Help with Kumata Trainmaster Reconstruction

[Ed Kapuscinski]

After reading this thread, I have to wonder, what sick human being designed these crazy things?

[mmagliaro]

Thank you, Mark and Ron, for clarifying.  NOW I get it (the way the two truck towers are wired and one is isolated from the frame).

[u18b]

I think his name was Mr. Kumata.  lol

Actually, I have to be honest.  I like the design.
What it has going for it is simplicity.

It is a whole lot cleaner and simpler than Samhongsa with all those wire running everywhere.

True, sometimes these locos have design flaws/weaknesses.

But I have learned how to overcome most of these weaknesses to produce truly wonderful running locos.

The only one that has been beyond my abilities is the Centipede.  It is in a class by itself.

[nkalanaga]

Actually, just looking at the pictures, the parts look (to me) a lot like the insides of a MiniTrix F unit. 

[mmagliaro]

Actually, just looking at the pictures, the parts look (to me) a lot like the insides of a MiniTrix F unit.

Funny you say that, because that was the first engine I thought of when I saw the insides of this Kumata thing.
As soon as I saw the way the gear and truck was locked in with a pin (okay, okay... it's a SCREW!),
I thought of the Trix F.   But then, the Trix F unit used a simple smooth pin.

[spookshow]

FYI, Kumata is still around. Total longshot, but maybe they still have parts for these?

http://www.kmt.co.jp/en/

-Mark

[johnh35]

Well, that is a bit smaller than the screw pins we use, but doesn't look to be impossible to fabricate. Any idea of the thread pitch? Since the hole it inserts in had to be tapped, I would think that there would be a die (Japanese metric I presume).


http://www3.towerhobbies.com/cgi-bin/WTI0001P?I=LXR775&P=8

[Bob Bufkin]

 I've got one of thsese plus 2 others (non PRR) in 2 different frame versions.  Can the body be placed on an Atlas frame?

[u18b]

Bob, when I get a chance, I'll do a quick check.  I suspect metal would have to be removed from the walkway at the ends since the shell is screwed to the walkway there.

[u18b]

Here is a very typical chassis for a plastic framed loco.
It is a Life Like SD7.

The primary difference between this chassis and so VERY many similar locos from the 60-90s is that there are no wires running to the trucks that can break off.  It uses wipers similar to the Trix chassis and the Key brass SD40-2 series.



Notice you have a FIXED gearbox.  On Samhongsa, the gearbox is a part of the truck and moves with the truck.  This gearbox is fixed.

Kumata follows this design.

This chassis uses a friction fit knockout pin to hold the trucks in place.  All the pin does is hold the trucks- nothing else.  If it gets loose- no problem since if it touches the plastic shell, nothing happens.

Kumata uses this pin/screw to transmit electricity.  So it should not touch the shell.

But otherwise, the chassis design is remarkably similar.

Meaning, the Kumata people were just trying to "brassify" a common design.

[ChristianJDavis1]

Okay, I sent an email to Kumata abou the screw/pin, but I have a feeling they are not going to be able to help me. I hope to go check through the parts-boxes of the second owner (who I got it from).

[u18b]

It would make you wonder if Kumata still has a few parts from 30 years ago.

Of course Atlas had a sale maybe 10 years ago where they tried to unload parts from the 60s and 70s!

[ChristianJDavis1]

Funny you should say that, as I just got a reply from them this morning, and was quite surprised at how helpful they were, and even more surprised that they believed they had parts available! They apparently still have some N scale in stock as well, including a Milwaukee EP-2 bipolar. This is the message they sent me:

Dear Mr. Davis,
Thank you for being a Kumata fan. Regarding your e-mail dated 24th, July, fortunately we still have the parts in our stockyard. I’m not sure if it is completely same with yours but I’m pleased to send it to you. So may I have your postal address?
BTW if you have interest in our N gouge products, we still have some stock of EP-2 Bi-Polar kit available(see attached).
Best Regards,
 
KUMATA Co.Ltd.

[spookshow]

"N gouge products"? Yeah, it does seem that way sometimes

-Mark

[chicken45]

"N gouge products"? Yeah, it does seem that way sometimes

-Mark

AAHAHAHAHA!