Brass KMT Centipede Re-powering

[u18b]

The decorating is done.

























Window glass and headlight add to the lifeless old brass model.

[u18b]

Oh, and by the way.  I know the window glass is not perfect.

But I just did not feel like all the effort required to get perfect glass (since it would be done by scratch).

I found something that was close.

You only notice it in close photos.  When this thing is running down the track pulling 10 passenger cars, you don't even look at the glass.

[u18b]

The reason this loco runs so much better than stock is because:

1.  One powerful motor instead of two that work against each other.

Before


Now


2.  Flywheels added

3.  The balance point is now DIRECTLY over the two driven axles.



Whereas before, it was BEHIND the driven axles (otherwise know as Design Insanity)



When I get more time and some more nylon 0-80 screws, I'll install the metal gearboxes in place of the resin ones.
Then I will be done!

[Jesse6669]

The decorating is done.

Wow really nice work!  Beautiful model.


Now to weather it! 

[u18b]

Thanks Jesse.

No.  I won't be weathering it.  I have found through the years that models go for less (on average) when weathered.

They tend to like them pretty.

[strummer]

A terrific job all 'round. The way the trucks were originally mounted was very similar to the old TT Scale HP Products E7; almost impossible to get to, and a crappy design...

Nice work,Mr. B...

Mark in Oregon

[eric220]

Most awesome. I feel for you on the PRR stripes; I've fought that battle several times.

[u18b]

Wow.  Finally finished.

Here is some more info on getting it finished.

I changed out the resin gearboxes for the cast metal ones.



Now, as all of you Kumata experts know...this would now cause an electrical short.
So I insulated one set of screws.
The black marking is so that no shiny metal shows through the grills.




I have not shown anything about the headlight.
I wired a TCS micro socket to the motor poles.




I then took an old extra board I had out of a Kato GP38/50.
Cut a new trace.
Soldered the plug to the board (just to left of KATO logo).
Also soldered appropriate resistor and a micro LED heatshrinked to the nose light.



The black marking helps keep orientation correct.



The location of the new shell mounting screws is so much better than before.
You can actually install/remove them without damaging the loco!




Now, when I THOUGHT I was finished, it ran OK, but it was just too loud for my taste.
(performance nut genes kick in...)

I then spent a couple of hours trying to figure out what was going on.

Gear mesh OK?  check.
gearboxes adjusted for more adjustment room to orient worm shaft.  check.
Runs ok bare chassis?  check
with the shell on?  loud.  hmmmm.

OK, I think I can conclude one of two things are going on.  This info might help someone in a similar situation.
Runs perfect with chassis alone.
Noise with the shell.

Either placing the shell on causes something to interfere (hey, how about the headlight plug?)
Or the adding of the shell actually causes a CHANGE to the frame.

I figured the problem was the latter.

If I had the u-joints in PERFECT position, but then, when the shell is screwed down, the frame might bend ever so slightly.
This then CHANGES all the work I went to.

Well, bottom line-  I could not tweak it out.

Sooooooo.... I tried Beardenizing it.
I removed the inner worm bearings..... and it ran PERFECTLY.



So I am now done.
It has been a long but rewarding journey.
I redesigned the Kumata Centipede the way they SHOULD have built it originally.



Oh, by the way, here is a one minute video.

Count the cars in the third segment.
It just barely started slipping with that many.

Not bad for a loco that can often barely even pull ITSELF when new.

/>

[peteski]

Very nice!

Since there is another current thread about the subject, have you checked how warm the motor gets when pulling all those cars?

[u18b]

The entire loco was barely warm.

But then I did not run it for an hour.
It was probably about 10 minutes.

[Altoona]

BRAVO
Now if can rebuilt the Trainmaster shell or get another one I would love to see that. I have have one that is basically a shelf queen that I would love to get running property.

Judd Barton
PRRT&HS #9210

[eric220]

Very nice Ron! I'm hesitant to point it out, but the PRR ran these in semi-permanently coupled pairs. You got a second one?

[glakedylan]

Ron, this is such excellent work, documented and photographed so well.
You really show your talent and skill in rebuilding these locomotives.
Thanks for sharing that here.
Sincerely--
Gary

[u18b]

Very nice Ron! I'm hesitant to point it out, but the PRR ran these in semi-permanently coupled pairs. You got a second one?

Yeah.  I knew that.  LOL.

Yes, I did have one that was in mint condition.  But I've already sold it.
So no, this is the only one.
But now you know how I did it!  You can too.

I figure Someone out there wants just this one.

Of course, this one is such a decent puller now, I wonder if it could pull a gutted dummy and a passenger train.

I bet it would.
 

[u18b]

Oh.  And just as a reminder of what I had to work with....

/>
Bob Bufkin loaned me his Centipede a couple of years ago.
It would barely pull itself.  And wobbled terribly.

I worked on it for hours and was rather proud that I at least got it to run and even pull 6 passenger cars.

But there was only so much you could do with that mechanism.

Starting over and repowering was definitely the way to go.