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Originally Posted by M. Krass
or "How I Need to Make A Turntable That Will Not Bind."
So, I am in the midst of designing a mechanism that rotates about a vertical axis and I'm worried that the enormous attached moment arm will cause binding in this vertical pivot joint.
McMaster-Carr shows needle roller bearings that are rated for 1900+ lbs. of thrust, but I assume that is assuming even thrust on the washers at each end of the bearing. How does an uneven load affect the performance of such bearings? Are they a viable solution for this problem, or is there some other method that's commonly used for supporting vertical axles under torque load?
Attached is a graphic and, by circumstance, a vague look at the arm design. I hope it makes my concerns clearer.
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Well, the easiest thing to do is to support the shaft by two bearings that are spaced a good distance apart. Then, instead of one bearing that has to take a large moment, you have two bearings that each have to take a small force. This is the principle behind why doors always have (at least) two hinges. If you only had one hinge, it would have to take a tremendous moment. But if you have two hinges about 6 feet apart, each only has to support a few pounds of radial load.