# Noob question



## rbahr (Nov 15, 2020)

Hi All,

I have a couple of projects where I would like to make some gears - I would prefer to use brass and/or aluminum. I have been wondering if I want a 3d printer and settle for plastic, or some form of CNC router.

Thoughts?

Thanks

Ray


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## ACHiPo (Nov 15, 2020)

rbahr said:


> Hi All,
> 
> I have a couple of projects where I would like to make some gears - I would prefer to use brass and/or aluminum. I have been wondering if I want a 3d printer and settle for plastic, or some form of CNC router.
> 
> ...


Ray,
There are much better qualified folks here than me to answer, but didn't want you to think nobody is listening.

What's the application, i.e. will 3D printed plastic gears hold up?  If not, you can look at hobbing or involute cutters.  A CNC would likely work as well.





__





						Gear cutting - Wikipedia
					






					en.wikipedia.org
				




Evan


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## Chipper5783 (Nov 15, 2020)

In selecting what sort of "gears" you want, there are many factors to consider (strength, material, size, . . . . ).  It is difficult to provide any sort of advice when you just want "some gears".  I'm guessing that you want gears from some sort of an application.  Provide more info - perhaps a 3D printer, perhaps a CNC, I made the gears in my avatar picture on a manual mill - etc, many options.

More information please.


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## Larry$ (Nov 15, 2020)

Boston Gear? I've made some gears on the mill, I'm really slow at it. Machine and tooling costs are high.  Plastic printed gears are easily made once you've mastered the process. But you have to buy the machine or have someone else make them. CNC, steep learning curve & cost. W/O  knowing more ....


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## rbahr (Nov 15, 2020)

Thanks all,

The application will be clock-like devices, the 1st project is specifically an Antikythera mechanism - https://en.wikipedia.org/wiki/Antikythera_mechanism

There will be other objects similar in nature. I have considered wood, as well as 3d printing, just uncertain of which direction to go in.

This is also an opportunity to start to learn another skill, 3d printing (CAD + misc) or CNC (CAD + a different misc).

My budget will not allow me to buy one of each or even a good quality one of either. I also don't mind putting sweat equity into this, I have a lathe and mill, and a bit of time 

Ray


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## DavidR8 (Nov 15, 2020)

There is also these folks. 




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						Gear cutting small fine pitch spur and helical gears
					

Gear cutting custom fine pitch helical and spur gears



					www.customgearsolutions.com


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## DavidR8 (Nov 15, 2020)

Duplicate post


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## rbahr (Nov 15, 2020)

Thanks David,

I am pretty sure that I want to be able to do this myself.

Ray


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## BGHansen (Nov 15, 2020)

Gear cutting can be done on a mill with an involute cutter and a dividing head to do the steps between the teeth.  You can do it with CNC, but you'll need a 4th axis which acts as the dividing head. I have a Tormach with a 4th and have cut helical gears with it. The learning curve is a little steep, but if you can follow a cookbook recipe,  you can learn G-code. 

Bruce


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## rbahr (Nov 15, 2020)

Thanks, I was imagining that the gear would lie flat and the bit would cut an outline - guess that is not how it works. I do have a dividing head for my mill...

WRT 'G' code, have been writing software for, as the say, a coon's age, would not expect it to be that difficult.

Ray


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## BGHansen (Nov 15, 2020)

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


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## rbahr (Nov 15, 2020)

Also considering a 3d printer


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## AlanB (Nov 18, 2020)

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.


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## spumco (Nov 20, 2020)

rbahr said:


> 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.


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## rbahr (Nov 20, 2020)

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


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## spumco (Nov 21, 2020)

rbahr said:


> 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


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## matthewsx (Nov 21, 2020)

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


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## vtcnc (Nov 21, 2020)

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


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## rbahr (Nov 21, 2020)

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


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## spumco (Nov 21, 2020)

rbahr said:


> 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.


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## rbahr (Nov 22, 2020)

Hi Ralpf,

Sent PM - How much would you like for this shipped to 01741?

Thanks

Ray


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## spumco (Nov 22, 2020)

PM received, email attempted but bounced.  Left msg on profile.


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## rbahr (Dec 6, 2020)

Hi All,

Did a bunch of research, and actually bought a 3D printer. Only AFTER I got it, did I check out the health issues, and bottom line not good, at least for me! Soooo, I returned it, and decided that what I absolutely need is a CNC Taig mill. They seem to be slightly better than the Sherlines, and a bit cheaper.

Will get something used, unless a killer sale happens!

Thanks

Ray


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## AlanB (Dec 7, 2020)

rbahr said:


> Hi All,
> 
> Did a bunch of research, and actually bought a 3D printer. Only AFTER I got it, did I check out the health issues, and bottom line not good, at least for me! Soooo, I returned it, and decided that what I absolutely need is a CNC Taig mill. They seem to be slightly better than the Sherlines, and a bit cheaper.
> 
> ..



Better research the ozone from the motor, the smoke and VOCs from the lubricants and chemicals, airborne particulates from the cutting, electrical and magnetic radiation from the electronics, motor and wiring. Then add all the physical mechanical dangers of flying cutter shrapnel, red hot razor sharp chips and sharp spinning cutters. Most every shop or maker activity has toxins and risks. Even sawdust is toxic. Part of the activity is learning how to handle the hazards. The mill is no different than the 3d printer (though the mill has more hazards to deal with). Each can be a danger to the untrained and inexperienced. Each can be managed.


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## rbahr (Dec 7, 2020)

Yep, I get the point, The 3D printer requires on the order of MERV 17 filtration with activated charcoal. This turned out to be more trouble and cost than I want to deal with, I already have sensitivity to the oils and VOCs which I manage with respirators. My wood shop is running MERV 13 filtration on the cyclone, and MERV 12 for the air scrubbers. I wear a P100 dust mask when I am working with wood, painting or finishing is done outside with a respirator. I wear glove when working on cars,respirators when dealing with some chemicals, some I will avoid altogether - pretty much anything ending in 'ene' 

My point is that I am aware of mitigation techniques, but it is not in the budget to solve the 3d printer problem, which seems to be largely ignored by many.

Ray


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## Boswell (Dec 7, 2020)

The good news about 3d printing is that it can do it's thing without you being in close proximity. Perhaps you can setup the printer is a seperate location? Also there are many different filaments to use with 3d printing and each will have it's own off-gas profile. there might be a filament that is less of a problem for you.  I know you have done a lot of research on 3D printers but just wanted to be sure these things are on your radar.

Good Luck


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## AlanB (Dec 7, 2020)

It is extremely dependent on which filaments are used in the 3d printer, and many other activities like cooking on gas or electric stoves, printing on a laser printer or burning a scented candle produce similar VOCs. The most popular filaments are PLA based and those produce the lowest emissions and are biologically compatible being vegetable based and commonly used in medical procedures. Filaments like ABS need to be done outdoors or with more exhaust control, not only are the particulates orders of magnitude higher they are not healthy to breathe.


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## rbahr (Dec 7, 2020)

What I found was that in addition to the VOCs that there were particulates on the order of <.3 microns. Yes the filament material has a lot to do with the quality and quantity of emissions, but I decided that I would just not bother. A good fume hood, vented outside would go a long way, but that would require managing the ambient temps of the printer as temps have an effect on quality. WRT 3D printing, I will wait for proper 'guidance' from the smart folks who do that stuff.

At this point, I will just focus on CNC as my next learning opportunity


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