170 replies to this topic

[havlicek]

Much appreciated, Pablo... I think I'll be OK for both of those but it sure is nice of you to offer!

Rick... 10-4 on the arm diameter and I've never seen the magnetic balancer thing so I have no idea what that is. PM sent.

[Rick]

And it does MUCH better if you grind one end of the shaft to a point. Almost zero friction...

[slotbaker]

Neat.

Does it make any difference to the accuracy of the balance if the ground point is not perfectly on the centreline of the shaft, i.e. how accurate does the point have to be?

[stevefzr]

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.

Marcus, this unit isn't pretty, but it does have a reversable ratchet and a counter:



I pulled apart an old fishing reel for the winder and ratchet assembly. I need the ratchet so I can keep the tension on with one hand while I use the end of a matchstick to push the winds down tightly between layers. The arm clamp is a converted curtain rod holder! It'll have to do until some LaGanke clamps turn up one day. No one who's seen it so far have believed it's serious, but trust me, it is! In fact, using this and a pair of geezer goggles I can get better winds than I did as a teen in the late '60s.

Regards,

[MarcusPHagen]

I believe it!

My problem when winding was always that I'd have the windings loosen when I took my hand off the crank to tape the loose end, prior to winding the next pole.

I'd like to try winding some 26D and 36D arms (I've picked up a few on eBay, as Jairus says, there are only a few of us looking for them, so the prices aren't too bad yet). In addition, I'm intrigued by Larry's Pittman five-pole winds. So this is more for personal education than anything else. However, if they turn out OK, I'll do some more.

In the mean time, though, I'll be looking for something which will allow me to change holders for different sizes. It looks as though both yours and Rick's would allow that. I've also been thinking of a way to put a ratchet on Rick's by silver-soldering a gear to the rotor shaft, with a piece of spring steel to keep it from unwinding. As you say, the counter is rough, but it looks like a workable system for hobby use.

Thanks for posting that picture.

[Pablo]

My problem when winding was always that I'd have the windings loosen when I took my hand off the crank to tape the loose end, prior to winding the next pole.

A drop of krazy glue and the wire stays put for a time out or before attaching to the comm. I actually secure each pole's wind with the krazy glue, then cut and label it, A1, A2, etc. Then I solder to the comm after all poles are wound.

[havlicek]

Well, I just got word from Mura that they'll sell blank arms and comms, and am just waiting for them to tell me the price. Getting the magnet wire is easy so it looks like I'll be experimenting away.

I love the smell of burning armatures in the morning, smells like victory

[MarcusPHagen]

A drop of krazy glue and the wire stays put for a time out or before attaching to the comm. I actually secure each pole's wind with the krazy glue, then cut and label it, A1, A2, etc. Then I solder to the comm after all poles are wound.

That sounds like a good technique, and I'll have to try it. As far as I can remember, when I was last rewinding Velcro was brand new (they had somebody on Johnny Carson using Velcro-soled shoes to walk on the ceiling) and I remember reading about this new super glue that was supposed to hold a ton with one drop... but they didn't have it in stores, yet. Pretty sure that the glues we use now were developed for surgery, and tested in Viet Nam. I digress.

I'll have to try that, especially now that we may have a source of armature blanks from Mura. Great work, Havlicek!

[havlicek]

.. Shucks, Marcus...'tweren't nuthin'. :-) Actually, since they have commutators listed on their site, it seemd as though they shouldn't mind selling some arms to go with them. I still don't know what they want for them... but how much could it be?

[Bill from NH]

I knew Mura was sold a while back when the then current owner got sick but didn't realize they were still in business. I haven't seen a Mura part in the local raceways here for more than three years.

[havlicek]

They're not set up for internet commerce so you have to prepay, but you can buy direct from them.

[stevefzr]

A drop of krazy glue and the wire stays put for a time out or before attaching to the comm....

My technique is a little different from you guys, which is why I need the ratchet. For starters, I wind with the comm on and already timed! I start by soldering the wire to one of the comm tabs and then wind the first layer on a pole. When the layer is finished I use the end of a match to push the winds closer together, and no matter how tight and cearefully I wound that first layer, I always manage to get a couple more turns on. The ratchet allows me to keep the wire tight with one hand while I compact the turns with the other.

Once I've got all the turns on the layer, I push it down in the middle using the match end again to make sure they're sitting tight against the stack. I stop every layer and push the turns down tight onto the layer below in this same way. When I finish one pole I work out where the wire will cross the comm tab for the start of the next pole, scrape the insulation off at that point and then hook it back over the tab and keep winding. It means that my whole arm is wound with a single length of wire and only one tab has ends soldered to it. The other two tabs have continuous loops passing over them that are also soldered. It means that the wire is very tight, including at the comm, so even without epoxy and binding thread it's unlikely to throw, although I always epoxy and tie them anyway. Because the wire is so tight, you can only adjust the timing 1 degree or so after you've wound the arm, so it's important to get it right before you start winding.

As for different size arms, the curtain rod ends attach with a 1/4 Whitworth thread, so I swap to different size curtain rod holders for 36D, 26D, 16D, etc. I plan to modifiy this one day with proper arm holders and the like, but only to make it prettier. From a functionality point of view it already does everything I need from a winder.

Regards,

[slotbaker]

Steve C,

Do you balance your own, or send them out?

If you send them out, to where? In Oz or O/S?

Ta.

[Ron Hershman]

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.

We do all of this... vacuum the hi-temp epoxy, spin off the excess, tie with Kevlar, and bake correctly using hi -emp epoxy for the application. We have done many hand-wound arms for other posters on this blog.

We also do dynamic balancing work daily. Razor blades, etc, is static balancing and is not that accurate or good.

We also have 100s of Slotworks 16D .600" length stack and Super 16D .500" stack length arms (.520" or so diameter ) we sell 10 for $5 that can be de-wound easily, comms reused, and you can even take plates of the stack length and make to any length you want.

Mura info here: Mura Motors

[havlicek]

Thanks for posting that info, Ron. This thread has pretty much all the info for the subject wrapped-up neatly... and now a cheap source for 16D arms as well. I'll probably be looking to use your services at some point.

[stevefzr]

Do you balance your own, or send them out?

If you send them out, to where? In Oz or O/S?

Unfortunately there's no one in AUS who does dynamic balancing. I know I could get them to the States and back in two weeks, but I'm not that patient. I do a static balance using the razor blades technique with a Dremel cutting disc to remove excess metal. I mostly wind for vintage kit cars (like Tamiya and Cox) running natural rubber. When I get around to building vintage scratch racers for a glue track, where I can use a lot more power, I'll send some arms away for the proper balancing.

Regards,

[mdiv]

I just wanted to poke my head in and say this is a very cool topic!

Onward, gentlemen!

[havlicek]

I agree! Winding/rewinding arms was one of the things I enjoyed the most when I first ran slot cars. Having a car with my own chassis running my own wind under a body I (very poorly) painted was a kick.

I should have all the pieces assembled to dive in to this within a week or so and I'm starting out with what should be (if they don't explode) some pretty hot stuff. I got a couple of the Mura C-can blanks coming but they are really expensive (like $10 for the arm and another few bucks for the comm) and Ron here is sending me a bunch of D can arms as well. Too bad blank arms aren't an off-the-shelf item any more.

[Uncle Fred]

I'm coming into this topic a little late.....like 40 yrs! But I used to love winding armatures back then and experimenting with with various turns and gauges.

In the beginning it was the only way to go fast. I NEVER used any sort of winding device. It was always freehand. I held the arm in one hand and slowly, carefully wound with the other keeping even tension on the wire. After a while I would use a 1/8 inch axle (!) to press the windings down between the poles. I would scrape the coating (Formvar?), attach it to the comm tab, and proceed to the next pole.

I advanced comms, removed and added plates to the stack, even angled the stacks in a vise like the early Globe motors were. Tried it all.

[gascarnut]

When I was still in high school and did not have much money (what's changed?) I used to take cheap Mabuchi 16D armatures, carefully unwind all the wire, then double it up and wind it back on as a double wind using half the number of turns of the original. Some epoxy to hold the wire, balance on two razor blades and into a motor.

I found out about blown commutators this way...

So then I would strap the top of the comm with thread. They only lasted a little longer then, but they were fast while they ran.

[havlicek]

I found out about blown commutators this way...

... been there, done that.

Well, I got my magnet wire and am just waiting on the arms to get here before I revisit all this. Hopefully will get that winder as well. I also got a Parma D-can setup to use for testing out some of arms Ron is sending, never messed with one before. Can anyone tell me what's up with the weird springs on these things?

[Rick]

Winder is done and going out tomorrow. Have fun...

[havlicek]

... Bingo! Much appreciated Rick... you've got mail.

[Rick]

I made six. If anyone else wants one, PM me...

[havlicek]

... I'm really looking forward to winding my first handgrenade... er... armature. I'll try and get some pics up before it explodes. :-)