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Help making a gear?

Avadon77

Plastic
Joined
Sep 9, 2019
Hello,

Can someone tell me how a gear like this is made? Is something like this machined or is it casted? I'm trying to figure out how to make something similar, although I want a gear machined in steel, metric pitch, more teeth, etc. and I want it to fit on a male servo spline like in the pictures. Just trying to find out if I'm going in the right direction by talking to gear & spline cutting services or should I try to talk to people who cast metals? It doesn't look very rough, that's why I was dubious of it being casted.
 

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It is machined from bar stock. If you just need a few it would probably be cheapest to use an existing gear as the hub by turning it down and fitting it to the bore of your desired larger gear. Making a new gear from bar stock won't be cheap unless you're looking at large quantities to offset the setup and tooling costs.

RT
 
I believe that is almost certainly a rotary broached serration in the center, and a Hobbed gear. Probably a fairly low quality, commodity type gear. That's good news for you, because it means that you can very likely accomplish both in a home shop environment. Make a single point tool to shape the serrations, and a single tooth space mill to make the tooth spaces. (you'll still have to calculate and make a suitable profile of what you desire, though) But yes, any actual gear shop should be able to make you one. Biggest issue you'll run into is the set-up will cost as much (or more) than the gear.
 
Unless you want to make them in the tens of thousands, I strongly recommend buying something as close as possible to what you need, and if necessary modifying from there. It'll be much cheaper, and made by people who know how to make gears.

If you do want to make them in the tens of thousands, hire someone who knows how to make gears, or job them out.
 
See if they have your size:
 
just out of curiosity why steel? only asking because of the brass gear you had in picture. The brass gear is used generally as a shear point to protect more expensive parts. I.E. servo
 
The gear teeth look a little weird compared to standard 20 degree pressure angle gears. It looks profile shifted, usually to get a certain gear ratio within a specific center distance..given the constraint of a standard driven gear.

That being said, the gear material does not matter..usually the current limit of the servo is well under the internal gears strength limit.. no way is the plastic gears in that servo going to break the brass gear in your hand.

If you want to buy nylon gears and then drill the bore out to a certain diameter, them heat up your stock brass gear and press it into the hole.. thats fine, it will work reliably.

If you want a steel pinion smaller than the brass gear shown..for the purpose of a substantially higher torque output.. you may have better luck with miniature planetary reducers for the smallest cordless power tools you can find.
 








 
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