2-10-2 project idea

[mike_lawyer]

I was thinking over the weekend of a neat project that would be interesting, but I have no idea how to do it!

Basically, I was looking at the Con-Cor 2-10-2 and seeing how the wheelbase is too extended, as well as the shoddy pickup system.  That got me to thinking that a good USRA heavy mechanism, with closer prototypical proportions, is needed for us kitbashers who want to model 2-10-2's or decapods.

What would be interesting would be for someone to make a frame that basically is a Kato Mikado extended with an extra driver slot and the drawbar pin pushed back behind the fifth driver.  I scratchbuilt a PRR I1 by adding an extra slot made of styrene (like Max did on his I1).  In that situation, the fifth driver is really just for show and does not add much in the way of pulling power.

Here is my proposed project.  As I said, you would basically need a Kato Mikado frame with an extra fifth slot.  This design would have the fifth driver being geared instead of moving with the crank pins on my I1.  An extra idler gear (sold separately by Kato) would be used to power the fifth driver.  This would require an extra slot and pin in the frame with the same proportions as on the Kato Mikado.

With regard to the siderods, these would act just like the Kato Mikado in that only the 1st and 3rd drivers would be connected.  The fourth and fifth drivers would not be pinned, just like the 4th driver is not pinned on the Kato Mikado.  This keeps the design simple and prevents quartering issues.  It is also the design that appears to be used on the Con Cor 2-10-2.

By having the fifth driver geared, it would add pulling power.  You could even make the fifth driver another traction tire driver if you wanted even more pulling power.

All of the parts for this project would come from a Kato Mikado, except you would need a new main driver that is extended (superturbine, that's where your scratchbuilt siderod would come in handy).

So how could this project occur?  Is there a milling company that could make these frames if we made a master, and how much would it cost?

[mmagliaro]

I don't know why gearing that 5th driver would be important.  The Kato Mikado is no slouch for pulling power once you put the traction tire driver in it, and with a heavy boiler on it (like the I1), it pulls a ton (like 80-90 cars!)

I agree that a nicely milled, mass-produced frame that can accept 5 Mikado drivers would be nice.  In fact, if such a thing existed,
people could make all manner of engines out of it by just using it as-is, or cutting it off for 2, 3, 4 or 5 drivers, depending
on what they want to make.
But getting that mass-produced?  I have no idea.

As for the 2-10-2, what about the boiler?  That, to me, is a bigger problem than the frame.   Hacking away at the back of a Mikado
frame and putting on the 5th driver takes some work, but now that people know how to do it, it's not as bad.
But there are a lot of different types of 2-10-2, and the Con-Cor boiler is too long to go on a mechanism that has
closer-spaced drivers. 

[mike_lawyer]

Max -

My idea with regard to gearing the fifth driver is just for simplicity.  You do not have to purchase extra crank pins, make holes in an extra driver, etc.  You can just pop in the fifth driver and go.

[Dave V]

Here I thought you were going to Belpaire it and make a decent N2sa out of it...!

[Chris333]

https://picasaweb.google.com/ErieChris333/NScale#5276961413294646978

You can see right in front of the steam dome I took a section out of the shell. Smokebox is from Kato with the CC (bigger) stack used.

[Ed Kapuscinski]

Keep in mind, Bachmann makes a 2-10-2 with a proper length, or so I seem to remember.

[conrail98]

Keep in mind, Bachmann makes a 2-10-2 with a proper length, or so I seem to remember.

But is that the version he's looking for? If I remember correctly, there are two different 2-10-2 types, a light and a heavy. I think Bachmann's is the light version,

Phil

[mike_lawyer]

The Bachmann 2-10-2 is a light USRA version.  It will not work with the Kato drivers. 

[fredmoehrle]

For milling the frame, all one needs is accurate drawings.
A mock up is actually more trouble, because one would have to backwards engineer it.

As far as the Bachmann, are they not doing spare parts now?
I would think that driver size would be more an issue then who made them.
My 2-10-2 has two traction tire axles.

I might be able to come up with a mill.
www.moehrleinc.com
 

[mike_lawyer]

For milling the frame, all one needs is accurate drawings.
A mock up is actually more trouble, because one would have to backwards engineer it.

As far as the Bachmann, are they not doing spare parts now?
I would think that driver size would be more an issue then who made them.
My 2-10-2 has two traction tire axles.

I might be able to come up with a mill.
www.moehrleinc.com
 

Fred -

The Bachmann light 2-10-2 has much smaller diameter drivers than the heavy USRA 2-10-2 had, so it cannot be used as a substitute.  I'm curious how one would go about reverse-engineering a mockup for one of these for milling purposes.

[superturbine]

There is one solution to the frame..... Ready made.   Lost urethane castings in brass.  I was about to mass produce these but found it was pretty easy to mill and extend the frame.  Lost urethane casting to brass would have a total shrinkage rate of 1%.

So in other words.... Build a kato frame with the drive box added, cast in urethane, melt out urethan and pour in the brass, clean / polish up bearing surfaces.

[superturbine]

Also, the traction tire does not have a pin hole in it.  So to get perfectly quartered on would not to build a jig to drill the pin holes on both sides..... Victor what say you?

[strummer]

Gawd, I just love these topics!

Even though I could never in a million years attempt something like this, watching the discussion amoungst those who can is just fascinating...

Mark in Oregon

[Mike C]

https://picasaweb.google.com/ErieChris333/NScale#5276961413294646978

You can see right in front of the steam dome I took a section out of the shell. Smokebox is from Kato with the CC (bigger) stack used.

Um Chris, I'll take one of those.....Nice loco ! Really like the look !!....Mike

[Lemosteam]

Maybe a Shapeways design ordered in sintered metal might be the answer here. One  just simply has to pull the chaasis apart then measure and model it in cad. Cost would likely be the same as costom machining.  The tolerances might be good enough for this.