Author Topic: Loco Scale  (Read 2418 times)

Offline PeeWee

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Loco Scale
« on: April 20, 2011, 01:14:16 PM »
Hi All,
I was wondering what the multiplier is to scale a 3 1/2 scale loco to 5 inch scale.  a straight calculation gives 1.43 though on a Climax page the builder says he multiplied everything by 1.5. 

I am off to Harrogate show and will be looking at the Kozo books, these are in 3 1/2 and i am wishing to make one in 5" so am hoping for some guidance on the practicality of this idea.

cheers
Ian
Sane? who knows, who cares

Offline Jasonb

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Re: Loco Scale
« Reply #1 on: April 20, 2011, 01:25:05 PM »
You probably need to apply a bit of both depending on how true to scale you want the model. Main dimensions would be better upped by 1.43 but smaller details by 1.5 eg an 1/8" rod would be a lot easier at 3/16" than 0.179" not to mention a lot less work.

If I'm enlarging things I prefer to take them back to full size then reduce to what I want as the original reduction may well have been rounded up or down to suit fractional sizes.

Jason

Offline kvom

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Re: Loco Scale
« Reply #2 on: April 20, 2011, 06:11:28 PM »
The gauge is 3.5", but the scale is .75"/foot.  Assuming that your track gauge is 5", then you'd need to scale everything that depends on the gauge by 1.43.  However, you can scale anything that's not dependent on track gauge by a different factor.  I'm building the A3 in 1.5" scale, meaning I can double most parts' dimensions.  But anything that is transverse to the frame needs to be recalculated.  Things like fastener sizes, rod diameters, etc. can be adjusted pretty freely.

There are castings for the A3 drivers and cylinders in both scales; for 5" gauge you might want to get castings locally for a different engine unless you want to machine to cast your own.  The shays wouldn't have that type of problem.

Offline PeeWee

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Re: Loco Scale
« Reply #3 on: April 22, 2011, 03:47:59 AM »
cheers for the replies.  i thought the article was inaccurate but needed a sanity check after a small doubt crept it.
Kvom you mention castings, would you know if anyone did casting cor the climax/shay or at least the gears.
Ian 
Ian
Sane? who knows, who cares