Con-Cor 4-6-4 modification

[mmagliaro]

George, it there is any discoloration or blackening in the groove areas behind the wheels where those contact plates ride, it causes a lot of problems with pickup in those 4-6-4 tenders.   

Try cleaning those wheel slot areas with lacquer thinner, and brushing them
out really well with a toothbrush. 
A wire wheel brush may get them clean, but it will leave them all scored and scratched and they will
tend to get dirty a lot faster.

I have a 4-8-4 with those trucks in it, and I ultimately had to resort to soldering fine .008" phosphor bronze wires
to the plates and bending them "just so" so they would ride in the wheel grooves with light spring pressure
to get solid contact.

There's no getting around it: those 4-6-4 tender truck pickups can work great, but they are more finicky
than the axle-point style ones that came later to be sure.

[victor miranda]

the CC hudson pickup is pretty good.

when it is not giving me good service...

I clean all contact points.
this means you have all the pieces apart

the pick-up sleds should be loose
when set in the truck and with the axles in place.

hold the truck upside down
and all the wheels should spin freely.

A few times where this has not been the case,
I filed the  sled where it contacts the wheel nubs.
I have seen arced sleds. if it makes any difference, turn it around
or flatten it

in the tender I remove the contact strips and curve them
to get a bit more pressure on the truck contacts.

before I put the tender shell back I rock the tenderfloor
side to side and make sure the strips rise and fall with the truck contacts.
this last part is mostly to check for an assembly issue.

victor

[mmagliaro]

I have seen the phenomenon that Victor describes about the sleds having an arc or slight bow in them, or not letting the wheels roll freely because the sled binds a little in that groove behind the wheelback.

Sometimes there is a little metal "ridge" along the edge of the sled that needs to be filed off and then
sanded very smooth (with something like 800 grit sandpaper).    Those sleds just lie in there behind
the wheels with light spring pressure on them from those strips in the tender floor.
Everything has to be really smooth and the wheels and sleds have to float
without any hanging up.

At least one time, I can remember putting the sleds in my jewelers vise and giving them a squeeze to press them
absolutely flat.

[nickelplate759]

Thanks for the advice and suggestions.

There was crud in the wheel-back grooves originally, but I cleaned it out a while ago.  I then attempted to polish the grooves with thin strips of crocus cloth, but that was ridiculously hard to do and I don't think I did a great job.

Using an ohm meter, I can see that contact from the "sleds" into the tender is good.   Contact from the wheels to the sleds is not, unless I apply too much pressure.   I seem to need to apply a fair amount of pressure with the test leads just to show conductivity from the wheel tread to the groove (far more than if I test the sleds, or the wheel axle), which makes me suspect that the surface of the wheel or groove isn't all that good a conductor for some reason.  Goo Gone doesn't fix it.   Polishing the wheel tread helped, but not enough.

I may go ahead and build one of Max's bronze-wire modified sleds and see if that helps.

George

[victor miranda]

... weeeell... that seems a little odd.

I have to wonder what cleans off goo-gone.

if you have it, you could try conducta-lube or bulb-grease
on those wheel pickups.

For what you describe I used some polishing compound and rolled the truck
back and forth for a little while. (it was on a CC 2-10-2)

clean carefully.

victor

[mmagliaro]

Thanks for the advice and suggestions.

...

...
Contact from the wheels to the sleds is not, unless I apply too much pressure.   I seem to need to apply a fair amount of pressure with the test leads just to show conductivity from the wheel tread to the groove (far more than if I test the sleds, or the wheel axle), which makes me suspect that the surface of the wheel or groove isn't all that good a conductor for some reason.

...

George

Wait!  Before you go to all the trouble of making new sleds/wires.

I think you have your problem.   My wire wiper things are not going to help here, I don't think.
Your  ohmeter is revealing that the wheel tread to the groove is a lousy electrical path, so that
has to be fixed.   It ought to be possible to chuck the wheel itself into a Dremel right by the tread,
and when run some 800 or 1000 grit sandpaper in that groove behind the wheel back to really spin-polish
it.   I read in other posts on this that Tony Hines (I hope I am not misquoting him) did a spin/polish
on them with car body polish.    And maybe if you're lucky, you can chuck one wheel in the Dremel
and polish the opposite wheel's tread the same way.  It just takes light pressure when your
spinning it and holding some fine paper on it.

Try putting the ohmmeter probes both on the wheel tread, just at 180 degrees across from each other on the wheel.  I am betting that the tread blackening stuff still isn't really polished off those wheels and that's where your problem is.

[nickelplate759]

As is so often the case, Max's advice was spot on.

I don't have a chuck for my Dremel big enough to hold 33" wheels, but my regular DeWalt drill worked just fine. Spun the wheel treads and grooves with a thin strap of crocus cloth and really shined them up.   Runs pretty well at last!

Now on to fitting the boiler weight around the decoder, and then final assembly.

George

[strummer]

As is so often the case, Max's advice was spot on.
George

He's dah man!!! Glad it worked out for you...

Mark in Oregon

[mmagliaro]

As is so often the case, Max's advice was spot on.

I don't have a chuck for my Dremel big enough to hold 33" wheels, but my regular DeWalt drill worked just fine. Spun the wheel treads and grooves with a thin strap of crocus cloth and really shined them up.   Runs pretty well at last!

Now on to fitting the boiler weight around the decoder, and then final assembly.

George

Great news.  So the pickup works well now?

Those wheels are very deceptive.   My 4-8-4 just started acting up (same type of tender trucks as the Hudson),
and wouldn't run well until I cleaned the wheel treads with paint thinner.   

[peteski]

Great news.  So the pickup works well now?

Those wheels are very deceptive.   My 4-8-4 just started acting up (same type of tender trucks as the Hudson),
and wouldn't run well until I cleaned the wheel treads with paint thinner.

Try Toluene or Lacquer Thinner next time - it works much better!   

All kidding aside, I use 99% isopropyl alcohol to clean the wheel threads and it works really well.  And when do  a complete cleaning of the mechanical parts (including wheelsets)  I use VMP Naphtha in an ultrasonic cleaner.

[Doug G.]

Just make sure, if you use toluene or lacquer thinner, you don't get it on anything but metal or,...um...that's about it. Phenolic is OK too.



Doug

[peteski]

Just make sure, if you use toluene or lacquer thinner, you don't get it on anything but metal or,...um...that's about it. Phenolic is OK too.

;D

Doug

DISCLAIMER:  I WAS JOKING ABOUT USING THOSE CHEMICALS FOR CLEANING WHEELS.

The ones I then went on recommending are safe for all the plastics I have encountered in my hobbies (at least for the brief time it takes to clean the item).  Also, the 99% Isopropanol is sometimes used for removing certain types of point paint from model shells. It might also cloud Testors Dullcote.

[victor miranda]

DISCLAIMER:  I WAS JOKING ABOUT USING THOSE CHEMICALS FOR CLEANING WHEELS.

The ones I then went on recommending are safe for all the plastics I have encountered in my hobbies (at least for the brief time it takes to clean the item).  Also, the 99% Isopropanol is sometimes used for removing certain types of point from model shells. It might also cloud Testors Dullcote.

off the side note of a side side note
is another side note stating

Isopropanol does not remove point from posts.

and keep in mind I said "clean carefully"

[nickelplate759]

Great news.  So the pickup works well now?

Those wheels are very deceptive.   My 4-8-4 just started acting up (same type of tender trucks as the Hudson),
and wouldn't run well until I cleaned the wheel treads with paint thinner.

Yep - runs like  a champ (finally)!

George

[victor miranda]

ah peteski,
I thought that typo was funny and I liked it.