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Sam Skoglund
30-11-2016, 20:33
I can't seem to find the pitch diameters of the 32 DP gears from WCP (pinion and 3/8" hex). Does anyone know these numbers? Or is there a way I can calculate them? Thanks in advance!
Cothron Theiss
30-11-2016, 20:37
Number of teeth / Diametral pitch = pitch diameter.
s_forbes
30-11-2016, 20:38
I can't seem to find the pitch diameters of the 32 DP gears from WCP (pinion and 3/8" hex). Does anyone know these numbers? Or is there a way I can calculate them? Thanks in advance!

32 DP means that a gear with 32 teeth has a 1" pitch diameter.

If you want to calculate the diameter for any 32 DP gear, then: (Pitch Diameter) = (# of teeth) / (32)
Andrew_L
30-11-2016, 22:38
Number of teeth / Diametral pitch = pitch diameter.

Alongside this, it's also helpful to know the equation for a gear's outer diameter: OD = (N+2)/DP, where OD is the Outer Diameter in inches, N is the number of teeth, and DP is the Diametrical Pitch of the gear (32, in this case).

Modeling the outer diameter of a gear is helpful in seeing where there's interference with other parts of the robot near the gear.

Unsure if this would be helpful, but I made this video for my students a while back (https://www.youtube.com/watch?v=HdvgUwJ45kQ), and it covers some useful gear calculations.
avanboekel
30-11-2016, 22:43
What kind of adder do teams usually use for 32 DP gears? I know its usually .002"-.003" for 20 DP.
Cothron Theiss
30-11-2016, 22:51
What kind of adder do teams usually use for 32 DP gears?

Two to four thou is a good place to start, but if you use the same "fudge" distance (never heard it called adder) as 20 dp gears, it won't be the end of the world. To be honest, most teams can't hold tight enough tolerances to worry about the difference.

EDIT - WCP suggests adding three thou to center distances, and it's always a good idea to listen to the manufacturer. I don't know how much clearance is added to these gears since that spec is rarely posted. I always suggest a small range so that you can adapt your adder to the application, either high torque or high speed. Course, that's assuming you can hold a thou tolerance on everything.