# 'Other' pancake arms...



## lenny (Feb 29, 2000)

What do you like/dislike about the pancake arms that are 'available' from Model Motoring and JL/AW?? Much has been made of the 50 ohm catastrophe of MM, but was there anything about their arm that was notably worthwhile? Same for AW. 

Dan


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## Bill Hall (Jan 6, 2007)

*For a few dollars more...*

For me it's always gonna be a QC issue. Which ever one has the most desireable amount of good traights or least amount of undesrieable traights. The same way you'd grade out any pile of arms. 

I dont see any particularly new issues other than the USUAL, meaning chronic, problems that have plagued pancake armatures since day one regardless of who made them.

Feel free to pile on if ya have something to add

1. ballance, mechanical & electrical
2. Comm plate, correctly mounted; concentric and parallel
3. good clean solder joints void of stalagtites, goobers, and craters
4. tight wire bundles on the poles...aka no flubbering flappers
5. good linear response to input
6. repeat these steps for each unit

I would pay EXTRA for such a thing, in other words charge what they are worth, and have no qualms. Personally I've grown tired of the chronic whine about how MUCH everything costs. Fine! Run along and grubble through piles and piles of mediocre carp to pinch a nugget. My time is valuable. I for one wouldnt mind coughing up a few more bob to save some time and have piece of mind.

Drop in a zinger and go play little cars.


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## lenny (Feb 29, 2000)

Bill Hall said:


> 1. ballance, mechanical & electrical
> 2. Comm plate, correctly mounted; concentric and parallel
> 3. good clean solder joints void of stalagtites, goobers, and craters
> 4. tight wire bundles on the poles...aka no flubbering flappers
> ...


of these, where did the MM and JL/AW offering fall short, or excel?


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## martybauer31 (Jan 27, 2004)

I totally agree with Bill...

As for MM and JL/AW, no experience with the former other than the legions of folks who watched them turn t-jets into smoking holes on the track, but the JL/AW have worked pretty well for me overall.

I made a post a while back about experimenting with my fray cars, taking 5 random NOS arms and 5 JL/AW arms, the 5 NOS were mediocre at best and horrible at worst. The 5 random JL/AW, 4 were right on par with my very best fray arms, the 5th one was a bit behind but not bad.

So the big thing with me is consistency, if you can do that, you will be successful for sure.


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## tjetsgrig (Nov 1, 2009)

I don't like how the JL/AW shafts are a single piece of stock "pressed" through the stack, then they used the spacers which leaves room for to many variables and extra parts, but they do have a nice comm plate. The MM had descent shafts with a shoulder, they pressed in to the shoulder. I like the "steps" on the Aurora arms instead of the spacers that JW/AW used. Aurora also used better steel for the laminates. I can wind an Aurora motor to the same spec as the JL/AW 3 laminate arm and it wil outperform it!


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## smalltime (Jun 3, 2006)

lenny said:


> What do you like/dislike about the pancake arms that are 'available' from Model Motoring and JL/AW?? Much has been made of the 50 ohm catastrophe of MM, but was there anything about their arm that was notably worthwhile? Same for AW.
> 
> Dan


I have no experience with the MM arm, I sent all of them back for a refund.

The JL/Aw arm is a fine peice. Is very solid,(never spins on the shaft,or throws winds) Performs VERY well. and is very consistent between arms (IE in the ohm dept.)
The commutator is SUPER. Flat and long wearing. Solder points are never globbed.

The only drawback is the "keeper" washer on the bottom of the arm shaft. I have to pull them off the comm on around 40% of the arms I use. If it is on too far, it "dishes" the comm, making for a lethargic (sp) performer.

Hope this helps.


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## lenny (Feb 29, 2000)

smalltime said:


> I have no experience with the MM arm, I sent all of them back for a refund.
> 
> The JL/Aw arm is a fine peice. Is very solid,(never spins on the shaft,or throws winds) Performs VERY well. and is very consistent between arms (IE in the ohm dept.)
> The commutator is SUPER. Flat and long wearing. Solder points are never globbed.
> ...


OK, now one of the raps against the AW arm is that the comm plate is warped (I attribute this more to the factory assembling them on the gear plate, using an incorrect tool). So you haven't had warped or concave comm plates?

Also, what is the 'keeper washer'?


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## tjetsgrig (Nov 1, 2009)

lenny said:


> OK, now one of the raps against the AW arm is that the comm plate is warped (I attribute this more to the factory assembling them on the gear plate, using an incorrect tool). So you haven't had warped or concave comm plates?
> 
> Also, what is the 'keeper washer'?


The "keeper washer" are the spacers that I refered to, they are small brass spacers pressed onto the shaft, the bottom one after the comm has been installed. It can be pressed on too far and suck the center of the comm up making it concave. They also act as the thrust surface, where the Aurora arm shaft is stepped in that area. They tend to move at times.


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## SwamperGene (Dec 1, 2003)

tjetsgrig said:


> The "keeper washer" are the spacers that I refered to, they are small brass spacers pressed onto the shaft, the bottom one after the comm has been installed. It can be pressed on too far and suck the center of the comm up making it concave. They also act as the thrust surface, where the Aurora arm shaft is stepped in that area. They tend to move at times.


They can also be too far down on the shaft, pushing the arm up too high when everything's assembled. This affects spring pressure and gear alignment, even if it's only down a few thousandths too far.

I tend to agree with Dan on this one, on the few warped JJL/AW comm plates I've seen, the bushing wasn't even touching...I've always considered the warped plates a manufacturing issue.


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## grungerockjeepe (Jan 8, 2007)

I agree with what everyone's saying about the AW arms. Generally they run real strong, outside of that one here and there that'll have the 'keeper' pressed on to tight and warping the comm plate. Im not involved in any sanctioned racing at this point, since there doesnt seem to be any near me. I collect cars, and run them for fun against friends here and there. Say what you want about some of AW's other QC issues, but ever since the X-Tractions have gone to the stiffer plastic material the performance is very consistent and theyre all torquey with decent top end. 

Even if the Dash arm performs exactly the same as the AW piece, that still makes it an upgrade for most AFX or MT chassis and Id definitely be buying some.


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## SwamperGene (Dec 1, 2003)

lenny said:


> OK, now one of the raps against the AW arm is that the comm plate is warped (I attribute this more to the factory assembling them on the gear plate, using an incorrect tool). So you haven't had warped or concave comm plates?
> 
> Also, what is the 'keeper washer'?


This:









This is an example of my previous post, warped comm plate, bushing not touching.


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## tjetsgrig (Nov 1, 2009)

SwamperGene said:


> This:
> 
> 
> 
> ...


Nice example photo. The concave comm is the result of the keeper being against the comm at one time though. I use the JL comms for some of my custom winds and most times the keeper is really crammed on there!


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## SwamperGene (Dec 1, 2003)

tjetsgrig said:


> Nice example photo. The concave comm is the result of the keeper being against the comm at one time though. I use the JL comms for some of my custom winds and most times the keeper is really crammed on there!


Thanks....but this was fresh out of the box, this one was crimped too tight. 

I have seen them pressed on too far as you mentioned though, but most I've come across are like the photo (the bushing, not the warped plate  ).


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## smalltime (Jun 3, 2006)

lenny said:


> OK, now one of the raps against the AW arm is that the comm plate is warped (I attribute this more to the factory assembling them on the gear plate, using an incorrect tool). So you haven't had warped or concave comm plates?
> 
> Also, what is the 'keeper washer'?



The Keeper has already been covered.
I have not detected the warping you speak of. The plates seem to me to be thinker and more robust than the Aurora offerings. 
So I would answer your question this way:
No to warping, and Yes to concave plates.


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## Bill Hall (Jan 6, 2007)

lenny said:


> of these, where did the MM and JL/AW offering fall short, or excel?


A. Oh man....I didnt know there was gonna be a test. 

B. Someone told me I'd get a free camera if I attended this time share seminar.

C. My dog ate my homework.


Didnt ever see the need to keep notes Dan...sorry. I'm more of a tendency guy. In other words your not gonna see the same tendencies from a product that is made kinda the same but differently. The question before you is what tendencies will you accept vs the cost to narrow them down.

Bushed or spaced arms are done to cheap out on the machining cost of stepping a shaft. Yeah duh, we know that. But obviously one might consider the idea that the frequency of cupped comms might be increased compared to a stepped shaft in that we are seeing a rash or epidemic of a certain symptom. 

Personally I've seen many AW arms push their windings out and a few have spilled their guts. The reason? My fault! 22 volts at 20 amps with geeked up magnets, better brushes and higher comm spring pressures, buffed gear sets. The more Revs you put to them, the greater the oppurtunity for failure. My 2 cents is that the bundles might be a hair loose. 

You'll see tossed windings in a certain percentage of AFX armatures as well...and why not? When ya toss some polymags and wizzard brushes at them...interestingly I havent noticed it so much with later high ohm magnatractions...the vast majority dont wing up all psycho like the 6 ohm burners.

I also always thought the AFX comm plate had some concentricity problems, either the tabs were mislocated or the hole was placed off center. Even worse were the AL repops where the brush tracking looked like the orbit of Pluto. Often 3 out of 4 were garbage because they wobbled like a fat chick in spandex, didnt have good resonse, or ran too hot. 

All my MMll arms went cajun style so there really wasnt an oppurtunity to observe much through the smoke.

As for the t-jets, I can say that the vast majority have decently centered comms, maybe not always perfect but passable to the point where ya generally have to look close. While other folks results may differ I have never seen a t-jet comm plate that could be used as a soup bowl...unless it's been molested. If anything they fall way short in the natural balance department, as I dont think it was a huge consideration back in the day. Barfed windings are fairly common given that we expect them to take whatever we throw at them...and most of them are as old as I am. Ok maybe just a bit younger.


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## partspig (Mar 12, 2003)

SwamperGene, Looks like a plethora of loose wire on the poles on that armature too! The JL series one motors to about series three motors all were notorious for warped com plates and loose retainers. I sold many, many of those to motor builders! They were not much good for anything else but parts!


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## tjetsgrig (Nov 1, 2009)

Bill Hall said:


> wobbled like a fat chick in spandex, didnt have good resonse, or ran too hot..


Fat chicks in spandex will usually perform like this!!


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## lenny (Feb 29, 2000)

SwamperGene said:


> This:
> 
> 
> 
> ...


was there a photo attached? I can't see it...


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## SwamperGene (Dec 1, 2003)

It's still there for me...I emailed you a copy just in case.


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## NTxSlotCars (May 27, 2008)

I just had to see what the crowd was all about.


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## noddaz (Aug 6, 1999)

*So we will borrow the picture*

And host it on the Hobby Talk site..









Did that work?

And a note about MM arms.
I dropped one on the floor while working on a chassis. (oops)
Picked it up and found that the shaft had been bent by the fall.
While I don't make a habit of dropping armatures, I don't remember bending a shaft before that or after that...


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## 1scalevolvo (Feb 5, 2004)

noddaz said:


> And host it on the Hobby Talk site..
> 
> 
> 
> ...



MM arms are the worst ! Poorly soldered & to easy to "Cook".The solder has too low a melting point which is its worst feature.I have a lot of MM chassis with good used Aurora arms with gear plate or without.


Neal:dude:


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## Grandcheapskate (Jan 5, 2006)

I got my first T-Jet back in 1969. In all the time since then, I have only burned out one pancake armature, and none in the past 35 years. Now, for a lot of that time I didn't run the cars, and I don't compete. I just basically take a stock car, do what I can with the parts it came with, and run it. Even the only T-Plus chassis I run works just fine.

Dan, you need to decide which market you want to go after. The guys who want a top of the line armature, or the guys who race in their basement (or in little groups) just for fun. The quality that goes into the armature will determine it's cost and customer base. There are guys who will put $100 of parts into a chassis. There are others who use what the car came with and only replace worn/damaged parts.

If you want to go after the competive racers, then the quality will need to be really good, with a price tag to match. That may discourage the non-competive guys who just want some replace arms for fun.

My guess is you may want to go for superior quality and let guys who want the "basement arms" get them from parted out JL/AW chassis.

Thanks...Joe


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## hartracerman (Jan 9, 2005)

There are already at least 3 guys who do hot arms. Nobody does just stock arms. Most of the clubs I see and at HO shows always have just stock races so anybody can buy an off the shelf car and join in the fun. I think your best bet is to fill that void


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## Grandcheapskate (Jan 5, 2006)

Hard to know which group to please. Actually, not so hard. The group to please will be the group that is going to buy the most armatures.

If you go for stock replacement arms, the price will be lower, but the quality may not be what the most competive racers want (and hence, the inevitable complaints). Go for a superior quality arm, and the casual slotter may decide it's more cost effective to part out an entire JL/AW car.

I don't know enough about the marketplace or the technical aspects of the armature to make an informed opinion. Personally, if I needed replacement armatures, I'd want one that was low cost and Aurora-quality. If the armature was of high, race-competive quality, but cost as much as a low end JL/AW car, I'd go for the complete car.

Your magnets are a great addition and very resonably priced. An armature with characteristics that worked well with those magnets would make a nice matched set.

Joe


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## NTxSlotCars (May 27, 2008)

Tycos :thumbsup:


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## lenny (Feb 29, 2000)

Grandcheapskate said:


> Hard to know which group to please. Actually, not so hard. The group to please will be the group that is going to buy the most armatures.


then that settles it. I'm going after the drag racers...:wave:

(that was a little ha-ha...)


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## grungerockjeepe (Jan 8, 2007)

NTxSlotCars said:


> Tycos :thumbsup:


YEAH!! Dan, whats the status on that redesigned HP-7 you mentioned a year or 2 ago? Thats what Im waiting for.


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