Quote:
Originally Posted by helgy8
1>PVC for the shaft
2>Shaft
3>very little, made of copper piping
4>need bearings for testing first.
What should we use for a bearing
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Depending on the length of your PVC shaft, it's going to bend ... possibly a lot. I'm not concerned about it breaking, though, as PVC is very resiliant, however,This will make coupling on the bottom (away from your motors) difficult since the angle for the coupling will change as your load changes. You may want to also look at the side loading of the drive motor ... most motors/gearboxes don't like side loads.
You may also find that the balls will get hung up in the 'middle' of the Archemedies screw if the balls at the top/bottom of the screw bend the shaft enough to take the load off of the balls at the center of the screw.
My suggestion for a bottom bushing is a flexible metal pin (maybe a spring?), greased up good, that is long enough so that the change in angle does not pull the shaft off of the pin.
I would also suggest something more rigid for the shaft.