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Unread 22-08-2014, 15:29
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ToddF ToddF is offline
mechanical engineer
AKA: Todd Ferrante
FRC #2363 (Triple Helix)
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Re: Chain Tensioning

Quote:
Originally Posted by Michael Hill View Post
My instinct says to add more for #25 chain (given the same C2C) because there are simply more chain links and the tolerance will stack up even more.

Also, I'd be curious on the additional Run-out the hex broaching causes to the bearings.
As Matt said, this was done with #25 chain.

We believe the tolerance stack up is due to the following fits:
-sprocket bore to shaft
-bearing bore to shaft

The bearing fit into the bearing blocks was a tight slip/light press, with no observable play.

We tested two lengths of chain specifically to see if the chain itself was a contributor. If it were a major contributor, we would expect the delta values to be somewhat related to the lengths of the chain. Instead, the delta values for the two cases were nearly identical (.001" is probably within the margin of error of our measurements). We concluded that the chain was not a source of the delta.

Another possible contributor could be that the sprocket pitch diameters are undersized. It would take some thinking, and maybe a different test setup to check this.
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