stepper construction

I endorse the "for education" part. I don't think you'll gain enough expertise do really nail the "precisely designed for a specific application".

And, since I'm biased against steppers, I think you'll do better with some sort of a geared closed-loop solution for most applications. But I freely admit that I'm biased.

Years ago, when I first got interested in stepper motors, I learned what I could from books and taking them apart. The hybrid steppers at that time were magnetized after the motors were assembled. Taking a motor apart would break the magnetic circuit and much of the magnetic strength of the rotor would be lost. This resulted in a drastic reduction of torque output from the motor when it was re-assembled. Aside from learning that I also saw how the teeth machined in the rotor and the teeth machined in the stator caused rotation when the coils were energized in the proper sequence. And I was reading in NASA Tech Briefs about a month ago about a new hybrid step motor design that uses magnets in the stator to redirect the magnetism from the rotor which increases available torque significantly. Since I'm a machinist I have some idea of what it would take to machine the parts for a stepper motor and since I have rewound a couple simple motors in the past I have some idea of how hard it would be to duplicate the windings in a comercially made stepper. It would take many hours to build a stepper from scratch and building one that is even close to being as efficient electrically or volumetrically as a comercially available one would be a full time job for quite a while. Good luck. Please let us know how you do on your project. Learning is fun. Eric

They did. Many universities, observatories, and planetariums held classes in mirror grinding, as well. There were several places where one could send one's blank to have it aluminized and coated. Some of the above classes used silver, as well (could be done without expensive equipment).

I would bet that *very* few refractors were built by amateurs. They're rather pointless.

On Wed, 20 Mar 2013 11:28:58 -0500, Tim Wescott wrote:

I very well may have to go with that. But I'd like to explore and learn. And if I buy everything premade, the learning experiences will be ... very expensive. Plus, you only learn how to _use_ something that way. You don't learn deeper concepts because they aren't exposed to you, then.

Just to make it clear where I come from....

I'd rather spend $1000 buying tools and parts and making something I need than spend $1000 to pay someone else to do it. In one case I have some new tools and parts for later, have learned a lot more than I knew before, and also have my solution. In the other case, I pay someone else to do it, learn nothing new myself in the end (though they may learn something from doing it), but I get a finished end result. I like learning and don't mind paying money and time for that.

(Even when I just can't succeed at it -- even then I've learned something more and can be a much smarter purchaser for that spent labor. Even failure is success.)

I'll give you a recent example to illustrate. I could hire someone to build me a specialized door I needed (pocket door, exterior style thickness, designed to withstand my profoundly autistic daughter's pounding and kicking, with a top rail strong enough to carry the door and a person hanging on it.

-- I actually need 5 of these.) Hiring someone to build a custom door, or else compromising and accepting some mass manufactured door, is what MOST people would do, especially if they have never built a door before (as I haven't.)

I first shopped around (literally for a few months because some of the dealers needed the time -- one of them took 3 weeks to quote a price, for example.) I called distributors in other states (they aren't in Oregon.) I finally called the few companies that ACTUALLY make the doors themselves (many distributor roads lead to the same few places, it turns out) and spent some good time learning about their processes and capabilities. In the end, I realized it would have to be custom to satisfy the necessary parts of my requirements. Once I realized that, and the price for each door (approx. $800 ea, delivered), I set out to make them myself. I bought the necessary router and bits, various clamp types and clamps, glues, sanders, and so on. In the process of making these doors, I've learned a great deal and the result is actually much better than I could have requested by custom order. (I was able to custom design the rails and the hanging hardware for it to make a perfect and extremely strong blend that can support a hanging weight of 800 lbs for each door.) These doors are stunningly beautiful, made from hard woods and a custom interior fill, four rails, two stiles, custom locking system, and custom hanging system. Took interior walls down to the structural members and built it all back up in the house. Myself. And I'm proud of the result. It's really wonderful. And I learned a lot from doing it. I would have learned NOTHING from having hired it done. I'd rather spend the money on myself. I change. And that's what's valuable.

Education is a lifestyle.

I'm looking to see if that is possible here. I have end goals and don't need to include this process, of course. If it isn't possible, then it isn't and I'll have to move on. I was just entertaining the idea and asking for informed opinions about the possibility. I have a few other lines out on this topic, as well, and I'll see what I catch in the process. Might get lucky. Might not. Either way, life moves on and I won't look back. But this project is out about a year so I have some time to dawdle a bit.

Jon

Okay. That's interesting to note!! Thanks.

For hybrids, right? (But possibly not in the case of some others?)

Any links you may share?

I would be hoping for "standardized" parts that are pre-made to a specific frame size, but could be assembled into longer or shorter motor structures. I don't have the equipment here to build all this from scratch. (I have plate steel up to about 1/3" thickness and can do some modest cutting and welding, but no precision equipment for metal working.)

If I find some generous suppliers, I'll post it up. I'm not expecting much. From comments here and the relative "hearing crickets chirp" when looking for suppliers so far, it may be the case that I've no reasonable options outside of buying. But it would be a lot of fun if I could find just one practical alternative where I get to assemble and wind my own steppers.

Tim has also made some strong recommendation about geared DC motors and I take his point and must investigate that side, as well. I can fabricate custom gearing, including planetary gear systems. Which then would leave open the idea of winding my own DC motors, as well. A separate, but related question. And in that case, I've actually observed hobbyists winding their own for the first time. But it was years ago and I've no idea how to track down their supplier. So I'd be back here asking about that, as well.

It's all fun. Maybe I'll get a good bite at some point.

Thanks so much for your comments. Appreciated a lot!

Jon

I'd like to learn something new. I'll keep looking a bit longer before giving up.

Jon

AFAIK only AlNiCo magnets need keepers, I think most steppers use ceramic or neodmyium magnets.

A few wooden yoyos, some scrap metal cut to size and a few magnets and a few electro magnets and have fun.

Larry

I'm a little past that.

Jon

My last homemade one was a magnet, a nail, some wire and some brass strips, around 60 years ago ;-) ...Jim Thompson

I think we've all built ourselves a motor like that at least once in our lives. I even built an earphone once, too, that worked tolerably well. Of course, I'm on about something else now.

Jon

sounds like a great book. At least tell us how far you get. I've always just looked for something I could use and work around the problems.

Larry