small motor "brush" material ?

[N_Cook]

Trying to keep some 1960s junk going. Uses a long thin 1.5V motor so CD
motors won't fit. A failed brush/contact. Before I randomly open another
CD/cassette motor to rob a brush, anyone know the what the material is?
All I've found so far is phosphor-bronze carriers with a brush insert,
but the original is either 2 or 3 fingers conjoined, 2 on one side 3 on
other side of the comutator, of a non-magnetic strip material, shiney
material like tin, but obviously must have some spring and withstand
spark errosion.

[pf...@aol.com]

On Monday, May 9, 2016 at 6:25:34 AM UTC-4, N_Cook wrote:
> Trying to keep some 1960s junk going. Uses a long thin 1.5V motor so CD
> motors won't fit.

The brush material is graphite often with various admixtures depending 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.

I suggest you look for something close, and then careful application of a file 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 well, as it could also get into your lungs.

Peter Wieck
Melrose Park, PA

[N_Cook]

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

[Clifford Heath]

On 09/05/16 21:57, N_Cook wrote:
> 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.

[pf...@aol.com]

On Monday, May 9, 2016 at 7:57:50 AM UTC-4, N_Cook wrote:

>
> That is the 3 motors I've broken into , the original has shim thick
> tiny fingers of metal, flexed against the comutator.

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 having enough spring. Too hard would eat into the commutator, not hard enough would anneal and fail quickly.

http://www.mabuchi-motor.co.jp/en_US/technic/index.html

May be a link to some source for OEM parts.

[N_Cook]

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

[gghe...@gmail.com]

On Monday, May 9, 2016 at 7:57:50 AM UTC-4, N_Cook wrote:

I think gold leaf is used as a garnish on Indian sweets.
https://en.wikipedia.org/wiki/Vark

Something like that.

George H.

[N_Cook]

This is the bruxsh material, wrong angle to see any 2/3 fingers
http://pacificstereo.net/motor/Mabuchi%20brushes.jpg

[pf...@aol.com]

On Tuesday, May 10, 2016 at 6:49:16 AM UTC-4, N_Cook wrote:
> This is the bruxsh material, wrong angle to see any 2/3 fingers
> http://pacificstereo.net/motor/Mabuchi%20brushes.jpg

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

http://www.gasolinealleyantiques.com/kits/images/CarLindberg/lind-t1.jpg Look at the motor pictured on the box. These used spring-bronze brushes.

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 wear, and the little black bits were for vibration damping. This goes back to my slot-car days, too long ago to admit to in cold blood. So I am not sure 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 mind, 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 may be cut with sewing sheers, so there is no roll at the edge. You really don't need the tin as a somewhat shortened service life is of less moment given a near infinite supply of material.

[N_Cook]

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

[et...@whidbey.com]

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

[N_Cook]

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?

[pf...@aol.com]

On Tuesday, May 10, 2016 at 11:59:48 AM UTC-4, et...@whidbey.com wrote:

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

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.

[MJC]

In article <f6e561cf-16a8-4d0b...@googlegroups.com>,
pf...@aol.com says...

>
> 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 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.

[John Sabino]

Vintage College Football program


https://www.collectableivy.com/

[John Sabino]

https://www.collectableivy.com/

[Mike Coon]

In article <fb00fe6c-406e-4a27...@googlegroups.com>,
valuab...@gmail.com says...

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.

[Liz Tuddenham]

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.)


--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Mike Coon]

In article <1pmtldd.105m2vn1p4x1naN%l...@poppyrecords.invalid.invalid>,
l...@poppyrecords.invalid.invalid says...

>
> John Sabino <valuab...@gmail.com> wrote:
>
> 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 (https://en.wikipedia.org/wiki/9.5_mm_film) and after fixing
the mechanics the motor commutator developed a fault.

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
0.565kg left!) I turned a brass central bush, a mandrel to mount it on,
and a short copper tube for the commutator.

See
https://drive.google.com/file/d/15GOegJInJUCxQbS8BduOh73JMqEuaF3t/view?
usp=sharing

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!