170 replies to this topic

[havlicek]

One of the things I'd like to try again is winding armatures.

I've done slot cars since the '60s, but really three different times. After the first time, when I was really young, I did it for a couple of years when my oldest son was born and then again now. I only did rewinding when I was really young and have only the faintest recollection of it. There was a nice little rotating clamp thing you simply put in a vise and moved with a crank handle. It used a set screw to tighten a set of jaws on two poles of the arm as you wound the third. Is this or something similar still available?

Also, is there a source for blank arms or do people just take apart unbalanced/unepoxied arms and rewind them? Also, what's a good source for magnet wire? Looking to do some C-can arms and see what's what.

[Hworth08]

I believe Rick, here on Slotblog, can provide what I think was a Simco rewinding machine.

Radio Shack sells three spools of magnet wire in a bag. 30, maybe 24, and something bigger? for about $5. eBay has lots of 155 C wire. Don't know where to find the "premium" wire.

Pro Slot might sell you some blank arms? Dan Debella is a member here, a PM to find out?

[Bill from NH]

As Don said, Rick B. on here made some winders. Simco published a rewinding instruction sheet, LaGanke made most of the old winders.

For wire, check with Pablo (Paul Wolcott). He's recently wound an arm or two but I'm not sure what he used for wire. He'd be helpful with other questions you might have too. Good luck finding blank arms or quality comms. I don't think any manufacturer wants to sell them today.

If you just want to experiment and play with a couple, use a Chinese 16D arm. The wire comes off pretty easily and they have a decent but not great comm. You could probably shorten up the 16D stack for the C-cans by removing several segments but I've never tried.

[Jairus]

Blank arms pop up on eBay from time to time and there are usually only a few buyers interested so most times you won't get into a bidding war over them. I have a couple of blanks here and was planning on winding a couple of arms for myself just to say that I did it.

Got my 24 wire from Radio Shack. It has a bright red lacquer coating so the arm will be beautiful when I finally get one done.

Good luck, John!

[Mark Wampler]

I'd sure like to get some tips, too. I can think of only one successful rewind I did in the '60s It was a 26D with 28 wire. The ones I used to do overheated and burnt up.

The other thing that's real important is timing of the comm. There are tools out there to measure degree settings. Hopefully some more experts will chime in here.

[havlicek]

Thanks for all the (as usual!) really helpful information all. There was a small (whatever the smallest size was) Mabuchi motor... whoever used the bright yellow color... that I used to buy just to rewind for F1 cars that used to scream. Of course I don't have a clue what gauge wire, # of turns or com timing it was... but it shouldn't be too hard to work up something with a little screwing around.

Back then, you could just buy arms and even commutators at any track as well if you didn't need the can, endbell, and magnets. The good thing is that, once you get going and have a formula... winding armatures is not very difficult... MUCH easier than scratchbuilding some of the beautiful chassis I see around here. Heck, if I could do it as a kid... how hard could it be ? Anyway, I only remember that my buddies and I were using some pretty hefty gauge wire (maybe 25???) and by those standards they ran like heck, although we were blowing commutators like crazy for a while before the "blowproof" comms came out.

Looking around the Mura website, the cheapest arm I could find for tearing apart is like $20... so that isn't going to work on a carpenter's paycheck. The PCH site has a "Mura Challenger Armature - M2200" that goes for $9... still a little steep but better (if that's a good quality arm???). I was hoping to get a dozen and wind up with maybe three or four keepers at the end.

Jairus, I'm not sure what the coating was on wire... and don't know if lacquer will hold up under heat. I know that you can get magnet wire with all kinds of different coatings on it, but magnet wire is used for all kinds of things besides armatures and maybe the lacquer will work. #24 awg sounds about right though.

I'll try and contact the folks mentioned here and see if I can come up with stuff. Here's a crude picture of what the "winder" looked like and after I started using it, the jobs came out much better and the results were more predictable. I think probably somebody with a machine shop just made them and bagged them for sale at the tracks.

[rdmac]

... I think probably somebody with a machine shop just made them and bagged them for sale at the tracks.

John, the armature winder was made by LaGanke.

[havlicek]

Yikes!... that's it (or the same exact design). Can those still be had?

[jlsinz]

Try these guys for wire.
Small spools and high temp, every size you could want.

[Mark Wampler]

Thanks for posting that pic, Bob. I never had access to one of those. Notice the small spool of 27 wire. As I remember, anything bigger than 28 wire required aftermarket strong magnets like Mura white dots and so on, otherwise you wouldn't have brakes.

[Mark Wampler]

Larry Shepherd is really good in rewinding those old five-pole Pitmans. He used wire with "polythermalese" coating. No bigger that 30 ga. Another thing to remember is that the PS pup and FK motors only use 30 wire. I'd try 29 or 28 using standard magnets.

[Larry LS]

Haven't done much re-winding lately. Did a lot in the '60s til you need to have them professionally balanced on a precision balancer. The old razor blades didn't do it anymore when you got into the big hot winds.

I do wind a motor now and then for my 1/32 scale stuff that is not into the need of honking motor power.

Here is what Rick had shown as his rewinder he was going to make.

I of course told him his needed a digital counter built in, which he said he thought about but did not get many takers for re-winders, I think.

[Rick]

I made some of these, sans the digital counter Larry installed in the pic, LOL. I can make another. Digital counter is also doable but a PITA. ...

PS: I will look around, I had dozens of old 12 and 15 arms that could be dewound and rewound, if I could only remember where they are today. I let a bunch go to Rocky so he could play a couple of years ago.

[MarcusPHagen]

Rick, did that winder have a ratchet so it wouldn't wind backward? I don't mind not having a counter, because I measure the wire. But I do need some method of keeping it from unwinding under tension. PM me if you've still got one for sale.

[havlicek]

Rick...

I would be real interested in one of those and knowing what they would cost. I realise that "one-off" machine work can be expensive. If you are thinking about doing them, PM me or just post publicly. The ratchet thing would be cool as well but I don't really "need" that feature.

[Don Weaver]

For magnet wire try a local motor repair/rewind shop. They will have any wire size you want and for no more wire than you will need they will probably just give it to you since they buy it in 100 lb. buckets.

Class F wire is standard but you can find Class H wire which is 155c if I remember right.

[Prof. Fate]

Hi,

My first wind was in '60, taking a 3 volt arm out of a government servo and rewinding for a car on 12v!

And I didn't use a fixture more complicated than a small bench vise.

The rachet to stop it from going back isn't the issue. One of the advantages you have as a human rather than being the "six million dollar winder' is you can FEEL.

With practice you will feel that the wire varies constantly and slightly in diameter, and strength. So you can get a better tighter coil by constantly adjusting the tension based in the feel of how the wire stretches.

Which explains why once it was a feature that increased the price of the arm if it was "hand-wound".

I gleefully bought those arms from Rich for a stupid cheap price, that he keeps mentioning, for this reason. Parts is parts! In 1/32 we commonly built SHORTER motors. I think some of you have seen a couple of my shortened "P" cans, one of which was one of my "cheater motors". Modern arms are to a size, but in the day some of us built motors to size to fit the needs.

It ain't "rocket science", it is just fun. Don't over think the process, and don't wait around for advice. GO BLOW STUFF UP!

Fate

[Pablo]

John,

It ain't braggin if you can back it up....

I have done them by hand, works fine if you don't get arthritis... I have an R-Geo (Rick B.) winding tool, works super.

- Don't sweat the exact degrees of timing, just advance until the comm post is even with the next leading edge of the lams.
That's "hi timing", in the ballpark. You need strong mags and tight (15 to 20 thou) airgap for this much advance. Weak mags, bigger airgap, use less advance. Apply the correct amount of spacers to align the arm and comm in the motor, then super glue the comm and spacers in the desired positions before winding.

- I used the best two-part, clear, store-bought epoxy I could find. Baked it in the oven, rotated it and inverted it occasionally.

- I have a winding instruction guide and can send it via email if you like.

- In general, more turns of thinner wire=more torque and brakes, less horsepower, more longevity, cooler running.
Less turns of thicker wire=more horsepower, less brakes, less longevity, more heat.
Also, less turns=less weight (duh).

- Standard Parma Super 16D arm would be my recommendation to use, as it will fit some vintage applications...

- I have blank, wire, and comms if you want. Just let me know in a PM.

- I used dental floss to secure the windings around the comm before epoxying.

- Make sure the shaft is straight before you waste lots of time on an arm that will never run right! Lots of blanks on eBay are not straight, long-ago rejected. Once again, I think my axle and shaft straightness dial checker is an RGeo tool.

- Most important, send it off to a pro arm balancer for a balance and a comm true. What a thrill when you run it and it howls like a dental drill on steroids.

[havlicek]

Now that's some good info, Pablo... Thanks! I learned one thing right off the bat, the little tip about epoxying the arm BEFORE winding to prevent shorts. That's one thing I never did, but I can recall specifically worrying about all those sharp edges! On the comm timing:

-Don't sweat the exact degrees of timing, just advance until the comm post is even with the next leading edge of the lams.

... that's the kind of "precision" I DO remember :-) and while there was a lot of variability in my results, the "keepers" were worth the hassles.

-Standard Parma Super 16D arm would be my recommendation to use, as it will fit some vintage applications...

... have some extra C-can setups so for now, I'll stick with those for my little experiments.

-Most important, send it off to a pro arm balancer for a balance and a comm true.

... that is one thing I WILL do once I settle on a formula. For now, two razor blades in clay or wax will do fine for getting an idea how they run. If I can get an arm winder, I'll do that too because I had the experience years ago of seeing an improvement because of the tool. It won't stop me from messing with this anyway. I sure appreciate the great info, Pablo!

[Larry LS]

Over the years I wound many arms and not once did I use a winder to hold the arm.

My left hand and fingers always did a great job of holding the armature still or moving as needed to get the feel of the wire being wound around a segment. I tried a winder once and I instantly realized I had lost the total feel of the wire and arm as a whole. I had also lost the sense of feeling if I was winding it too hard and stretching the wire or being too loose in the wind. I measured my wire lengths to start with. But kept counting winds to compare segments as to count and see if one or another was pulled too tight or too loose with same length of wire.

I did make a nail and spindle tube on the edge of the bench so I could have the wire spool spin easily as I need the wire to advance for the winding. Worked great to keep that spool captive but free to rotate as needed. I measured the wire length on the spool with a small piece of tape and then wound it back on the spool loose so it would not get tangled up before being wound onto the arm. Then I would mark the next one, etc., etc., etc. I only wound one seven-pole arm and that was enough for me.

It is always a fun thing to do something for yourself and seeing it run, sometimes great and sometimes just so-so or smoke.

But that is JMHO. YMMV.

[Bill from NH]

John, you must have a pin vise. It'll hold the arm while you wind, too.

[havlicek]

10-4 on the pin vise... as a kid I stole... er... borrowed everything my dad had in his workshop to do this stuff and yes... I wound many simply with two hands. Still, I got the neatest result by using the winder. I also made sure I was using the same number or turns per layer and the same "design" on each pole rather than the same length. I figured that I'd be close enough that way to the same length of wire per pole I smoked a bunch, but also got some really nice motors out of the whole deal.

[Hworth08]

If I was winding a hot arm I would send it to one of the people that work arms for a living to be epoxied and tied. They use a vaccum chamber that sucks the epoxy down into the windings and they use Kevlar to tie the comm.

Let them balance the arm and true the comm, then run the new arm through a few heat cycles. After being heated and "spun" the wires will shift a bit, enough that the arm will at least need to be checked for balance again. Re-cut the comm and the arm should be ready to run till the comm needs cutting again.

Ron Hershman can probably perform this service.

[Pablo]

OK John, just give me the word if you want some wire and a comm, I'll hook you up, no strings attached. Lots of folks here helped me, and I'll do the same.

You can find arm balancers on eBay also, I have one. Uses magnets. I had very good results with it. If you taper the ends of the shaft to a perfect taper, it works super.

[Rick]

OK gentlemen, a few arm winders it is. I am asumming you are going to wind .510-.520" arm diameters?

I also made and sold the arm balancers with the magnets a while ago on eBay. I can make a few of those up, too. Send a PM if you want one or either.

Thanks...