Caveats for Meshing Gears of Dissimilar Pressure Angle?

[Cothron Theiss]

Originally Posted by Tom Ore

I think if you compare base pitch you'll see if the gears will work together.

Are you referring to the diametral pitch?

[Tom Ore]

Originally Posted by Cothron Theiss

Are you referring to the diametral pitch?

No, base pitch. The pitch diameter and pressure angle are sort of random numbers. You can rate them anywhere you want. Standard gears have standard tooth proportions. If the gears aren't standard, the pitch at the base diameter needs to be the same for both gears (IIRC.)

[InFlight]

Both the normal gear, and these profile shifted pinion gears have involute tooth profiles. In use the pressure angle (and thus the net force vector) will be different than the standard 20 degrees.

The change in pressure angle alters the efficiency somewhat; as the Tangental force turning the gear is a function of the cosine of the pressure angle.

Buckingham's text is 50 years old. Shigley's Machine Design book has been the standard ME text book for thirty years at just about all major US universities.

The fatigue life of these gears might be lower, but it would never be an issue during a single FRC season or two.