3573 replies to this topic

[havlicek]

A motor for my buddy Jeff Easterly. Arm is a #29awg doublewind that comes in at around .2 ohm and draws approx 2.7 amps. Setup is a minty-clean Mura, and the motor sounds wonderful! No doubt Jeff will further tune this thing playing with the airgap...maybe even the magnets and such to get even a little more out of it. Should be a real tire-chewer There's a second "special" motor going in the package as well that I'm looking forward to seeing him build around, but I'll leave that as a surprise Merry Christmas Jeff!



-john

[Slotgeezer]

Holy Smokes, Batman !!!!!

Wow, John... Many, many thanks... That black can & white endbell sure brings back a flood of memories about the period-correct stuff we ran back when I ran inline CanAm at my local raceway..... Big A in Anaheim!

I ran so many double-29 Thorp arms back then, I wish I'd kept them... but I only had $ to afford to buy Mabuchi FT-16BB motors, & then add a "no-melt" Mura endbell, & a pr. of Champion DZ magnets or a pr. of 88X Mura's... We ALL remember dealing w/ those magnet shims, eh? LOL! ... Even geared 4 : 1, we'd fry those things, & buy more parts and build another motor for next week's race! LOL!

Then, the Mura pink "Cukras Signature" motors appeared, & the Mabuchi cans were instantly in the "B" race....

That motor looks just like the Zimmerman motors they had in the counter at Big A & at Monaco Miniatures in Buena Park, CA... Pete & Bill Steube Sr. had the motor market covered, w/ Thorp just behind the two motor wizzards... Boy, to think we used to run them things straight-up, & w/ no choke... Amazing ...

Many thanks, John... Barney is working on that 24-single you'd sent me, & I need to open-up that 25-single & turn the comm, after cooking a pr. of motor brushes... Darkest pr. of brushes I've EVER seen! ... LOL! ... I think that 25-single liked all those big batteries on BP's Gearding King track! LOL!... That thing in the 90's-era CanAm I built is easily the fastest car I've EVER run.... bar none! LOL! ... I love C-can opens! LOL!

Enjoy the season, John... Catch you soon... Keep up w/ the great winding articles, they're always awesome!!!

C-ya!


Jeff Easterly

[havlicek]

Hi Jeff,

Your enthusiasm is absolutely contagious...plus you know more about this stuff than I could ever hope to so I get a history lesson every time we talk On this motor specifically, a 29D is a pretty hot motor...or at least can be depending on the wind and the setup. This one isn't ridiculous (@ 2.7 amps no load) in the current setup, but pretty freakin' serious none the less. The airgap is on the generous side as it stands, but that may be a good thing as the motor will wind more freely and maybe stay a bit cooler. I'll leave it to you to decide (for your track and power) what's best so the motor can live...there are no shims in the setup now. The "second motor" is completely experimental and I've been waiting for an opportunity to see what a creative mind will build around it. Have a happy!

-john

[don.siegel]

John,

I have to say, this thread is one of my all-time favorites on SlotBlog - thanks for starting the thread, and for your enthusiasm and talent!

All that to say that it finally inspired me to wind another arm, about 4 or 5 years after the last pair I did - which were the first since 1968 or so... This time a friend in Bordo fried one of his motors at our last vintage race, so I told him, "never fear Samy, I'll fix it for you!" Hmmm, famous last words... I was stuck!

It was a hot 26D in a simple piano wire/rod chassis and a fast one! I checked it at home, and there was obviously a short somewhere, even tho I couldn't spot it, so.... got out my box of wire and realized all I had was everything except the 29 I wanted! So I did a 28, 50 turns.... I actually realized that I had probably never rewound a 26D! just the 16Ds... How is 50 x 28 as a wind? It's mostly for the Bordo American Black, with a heavy duty power supply. I also kept the stock com, and realize I may be playing with fire...

Here's the arm as wound, before epoxy, tieing and balancing. I'm afraid it looked better to my weak eyes, before the close-up! But it works, drawing less than an amp on 5 volts, even tho it sounds a bit rough.





Actually, when I unwound it, there were 75 turns so I wonder if it wasn't just a stock 26D arm - isn't 75 x 30 about the norm? I'm also wondering about that big brass spacer on the can side, which is fit very tightly on the shaft - was that normal? Strangely enough, there was a fiber washer between it and the stacks, so I assume it was added later... Anyway, I tried to twist it off with pliers but it was pretty tight and I was afraid of bending the shaft or something else... it may be a bit cockeyed too, so I'll have to try to file the face in a dremel, if possible...

Carry on constables....

Don

[havlicek]

Hey Don...that's excellent! 26Ds are a bit of a pain for me because the darned things are so stubby. I pick up some room by not using the insulators on them sometimes and then just doing an extra turn or so of wire, but I've gotten a new appreciation for the things. It looks to me like you've done a fine job on that old motor and 50T/28 and less than an amp draw sounds like you might be just on this side of safe with the Mabuchi com I like to tempt fate myself so we're in the same boat. Close up or not, I think the wind looks fine (did you do that holding it in your hands or with a LaGanke? If you did that in your hand, it's even more impressive...very difficult to tension the wire and get it to lay nicely.

Actually, when I unwound it, there were 75 turns so I wonder if it wasn't just a stock 26D arm - isn't 75 x 30 about the norm?

...sounds about right, but I don't keep track of such things. In any case, I've had all different winds with the Mabuchis and would have to keep a ledger to keep them straight. In any case, getting enough #28 wire on there to keep the current draw down to an amp means (with my caveman-rough way of looking at these things) you did well The Tradeship 26D blanks come with the little fiber washer you mention and like a lot of other stuff...I just toss them and don't use them. I wouldn't know about the brass tail spacer/washer...those are on a lot of modern motors like the little SCX RXC42 and the D can arms. If it's cocked and causing the arm to vibrate, you can try carefully chucking the arm in a Dremel and playing an X-Acto blade against it at a down angle with the arm spinning away from (not into) the blade. One slip though and you may well damage the coils at the tail of the arm. If the shaft is out, it will be even harder as the vibrations/wobble will make it almost impossible to keep the blade on it even at low speed. If you have the room, maybe just installing as many washers as you can on the tail end to help dampen the vibratiuons will do it. Otherwise, you can face the washer with one of those carbide arm tools...as an option, you can simply glue a Dremel sanding disc to a spare bushing and use that to face the tail spacer by spinning it in your hand...MUCH safer for the arm and for yourself!

Lovely job Don, and now for that extra "vintage appeal" you have to tie it with...dental floss (unwaxed of course)

-john

[Bill from NH]

Those arm tools are actually diamond coated rather than carbide. John, I like your idea of using a sanding disc glued to a bushing. A length of brass or aluminum rod with a centered 2MM hole(drilled on a lathe) ought to work as well, plus provide more material to hold onto.

[havlicek]

...bingo Bill. I say we go into business Have a happy, I'm headed out to eat too much at my brother-in-law's house (urp!)

-john

[Champion 507]

Don,

After unwinding a burned up stock 26D recently, I counted 'em and, yes, you are correct...75 turns #30 wire.

After Mabuchi wound the arm, the red fiber washer was installed, presumably to protect the winds from touching and possibly shorting against the tight fitting tail shaft washer that was installed afterwards. It served as a spacer on the can end of the arm, similar to what the Speed FX arms are today.

To remove the tight fitting washer I have a pair of hemostats that I use after I have unwound the arm. I insert the hemostats between the end of the arm and the washer while grabbing the shaft lightly in the jaws. Then I bridge the jaws and handles of the hemostats in the open jaws of a bench vice opened appx. 3/4" and gently tap the end of the arm shaft downward and the tight fitting washer is very easily removed from the shaft.

[havlicek]

Actually, those tail spacers come off fairly easily with a pair of linesman's pliers if you don't grab them hard enough to crimp them onto the shaft. Just grab, twist and slowly pull and there's not much chance of damaging the shaft.

-john

[Prof. Fate]

Hi

the stock mabuchi wire is blue and a 30s wind. The brass spacer at the end helps protect the fragile stock ball bearing from bending or punching out if you get the magnet set wrong or the car takes the wrong hit.

The easy way to remove it is just use a gear puller!

The 28s were pretty normal in the day, though I think I was doing 55 at the time. And I was using silver coated wire then. Commonly, we used the pittcan endbell on the motor as it could not melt.

Fate

[Horsepower]

Hey John! I may have missed something here, but what do you use if you don't use the fiber washer on the comm end? It seems on the 26D that the segments are right up to the ends of the comm and a brass washer could short them. How do you do it?

[havlicek]

Hi Gary...I just insulate the whole stack and shaft where ever the coils will be. Seems to work just fine.

-john

[don.siegel]

In fact, that's what I did with this one, just using epoxy before winding.

Thanks for all the tips and information guys! Had no memory at all of that extra fiber washer on the off-side, but your explanations make sense.

I've had to put the next steps on hold for a couple days, while various family and friends sleep in my office at home, so this will be continued in a day or two.

Merry Winding!
Don

[Horsepower]

Oops, sorry! I was thinking not about the stacks but about the comm end and shaft that goes through the endbell and how you would use washers to space it out from the can bearing. When I've worked on a motor, I always try and use a small fiber washer to keep the spacing correct and avoid shorting the comm segments at the end of the commutater (if any of that makes sense to you ). I use the brass washers at the opposite end if needed.

[Bill from NH]

Gary, traditionally, the comm end has a phenolic(fiber) arm spacer to deflect oil from the comm plus a number of metal spacers to properly space the arm in the endbell. Monty Ohren, one of the top US motor builders, doesn't use any phenolic spacers because he says they wear as a motor is run & upset the arm's spacing. Most, if not all, metal arm spacers I have aren't of a big enough diameter to short comm segments. They're nowhere near the size of a phenolic spacer.

[Horsepower]

Bill to the rescue again! Thanks, Bill. That makes sense and you can't argue Ohren (and win), but I just feel better using a non-conductive spacer there. Mine never go fast enough to wear out the spacer.

[Bill from NH]

Gary, I've never not used one either! Some day I got to try Monty's motor brush break-in procedure under water. Have you ever tried using it? I know it works because I've seen other locals successfully use it.

[havlicek]

You know...I've always used the fiber washers too until recently, just because of the supposed "oil shield" thing. It never seemed as though shorting the com on the brass endbell bushing or steel bearing was much of an issue. Many coms have extra phenolic at their end which would prevent this and even adding a brass washer to those that don't should prevent this because they're smaller diameter than the coms in most all cases. I started setting up the arms for a particular motor so there's just a bit of wiggle room to add a brass washer or so at each end because they can prevent wear and make an arm run smoother in some cases. Sometimes I'll add a fiber washer just because they fill more space than a thin brass washer.

-john

[Bill from NH]

John, when you need to fill more space, brass arm washers(spacers) are still available in .020 & .030 thicknesses. If you use one thick one rather than 5 or 6 thin ones, you get less harmonics.

[havlicek]

10-4 Bill and roger-wilco I try and keep an assortment of the different thicknesses on hand...but also resort to using what I've got often You make another important point though (as usual), it's not just how much endplay an arm has in a setup that counts, but what "kind" of endplay. If the com and tail end of the arm aren't "true" in relation to the bushings and bearings faces, that can setup some weird vibrations. I've come late to this realization and how significant it can be sometimes, that's where guys who (unlike myself) can really setup a motor can really make it sing just by how they handle the details. When you have something that's spinning as fast as some slot car motors...everything counts!

-john

[havlicek]

Some more info for anyone looking for parts. I recently got some Wasp and Super Wasp arms from Jeff Easterly (thanks Jeff) and the coms on these arms are relatively easy ("relatively" being the operative word) to reclaim. The crimped tab can be opened carefully with an exacto knife blade and afterwards, you can cut off the shaft with the rest of the arm and tap the remaining shaft out of the com hole using another shaft as a pin punch. Of course...if you actually own a properly-sized pin punch, that would be fine also For a couple of hours work I got a bunch of very nice coms.

-john

[NSwanberg]

Hi Ken,

Also Simco...I remember the Simco being more available than the Belden myself as the slot tracks seemed to carry that brand, but maybe that was a local thing and other areas had the Belden more frequently(?). I don't remember who made the silver stuff...maybe they all did. The wire from Planet Engineers is very good stuff whoever they source it from, and the one pound rolls they sell will last for many many rewinds. From time to time people give me some of the old stuff, but I worry that the insulation might have gone brittle after 50 years or so...after all...I have In any case...magnet wire is magnet wire, regardless of who it comes from and it's the type coating that's really important. There are also ceramic-coated magnet wires rated for very high temperatures that I haven't tried because they're very expensive. There's also flat magnet wire that really seems cool and looks like it would produce a very compact and symetrical coil, but I never found small quantities in small gauges that might be suitable for slot car motors. I remember Tony P saying that they tried the stuff for RC cars, but I think he said it didn't have any significant performance advantages.

-john

Isn't the theory on flat wire enhanced surface conductance?

Not that I am an experienced winder but it seems to me that flat wire might bend around the poles better.

Any thoughts from the master?

[havlicek]

Well, "the master" isn't here Nelson, but from what I understand Tony tried flat wire with RC motors (the application is finctionally the same) and found no real-world benefit. I wanted to try some but couldn't find any in a suitable size and small quantity that would make this feasible. Winding flat wire around the poles might make a more compact coil, but it might also be a little more fidgity around the com tabs. It would be cool to try though if some of the stuff were around.

-john

[Phil Irvin]

I try and keep an assortment of the different thicknesses on hand...but also resort to using what I've got often You make another important point though (as usual), it's not just how much endplay an arm has in a setup that counts, but what "kind" of endplay. If the com and tail end of the arm aren't "true" in relation to the bushings and bearings faces, that can setup some weird vibrations. I've come late to this realization and how significant it can be sometimes, that's where guys who (unlike myself) can really setup a motor can really make it sing just by how they handle the details. When you have something that's spinning as fast as some slot car motors...everything counts!

-john

Manny moons ago. A heep big motor builder said he dresses both ends to make then square to the bushing & shaft.
I had complained about some large stamped motor spacers that were out of round and on a hot motor. They would make the motor 'sing' funny. I found that the motor would really sound good till I put the motor spacers on to limit the play. Out of habit. I now dress both sides. I have a diamond brush tool that has holes in it just for this reason. I still check ALL my spacers and still every once in a while will find one out of round or bent & will toss it....

OLPHRT
PHIL I.

[havlicek]

For sure Phil...like I said, I'm learning slowly On a related subject, I spent some time yesterday and today and recovered 11 lovely Mura coms and 6 or 7 arm blanks from used arms. I'm loaded for bear I also straightened-out a Champion 26D can and polished it up. Afterwards, I removed the bearing which had lost it's balls and replaced it with one of the couple I salvaged from some other motors...so next project will be a beautiful Champion 26D with a minty fresh endbell from Roger at Mid America that I also added an original ball bearing to so the whole thing will be a fairly period-correct mild rewind. I assembled the arm from some stack plates I had left from other motors and used a new drill blank for the shaft. I don't have any specific person I'm building it for, but I'm stoked!

-john