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Unread 14-04-2014, 11:28
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Simplicity by Design...
AKA: Tim Miedzinski
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Re: Amount of coupler purchase required on 1/2'' hex?

Quote:
Originally Posted by Oblarg View Post

Coupler is, as mentioned, just a hex sleeve sitting on the ends of both shafts. Not sure how the specifics of the shaft support affect anything, so long as neither shaft is being supported by the coupler (which you clearly wouldn't do with a sleeve on a shaft taking a large load).
What is the OD of the 'hex sleeve'? If it is thin walled I'd be worried. We run a Colson Live Hub in a similar application; albeit not drivetrain. Glad you are supporting the axles such that the coupling isn't taking any load other than torque, this can easily be overlooked. Why not just use a longer shaft?

Quote:
I know that for reference VexPro's gears all have 1/2'' of engagement on the shaft, but I have no idea how conservative that is.
I would say, based on your assumptions and some back of the envelope calculations, that 3/8" engagement would be ok. Would I feel super comfortable with it, probably not - especially something as critical as the drivetrain.
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