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# Spur gear help needed

## Spur gear help needed

(OP)
I'm trying to create a mating gear from a supplier. Here's the information the supplier has on it's gear:

Tooth Involute gearing
P.C.D. 0.35 in
No. of teeth 11
Module 0.8

The actual part is from ACE Controls, p/n FRT-C2-301-G1 (just in case anyone needs it). The distances between center to center of the gears I would need to be is 1.18. But I don't even know where to begin to create my 3D part. Can anyone help me with this?

### RE: Spur gear help needed

There are a lot of gear generators on line.

Note that PCD = Pitch Circle Diameter = Module * # teeth, so that is an 8.8mm PCD, 0.3465 inches.

So subtract half the PCD from 1.18 inches to get the pitch radius of the other gear, then double that (in millimeters) and divide by the module to get the number of teeth. I get 52 teeth, rounded down.

### RE: Spur gear help needed

Per my calculation no. of teeth on the mating gear should be 64:
Center distance then will be 0.8*(11+64)/2 = 30mm (= 1.1811")

To create the mating gear more data is needed: pressure angle, tooth thickness, outside dia, root dia...

### RE: Spur gear help needed

Ahh - failed my own advice and did not divide the 8.8mm by 2 before subtracting from the center distance.

### RE: Spur gear help needed

I have checked the ACE Controls' website for the specs. The OD is 10.4 mm and 20°PA. Looks to be a standard metric gear with 0 addendum modification. A decent gear generator should handle this.

### RE: Spur gear help needed

(OP)
Thank you for everyone's reply. I'm still stuck as to what numbers to place where, I suck at this.

### RE: Spur gear help needed

what is the starting input gear rpm and the final rpm of the output shaft?
starting torque, and final torque?
what is the function of the gear train?

### RE: Spur gear help needed

(OP)
I'm not sure a RPM would apply here. So the user will push on a UI screen, which will make the small screen pop out at an angle. After the user inputs some info, the user we'll be able to push back on the screen, and a locking mechanism will lock it down parallel to the rest of the panel. So the ACE control gear damper is just so the screen doesn't pop out harshly. Of course, to do that I needs its larger mating gear. I'm using a pin on a housing of the screen that will have a torsion spring, that's what will make the screen pup out when push on it to unlock it. I hope this helps.

Again, thanks to everyone who's responded.

### RE: Spur gear help needed

Looks like the data needed to create your part is:
.8M 20PA 64T xm=0
Here's one place where you could do this (no affiliation): http://www.me-bac.com/index.php?task=gear

### RE: Spur gear help needed

Now as per my calculation & what has been told in above posts, 2*(1.15-(0.35/2))=PCD of mating gear, which is 1.95 inch.
The module of pinion & gear is considered to be same in many design problems,
No. of teeth=(1.95*25.4)/0.8 = 61.91 approx. 62 teeth(by standards)
Above is normal calculation.

If we go with minimum no. of teeth=(2*Addendum)/((1+((1/G)*((1/G)+2)*sqr(sin(pressure angle))))^0.5-1)
if u take gear ratio as 1.95/0.35=5.57, min. teeth would be around 41(addendum=1) so you should go with 41 teeth to avoid interference with dat center distance.

I would suggest u to go with second approach change addendum & pressure angle based on your supplier requirement, just calculate gear ratio mathematically.

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