Need help building a simple standalone stepper driver box

Hi all,

This isn't specifically for CNC, so I hope it's ok to ask for help here.
I recently bought a Jet 12x36 metal lathe, and I'd like to add a very fine longitudinal feed to the lead screw for doing finishing cuts.
I have a smallish 5-wire (unipolar?) stepper motor that I pulled from a plotter. It has a word gear on the end, and a plastic gear that it meshes with. I think I can adapt that drive system fairly easily to my lathe.
What I'm hoping to do is buy or build a control box that will give me simple low-RPM constant rotation in either direction.
I'd like a FWD-OFF-REV switch (or some equivalent) and a rotary knob that I can use to adjust the rpm. The exact rotational speed is not important.
I need to avoid any sort of computerized control, so I can make the box rugged and mount it to the lathe somewhere.
I know this is doable with an Arduino or similer, but I'm hoping to end up with something much simpler.

I realize the motor itself is an unknown, and I'm trying to look up the specs on it. I know it's a 25V DC stepper, made in Germany by Buehler. It's HP part #C 4699 60032 if that helps any.

Is this possible, or am I dreaming?
If it turns out that such a product exists at a reasonable price, I'm happy to just buy it and be done. :)

Thanks in advance for any help you can offer,
-Mike

Sounds like your over thinking it, a stepper is going to require not only a stepper driver and associated reasonably high VDC power supply, but also some sort of signal conditioning and control signals to actually drive it.

A simple geared DC motor with a forward/reverse switch, and a speed control is what would be most practical and dirt cheap. You'll probably spend $20-$25 all up off ebay. Simple DC speed controllers for a vast array of motors are amazingly cheap on Ebay.

cheers, Ian

Possibly, but the motor itself is a cost as well, whereas I have the stepper.
I'm a fan of reusing equipment where possible, but I'm not a fan of throwing away money.
My other thought about using a stepper is the basically infinite range of speeds, all the way down to 'can't hardly see it turn'. :)
It seems like there should be an easy way to do this, I just have found it yet....

You can buy really simple stepper controllers on ebay for peanuts that will provide the same simple forward/reverse and speed control. For what you want though, a DC motor will be the simplest and most reliable. Steppers aren't really that ideal in continuous mode, certainly not compared to DC motors anyway..

cheers, Ian

"You can buy really simple stepper controllers on ebay for peanuts that will provide the same simple forward/reverse and speed control."

Yes! This is exactly what I need. Do you have a link for an example or even a particular description to search for?
I'm not looking for a stepper driver that is made to interface with a microcontroller, such as an Arduino or similar.
I need a standalone driver, that can take input power and drive the stepper with a couple switches and a speed control knob.
-Mike

Well there's ones like this I'm fairly sure would be crappy, but it's dirt cheap so who cares:

DIY Speed Stepper Motor Click Driver Controller With Remote Control 9 Levels | eBay

This one is possible very less crappy, and you can team up with a cheap driver to achieve what you want:

DC12V Stepper Motor Speed Pulse Controller Speed Direction ON OFF Control | eBay

There's plenty more if you just search "stepper driver -arduino" on ebay, and just look for ones with a pot.

cheers, Ian

Sounds like this is more complicated/expensive than I want to get into right now.
I figured there was a simple way to drive a monopolar stepper with a couple components and a simple circuit. Guess not. :)
Thanks anyway.
-Mike

Quote:

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Originally Posted by Elmojo

Sounds like this is more complicated/expensive than I want to get into right now.
I figured there was a simple way to drive a monopolar stepper with a couple components and a simple circuit. Guess not. :)
Thanks anyway.
-Mike

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Mike I have been researching the same thing for about two weeks now, I did find this one on eBay.
CNC Stepper Motor Step Dir Pulse Generator | eBay
I plan on buying another version of this, reverse engineering it and building more for myself and the one I thought to buy is $34.00 includes shipping, this one connects to the stepper motor driver, driver connects to the stepper motor. It will give you full control, speed and direction. I am also looking into just building my own 556 timer version. Hope this has helped some what, Jeff.

Or you could just buy any of the dirt cheap H-Bridge boards on Ebay and a cheap DC motor that's designed exactly for what you want, and still have heaps of change left.

Seems strange to me to try and cobble a more expensive solution with steppers to simply have them emulate a DC motor.

cheers, Ian

Well you are correct in a sense, but if you think about it, there would be many other applications for this type circuit (testing and checking CNC movements is one). In my case, I already have most of the components to build the circuit, also have about 10 stepper motors and a few drivers to chose from, without spending money.