# KOZO A3 switcher in G scale any advise?



## AlanB (Oct 6, 2009)

Hi,
Brand new to the forum. I have Kozo's book on the A3 switcher. I am seeking advise on building it to a smaller scale. 
My hope is to build the A3 to G scale, or I guess 45mm gauge track. I'm sure someone has done this already.

If so, please direct me to the thread, or web site. If not, do I simply divide all the measurements for the 5" gauge A3 by 2.822?

Thanks in adance!

AlanB


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## Mik (Jan 2, 2008)

Some, but not all, dimensions can be scaled down that way. Simply put, 'physics doesn't scale'. Grab a copy of Machinery's Handbook, if you don't have one already. Brand new copies border on outrageous, but the part you'll need on various 'fits' hasn't changed much in 50+ years.... so go used. 


Also remember that steam engines simply won't run if built to aircraft tolerances. A little sloppy is often better than a little tight.


Bore and hone the cylinders, THEN make the pistons to fit. This isn't mass production, a few thou either way won't matter much.... unless you break through. 


Last thought, you'll pretty much have to redesign the boiler. You'll probably want to use a monotube (or a few large tubes) design, and bridge stays (or a very few largestays) if you insist on building a wet firebox. You might want to look to LBSC (aka Curly Lawrence)'s designs for small engines like the 'Tich', since they've pretty much stood the test of time.


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## JEFF RUNGE (Jan 2, 2008)

You may want to look at this: http://www.thms.tedatum.com/BBoard/Hume01.html


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## AlanB (Oct 6, 2009)

Not 5" gauge, I meant to say 3.5" gauge!







I have been looking at too many different locomotives! I have the Machinery reference book, and have built boilers for Brazil Loco using a poker burner.
I just want to get the sizes correct first. So, do you think dividing the 3.5" scale by, say, .5062, would get me pretty close? I can tweek it to use more standard sizes of material if needed.

Thanks for the link to the Heisler. Ed's work is amazing, and a level of craftsmanship to strive for.

Thanks

AlanB


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## Scottychaos (Jan 2, 2008)

Alan, 
technically 3.5" track works out to 1/16.14 scale.. 
but I dont think the 3.5" gauge modelers pay attention to the 0.14 
(although I could be wrong) 
I think its just 1/16 scale even.. 

So if your drawings are 1/16 scale, you can simply cut in half evenly to arrive at 1/32 scale.. 

Scot


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