N scale motor brush source

[ClubberLang1]

For most N scaler’s out in the world, there seems to be an issue concerning replacement motor brushes for some of the various n scale motors such as the ones used by Atlas, Intermountain, BLI, ScaleTrains, etc.  The question is what is used as replacement brushes for these motors?

Once upon a time, Atlas did sell replacement brushes for these motors.  Though, this is no more.  At the current time, is there another way to obtain replacement motor brushes for these types of motors?

This issue has been discussed a few times on various forums.  Based upon web searches, it seems some alternatives are as seen below:

1) Pencil lead – source a Ø 2mm pencil lead and use this as replacement.  Though, there are various grades of pencil lead such as HB, H, 2H, B, etc.  Has anyone tried to use the pencil lead?  If so, what grade of lead was used or what grade works best?  How well does the pencil lead last?  Is the performance satisfactory?

2) Battery carbon rod – using a used AA (or maybe a AAA) battery (non-Alkaline), cut the battery up to remove the carbon rod attached to the positive end.  With the carbon rod, make that into a motor brush.  Has anyone tried this battery carbon rod method?  If so, how does this work?  Does one battery brand work better than other brands?  How well does the battery carbon rod last?  Is the performance satisfactory?

3) Kato N brushes – it was mentioned that a Kato brush could be used.  The Kato brush Ø would need to be thinned down a bit but this could be done with a file or similar abrasive.  The issue for this point is that the Kato site reports this N brush as out of stock.

If someone has more consistent solution for this issue, kindly include your input for this.

Thank you for your help with this.
      ClubberLang

[wm3798]

Interesting question.

For me, the immediate source would be the endless stockpile of spent motors I've accumulated over the years.
Since most of my stuff is older junque anyway, this works fine.

The pencil lead question is fascinating, though.

I would think that the harder varieties would be the most durable, and leave behind the least residue.  If the conductivity is good it would be worth experimenting.
Lee

[mmagliaro]

Copper graphite.
https://www.graphitesupplies.com/Poco-EDM-C3_c_30.html

They have 12" sticks of it in any diameter you could possibly want.   I've tried it out in Kato/Atlas motors and the old Rivarossi
motors.  Works great.  I can't say how well it wears, but I did let the motors run for a few hours and the brushes looked fine after that.   Because it's graphite impregnated with copper, it is much more conductive and is harder than just plain graphite + binder.

Cutting it is a little tricky because it's like cutting a little 1/8" or 1/16" bit off a 12" long fairly brittle rod of brush material.
I found a Dremel cut-off disk works well.  Just cut off a bit to get close, then use the cut-off disk to gently grind and square up the end down to the exact length you need.   You can just put the piece of rod in a pin vise to work on it (gently, not too tight so you don't crush it).

[peteski]

Copper graphite.

I believe that is the exact material our N scale motor brushes are made of.  Or something very similar. If you look at the factory installed brushes they have a metallic copper-colored sparkle to them along with the dark graphite color.  They are also somewhat soft (not as hard as larger motor brushes (like the old Dremel tool, or vacuum cleaner motor brushes).

While I don't recall if I ever measured the various cylindrical brushes used in Kato and other Kato-clone motors (Atlas, Life-Like and many others), but I thought they all were the same diameter.

Couple of years back, on eBay I bought dozens of dirt-cheap motors which looked like Atlas motors. Not sure if they are still available.  Those are excellent sources for parts.

In my experience I wouldn't consider brushes as a heavy wear item in model locos. Even with extensive running time, brushes don't seem to wear much.  However I did notice a heavy commutator wear in a Kato model which had extremely long running time. In that motor the brushes were not even half worn down, but the relatively soft brush wore down the copper commutator segments.  I was surprised to see that because I thought that the brushes would be the wear item,  leaving the commutator relatively intact.

[nkalanaga]

Normally the brushes should wear first.  We had brush-type motors in the tape drives for our 1960s computer, still in use in 1980.  The brushes usually lasted about a year.  I only worked on that system about 3 years, but others said they had never had a motor fail, just worn brushes. 

[mmagliaro]

Normally brushes are the wear item.  But I'd wager than in these tiny motors, if the brushes were soft enough to fully protect the commutator, the brush material would clog up the comm slots much worse than it does now and the motor would fail faster from overheating than from letting the commutator just wear down.  These things are dang small.