# 0.5 modulus pinion for brp?



## GiantScale (Sep 12, 2002)

I might have found that damn pinion Iv been searching for for my hacker 2.3mm shaft. Its 48 pitch metal set screw available 9-15 tooth for the Trex chopper.

What does 0.5 modulus mean though? Are brp pinions 0.5 modulus?

Thanks


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## RAFster (May 29, 2002)

BRP pinions and spurs are American Inch gear 48 pitch. 
0.5 modulus pinions are the closest Metric pitch equivalent of the pinion gears in American Inch gears. 
The "module" of a metric gear is nearly equal to the "diametral pitch" for an American Inch gear. American gears use pitch when referring to the density of the teeth and pitch angles and the like and it is the diametrical pitch that is the technical term for this measurement. American Inch gears diametrical pitch commonly used for RC cars are 32, 48, and 64 Pitch. Common Inch gear pitches are 16, 20, 24, 32, 48, 64, 72, 80, and 96.
There are several different metric gear standards as well...to name a few: ISO standard, JIS (Japanese Industrial Standards) standard, BSI (British Standards Institute) standard, German DIN (Deutsches Institut für Normung) standard, Italian, French, etc.

The metric gear you have is close to the pitch used by the BRP America Inch gears of 48 pitch. You will probably have a little more gear noise and lose some efficiency, as well as see more wear to the Spur gears (whichever gear is softer). 

The tooth contact area will be different mixing the metric and American gears and it will be important to set the mesh properly. 

While not very straight forward there is a decent online section of info about Metric gears on http://www.qtcgears.com/Q410/Q410Cat.htm

W.M. Berg Company has much better explanations in their Gear catalog. 

I hope this helps some...I know it is confusing. There is a lot of engineering measurements and terms when dealing with gear designs.

RAFster
David


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## k1m (Sep 25, 2001)

I knew we could count on you on this one, David! Thanks

:thumbsup:


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## GiantScale (Sep 12, 2002)

Yes,, thanks. Now Im wondering if I should stick with the BRP press on brass pinions which must be drilled out to 2.3mm since the only set screw type I can find are 0.5 modulus.


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