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Unread 29-01-2010, 13:31
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Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
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Re: moter tooth size

Quote:
Originally Posted by dodger273 View Post
What is the tooth size of the 00968-9015 Fisher Price motor
I don't have it with me but my recollection is that FP uses English sizes and "standard" forms on all its gears (even small pinions mating with plastic gears-- go figure)...

...so...
  1. measure the Outside Diameter, OD (in inches)
  2. count the number of teeth, N (in teeth)
  3. the Diametral Pitch, DP (Teeth per Inch of Diameter) is calculated as follows:
DP = (N+2*) / OD


It should be something like 24 or 32 or 48 (I am betting on 32 but that is just my memory).

Cheers,
Joe J.

*the 2 is because Fisher Price uses the standard 1.0 X DP addendums for their gears and there are two addendums that go into making the OD of a gear 1 X 2 = 2 .... as an exercise for the reader, if you used the ROOT Diameter what would the formula be (oh, you have to know that the standard dedendum is 1.2 X DP) JJ
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Last edited by Joe Johnson : 29-01-2010 at 15:39.
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