[mayhugh1]

I'm getting ready to get back into my shop to continue work on my V4 engine project since the Texas heat here is finally starting to die down some. I usually work on larger outdoor projects during the summer, but this past summer I designed and built a piece of kinetic art in a rear corner of our yard that you might find interesting. A Youtube video that I made of it running (during a rainstorm, in fact) is located here:

[nomedia="http://www.youtube.com/watch?v=a7tD3K_YKBc"]YouTube - Kinetic yard art.MP4[/nomedia]

The two spinners are 54" in diameter and the whole piece of art is fabricated from 303 stainless bar and .030" copper sheet that I have had laying around for some 20 years. Each spinner rotates on a pair of sealed ball bearings and the whole assembly rotates on a pair of radial/thrust ball bearings. I was able to achieve a balance such that 5 grams of weight on any arm will cause either spinner to rotate a quarter revolution to a stable position at the bottom of its rotation.
The interesting part from a machining perspective, though, might be the way I formed the compound copper cups at the ends of the arms. I used SolidWorks to design the positive half of the mold and then mirrored it with a .060" offset to create the negative half. Sprutcam created the toolpaths. The mold halves were machined from glued up blocks of red oak that I had laying around. Total machining time was about 1 hour per side as I was able to feed close to the limits of the machine. I had plastic garbage bags taped around the workpiece to keep the wood shavings from making a mess in the chip tray. And the cutter inadvertently caught one of these and made things exciting for a while. After annealing the copper blanks with an acetylene torch I used my homemade 20 ton press to press out the 16 cups. The cups are about 17" long by 6" wide by 1.5" deep. The mold was also used as a drilling jig for the fasteners that secure the cups to the SS arms. - Terry