# Need help choosing a high torque stepper motor



## jdebott1 (Nov 28, 2012)

I built a ShopNotes Router Milling Machine which I now wish to turn into a CNC router lathe.

The router is mounted on a carriage that moves with a 1"-5 acme threaded rod and 1"-5 nuts.

I need to find a high torque stepper motor that can turn this large rod, and a suitable coupler.

Can anyone offer guidance and suggestions on this issue?

Thank you,

Joe D.


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## mgmine (Jan 16, 2012)

Surplus center has a lot of weird stuff.
Surplus Center


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## bloomingtonmike (Dec 13, 2011)

What controller are you going to use? Its Amp rating will help determine the stepper you choose. Since the controllers can be very heap or expensive that may be important before you choose a relatively inexpensive stepper motor.

That being said I use nema23 steppers from cncrouterparts. They are 3.5amp phase 380oz/in of holding torque. It is designed to be driven very well by a G540 or G251x gecko controller. 

He also sells 960oz/in nema34 motors. It did not list amp requirements. Gecko 203 vamp drives would be my guess/choice. 

Ebay has a ton of steppers too. Ahren and cncrouterparts is just a safe bet on support too. Many guys also order from Keling in Chicago.

For the coupler just get the shaft size of the stepper and order a coupler from mcmastercar. A spider design sould work to make up with your rod. Many guys will use a metal lathe and turn down the end of the rod if needed to fit the shaft coupler.


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## jdebott1 (Nov 28, 2012)

Yep, but I need to determine what size I need. This milling machine is a handcrank unit, and with the large acme rod and rotor platform, I'm wondering just how big a stepper I need.

thanks for your reply, though.


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## Noob (Apr 18, 2009)

Bloomingtonmike has given great advice and you should contact Ahren at CNCRouterparts. He would probably be the best one to answer your question as to what size stepper you would need. Look through his site to see what he has to offer and on the "Contact Us" form tell him what you want and also send him this Router Milling Machine Video link so he will have a better idea of what you are building.

He doesn't carry a shaft coupler for your lead screw, but he might be able to lead you in the right direction or you can also check out McMasterCarr shaft couplers after you find out what size the shaft diameter on the stepper is. As stated already, you might want to try Ebay. By the way, it might be cheaper to find someone with a metal lathe to make a coupler for you if you don't have one because so far the attached PDF shows the smallest shaft coupler for 1" is a 1" to 1/2" coupler and I don't know what the diameter on the stepper you are going to use is.


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## jdebott1 (Nov 28, 2012)

Paul,

Thanks for the suggestions. I'll surely follow up on them.

Also, I'm looking at the Lovejoy 1" coupling hub, and I'm wondering if I can buy two of these and them use an bore insert/reducer in one side to fit either the 1/2" or 1/4" shaft of the stepper motor. I think that I will need a substantial size stepper which will have a 1/2" shaft for enough torque to turn the 1"-5 Acme Rod.

What do you think of this option?

Lovejoy 11091 Size L095 Jaw Coupling Hub, Sintered Iron, Inch, 1" Bore A, 1" Bore B, 2.11" OD, 1" Length, 561 in-lbs Nominal Torque, 0.25" x 0.125" Keyway: Amazon.com: Industrial & Scientific

Joe D


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## jdebott1 (Nov 28, 2012)

Mike,

I did follow up a bit on your post, and Paul sent me to cncrouterparts where I'm now looking at their 960oz/in nema34 as per your post. I'm thinking this huge stepper should be enough to turn the Acme 1"-5 rod. I emailed cncrouterparts and will await their reply.

Joe D.


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## neville9999 (Jul 22, 2010)

*Router Milling Machine*



jdebott1 said:


> I built a ShopNotes Router Milling Machine which I now wish to turn into a CNC router lathe.
> 
> The router is mounted on a carriage that moves with a 1"-5 acme threaded rod and 1"-5 nuts.
> 
> ...


Joe can you post a photo of your Shopnotes Router Milling Machine please. NGM


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## jdebott1 (Nov 28, 2012)

Neville,

Yep, milling machine photos in my uploads already. You'll see that I removed the gears and run it with an old garage door motor now. I've wired it up so that it's reversible. That way I can control the rotation for cutting left and right edges with the router bit. Gives me a very smooth cut and finished edges.

Joe D.


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## bloomingtonmike (Dec 13, 2011)

jdebott1 said:


> Neville,
> 
> Yep, milling machine photos in my uploads already. You'll see that I removed the gears and run it with an old garage door motor now. I've wired it up so that it's reversible. That way I can control the rotation for cutting left and right edges with the router bit. Gives me a very smooth cut and finished edges.
> 
> Joe D.



Ahren sells gears and belts to work with his steppers too so you could gain torque that way as well. I am definately thinking a nema23 geared correctly would more than drive your machine. With a 3.5 ampstepper you could research a much cheaper controller as well. 

Which leads me to the next question - do you want precises control of the revolutions via software or just motion? Are you planning to use a post processor?

What is your goal with using a stepper?


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## jdebott1 (Nov 28, 2012)

Mike,

My goal is to use the stepper on x and z axis (I'm told those 2 are for simple router turning with the piece spinning independently) to control depth and motion. 

I have contacted Ahren and they are helping me pick out a suitable nema23 and gear setup for the x-axis (1"-5 Acme Rod). The Z-axis is a simple 1/2"-20 standard threaded rod and will have just a stepper and coupler. The greatest diameter I can turn on this milling machine is probably 6", so I don't see the need to replace that steel rod now since I believe it will be adequate for my simple needs.

If I can get this all working properly, then I will add a third stepper to turn the workpiece for more intricate design work. But, I will also begin to look for designs of platform CNC's that incorporate lathe capabilities as well. I'm hoping that I can end up with just one machine to do cabinet work and lathe turning all in one. I've seen one of these on Youtube (from an Australian company, I believe).

So, those are my goals with the steppers.

Joe D.


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## bloomingtonmike (Dec 13, 2011)

Check out the video I just posted in the 3D printer write up. It shows driving a 4th axis on my cnc machine which could be a lathe or ay device you want it to - 3d printer extruder in my setup. There are some smaller chinese 4th axis lathes out there that would making playing with it fairly cheap depending on the controller you have for your bed/cnc router. 

Do you plan to control the Z with gcode was my real question when using a stepper or do you plan to operat it manually? If you plan to use g code then really you will need to control the router motion and rotation too which is the same axis correct in your shopnotes mill?


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## jdebott1 (Nov 28, 2012)

Mike,

I'll watch all your youtube videos today.

The Z-axis (router) will be controlled by a second stepper. X-axis is the rod, router z-axis. Y-axis will turned by the garage door motor via rheostat, reversible and controlled by the Arduino Uno.

I may decide to go with a third stepper on the Y-axis at some point.


If this works like I plan, I will begin researching to build a platform CNC with lathe capability so that I can have an all-in-one unit. The milling machine will then just be used to round stock and general leg/center post work.

Thanks for you guidance, I've found the belt drive unit on eBay that will match with the stepper for the acme 1"-5 rod.

Joe D.


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## kolias (Dec 26, 2008)

Dumpster has good couplings / parts and service at dumpsterCNC - anti-backlash solutions for home and industrial linear motion

Interesting to see why you use 1" ACME and 960oz/in nema34 motors. Quite often bigger is not better


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## jdebott1 (Nov 28, 2012)

Nicolas,

You are correct about the large 960oz/in nema 34 motor. I've been provided with torque calculations and it seems that I will not need one quite that large.

The 1"-5 Acme rod was the requirement in the ShopNotes plan that I used to build this machine. So, I'm trying just to mod what I have and not spend any more than I have to to get this the way I want it.

Joe D.


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## bloomingtonmike (Dec 13, 2011)

jdebott1 said:


> Nicolas,
> 
> You are correct about the large 960oz/in nema 34 motor. I've been provided with torque calculations and it seems that I will not need one quite that large.
> 
> ...


Just had a thought - wonder if someone with a 3D printer could print the coupler if it does not exist.


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## jdebott1 (Nov 28, 2012)

Mike,

Um, print the coupler? So it could be created on a CNC? Is that what you guys use 3D printers for? I was wondering about this.


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## StevePixley (Aug 10, 2012)

you can try with this

1.
MicroKinetics Corporation Stepper Motor Drivers


2.
Stepperhead Universal Machine Tool
Only few were constructed, as home-built kits. More than 50 years have passed since his ideas were translated into metal and, in an attempt to update the Metalmaster and improve its performance, Alan has taken full advantage of recent developments in technology and incorporated a host of new features and control systems.and i think you can also get some idea via this.
Page Title


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## StevePixley (Aug 10, 2012)

Stepperhead Universal Machine Tool
Only few machin were constructed, as home-built kits. More than 50 years have Very less tools are available as home-built kits.Over 50 years back this idea was translated into metal and day by day its going improved.I think you can also get some idea via this Page Title


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## jdebott1 (Nov 28, 2012)

Steve,

That machine is way too cool! Should give me some really great ideas. thanks!


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