% fill. The stands are plenty stout, but if I had more time I would have printed them at 100% just to make a really solid machine. I plan on reprinting them at 100%.
If you have any questions or suggestions for improvements, please do not hesitate to comment!