Instructables

I need a source for miniature gears fast?

I'm refurbishing some old aircraft gauges and I need a replacement for a very small spur gear measuring .175" in diameter with 12 teeth not sure what the pitch is, and it needs to be made of metal if anyone has any ideas please help me out? I'm kind of on a short deadline here to so I would be grateful for any info anyone can give. Thank you all.

rickharris2 years ago
Brass and a file will work wonders!! DIY
jeffrey4283 (author)  rickharris2 years ago
I wish it was that simple but these gauges are going into a flight simulator that is shipping out on Friday and need to function perfectly for a considerable amount of time.
What kind of speed is this gear running at ? What kind of precision is needed ? What pressure angle are they - would they just have been punched originally ?
jeffrey4283 (author)  steveastrouk2 years ago
I'm not sure and I don't have the measuring equipment here to be able to take good measurements. They're from an old Italian aircraft that was at some point upgraded in America and these are unmarked so I can't even find documentation for them. The precisions has to be fairly high because this turns the encoder inside of the gauge relaying it's position to the simulator computer.
Well, you're in the doo-doo, unless you can get a wire EDM shop local and fast.

Ironically, if you're really, really stuck, I could get it done for you here in the UK, and courier it personally - I'll be in Orlando on Thursday afternoon !

Steve
jeffrey4283 (author)  steveastrouk2 years ago
Very ironic indeed, however i need it by tomorrow ideally. I finally convinced one of my usual local machinist's to take a look at the damaged one and see if they can replicate it so we shall see or maybe my internet searching will bear better fruit or perhaps someone from Instructables. Everyone here has been most helpful and pretty quick to respond to my question.
Try a local "Horologist" ?
jeffrey4283 (author)  steveastrouk2 years ago
No luck there they need to much time. However i may have found a a pinion gear that fits our needs and would only require a bit of machining.
rickharris2 years ago
Many engineering companies could make one for you with a suitable spec. I don't see why you can't DIY after all clocks were made by hand for 100's years before machinery stepped in.

I might be tempted to address a local model engineering club to see if someone with a lathe could do the job ASAP if you can't.
old clocks, there full of brass and iron gears of all sizes. one that winds and not electric will have more gears though
Take a look and see if horology suppliers can help you. Otherwise, you're looking at making one.

Wire EDM would be favourite, and in a thin piece of stock quite cheap. Failing that, you might get away with photo-machining/etch.

Steve
jeffrey4283 (author)  Jack A Lopez2 years ago
Thank you unfortunately they are not small enough for what I need but I really appreciate it.