micro-controller based dividing head

Here's my latest homemade tool...just finished the wiring and testing today. It's a dividing head, using a NEMA 23 stepper motor, coupled to a ER20 collet chuck via timing pulleys and belt. The ER20 is mounted in a couple of sealed ball bearings, that are in turn pressed into a 3" x 3" x 5" block of aluminum. The stepper is capable of 400 steps (0.9 deg/step), with a 4:1 ratio on the timing pulleys. This results in a maximum resolution of 1600 divisions...

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I plan to use this dividing head, to cut spur gears and timing pulleys for other projects.

-EN

EN,

Nice design and something I could definitely use. Can you describe the electronic circuits or point us to a website with the info? Does the LCD panel display a self-contained interactive dialog or is the setup for number of divisions all done via a computer interface? I am interested in building something similar.
Thanks, Paul

Hi Paul,

Interaction is completely via the LCD display and buttons (i.e., the SainSmart LCD Keyboard interface). The display mounts 'piggy-back' onto an Arduino UNO, and uses firmware written (I think) by Chuck Fellows. This unit mimics one produced by Chuck, which is described more fully here: (Electronic Dividing Head using the Arduino - Home Model Engine Machinist). You can find a lot of info on the web just by searching for terms like "electronic dividing head", or "stepper motor dividing head", etc..

From that you will see that the idea isn't unique to Chuck, as there are others who have done this as well. Some start with an old surplus mechanical dividing head, and simply fit a stepper motor to it, along with some sort of controller and brains...

In my case, I didn't possess a dividing head, but had previously built an indexing head with crude hand made indexing wheels. The accuracy just wasn't there... so when I found this solution, the decision to build one was simple. I have a number of small micro controllers from past projects, and was able to slap this thing together once the mechanical aspects were made. I'll likely gravitate away from the arduino, and to something like the MSP430 by TI as time allows...

Good luck, and let us see what you've built!
-EN

p.s., one other modification I'll be making to this EDH, is to shorten the motor mounting plate; which will bring the stepper closer to the spindle. That will reduce chances of interference with parts of the mill.

Thanks EclecticNeophyte! I've added your Electronic Dividing Head to our Machining and Measuring and Marking categories, as well as to your builder page: EclecticNeophyte's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="/electronic-dividing-head"><img src="/uploads/105685/electronic-dividing-head.jpeg" alt="Electronic Dividing Head" /></a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="/electronic-dividing-head">Electronic Dividing Head</a> <span> by <a href="/builder/EclecticNeophyte">EclecticNeophyte</a></span> </div> <div class="tags"> tags: <a href="/tag/arduino">Arduino</a>, <a href="/tag/divider">divider</a>, <a href="/tag/electronics">electronics</a> </div> </div> </div> </div>

EN,
Thanks for the references and info. This is very helpful. I too like looking through Home Model Engine Machinist for ideas and have published a few articles there. I am also starting to follow John Saunders (aka NYC CNC) on YouTube for his future project about a 3D engraver using stepper motors controlled via Arduino and programmer using common G-codes.
Regards, Paul Jones

EN,great project,I think the ratio you're using should put it on the money for layout work! Good craftsmanship .

This is new to me, an electronic dividing head. Great handiwork!

Quote:

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Originally Posted by kbalch

Thanks EclecticNeophyte! I've added your Electronic Dividing Head...<snip>

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Thanks Ken! And thanks everyone for the kind words!

-EN :)

I started with this project some time ago, but never really got it running . I must get back to this soon. I have all the arduino and I have worked with Chuck trying to see where I went astray. This has just given me the kick I needed to try again.

I realize the OP is more than 5 years old but for some reason Jon has just recycled this very interesting thread.

EN: if you are still around can you give us an update on the dividing head. Did you ever convert to the TI MSP430? And why do you consider that a better choice that the Arduino?

Quote:

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Originally Posted by Saltfever

I realize the OP is more than 5 years old but for some reason Jon has just recycled this very interesting thread.

EN: if you are still around can you give us an update on the dividing head. Did you ever convert to the TI MSP430? And why do you consider that a better choice that the Arduino?

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Hello Saltfever,

Thank you for your interest!

However, I'm afraid there's not much to report. I recall using a more robust stepper interface, as the one originally implemented burned out easily...

...later, other projects and work concerns took precedence, then in 2016 the neighborhood where I live suffered a flood. As a result of that, EVERYTHING went into storage (on higher ground), and any planned changes to my version of Chuck's electronic dividing head were put on hold. Which is where it's been ever since, I'm afraid. It's like having to suddenly pack up everything you own (that didn't get wet), as if to move.

Now that I'm officially retired, and with winter rapidly approaching, your inquiry might be the incentive I need to drag it into the light once again... :)

As for the MSP430 vs Arduino thing, it's really more personal preference than anything. In a previous life, the company I worked for handed me a project which required controlling a motorized 'gizmo' with valves, using the MSP430(F149). I spent the next several months developing the firmware for it, and was completely interrupt driven. Years later, when I constructed the EDH, built around the Arduino; I didn't see an easy way of implementing interrupts (I don't recall now if 'at the time' they weren't available, or I simply didn't spend enough time researching...). Polling for a button press is simply "not to be done" in my world...

A quick search prior to replying here, shows that hardware interrupts are indeed available to the Arduino developer. I seem to recall some revisions to Chuck's original code by others, so this may have already changed as well...(?) But I need to catch up. If circumstances allow, I'll do what I can to update and make any (noteworthy) updates available here...

Hope this helps,
-EN

Many thanks for updating, EN. Very sorry to hear about the flood but extremely happy for your retirement!

I been thinking about a design for a while and bought a couple of these Harbor Freight winches on sale a couple of years ago to just get the 40:1 worm and wheel. Can't remember exactly but I think they were about $23 ea. At the time I couldn't find any worm-gear set for close to that. I am not challenged by machining or mechanical fab and was going to make a purely mechanical indexing head, machining the worm gear parts to fit my needs. However, your project has encouraged me to go the stepper motor route. Unfortunately, electrical or digital implementation of anything, is a challenge for me and will take time and effort! Due to current commitments I plan to revisit this project in a couple of months.

Hello, I would like to build some thing similar to your design
What torque (NM) output stepper motor did you use
Thanks

LeighS are you trying to react dynamic machining forces or do you just want to use motor resistance to hold position?

Quote:

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Originally Posted by LeighS

Hello, I would like to build some thing similar to your design
What torque (NM) output stepper motor did you use
Thanks

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The one I used is a NEMA23, 283 oz/in. No idea what that is in metric, but I'm sure there are calculators out there that can convert...

Specs can be found here: https://www.automationtechnologiesin...t-282-oz-in-2/

Hope this helps.
-EN