[Elmojo]

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

[aarggh]

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

[Elmojo]

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....

[aarggh]

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

[Elmojo]

"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

[aarggh]

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

[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

[jlnading]

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

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.

[aarggh]

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

[jlnading]

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.