small motor "brush" material ?

The brush material is graphite often with various admixtures depending on t he application, voltage and other requirements. There are thousands of type s and at least dozens of sources for specific brushes, including Amazon. Do a search for Aftermarket Motor Brushes.

I suggest you look for something close, and then careful application of a f ile or Dremel tool could do the rest. DO THIS AWAY from anything electrical as the carbon dust is very fine and very conductive. If done in doors, you will find that fine dust will travel many feet. Wear a particle mask as we ll, as it could also get into your lungs.

Peter Wieck Melrose Park, PA

That is the 3 motors I've broken into , the original has shim thick tiny fingers of metal, flexed against the comutator. Reminds me, last week, I was surprised to see 2 inch squares of gold leaf in a food supermarket. Apparently some people eat this stuff, 23 carat gold foil, 2 such squares per pack, thickness not stated, 3GBP

I think if you did the investigation you'd find that the folk why buy it are quite thick.

AH! that is an OLD Mabuchi-style hobby motor cheap as cheap can be.

Those fingers are spring bronze, very thin and relatively hard to duplicate as the bronze alloy is a delicate balance between being too hard and not h aving enough spring. Too hard would eat into the commutator, not hard enoug h would anneal and fail quickly.

May be a link to some source for OEM parts.

Peter Wieck Melrose Park, PA

The metal is not any sort of yellow colour, tin/silvery colour throughout, so not a plating over bronze of any sort

on the application, voltage and other requirements. There are thousands of types and at least dozens of sources for specific brushes, including Amazon . Do a search for Aftermarket Motor Brushes.

a file or Dremel tool could do the rest. DO THIS AWAY from anything electr ical as the carbon dust is very fine and very conductive. If done in doors, you will find that fine dust will travel many feet. Wear a particle mask a s well, as it could also get into your lungs.

I think gold leaf is used as a garnish on Indian sweets.

Something like that.

George H.

This is the bruxsh material, wrong angle to see any 2/3 fingers

OK - that is a "between" motor after what I thought you were discussing:

Your pictured motor is a substantial improvement over the older stuff, and those brushes are plated spring steel. As I remember, the plating was for w ear, and the little black bits were for vibration damping. This goes back t o my slot-car days, too long ago to admit to in cold blood. So I am not sur e of the material and type of plating. I suspect a flash rather than a true 3-metal process - that would be too thick and too costly. With that in min d, I suspect tin as the material.

If you are looking for a stock material for making new ones, K&S has a line of hobby sheet goods all the way down to 40 gauge (0.0055") that would do. Typically their sheets sell in the US$7-10 range. The really thin stuff ma y be cut with sewing sheers, so there is no roll at the edge. You really do n't need the tin as a somewhat shortened service life is of less moment giv en a near infinite supply of material.

Peter Wieck Melrose Park, PA

I reckon it might be stainless steel, as in the almost foil thickness you find in FDs and HDs . The original is spot welded to brass standoffs, which tin would not necessarily require. I suspect st/st would take arcing better. Any way to avoid swaging something soderable to st/st fiddley foil, I'm trying one of the phosphor-bronze and graphite brushes , there is enough room to solder 3mm offset from the original line, to allow for the brush thickness. Motor run for a couple of hours without hiccough

They might also be nickle, like the stuff used for connecting cells together in battery packs. Eric

I always thought that was stainless steel as was the casing. My hot air gun has survived hundreds of extra hours of use, by crimping the broken ends of the heater wire with bits of that strip, would nickel survive that?

Probably not. Nickle is not hard enough to stand up to the heating. It will anneal to a very soft state, even with the stiffener/vibration damper attached.

It is used for the links you describe because it spot-welds very well, and is a much better conductor than steel, and it also takes stress better than copper.

duplicate as the bronze alloy is a delicate balance between being too hard and not having enough spring. Too hard would eat into the commutator, not hard enough would anneal and fail quickly.

Back in the 1950s (I guess) when my Dad and I were playing with toys, we also thought that a small motor had phosphor-bronze spring brushes. Having no idea where to get stock metal we tried cutting up slices from a roll sold by a local hardware as draught-prevention seals for doors etc. I don't remember how durable it was!

Not sure if it is the same stuff, but I have some more recent "Atomic Weather Strip" made of "specially prepared copper alloys" and carrying a ten year life time...

Mike.

Vintage College Football program

I think that is called a "non sequitur". But thanks for reminding me of what I wrote ~5 years ago, remembering my long-dead father. Mike.

I've missed out on the beginning of this thread, but I had a problem with worn phosphor bronze leaf brushes on a small motor many years ago. They had worn right through and the ends had fallen off. I took an ordinary carbon brush from a much larger sized motor and cut a pair of cubes from it. Then I copper plated one side of each cube and soldered it onto the remains of the original brush, which just acted as a mounting spring.

The commutator segments had also been cut through, so I flattened some copper wire and made some grossly oversized segments which I fixed in place with epoxy resin. When everything had set hard, I mounted it in the chuck of a small modeller's drill under a microscope and used a jewellers file to shape it back to size. The final trimming was done by driving the shaft from the far end and mounting the commutator end in a temporary bearing to keep it exactly concentric.

The motor caried on working for a long time after that and its performance didn't seem to suffer from the extra resistance of the carbon brushes.

(We are talking about a very long time ago, when small motors were almost unobtainable and I had no money to spare.)

That's a great story; I especially like the successful copper plating!

Conversely, in the early 1960s, I was trying to recondition a 9.5mm projector

I had access to company (I was an apprentice) supplies and machinery, and was allowed to purchase a short lenth of copper rod 1" diameter. (I don't remember the price but I only needed a few mm length and have

See

I don't remember how I kept it all concentric while I filled the gap between bush and tube with epoxy. But when I started using a dividing/indexing head to start slicing the copper into the (IIRC) 14 segments, the adhesion failed and th segments fell off; see photo!

At which point I'm afraid I gave up on the projector!