28 replies to this topic

[Dave_12]

Which brand motor brushes to you prefer and why?

[Dave_12]

The reason i am asking is that there are so many different makes of premium brushes available these days.

[Bill from NH]

Are you asking about brushes for open class motors, or what? For various classes, you'll get different answers. The last time I ran wing cars competitively, I used Mabuchi "pull-outs". Today, both Koford & Proslot sell brushes that'll wear better.

[Dave_12]

Bill these days there are Red Fox, Cahoza and Mid America brushes as well as Koford and Proslot. 

[Bill from NH]

There is no magic answer. Buy a pair of each or a couple & see how the brush wear compares & if any dig up your comm surfaces. See if they all draw about the same amperage while breaking them in on a supply.

[MSwiss]

Are you asking about brushes for open class motors, or what? For various classes, you'll get different answers. The last time I ran wing cars competitively, I used Mabuchi "pull-outs". Today, both Koford & Proslot sell brushes that'll wear better.

I recall reading the factory that manufactured Koford and Proslot high end brushes doesn't exist anymore.

[mreibman]

I recall reading the factory that manufactured Koford and Proslot high end brushes doesn't exist anymore.

I heard something similar - that brushes are going to be hard to come by.

 

That being said, personally, I like both the Koford SBF2 brushes and the Proslot X7 brushes.... (for ceramic group motors) and I've HEARD that there are some very good motor builders out there who use 1 of each on their motors.

[Phil Hackett]

I heard something similar - that brushes are going to be hard to come by.

 

That being said, personally, I like both the Koford SBF2 brushes and the Proslot X7 brushes.... (for ceramic group motors) and I've HEARD that there are some very good motor builders out there who use 1 of each on their motors.

So....hanging onto the big bag of Mabuchi pull-outs might actually have paid-off?

[Bill Seitz]

When I asked this question of Joel Montague (Camen) some years ago, his reply was "Big Foot". This was what Mura called their brushes, and Koford now has the "Super Big Foot". I'm sure everyone has their secret recipe for brushes, but I've used Koford, ProSlot, no-name (probably Parma), take-outs, and more recently DMW Products brushes. I'm not a serious competitor, but I can't tell any difference. The motors perform the same with all of them, though you might get more comm wear or longer brush life with one brand over another. If I were to pick a preferred brand, it would be Koford, but the DMW Products brushes are cheaper than others and seem to work just fine.

 

As far as a shortage, I haven't discovered one yet. China (and others) still make lots of brushed DC motors despite what the BLDC crowd wishes us to believe, and I'm reasonably certain that won't be changing any time soon. They've got to get their production brush material from somewhere.

[Ken Lenz]

despite what the BLDC crowd wishes us to believe

Just cant help yourself can you Seitz

[Phil Hackett]

Slot car motor brushes aren't "off-the wall" items. There's a specific formulation and the "mill run" isn't a trivial amount, either in money or quantity.

 

Bob Green (R.I.P.) was probably the most knowledgeable person in the slot car industry about how, what, why brushes work and don't work. It was an honor to listen to him about the various qualities our little motors require that general use DC motors don't. Here's a tid-bit: slot car motors have a ***VERY*** high current density compared to the usual brushed DC motors. In some cases over 2000 amps/square inch, momentarily. That's enough to vaporize many materials. It does....and makes a plasma between the brush and the commutator...the commutator doesn't wear because of mechanical friction but because of the heat/plasma of the brush/commutator interface. Something has to wear and the brush better than the comm.

[Mark Onofri]

Well put Phil, not to mention arcing, poor radiusing,misalignment and, a bad sunting job. I've found that the last 4 seem to have more effect than the type of brush.
Can't remember who made "gold dust" brushes but I had the best results with them.

[Bill from NH]

Gold Dusts = Proslot

[Dave Crevie]

For a while I was cutting down R/C silver brushes. I made a fixture to hold 8 at a time so I could do them in the surface grinder. In the end though, I don't think they were any better than the "brush of the month" at the time. If brushes get rare it might be a way to solve the problem. But with R/C going all brushless, they may be in the same boat.

[Bill from NH]

Does anyone think 36D sized brushes are only used in slot car motors?

[Mark Onofri]

Thanks Bill. As far as the 36dd brushes, there's gotta be another use for them. Just like track braid.

[Bill from NH]

I think it was RGEO who once sold a jig for filing/sanding 36D brushes down to 16D size.

[Mark Onofri]

This might not have anything to do with your question but, I was messing around with some old 16d's sitting on my bench. Don't know why but I thought I'd put a few together. Grabbed some rewound arms from IDK who and I think some cat mags. Suddenly I remembered that I had some shunted brushes. Wow, do they scream! Leading me to believe that's the way to go, if you can find them. These are the ones that have the shunt right in them. Maybe they form them from a slurry or something.

[Bill from NH]

I've never bought any shunted brushes, but I'd assume the shunts were placed in the brush as part of the manufacturing process. I sort of made my own. I used a micro drill (probably between a #45-50, my dad was an LP gas serviceman) to drill a small hole half-way into the brush from the spring end. I then took my shunt wire & twisted one end tightly so it would fit into the drilled hole. I cut the twist about 1/4" long & stuck it into the hole dry. As the brush wore, it just slid along on the wire twist, never hanging up the brush, spring, or shunt wire. I used this shunt arrangement on all my open class motors when I ran wing cars in the 70s & 80s.

[Jaeger Team]

I've never bought any shunted brushes, but I'd assume the shunts were placed in the brush as part of the manufacturing process. I sort of made my own. I used a micro drill (probably between a #45-50, my dad was an LP gas serviceman) to drill a small hole half-way into the brush from the spring end. I then took my shunt wire & twisted one end tightly so it would fit into the drilled hole. I cut the twist about 1/4" long & stuck it into the hole dry. As the brush wore, it just slid along on the wire twist, never hanging up the brush, spring, or shunt wire. I used this shunt arrangement on all my open class motors when I ran wing cars in the 70s & 80s.

so the spring only pushes the brush and not the shunt, correct?

[team burrito]

so the spring only pushes the brush and not the shunt, correct?

if that was true, the shunt would fall out & possibly short out the other side.
 

[Bill from NH]

I used these shunts on Mura "over & under" endbells & with buss bars on them all. I never had problems with a shunt falling out while racing. Perhaps you might, depending how you routed your shunt wires.

[Dave Crevie]

I used to get shunted brushes on my trips out to LA. Don't remember the make.

 

I always hooked the free end of the shunt wire under the brush spring, in the slot in the brush made for the short leg of the spring. I would widen the slot with a jeweler's file if necessary. Then insulate the spring with Teflon medical tubing, to keep it from arcing and loosing it's tension. I have seen guys run the shunt from the buss bar to the brush hood. I don't think that has the same effect. You only have contact between two sides of the brush and the hood. Running the shunt wire from the buss to the brush creates a direct path for electricity to get to the brush. 

[Mark Onofri]

Your right, it would have to jump the space unless you use conductor paste. You only do that once.
I thought that by insulating the spring, you stopped the current from passing through it.
Have we answered the question or, complicated it?
Pro slot Gold dust are my choice.

[Dave Crevie]

Power should never pass through the spring. You risk heating it and loosing the spring's tension. Current should pass through the buss bar to the base flange of the brush hood. That means the contact surfaces of the buss and hood need to be super clean. And the attaching screw must tighten down on the buss bar. On an aluminum end bell, that creates a problem. The screw makes a direct short from the bar to the end Bell. The screw needs to be insulated from the buss bar and brush hood with a tiny Teflon tube and fiber washer.