You make some slick stuff...
Have you already figured out what happened to the gear?
Thanks! Yes, i figured out why it failed. I believe it was a combination of two factors. One, the motor uses a woodruff key (small half moon shape) which does not come close to using all of the keyway of the sprocket. So a lot of torque focused on a small area. Second, the combination of a 7/8" thick motor shaft and a small number of teeth (10), requires that the sprocket be recessed on one side to make room for the chain. This recess leaves very little metal thickness at that point and creates a weak spot. In my case, the woodruff key was directly below the weak spot of the sprocket and it failed.
To solve the problem, I am swapping the 60 tooth rear sprocket for an even larger 71 tooth and the front 10 to a 12 tooth. Larger diameter front sprocket equals smaller recessed area, so stronger sprocket. Both sprockets are larger and the combination yields the same gear ratio as before.
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