How to make a ring gear?

[Kirk Rudolph]

During my initial training in the metal shop yesterday, I showed Derek the gears I'm wanting to make. We were both unsure about the best way to make the ring gear. My current strategy would be to broach the gear but I'm curious if anyone has other ideas? A backup would be to purchase a nearly identical gear and post-process it. However, it's not exactly what I need and I want +10 which would start to get expensive quickly.

Also, does the makerspace already have a rotary table or indexing head for the lathe / mill? If not, I think I'm planning on purchasing a BS-0 for all the operations unless there are other recommendations. The BS-0 looks like it'd stand ~10'' tall in the 90 degree orientation and I'd like to verify it'll have enough clearance for a broaching cutter to fit. Does anyone know the mill's model number or how much vertical space it has?

Thanks,

Kirk Rudolph

[Brad Freese]

When I was trained on the lathe last year we didn't have an indexing head for it. I haven't heard of any additions but Caroline would be the one to ask. I also don't know the model number of the mill, not to be glib but I think the easiest way to find that is to look under the tarp.

For what it's worth I've been interested in gear making too, although I have no training in metal working beyond what I've learned at the space. When you get this figured out I'd love to learn how you did it!

[Caroline Longnecker]

What's the application? If it's not too high of a load, the gears could be printed out of a high performance material like a CF reinforced nylon, or you could send it off to JLCPCB or one of those other places to get it printed in metal. The latter might actually be fairly cost competitive with the indexing head or modded prefab gears.

I can't remember if an indexing/dividing head was included with the stuff Ryan gave us for the mill. I haven't given the mill much thought in a while since we still don't have power for it. We have no such tooling for the lathe.

Are you planning to make all of the gears in the first image?

I don't know the exact model or how much vertical space there is, but that's not a very big dividing head. I can't say how much room you'll have for a tool, but as long as the tool isn't excessively long you'll have plenty of room. The bigger issue is I don't think that mill has a spindle lock, meaning it can probably rotate out of alignment in the middle of a cut.

Caroline

--
You received this message because you are subscribed to the Google Groups "Area515 - Des Moines Maker Space" group.
To unsubscribe from this group and stop receiving emails from it, send an email to dsmhackerspac...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/dsmhackerspace/d82f0133-2a4b-4d20-8a56-4d6a3f6bd000n%40googlegroups.com.

[Kirk Rudolph]

Thanks for the help, Brad and Caroline! I'll look for the mill's model number and see if I can roughly measure the vertical clearance next time I stop by.

Looking into other suppliers is a good idea too. PA12-HP Nylon and the 316L Stainless Steel book look reasonable on JLCPCB. I'll probably order a few test parts to see if they're good enough. That'll be a faster way to get a semi-functional prototype anyway. I'm not convinced that additive-manufactured gears are right for this application. I've reached the limits of my 3D printer (albeit an old, cheap printer) and need more accurate and durable parts which is why I was looking into machining.

Yes, I'll need all the gears in the first image. From what I've read, the standard spur gears seem more straightforward to make but information on ring gears is a lot harder to find. Regarding the application, the gears will be housed inside the motor's stator.  There are a few designs like this online. The elevated operating temperatures and relatively high loads eliminate most plastics. I'm a control engineer looking to make some unusual higher-performance motors/actuators for various projects.

Thanks,

Kirk Rudolph