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Originally Posted by ChrisH
Last week I posted a question and got no response so I'm going to try one last time. So now that I've got you attention:
Does anybody know what the tooth profile is on the final gear in the Fisher-Price gearbox?. The best I can measure the pitch is 14. But what is the pressure angle? It looks to be more than 20deg.
The first person with a correct response will recieve, absolutely free, a custom encoder gear to use as you see fit. Correctness will be determined by the mesh of a fabricated gear with the FP gear. Partial credit if you can tell me how to figure out what the pressure angle is with a pair of calipers and not much else.
ChrisH
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Chris,
I seriously doubt that it is a 14 DP. It is almost certainly 20 deg pressure angle.
What is the OD? To first order, the OD is (2+Nteeth)/DP Does this match up.
I confess that I don't have the gear in hand so I can only advise.
From talking to the folks at Fisher Price (several years ago, when I was explaining FIRST and begging them to donate motors/gearboxes) I am fairly sure it is an English gear, that it is not modified (enlarged) and that it is a standard 20 degree pressure angle gear. But... ...time passes, perhaps they have gone more exotic designs.
I wish I had more for you.
Joe J.