MTA
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Scaling up & downDoes anyone know how to scale sizes? I am scaling some sizes for a loco I hope to build at a scale of 2 1/4 inches to the foot, so for every 2 1/4 inches on the model = 1 foot on the prototype.
So does anyone have a formula for scaling sizes?
All the Best,
MTA
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James
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what you mean? You mean like the thing in maths where you have questions on 1:72 model kits and all that? 
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mj
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Re: Scaling up & down | MTA wrote: | Does anyone know how to scale sizes? I am scaling some sizes for a loco I hope to build at a scale of 2 1/4 inches to the foot, so for every 2 1/4 inches on the model = 1 foot on the prototype.
So does anyone have a formula for scaling sizes?
All the Best,
MTA |
It's 3/16" to the inch in smaller dimensions
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MTA
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Yep! That's the exact thing, although not in ratios (annoying things!). Right, let me give you more info on what exactly I am doing... As you guys know I volunteer at the South Downs Light Railway which is a 10 1/4 inch gauge railway. I've always wanted a 10 1/4 loco and now there is light at the end of the tunnel. I plan to build a LSWR M7 0-4-4T, I mean...one of these:
So 12 inches to the foot is 1:1 and 6 inches to the foot is 1:2 etc. So let me give you an example of what I mean:
Length over buffers of the prototype is 36 ft 3 in. At a scale of 2 1/4 inches to the foot what would that be? You mathematicians out there, your assitance is urgently needed!
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mj
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| MTA wrote: | Yep! That's the exact thing, although not in ratios (annoying things!). Right, let me give you more info on what exactly I am doing... As you guys know I volunteer at the South Downs Light Railway which is a 10 1/4 inch gauge railway. I've always wanted a 10 1/4 loco and now there is light at the end of the tunnel. I plan to build a LSWR M7 0-4-4T, I mean...one of these:
So 12 inches to the foot is 1:1 and 6 inches to the foot is 1:2 etc. So let me give you an example of what I mean:
Length over buffers of the prototype is 36 ft 3 in. At a scale of 2 1/4 inches to the foot what would that be? You mathematicians out there, your assitance is urgently needed! |
6' 9" & 9/16
This isn't your maths homework we're doing is it
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Chris
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I'm so damn glad we went metric!
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MooseMan
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Can I have that in Angstroms please?
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mj
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| MooseMan wrote: | | Can I have that in Angstroms please? |
42?
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MTA
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This is more confusing than first thought! I think I've sorted it lads, asked some guys on a miniature railway forum I frequent regularly and it's a good thing they work in mm's! Although I have a very good converter on my PC to save me the trouble
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MooseMan
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Seriously though, it works out at about 6 foot 9 inch. Great girth bugger, in other words.
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MooseMan
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| mj wrote: | | MooseMan wrote: | | Can I have that in Angstroms please? |
42? |
Very, very good!!!!
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mj
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| MooseMan wrote: | | mj wrote: | | MooseMan wrote: | | Can I have that in Angstroms please? |
42? |
Very, very good!!!! |
what are angstroms by the way 
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SPOKESMAN
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Very small units!
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James
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| MooseMan wrote: | | Seriously though, it works out at about 6 foot 9 inch. Great girth bugger, in other words. |
LMFAO!
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MooseMan
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1 hundred-millionth of a centimeter......used for measuring the wavelength of light.
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yosa
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| MTA wrote: | | This is more confusing than first thought! I think I've sorted it lads, asked some guys on a miniature railway forum I frequent regularly and it's a good thing they work in mm's! Although I have a very good converter on my PC to save me the trouble |
Doesn't his mum mind?
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MTA
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MTA
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Right, this is how you work it out...
2.25 divided by 12 = 0.1875
full size measurement times 0.1875 = scaled down size
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Graham-Jilly
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I was never any good at math or spelling
come to think of it how did i survive the last 55 years  
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Chris
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| MTA wrote: | Right, this is how you work it out...
2.25 divided by 12 = 0.1875
full size measurement times 0.1875 = scaled down size
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That is correct MTA. I would suggest you make up a conversion table to save calculating each dimension, and possibly make yourself a scale rule if you can't buy one with the correct scale on it. Mind boggles where these strange scales comes from. 2.25 inches to the foot is 1:5.33333.
People in the olden days liked to make life difficult for themselves.
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mc_mc
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Sorry for a newbie question: But you can't just scale everything down mathematically? Say the real engine had a 3mm thick plate for one of the components, you can't scale that down to 0.3mm and expect it to still perform it's function.
The boilers and cylinders must have a certain strength to them to function (safely). Someone must have already worked out what the smallest working dimensions / specifications of such things are.
I assume there would be problems scaling up the other way too, materials would get so thick that they start to act as heat sinks etc.?
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James
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Aye, it is what I am doing when I make old Girthy.
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SPOKESMAN
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| mc_mc wrote: | Sorry for a newbie question: But you can't just scale everything down mathematically? Say the real engine had a 3mm thick plate for one of the components, you can't scale that down to 0.3mm and expect it to still perform it's function.
The boilers and cylinders must have a certain strength to them to function (safely). Someone must have already worked out what the smallest working dimensions / specifications of such things are.
I assume there would be problems scaling up the other way too, materials would get so thick that they start to act as heat sinks etc.? |
Very good point mc . . . .
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Sandman
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| SPOKESMAN wrote: | | mc_mc wrote: | Sorry for a newbie question: But you can't just scale everything down mathematically? Say the real engine had a 3mm thick plate for one of the components, you can't scale that down to 0.3mm and expect it to still perform it's function.
The boilers and cylinders must have a certain strength to them to function (safely). Someone must have already worked out what the smallest working dimensions / specifications of such things are.
I assume there would be problems scaling up the other way too, materials would get so thick that they start to act as heat sinks etc.? |
Very good point mc . . . . |
I remember reading an article about die cast cars that suffered from the same problems.
They have to make their window frames much bigger than scale size as they need to be strong enough to hold the roof, and of course, be played with.
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SPOKESMAN
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| Sandman wrote: | | SPOKESMAN wrote: | | mc_mc wrote: | Sorry for a newbie question: But you can't just scale everything down mathematically? Say the real engine had a 3mm thick plate for one of the components, you can't scale that down to 0.3mm and expect it to still perform it's function.
The boilers and cylinders must have a certain strength to them to function (safely). Someone must have already worked out what the smallest working dimensions / specifications of such things are.
I assume there would be problems scaling up the other way too, materials would get so thick that they start to act as heat sinks etc.? |
Very good point mc . . . . |
I remember reading an article about die cast cars that suffered from the same problems.
They have to make their window frames much bigger than scale size as they need to be strong enough to hold the roof, and of course, be played with. |
They do indeed SM, Ill post some pics of my Corgis and you'll see the detailing looks totally out of scale.
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Steve_S
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The problem is that if you reduce dimentions by a factor of N, then areas are reduced by N squared, and volumes are reduced by N cubed. As strength is mainly a function of volume, things rapidly get too weak. It also means that a half sized cylinder and piston has only one eighth of the volume so power is reduced drastically. Too small and it won't work. So working models are very rarely exact scale models.
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sparky
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| SPOKESMAN wrote: | | Sandman wrote: | | SPOKESMAN wrote: | | mc_mc wrote: | Sorry for a newbie question: But you can't just scale everything down mathematically? Say the real engine had a 3mm thick plate for one of the components, you can't scale that down to 0.3mm and expect it to still perform it's function.
The boilers and cylinders must have a certain strength to them to function (safely). Someone must have already worked out what the smallest working dimensions / specifications of such things are.
I assume there would be problems scaling up the other way too, materials would get so thick that they start to act as heat sinks etc.? |
Very good point mc . . . . |
I remember reading an article about die cast cars that suffered from the same problems.
They have to make their window frames much bigger than scale size as they need to be strong enough to hold the roof, and of course, be played with. |
They do indeed SM, Ill post some pics of my Corgis and you'll see the detailing looks totally out of scale. |
yes, i no about that. Its even the same story with the corgi lorrys bits being out of scale, i get used to it!
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sparky
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and as for the dinkys there even worse!
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SPOKESMAN
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Some details becaome so small they have to 'scaled' up to be physically viable . . . .
Thing such as radiator grilles, bonnet and door detailing, same with modelling a steam engine, some details physically have to be out of scale.
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SPOKESMAN
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These Corgis are approix 1:64 scale - the tail pipes on this very rare white base Morgan +8 would be so small as to be the thickness of tin foil if true to scale.
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SPOKESMAN
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OO guage train on oversized track - code 100 (I think) code 75 is better but still overscale.
The loco is 4mm to the foot.
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