A question of scale...

[midlandmodeller]

I posted this on another forum earlier, but wondered if you would be able to help too.

I have a question about OO scale conversion. I am currently putting together a simple OO Scale Calculator program that will work on a web page and on the desktop, to speed up converting actual measurements into OO scale.

I understand that OO scale is 1:76, however I have also been told that 4mm = 1 foot and 13mm = 1 metre. The problem is that these are not all to the same scale.

1 foot @ 1:76 scale = 4.01mm, so it's fair to say 4mm.

However 1 metre @ 1:76 scale = 13.15mm, which means that over longer distances, using only 13mm instead of 13.1mm or even 13.2mm the scale model will become progressively too short.

How do you deal with this? Do you think it matters? Do you use 13mm or 4mm? Or do you divide by 76?

Am I being too picky? Ordinarily I would probably use either and not worry too much about being a couple of mm out over a longer distance, but since I am now putting together a program to make calculating quicker, it suddenly seems to matter since it will give me a result to several decimal places.

What are your thoughts?

Happy to let you all have a copy when I am done (already have a prototype running based on 13.1mm to the metre).

Thanks in advance.

[southern]

well at my model club we work to 4mm or 1.76 scale . but the model cars are 1.72 they dont look out of place evan at shows.

[rustynath]

Why not use both? Giving two answers - that way - the modeler can choose which they prefer?

The other option would be to take an average - half way between the two?

I think the first would be better if you can do so?

Looking forward to seeing it, rustynath

[midlandmodeller]

Thanks for the replies.

What you say ties in nicely with what I am hearing on other forums too.

I have decided to allow the user to select the conversion scale they want to use (e.g. 1:76.2, 13mm = 1 metre, 4mm = 1foot, 2mm = 1 foot (N gauge) etc...) then input the actual length in Metric or Imperial and get a result in millimetres at the click of a button.

The prototype will be ready later tonight, I will post a link, you are welcome to pass it on to friends as well.

Thanks again for your input. Any more suggestions most welcome.

[midlandmodeller]

Well folks, thanks for all the feedback. I have now completed the prototype with a lot more features than I originally intended for the first release, but hey while I was on a roll who cares.

For now I have posted the online version here: http://www.coalvillemodels.co.uk.

When I am satisfied no major flaws exist I will compile a windows desktop version for you to download and keep forever.

You can give me feedback here or via the website.

Thanks again for all your input. :D

[rustynath]

That works well :)

Has gained the "thumb's up" from me :D

rustynath

[TWICK9]

Great work midlandmodeller, works fine well done. Brian.

[midlandmodeller]

Thanks for the feedback, that's great.

I aim to have the windows desktop version available next week.

Any bugs, just let me know.

Thanks.

[midlandmodeller]

Once again thanks for your input on my scale calculator project. The desktop version is now available as a free download from:

http://www.coalvillemodels.co.uk

Any problems, let me know, otherwise I hope you find it useful.

I am currently working on a version that allows you to save the results of your calculations for future reference. Very close now, but not enough free time so it will be a couple of weeks. For now I hope you enjoy using the current version on the link above.

Thanks again.

[nigelwright7557]

2.54 millimeters is exactly equal to 0.1 of an inch

[midlandmodeller]

2.54 millimeters is exactly equal to 0.1 of an inch

That is correct, the formula uses the value 2.54 in the conversion of imperial to metric before converting again to the scale equivalent.

[TEAM YAKIMA]

Hi all

Sorry to come into this a bit late but as far as I know the official definitions of OO / EM / S4 are

The scale is 4.00mm to the foot and the ratio is 1: 76.2

Regards

Paul

[nickinwestwales]

Looks like some good work done for the greater good there-well done -for myself I use a vintage ERG brass `scale rule` marked out to 3.5,4 & 7 mm scales for small stuff and `lean slightly to one side and squint a bit` for longer distances-on a more serious note,since OO is,by definition,a compromise scale it permits of a more `if it looks right...` sort of approach-but then again I`ve always been a bit of a cowboy in these matters......
ATB
Nick