3573 replies to this topic

[Horsepower]

That's exactly the grit I've been using, so maybe it's my rush to brush that's makin' it mush. I'd be interested to know if anybody has any other brands that they have had good luck using.

[havlicek]

Hi Gary,

What about regular old machinist's dye, the stuff you use for marking and layout? I don't know how well it would hold up or how it would be to try and put it on evenly, but it should help prevent rust.

-john

[Bill from NH]

The first arm dye sold for slot cars was the blue machinist's layout fluid. As I recall. it went on okay but a coating didn't last all that long. Gary, later Parma would sell some slightly different stuff in at least red, blue, & yellow. I still use a bottle of their yellow. I wouldn't say it goes on any differently than the popular Lucky Bob's dyes. Lucky Bob's is available in black, purple, red, yellow, & green. They used to also sell blue in their line but stopped because after a few months it would break down & separate. Ask me how I know, cause I still have a bottle.

[havlicek]

I did a second arm for my 36D project. This one is a #27 that's overwound a little so it isn't too crazy. I used what I think is a Champion com rescued from an old arm and a stack of unknown origin. This is a lot more like what I want to get from a 36D and the arm measures somewhere between .4 and .5 ohm, drawing about 1 amp.



I also wanted to try the arm in a can that I installed ball bearings in, but was unsure about how it would run since all the bearings I have seem a sloppy fit by today's standards. So I had a Champion can that I had to strip because the paint was wrecked. When I stripped it, I found that the can was in perfect condition, so instead of repainting it, I polished the thing up. I drilled/reamed the brass bushing retainer and solderd-in a bearing and I really like the way it looks all shined-up. Anyway, the arm runs really nice and this can has regular Mabuchi 36D magnets (all I had), so I think that with Arcos I can get even more out of the thing. I still have to see about soldering the brush hoods and I might also try winding a set of heavier springs to see how that affects things.



-john

[Tex]

Gosh, just looking at those copper winds lined up perfectly symmetrical is... is? ... makes me... ? .... well, I could just stare at it for a long time!

[Old pink can guy]

john sorry I have not sent the pictures we talked about will try and do it this week end things have been a little hetic for me. and wow you have acheaved the status of A master crafts man!!! just plain beautiful!!!!

[havlicek]

Thanks for looking in guys. No worries Ken...things have been crazy here as well, what with trying to survive until the economy recovers

I wound a set of springs for this motor using .016" electric guitar strings as spring stock, figuring that the stock springs were kind of weak. Sometimes you can hear when a motor spins up that as it goes higher it gets to a point where it doesn't seem to be running proportionally faster as you increase the voltage. Assuming you don't have arcing, I think this can be a sign that the springs aren't up to the task of keeping the brushes in solid contact with the com. These springs are significantly stronger than the factory 36D springs and now the arm spins with real "oomph"!, drawing about 1.75 amps as opposed to 1 amp or less before. I think that's a good compromise, but just as added insurance I added my one and only set of Steve O'Keefe spring post protectors. Like everything he does, these are just beautiful...who'd have thunk that something as mundane as post protectors could be so lovely!



I'm going to keep this setup and this arm just as-is as the stock magnets seem entirely appropriate here, and I'll save the other can with the Arcos for another project. Now that I'm comfortable with where this is headed, I'll tear it apart so I can clean it all up, drill the endbell for screws and make sure the arm is centered in the field. I like this motor! I can also, after doing a little break-in, try winding a set of springs out of .011" guitar strings or with an extra coil to lighten them up and see how those work...but things seem fine with the heavier .016" springs

-john

[proptop]

John...your work is awesome ... there's something about the vintage motors that so cool...reminds me of watching my brother working on his motors back in the mid 60's. Love the pics

One thing I left out when talking about using Sharpie or Magic Marker...something that Bill mentioned...how long the colors last, especially when you use motor spray.

I used to clear coat the stack with VHT High Temp clear, (after masking the ends of course) and that would keep the motor spray from washing off the colors..at least for a while.

I also tried a 15T of 22 on a Mura blank...it was a burned up Challenger I that a friend gave me...
I was so inexperienced at it that I neglected to tie around the comm or "cap" it w/ the dental floss that I used to "tie" it...
It didn't last long...I can still remember the comm segment bouncing off my forhead as I zinged it up on my battery charger (after that I started wearing safety glasses when test running motors...and don't run 'em on a 13.5V. battery charger)

[havlicek]

Thank you very much Tom. I don't want to sound falsely modest, but I've made about every mistake and poor judgement call there is to make in the last two years getting back into winding, If I'm lucky, I don't repeat those errors...much Part of doing all this is just learning how to recover parts as the days when arm blanks, coms and other materials were easy to get are long gone. Sometimes you do a lot of work to get a useable blank or com and then find out it wasn't worth it The only good news is that there seems to still be a fair amount of Mabuchi stuff out there that people no longer use and they sometimes send it to me...often for nothing in return!?

I've blown-up my share of coms both as a kid and even still today, so I know what you're talking about One thing I've really started devoting time and effort to is how I tension the wire as I'm winding. The insulation on this #27 wire I got seems more slippery than the other gauges I have, so you have to be careful as you come back towards the shaft on each layer to start easing-up a little until after you've fully turned around or the patterns will fall apart. Also, the tabs on this com do almost nothing to hold the wire until it's soldered which made this one even more difficult. I put little nicks on each side of each tab to give the wire somewhere to grab onto, but still had trouble keeping the wire on the tabs. Anyway, thanks for looking in and the encouragement!

-john

[havlicek]

The 36D is dun-dee-dun-dun. I disassembled it and cleaned it all up, drilled the endbell for screws, centered the arm in the field, fixed the post protectors to the posts, marked the endbell and can so they get reassembled the same way every time, soldered the brush hoods to the heatsinks, flushed the endbell and brushed it clean with denatured alcohol to get rid of any flux or whatever, gave it a quick breakin at both 2V and 4V and a couple of spin-ups and stuck a label on it.



-john

[havlicek]

So I've sorta hit a wall with the 36D bearing thing. All the ones I've gotten from bloggers are really 3/32" bearings that are a fairly loose fit on a 36D arm shaft which is actually several thousandths under 3/32". Surprisingly, these still seem to work just fine as I've got them in the above motor. This got me to thinking though; why fight it?, I could just install a 3/32" axle on a 36D stack and get a nice tight(er) fit for the shaft by using 3/32" bearings. Considering all the possible "gotchas"...the only problem I can see (and it's really not a problem at all) is that whatever pinion is to be used may have to be slightly opened up to fit. That doesn't sound like any real problem at all. Another nice benefit is that very hard/straight/strong 3/32" drill blank axles are dead-easy to get and they would make lovely arm shafts. This should all make for a better running motor and so..."I'm going in". Somebody send a search party if you:

1)Don't hear from me in not too long

---OR---

2)You hear cursing coming from the direction of Long Island because I didn't take something into account

-john

[don.siegel]

Good luck Private Havlicek! Sounds like a good idea actually, and shouldn't be too hard to ream/file out the pinions.

Speaking of 3/32 shafts, have you ever tried to rewind a 5 pole arm? All this 36D talk got me thinking about the Ram-Boochie, which was the Ram hopup kit for the 36D with their 7-pole arm and a Pittman style endbell... 7 poles may be a lot, but a 5 pole arm could be interesting (not that I've ever dared try one...). I've found a few interesting experiments with 5-pole Pittman arms in 16D cans as well (and I think Rick/DC65X has tried this as well - I believe he's still cursing in fact...).

Just a thought...
Don

[GTPJoe]

Hi John,

Sir, I've seen eurosport racers here turn down the end of their eurosport arm from 2mm to 1.5 to fit new 6 tooth euro pinions so why couldn't you do the same??

These are expensive Lee Gilbert motors that they just use a dremel and a cut of disk to slowly take the end of the shaft down. They spin the motor slowly as they do it. Beats drilling out a pinion.

"Try it, you'll like it!"...

See ya!!

[havlicek]

Hi Don,

I've never even held one of those motors in my hand much less rewound one :-) They look difficult because of the narrow gap between the poles and I seem to remember that the wind isn't supposed to be a regular series-type wind or something. Don't you wind one pole and then skip the next and wind the thrid and then skip and then wind the fifth and then skip to the 2nd, 4th or something like that ...or am I mistaken??? They look like very cool motors though and a five pole seems like it ought to be a smooth(er) running motor if the rewinder (moi) didn't butcher the thing

-john

[havlicek]

Hi John,

Sir, I've seen eurosport racers here turn down the end of their eurosport arm from 2mm to 1.5 to fit new 6 tooth euro pinions so why couldn't you do the same??

These are expensive Lee Gilbert motors that they just use a dremel and a cut of disk to slowly take the end of the shaft down. They spin the motor slowly as they do it. Beats drilling out a pinion.

Hi Joe,

Actually, slightly opening the hole of a pinion (remember these pinions are far larger than "normal") should be a snap. Also, many of the 36D pinions are the setscrew type with gobs of extra material...even though we're only talking about a few thousandths. Another thing is that what we have here is a shaft that's normally slightly undersize for the available bearings...we wouldn't want to be turning down the shaft...we'd want to be adding material to the shaft

-john

[Prof. Fate]

Hi

I have done both 5s and 7s and, really, they aren't as difficult as you try to talk yourslelf into them. I mean as a lad in 63 I was rewinding the pittman 703/4s for the longer tracks.

I have been pondering your bushing problem, john. And I am not sure what is happening. I haven't seen that and I wonder at the bearings we are doing. I remember that, in the day, one could find 3/32 bushings and bearins that were alternately .062 625 and 63. But I just haven't had that problem in recent times. One nightmare of the time was the MPC "high rise, which was .0635 and .....

Perhaps we need to step back here. Start with the arms you have, meter them, meter the bushings then talk to Rick and Duffy who have the equipment to, perhaps actually solve this stuff for us!

But I am wondering. I mean I have survivors that I still run!

Fate

[Buggyboy]

I guys , I have a question about the motors, but NOT being used in a slot car, I do race slot cars but I also have a few RC cars, in one case I have a XMOD rc crawler that runs on 6 volt power, I have tried several motors but none have enough torque, I would like to try and rebuild a motor ( I have several laying around and I have rebuilt a few of my 16d and 12x motors, I AM NOT A MOTOR BUILDER, just a MOTOR BUILDER LEARNER. ) anyway would I use more or less windings to create the low end ( slow ) torque I am wanting. AND do you have any other input for me ?

Thanks

[havlicek]

I have been pondering your bushing problem, john. And I am not sure what is happening. I haven't seen that and I wonder at the bearings we are doing. I remember that, in the day, one could find 3/32 bushings and bearins that were alternately .062 625 and 63. But I just haven't had that problem in recent times.

Hi Rocky,

I don't have a "bushing problem"...it's the bearings that cause the problem...but it's really not THAT much of a problem, more of an annoyance. I have worked on some 36D motors for others that had (what I assume) were factory bearings installed that were a perfect fit for the regular 36D arm shaft...actually even a little snug. However, I haven't found any on my own that fit properly. I have tried several different sets of vintage bearings and those have actually all been 3/32" ID bearings which are naturally a loose fit for a 36D arm shaft which is under 3/32" by several thousandths. If I hadn't seen some bearings that fit properly, I would have thought I was just expecting too much precision as the Mabuchi bearings were also a sloppy fit. I already have installed a set of vintage bearings in the 36D above and even though they aren't a precise fit, they seem to work just fine.

Perhaps we need to step back here. Start with the arms you have, meter them, meter the bushings then talk to Rick and Duffy who have the equipment to, perhaps actually solve this stuff for us!

It's really pretty simple, and I have carefully measured the shafts from many 36D motors and they all come out exactly the same (which is to say under 3/32"). These all fit the factory bushings very well, and all fit any and every bearing I have tried rather loosely. It's really not a matter of measuring anything and it all boils down to:

1)36D arm shafts are under 3/32"
2)Vintage bearings from three different manufacturers that are supposed to be for this application are all sized for 3/32".

Thanks for the thoughts Rocky, but I'm more than half way through a solution anyway and so far so good.

-john

[havlicek]

I guys , I have a question about the motors, but NOT being used in a slot car, I do race slot cars but I also have a few RC cars, in one case I have a XMOD rc crawler that runs on 6 volt power, I have tried several motors but none have enough torque, I would like to try and rebuild a motor ( I have several laying around and I have rebuilt a few of my 16d and 12x motors, I AM NOT A MOTOR BUILDER, just a MOTOR BUILDER LEARNER. ) anyway would I use more or less windings to create the low end ( slow ) torque I am wanting. AND do you have any other input for me ?

Hi Robin,

I'll offer what little I can and I'm sure others with more/better knowledge will chime in as well.

1)I would start with the assumption that the magnets and the arms in your motors are what they are (winds, stack height and diameter, magnet strength and gap etc.) because they were designed to a purpose. If all the motors you have don't have enough torque, my first assumption would'nt be the motor design at all since several different motors seem lacking...I would suspect gearing and would try a higher numerical gear ratio ("lower gears").

2)Assuming the magnets are up to full strength (?), I would also say that a hotter wind (less turns of thicker wire) will give you more RPMs and less torque because there's generally no free lunch. To a certain degree, more RPMs can also help in the punch department because of the ability to run higher numerical gear ratios. If there is such a thing as better magnets for your motors that will produce a stronger field, then a hotter wind with different gearing may produce the desired effect. The tradeoff will be that the motor will draw more current (and get hotter too) and in the case of a battery-powered car I would guess a significantly shorter run time before the batteries are discharged.

Like I said, there are others here who know much more about this stuff (Tony P for one)...the above are just generalities. Whenever you try and inmcrease the performance of a car, all the related pieces of the car can start to show their weaknesses.

-john

[tonyp]

Robin,

For instant torque use a motor with less turns and a small pinion gear. This combination will convert the higher rpm wind up of the motor into instant low end punch. The powerband will be short but the low end will be there.

If you are looking for a powerful motor with a big broad powerband so you can go slowly than you need to use a motor with more turns.

[havlicek]

...bingo! Thanks Tony.

-john

[havlicek]

Working on this 36D thing, I checked all the 36D endbells I have here and an old Champion was a perfect fit for the OD of one of the vintage bearings I have. The same bearings are loose in the Mabuchi endbells. This Champion had a crack that had to be repaired and as usual, the crack was at the weakest part...right on one side of the bushing. It wasn't cracked all the way through though and the rest of the endbell was in good shape. I did something like the bearing strap mod I saw in Philippe's post, but in this case, the strap only serves to strengthen the endbell and not to locate/mount the bearing.


Even though this endbell had the square Champion bushing beforehand, the round recess was a perfect "snap-fit" for the new/vintage bearing


I did the normal body and fender job on the can (stripped it, filled-in the magnet tabs and can screw holes with solder that were top and bottom) and painted it "New Hampshire Special Blue" (I hope Bill doesn't get wind of this) after reaming the brass bushing boss and soldering in the new bearing.



Arm is wound and in the easy-bake oven.

-john

[Buggyboy]

Thanks I will look over the motors I have. Good thread here I will need to read more of it , maybe I can even remember some of it.

Thanks

[havlicek]

The arm's finished. I sort of mangled the lams a little because I at first thought I could press them onto the slightly oversized shaft...wrong! I got two lams on there and realized it wasn't going to happen and had to drill out the lams and then install them on the new shaft (3/32" drill blank axle).



Installed it in the motor and it runs sweet! I have to take apart the endbell, clean up the hardware and solder the brush hoods, but wanted to try the thing first. Anyway, this is what I got before cleaning everything up.



-john

[Pablo]

"El Cracko"