Noob question

[BGHansen]

Depending on the gear profile you may be able to cut it flat. The tightest inside radii you can cut will be the radius of the cutter.

With CNC your imagination is pretty much your limit. Depending on the gear, you could rough cut it with a larger end mill, then do a tool change to get into the tight corners.

Seems like a lot of clock and hit/miss engine fly wheels use decorative shapes for the spokes. You could CNC the shape, then go convention for the gear cutting.

Bruce

 

[rbahr]

Also considering a 3d printer

 

[AlanB]

3D printing is a lot easier and cheaper to get started with than CNC. The gears won't be as precise or tough but you can do a lot with little noise, dust or space consumed.

 

[spumco]

My budget will not allow me to buy one of each or even a good quality one of either. I

Budgets are frustrating!

Assuming this is the case, I'll advise you not to run out and buy a budget CNC router. You can get a very nice 3D printer for the price of a mostly-junk router. There will be a learning curve for both, but the 3D printer will be making useable gear-shaped parts easier than a sub-$1k router.

If you just want to learn CAD/CAM/CNC, then a really cheap router is fine - as long as you don't expect it to make anything useable as a mechanism. Gears will not be precise (you mentioned Antikythera). But a really, really cheap 3D printer would get you closest to the ballpark first.

Find a local maker-space and try out a router and a 3D printer. See if the two machines can make gears and other bits you need/want to the quality level you desire - then decide which you want.

Obviously, if you want brass gears the printer is out... and you're down the DIY rabbit-hole so many of us tread because we want precise, fast, powerful, and cheap tools.

Final note - what kind of budget do you have in mind? It may be possible to build something that's perfectly capable of machining everything you want at a fraction of 'good quality' price. Depending on skill level and outside resources, of course.

 

[rbahr]

Hi Spumco,

Interesting because my 1st intention was to simply get a 3D printer, and use that, at least to mock stuff up. Then I shifted to perhaps a cheap router / engraver and the rat-hole I found myself in centered around needing a 4 axis machine. I saw one locally for ~ $500 and it was one of these Chinese / Alibaba things and...

I do have a mill and a lathe with a dividing head, so I could actually do the machining by hand - would probably be far better than any cheap engraver would ever be able to do..

I had thought that if I could get some entry level call them 'toys', it might be fun...

I could also build something, would not be to difficult, and in this case, I would prefer building a CNC machine over a printer.

I sorta (but not always) learned some time ago to buy the best you could afford and if it didn't pass some threshold, don't waste your time, this is one of those times...

I may be going back to the 3D printer as it represents a capability I don't currently have

Ray

 

[spumco]

I do have a mill and a lathe with a dividing head

Bingo.

If you want a "CNC" project that would be useful as heck, build a stepper-motor based indexer for the dividing head. There are plenty of good videos on youtube about using an arduino for this purpose. Very inexpensive way to dip your toe in the water with motion control stuff.

Once you build it I'm sure it'll occur to you that "Hey, I could use an output on the arduino to trigger a switch that moves the table power feed back and forth." Couple of limit switches to trigger the arduino start-stop points and you're in business. Would have all the functionality you need of a 4th axis mill for about $100 in bits.

Automation doesn't require G-code or full-blown CNC controls. There are, arguably, more single-purpose "dumb" machines out there making widgets than CNC mills & lathes.

Once you've got the mill paying off your mortgage making buckets of gears, check back and we'll help you design a DIY router that will run circles around anything you can buy from the usual suspects.

-Ralph

 

[matthewsx]

LinuxCNC

LinuxCNC: an open source CNC machine controller. It can drive milling machines, lathes, 3d printers, laser cutters, plasma cutters, robot arms, hexapods, and more.

linuxcnc.org

FreeCAD: Your own 3D parametric modeler

FreeCAD, the open source 3D parametric modeler

www.freecadweb.org

I have a few stepper motors I'll send you that I got from another member when I was starting out if you want them.

Homemade vertical mill/drill CNC project

I'm sure some of you have seen my posts in the general section about this project. https://www.hobby-machinist.com/threads/homemade-vertical-mill-drill.77611/page-3#post-664686 But now that I'm ready to start on the controls I figured it would fit better here (mods please let me know if...

www.hobby-machinist.com

John

 

[vtcnc]

If you are going to focus on flat, thin complex shapes, another option that might work for you is one of these hobby laser cutters. You are limited to thickness and very light materials but it might be the ticket for just starting out.


Sent from my iPhone using Tapatalk

 

[rbahr]

I considered those laser based devices, not sure what I would need for power to cut say 1/8 brass. The lasers grow i cost pretty fast.

Ralph: I have seen those videos on adding a control to dividing heads, I was intrigued at the time, perhaps I will revisit. I would not want to do anything that is not reversible as they seem to have value..

John: Thanks, I will PM my address, glad to pay for shipping.

Ray

 

[spumco]

not sure what I would need for power to cut say 1/8 brass.

You need >150W CO2 laser to cut 1.5mm steel. Even then it's not clean without O2 as a gas - the cuts I've seen look like a poorly-tuned plasma cutter.

The 'hobby' lasers excel at non-metallic materials but for various reasons are not suitable for metals. For metal cutting you really need >1kw CO2 or a fiber laser.

On the other hand, if you can accept plastic for your gears, a decent CO2 laser will run circles around a 3D printer when it comes to dimensional accuracy and surface finish.

If you want to keep your existing dividing head unaltered there are other avenues to an electronic indexer. Like the 4th axis I have sitting under my mill at the moment collecting dust. It's a worm drive 80:1, with a NEMA 34 mount on it. Has a little backlash but that could be dealt with via electronics and a brake.

It's heavy so shipping would be a fair bit, but I'd let it go really cheap. I built a new one based on a harmonic drive as the backlash was driving me nuts, but for an indexing head it'd be perfect.

Add a stepper motor & drive plus power supply. (sounds like John's got you half-covered there)
Add arduino and a little control panel.
Download arduino code from Github - the youtube videos I mentioned generally have links to the arduino sketches.
Edit code to suit your taste and the drive and you'd be done.

Does not currently have a motor on it, so the shipping box would be smaller.