Author Topic: What gauge/thickness phosphor bronze for cutting pickup strips and such?  (Read 582 times)

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Hedron

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I have a Kato chassis that is complete except for its contact strips that touch the tabs coming up from axle cups. The part is not in stock at Kato. But I have another project chassis where it could come in handy, as well, so might as well try to roll my own. I'm sure one sheet is a lifetime supply.

robert3985

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #1 on: November 21, 2021, 10:49:41 PM »
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The wipers on my Kato engines are about 0.006" thick.  That's about 0.15mm

Exact measurement is 0.00575", which is 0.14605mm

Have fun!

Cheerio!
Bob Gilmore

Missaberoad

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #2 on: November 21, 2021, 11:47:21 PM »
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What engine? Maybe there is another part that can be adapted...
Ryan in Alberta

Hedron

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #3 on: November 22, 2021, 12:13:19 AM »
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Well, it's a project that's in the mail. I don't have it in hand yet. Seller said Kato, but I think upon further reflection it's actually an Atlas/Kato GP-35. I see that Atlas does stock the parts. Of course, I'll want more than that in the order to justify shipping.

mmagliaro

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #4 on: November 22, 2021, 12:26:26 AM »
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https://www.eileensemporium.com/materials-for-modellers/category/phosphor-bronze-flat-strip

0.15mm thick phosphor bronze strip, any width you want from 1 to 6 mm

randgust

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #5 on: November 22, 2021, 10:15:19 AM »
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I've come to the conclusion over the years that whatever magic happens with Kato, part of it is that their metallurgy specs are the best.   Wheels, rail, pickups, you name it.

That means that tolerances are tighter, and the material is just better quality than what shows up in a Chinese-built model.

So for things that actually matter - like whether a pickup strip oxidizes up over time, if you can find a Kato part that you can trim/rebend shorter it may be a better bet.    I know that when I've been doing my little Climax conversions (since 2006) I'm always so impressed over the quality of the pickups in those and yes, over time, I can even spot the difference between a Kato one and and Atlas one just by the color as the Atlas will oxidize darker.

mmagliaro

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #6 on: November 22, 2021, 03:36:48 PM »
+1
I've come to the conclusion over the years that whatever magic happens with Kato, part of it is that their metallurgy specs are the best.   Wheels, rail, pickups, you name it.

That means that tolerances are tighter, and the material is just better quality than what shows up in a Chinese-built model.

So for things that actually matter - like whether a pickup strip oxidizes up over time, if you can find a Kato part that you can trim/rebend shorter it may be a better bet.    I know that when I've been doing my little Climax conversions (since 2006) I'm always so impressed over the quality of the pickups in those and yes, over time, I can even spot the difference between a Kato one and and Atlas one just by the color as the Atlas will oxidize darker.
I heartily agree with this.  I don't know what the heck they plate their wheels with, or what they make those axle point pickup strips out of in their tender trucks, but it way better than the stuff in other brands of loco.  The art of good electrical pickup depends on 4 basic things:

- clean surfaces
- enough weight to guarantee good contact
- SMOOTH surfaces
- metals that don't attract  dirt or oxidize easily.

I think #3 is the one people underestimate.  The more perfectly smooth the surfaces are, the more actual contact area there is.
Whether it be a wiper on a wheelback, or an axle point in a cone, or a wheel on rail, there are always microscopic imperfections in the surface.  If you have 1 square mm of contact area, you don't really get 1 sq mm *touching*.  The smoother surfaces are, however, the closer you get to that actual contact area, and the less weight you need to guarantee contact.

In my little Rocket project, I have some phosphor bronze wires that press on the bronze bearings of the engine wheels.  Just polishing the surface of those bearings where the wire touches, with 2000 grit sandpaper, made a HUGE difference in how reliable the pickup was from those wheels.  So now I'm keep to try a buffing wheel and polishing compound.

brill27mcb

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #7 on: November 22, 2021, 05:36:37 PM »
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I've come to the conclusion over the years that whatever magic happens with Kato, part of it is that their metallurgy specs are the best.   Wheels, rail, pickups, you name it.

That means that tolerances are tighter, and the material is just better quality than what shows up in a Chinese-built model.

So for things that actually matter - like whether a pickup strip oxidizes up over time, if you can find a Kato part that you can trim/rebend shorter it may be a better bet.    I know that when I've been doing my little Climax conversions (since 2006) I'm always so impressed over the quality of the pickups in those and yes, over time, I can even spot the difference between a Kato one and and Atlas one just by the color as the Atlas will oxidize darker.

I'd be interested in hearing your opinion of where the Tomytec power chassis pickup strips stand on that quality scale, like better or worse than Atlas?

Rich K.
Tomix / EasyTrolley Modelers' Website
www.trainweb.org/tomix
N-Gauge Model Trolleys and Their History
www.trainweb.org/n-trolleys

peteski

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #8 on: November 22, 2021, 09:23:23 PM »
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I heartily agree with this.  I don't know what the heck they plate their wheels with, or what they make those axle point pickup strips out of in their tender trucks, but it way better than the stuff in other brands of loco.  The art of good electrical pickup depends on 4 basic things:

- clean surfaces
- enough weight to guarantee good contact
- SMOOTH surfaces
- metals that don't attract  dirt or oxidize easily.

I think #3 is the one people underestimate.  The more perfectly smooth the surfaces are, the more actual contact area there is.
Whether it be a wiper on a wheelback, or an axle point in a cone, or a wheel on rail, there are always microscopic imperfections in the surface.  If you have 1 square mm of contact area, you don't really get 1 sq mm *touching*.  The smoother surfaces are, however, the closer you get to that actual contact area, and the less weight you need to guarantee contact.

In my little Rocket project, I have some phosphor bronze wires that press on the bronze bearings of the engine wheels.  Just polishing the surface of those bearings where the wire touches, with 2000 grit sandpaper, made a HUGE difference in how reliable the pickup was from those wheels.  So now I'm keep to try a buffing wheel and polishing compound.

Yes, another vote for #3.

I polish the metal nubs on the trucks that contact the springy contacts in the chassis, and those strips too.



On the metal nubs I use the 4-way fingernail buffer (from beauty supplies shop). I use all 4 grits. until the contact surfase is polished (I check under magnification, since it is a very small area).



The last step is final polish I do using polishing compound and a cloth buffing wheel in a Dremel tool.

The flat strips are smooth enough that they only require the polishing compound procedure. 

And yes, Kato does seem to use better quality materials.

. . . 42 . . .

woodone

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Re: What gauge/thickness phosphor bronze for cutting pickup strips and such?
« Reply #9 on: November 24, 2021, 06:01:46 PM »
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I would order the strips for an SD 70 ACe and bend to fit. Best material and the correct thickness and width
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