# Help please :)

19 replies to this topic

### #1 ashnathan

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Posted 29 August 2010 - 05:26

Ive searched high and low and everywhere in between, can somebody PLEASE tell me the scale of -

1:43 in mm or cm
1:18 in mm or cm
and
1:12 in mm or cm

Thankyou very much!

### #2 bill p

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Posted 29 August 2010 - 16:25

Ive searched high and low and everywhere in between, can somebody PLEASE tell me the scale of -

1:43 in mm or cm
1:18 in mm or cm
and
1:12 in mm or cm

Thankyou very much!

1/43 - 1cm equals 43cm, 1mm equals 43mm
1/18 - 1cm equals 18cm, 1mm equals 18mm
etc etc etc !!

### #3 Mal9444

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Posted 30 August 2010 - 11:14

1/43 - 1cm equals 43cm, 1mm equals 43mm
1/18 - 1cm equals 18cm, 1mm equals 18mm
etc etc etc !!

The 'real' answer is that 1:12, 1:16; 1:32; 1:43 etc all represent 'old-fashioned' model maker's scales in Imperial, based around the inescapable fact that, in the true order of things as God intended, there are 12 inches in a foot.

Thus, 1:12 scale means 1 inch to the foot, 1:16 = 3/4 inch to the foot, 1:24 1/2 inch to the foot, and so on.

There are no natural, convenient metric equivalents - unless of course you consider 2.325581395248837209mm to the metre convenient!

Edited by Mal9444, 30 August 2010 - 14:56.

### #4 Bloggsworth

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Posted 30 August 2010 - 20:29

The 'real' answer is that 1:12, 1:16; 1:32; 1:43 etc all represent 'old-fashioned' model maker's scales in Imperial, based around the inescapable fact that, in the true order of things as God intended, there are 12 inches in a foot.

Thus, 1:12 scale means 1 inch to the foot, 1:16 = 3/4 inch to the foot, 1:24 1/2 inch to the foot, and so on.

There are no natural, convenient metric equivalents - unless of course you consider 2.325581395248837209mm to the metre convenient!

I always use that, as a rule of thumb.... or 3" or 9 barleycorns

Edited by Bloggsworth, 30 August 2010 - 20:29.

### #5 Tony Lethbridge

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Posted 31 August 2010 - 08:54

I always go with 1/43 being 'O' gauge in model railway parlance therefore 7mm.

### #6 Mal9444

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Posted 31 August 2010 - 21:25

I always go with 1/43 being 'O' gauge in model railway parlance therefore 7mm.

Notwithstanding my somewhat Lordly reply in post #3, I have been struggling for two days with my schoolboy maths to remember (or work out - but I have forgotten all my decimal-to-fraction reductions) what 1:43rd equates with, under God's own natural law.

The best I can get to is 7/25ths of an inch to the foot, which is as unlikey as it is unhandy. 1/3rd inch (i.e 8/24ths) to the foot would be 1:36 so it is not an approximation of that, while 1/4in to the foot would be 1:48 so it ain't that either. The nearest I can get to (though not exact) is 3/10th of an inch to the foot.

But whatever it is, I feel sure it pre-dates the arrival of the metrictocrasty

Edited by Mal9444, 31 August 2010 - 21:28.

### #7 Bjorn Kjer

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Posted 31 August 2010 - 21:51

Can I help out here ? The real scale is 1:43,5 not 1:43 !

### #8 Mal9444

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Posted 01 September 2010 - 08:11

Can I help out here ? The real scale is 1:43,5 not 1:43 !

Bjorn: I think you mean 1:43 1/2 (one to forty-three-and-a-half).

They don't do .5 (or even ,5) in Imperial measurement.

### #9 Hamish Robson

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Posted 01 September 2010 - 08:40

According to that great oracle of truth Wikipedia, "O" Gauge is 1:43 1/2, which in model railway terms is spacing a standard gauge rail spacing of 4'8 1/2" at a scaled distance of 1 1/4".

HO Gauge, now common amongst manufacturers like Hornby, is half that scale at 1:87, hence Half O Gauge.

### #10 Bjorn Kjer

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Posted 01 September 2010 - 11:41

Right Hamish , that's why I said the real scale was 1/43,5 ! Not 1/43 !

### #11 ashnathan

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Posted 02 September 2010 - 08:21

Well can someone say ROUGHLY what 1/18 scale is in cm's? for example is it like 20 cm's? less? more?

### #12 Mal9444

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Posted 02 September 2010 - 08:39

Well can someone say ROUGHLY what 1/18 scale is in cm's? for example is it like 20 cm's? less? more?

Ashnathan: in metric terms it is really easy: 1:18 scale means that 1cm on the model equals 18cm on the real thing, as Bill pointed out in his immediate answer to your first question.

What we are playing around with now is how and why the modelling world has adopted these scales as standards - and that is because - for a reason that I for one do not know, unless it is simply that it was the British, with their fascination for things mechanical and where the Industrial Revolution began, who first set the standards in mechanical model making - model makers used the Imperial system of measurement, not the metric. Had the early industrial model makers worked in metric, I am sure our scales today would all be 1:5, 1:10; 1: 20 etc

As Hamish, Bjorn and Tony explain, the origins of 1:43 being a model-making standard lie in the fact that - for what ever reason - an early standard of scale in model trains was what came to be called O guage, in which a real track of 4ft 8 1/2in was scaled down to 1 1/4in in inches. And as is well known Frank Hornby began making his diecast model vehicles, the models that became Dinky, as accessories for his model railways.

Don't ask me why Hornby (whom I believe to have been the inventor of O guage) decided on 1 1/4inches for the width of his track. Maybe it fitted a job-lot of cardboard boxes that Frank had fallen heir to.

But the answer to your original question is exactly as Bill stated.

Edited by Mal9444, 02 September 2010 - 08:48.

### #13 Tim Murray

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Posted 02 September 2010 - 10:52

Well can someone say ROUGHLY what 1/18 scale is in cm's? for example is it like 20 cm's? less? more?

As Bill and Malcolm have indicated, you take the dimensions of the full-size object and divide them by 18 to get the equivalent dimensions on your 1:18 scale model of it. For example, the Chaparral 2F had an overall length of 12 feet 11 inches, or 394 centimetres. Thus a 1:18 scale model of the car would have an overall length of 8.61 inches, or 21.9 centimetres.

I have no knowledge of how the O gauge scale came about, but my calculator tells me that scaling 4 feet 8½ inches down to 1¼ inches gives a scale of 1:45.2, not 1:43.5.

### #14 h4887

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Posted 02 September 2010 - 11:18

There are no natural, convenient metric equivalents - unless of course you consider 2.325581395248837209mm to the metre convenient!

I suppose that's near enough! You're not the geek who has just calculated pi to 5 trillion decimal places, are you?

### #15 Bjorn Kjer

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Posted 02 September 2010 - 13:42

Tim , O = 1/45 "rounded up" , correct.

### #16 Mal9444

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Posted 02 September 2010 - 23:33

Tim , O = 1/45 "rounded up" , correct.

This has got to be the most circular thread in which I have been involved on TNF - but seriously, Bjorn.

How much fun are we having here?

On a scale of 1 to 43, I mean?

Edited by Mal9444, 02 September 2010 - 23:35.

### #17 D-Type

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Posted 03 September 2010 - 11:45

The trouble with 1:43 is that the gauge of a railway is the distance between the inside edges not the centrelines. And when Frank Hornby produced his trains, for ease of manufacture he may have made the centreline distance a sensible inch number, the most likely is 1 1/3 inches. With a rail width of 1 1/2 inches we get:
1.333 x 43.5 = 58 inches = 4 ft 8 1/2 inches + 1 1/2 in (assumed width of the head of the rail)
But a rail size of 1.5 x 1/43.5 = .011~ is too small so he made the rails for the Hornby trains bigger.
(But I don't know my model railway history that well. Possibly Marklin in Germany preceded Hornby in which case the above is poppycock and it is was originally a sensible metric dimension for either the gauge or the rail centres)

It is often said to be 7mm = 1ft, but I think that is pure coincidence.

These days 1 inch is defined as 25.4 mm. At one time the British, US and Canadian inches were all slightly different but in 1959 they agreed to standardise on the Canadian definition. So we 7 mm = 1 ft gives
7 x 43.5 = 304.5 mm while 1 foot = 12 x 25.4 = 304.8 mm (exact)

As stated previously HO is half O Scale at 1:87 or 3.5 mm = 1 ft. Again the model rails need to be oversized to have sufficient strength.

And finally 00 Gauge. When Hornby wanted to make smaller electric trains, they couldn't make an electric motor small enough to fit into a 1:87 loco so they went for the smallest they could make, 1:76.

And the original Matchbox Toys were to a scale of "The model fits in a standard box which is about the size of a normal match box"

As to the original question, I think the answer is

In imperial units
1:12 is 1inch = 1ft
1:18 is 1 inch = 1 ft 6 ins, or 2/3 in = 1 ft
1:24 is 1 inch = 2 ft 0 ins, or 1/2 in = 1 ft
1:32 is 1 inch = 2 ft 8 ins, or 3/8 in = 1 ft
1:36 is 1 inch = 3 ft 0 ins, or 1/3 in = 1 ft
1:48 is 1 inch = 4 ft 0 in, or 1/4 in = 1 ft
1:72 is 1 inch = 6 ft 0 in, or 1/6 in = 1 ft

In metric units
1:10 is 1 cm = 10 cm, or 100cm= 1m
1:20 is 1 cm = 20 cm, or 50cm=1m
1:25 is 1 cm = 25cm, or 40 cm = 1m
1:33 1/3 is 1cm = 33 1/3 cm, or 30cm = 1m

Edited by D-Type, 14 September 2010 - 21:47.

### #18 Bjorn Kjer

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Posted 03 September 2010 - 18:23

Malc , I have half ( ½ or 0,5) fun !

### #19 Tony Matthews

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Posted 13 September 2010 - 21:52

These days 1 inch is defined as 2.54 mm.

The inches I use are a bit bigger than that!

### #20 D-Type

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Posted 14 September 2010 - 21:50

The inches I use are a bit bigger than that!

Aaaargh!

I meant 2.54 cm or 25.4 mm. I've corrected my post.