Why is called HO?

On Mon, 27 Nov 2006 23:18:05 -0800, I said, "Pick a card, any card"


And I sent you a medal for that. Did it get lost in the mail again? -- Ray
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On Mon, 27 Nov 2006 23:18:05 -0800, "Roger T."

No one seems to have mentioned that it is half of British 0 scale (7mm:ft), not North American or European 0 scales :-)
Jim.
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Jim Guthrie wrote:

Why would anyone consider US O gauge? What 5 foot gauge railways are there to model anyway?
European 0 scale(s) is/are 1:43.5, 23mm:metre and 1:45 which makes present day H0 half of most of European 0 scale.
Regards, Greg.P.
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wrote:

It's possible that the majority of subscribers to this newsgroup are in North America, and to them, 0 scale is 1/4" :ft and H0 certainly isn't half of that.

No, H0 is half of 7mm:ft scale - the UK scale. The European scale is a slightly smaller scale ratio to get a more accurate scale/gauge ratio on 32mm track.
Jim
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Jim Guthrie wrote:

Fair point I suppose - however, all these scales began in Europe with the exception of TT and several we could argue about.

All the major sizes that started pre-mid-thirties were _gauges_, not scales.
Scales were ascribed to those gauges somewhat later, hence the weird ratios.
Forget millemeter:foot scales, those are the constructs of Henry Greenley long after the gauges were set. No-one in their right mind would set a scale ratio in two different measuring systems. Certainly no-one in mainland Europe would know how to utilize such a scale as they dumped such archaic measurements more than a century ago.
Most of Europe uses 1:43.5 scale, with a much smaller group in the south eastern corner of Central Europe using 1:45.
7mm:1' is in fact slightly _smaller_ that the standard European scale at 1:43.5428'57141428'57..repeating.
Imagine trying to measure a scale (say) 6 1/2" in that scale!
Regards, Greg.P.
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Greg Procter wrote:

That's wrong.
In Denmark we went metric by law as late as 1904, this means that feet and inches was still in everyday use when I was an apprentice in the 1970'ies at F. L. Smidth. We made a lot of spare parts in inches, and Whitworth threads were still much used.

Wrong again.
In Denmark, Sweden, Norway, most of Germany, Switzerland, most of Austri, Italy, and Eastern Europe 1:45 is used. 1:43.5 is used in France and by a few in Germany.
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Erik Olsen
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Erik Olsen DK wrote:

That's _102_ years ago - the number of people in Denmark old enough to remember pre-metric days would be almost down to single figures.

Did you make many parts in mixed Imperial/Metric measurements?

Lima produced in (ahem) 1:45 (cough) scale in the 1970s which lead to a small revival of European 0 Scale but 1:43.5 is/was more commonly used by established enthusiasts in France and Germany.
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Greg Procter wrote:

By law, I wrote. Half a century went by before people even thought of using the metric system in everyday use. When I was a child people still bought two pund of potatoes (or the Danish equivalent) or a 'pot' of sweet milk. In the 1970'ies, lumber was still bought in feet and inches (albeit Danish inches 'tomme', 1 tomme = 26.18mm).

One day we made parts in inches, the next day in mm. Some parts were measured in mm but had Whitworth thread, so yes, literally speaking.

In France yes, and a few in Germany.
But most of Germany is 1:45. The NEM standards states 1:45 as the scale ration for 0, see http://www.morop.org/de/normes/index.html .
Also have a look at http://www.argespur0.de/ which is one of the largest 0 scale 'Verein's in Germany.
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Erik Olsen
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Erik Olsen DK wrote:

Sure - it didn't matter so much in the first half of the twentieth century - potatoes didn't need the precision or interchangabilty of mechanical parts and timber is generally cut to precise size on site.

Two sets of precision measuring equipment required and the ongoing chances of using the wrong one time after time, plus you create yet another variation on Imperial nuts and bolts on top of all those different types for every specialist branch of engineering. <sigh>

OK, it seems you know better than I do/did. :-)
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That depends a lot on how precise you _need_ to be. An adjustable spanner is an adjustable spanner - it care little whether the gap is 7/16ths of an inch or 11 mm or somewhere in between.
I don't know how long we've used metric measures over here in Norway. A long time - probably about as long as Denmark.
Some metric units are in universal use. It would be weird to us to start measuring weight in pounds and stones and centuryweights and what not. Same with celsius instead of fahrenheit.
But we still call a yardstick "en tommestokk" (an inch stick ...), and we still buy lumber in standard sizes we call "2x4 inches" (which is approximately 54x 102mm) or "1 1/2x2" (approximately 38 x 54 mm) etc.
The _standard dimensions_ of lumber doesn't have to be measured in metric units.
I don't need to know how many millimeters wide a flathead screwdriver is - I just need to have one among the set I have that will fit the screws I use at any given time.
Or when I buy ground beef in the store - I just look at the packs and decides "that ones seems to be about the right size for making spaghetti for 4 people". It may be 420 grams or 510 grams - "about the right size" is close enough for practical use.
There is no need to actually sell ground beef packages in "standard metric sizes". The package have to be labelled with weight, both the actual price and the price per kilo. That allows direct comparison of price per kilo between stuff sold by two different companies.
Also it matters little if you buy one gallon of milk or whether you buy four liters of milk. Four liters is a little more than one gallon, but who cares ?
Where metric shines is where you need to do a bit of calculations.
Especially calculations where different parts are measures in different units - e.g one part is measured in centimeters, one in meters.
It is a heck of a lot easier to just move the comma one position right to convert from centimeters to millimeters or or two positions left to convert from centimeters to meters and then just add the numbers together than it is to multiply by 12 to go from feet to inches or divide by 16 or some such number to go or from some kind of floating ounces to some kind of gallon or whatever.
Metric is good for ease of calculation. But there is nothing about measuring stuff in metric units that makes the measure inherently more _precise_ than a measure given in imperial units. A measure of 35 milliliters (3.5 centiliters, 0.35 dl, 0.035 liters) is not necessarily more precise than one of say 1.2000456 gallons.
But we are getting pretty far off the topic of model trains. Time to go get some lumber and start building that layout!
Smile, Stein
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Stein R wrote:

If I have a worn threaded hole disappearing into the block of my alloy motor and two bolts of the correct length and diameter but with differing threads in the bucket, I'm in trouble! If they were standard metric bolts I'd only have a choice of standard or fine threads.
In fact I've come across this sort of situation repairing British and Australian cars where some major components were sourced from elsewhere.

My (most recent) grumble started while building a 1:24 scale goods wagon - the plan dimensions were in feet and inches (eg 18'7 21/64") My materials were in metric, inch fractions and inch thou'.
Take an actual example; the deck height of the wagon, 2'10 3/4" - simple conversion 34 3/4" - divide by 24 = 34 3/4 /24 or 1 43/96". Of course I can't get an inch ruler with 96ths of an inch 1.447917" ok 1.448" or 1.45"
My bogie center height is 22mm, my plasticard decking is 60 thou thick, the framing available in the shop is 7/16" deep, and my spacing washers are 0.75mm. So how many spacing washers will I need or do I need to buy another thickness of plasticard while I'm in the shop on my monthly visit?

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If you have a worn threaded hole and do not the original bolt, you do have a problem. Heck - you might have a problem even if you have the original bolt, if your threaded hole is worn enough.You might have to end up rethreading the hole to make it fit a bolt you have.
That's life. No matter how much bellyaching you do in this newsgroup - I suspect that the world will just keep on using screws that follow different standards.

So you convert the plan dimensions to metric before dividing them by 24 to get scale dimensions (still in metric). What's the problem ?

2' 10 3/4": 2' = 24". You have 34 3/3" or 34.75". Multiply by 2.54 cm per inch. 88.265 cm
Want that in 1:24 scale - divide by 24. 3.6777 cm. Round off to a _reasonable_ degree (for 1:24 scale) and call it 3.68 cm or 36.8mm. Close enough for all practical purposes. People are not going to do anything nasty to you for getting your floor 0.002 cm (0.02 mm) too high.
On the full size car, that would correspond to an error of about 0.048 cm, or 0.12" too high.
Not significant if the original measure is given as 34.75". I doubt that the people who built the original cars would have lost their sleep if the deck height of a specific car turned out to be 0.12" higher than what they had originally planned.

If you only get to go to a store once a month, then stock up on plasticard. If you can afford it. If you can't afford it, find yourself a cheaper way of doing your hobby.
If you are asking how much materials you need to build up your waggon floor from 22 mm to 36.8 mm, the answer is "36.8 - 22 = 14.8 mm". What combination of washers, plasticard and framing you use to get those 14.8 mms is up to you.
The plasticard apparently is 60/1000 (inches ?) thick, ie 1.5 mm thick. The framing is 7/16 inch * 25.4 mm/inch = 11.1 mm thick and the washers are 0.75 mm thick.
14.8 - 11.1 (framing) - 1.5 (plasticard) = 2.2 mm.
So you either throw in one extra plasticard, which leaves you with 2.2 - 1.5 = 0.7mm for washers. If you then use one washer, your floor gets raised by another 0.05 mm (since the washer is 0.75 mm instead of 0.7mm). If you use this combination, your floor gets to be 0.02 + 0.050.07 mm too high. 0.007 cm. Scaled up again that corresponds to your floor being too high by 0.168cm (0.066"). Not very significant when compared with the full size dimension (34.75").
Or you stay with one plasticard, and try to make up that 2.2 mm gap with 0.75 mm washers. That works out as "almost 3 washers". Using three washers will give you a floor that is raised by another 0.06 mm, for a total of 0.008 cm too high. Scaled up the floor gets to be too high by 0.192 cm or 0.076". Again, not very significant when compared with the full size dimension (34.75").
Closest match is then two plasticard, one washer, instead of one plasticard, three washers. In either case, the error is piddling - 0.18% in the first case, 0.21% in the other case.
As I wrote - metric makes for fairly easy calculations. It doesn't much matter what standard dimensions you can buy your supplies in as long as you convert to something you can do calculations in.
And by all means - do check my calculations before using my numbers :-)
Smile, Stein
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says...

You mention moving the comma to convert centimeters to millimeters.
Why is it the usage of commas and decimals are opposite on the two sides of the Atlantic?
The number 1,142.23 in the US is 1.142,23 in Europe. Why is that?
And although you mention the use of the comma, you use of decimals in your note is the US style. Hmmm...
Surely some knowledgeable person on this forum knows the answer.
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Ken Rice -=:=- kennrice (AT) erols (DOT) com
http://users.erols.com/kennrice - Lego Compatible Flex Track,
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snipped-for-privacy@email.ads (Ken Rice) wrote in says...

LOL - guess that's part of being functionally bilingual. I didn't even notice that I automatically changed to using the period (.) as a decimal point while writing a number in an American English text.
I do a _lot_ of (more or less) automatic conversion when I write in (US) English instead of Norwegian.
We do use the comma (,) as the decimal separator in Norway. And a space ( ) as the thousand separator instead of using a comma (,) in the US style. So in a Norwegian text I would write "1 245 127,32" and in US English I would write "1,245,127.32". Please feel free to change my comment above from "moving the comma" to "moving the decimal separator" :-)
Same thing with dates - in Norwegian I would write today's date as "30.11.2006", in US English as "11/30 2006". Sometimes when I know I am writing for an audience consisting of both Yanks and Norwegians, and I have dates where a number could be either the day number or the month number (ie day number less than 13) I might write a date like "11-SEP- 2001" instead of "11.09.2001" or "9/11 2001".
Of course, the smartest way of writing dates would probably be to do as the Swedes and write them "2006-11-30" - that way you have most significant part (year) to the left, and pretty easy sorting and grouping.
In a similar vein, I also think using the 24 hour clock is way simpler than the am/pm system. Over here the new day starts at 00:00 (midnight), noon is at 12:00 and the day ends at 23:59:59 (a second to midnight).
True - with a 24 hour clock you have to get used to what 1800 hrs mean (6 hours past midday, ie 6 pm), but there is a natural sort order to timestamps within the day. 00:30 is unambiguous 30 minutes past midnight and 12:30 is unambigously 30 minutes past noon.
In the am/pm system I tend to get a little confused about times like 12:30 pm and 12:30 am. One is 30 minutes past midnight, one is 30 minutes past noon. But which is which? One rule is "am" for "ante meridiem" - before midday, "pm" for "post meridiem" (past midday). Another rule is "higher number within same am/pm means later" - 11 pm is later than 10 pm.
So is 12:30 am in the morning ? or in the afternoon ? Does it come 1 hour 30 minutes after 11 am or 10 hours 30 minutes before 11 am ?
BTW - I _do_ know the answer - but it does not necessarily feel logical to me, so it takes a little extra mental effort for me to convert to am/pm for times between midnight and 1 am and between noon and 1 pm.
What else ? I often switch to "miles" instead of "kilometers". If I just need a rough distance I cheat and just multiply or divide by 3/2 or (ie I approximate an english mile as being about 1.5 kilometers instead of the correct 1.620 kilometers).
If I need approximate conversions between inches and centimeters, I approximate an inch as being about 2.5 centimeters instead of 2.54 cm). That way 10 cm is about 4 inches, and e.g 50 centimeters (5 x 10 centimeters) is about 20 inches (5 x 4inches)- close enough to estimate how much space you need for 20" curve radius or mentally convert track lengths on a model railroad layout plan.
If I need rough temperature conversions for everyday life, I know that a rough conversion factor is that a change of 10F corresponds roughly to a change of 5 celsius (not quite true - the factor is 1.8, not 2.0). And that fahrenheit has its freezing point at about 30F (not quite - 32F), while celsius is at 0C.
So 40F (30F+10) is about 5C (0C+5), 50F is about 10C, 60F is about 15C, 70F is about 20C, 80F is about 25C, 90F is about 30F and 100F is about 35C. 70F/20C is "pretty pleasant", 100F/35C is "too hot". Going the other way 0F (about -20C) means "a little on the cold side for barbecuing on the porch", anything between 0F and 32F is "pretty nice day for the wintertime" and anything below 0F is "maybe time to put on a sweater over the T-shirt before going outside". -40 (celsius or Fahrenheit) or colder means "it's a good day to stay inside and fix some stuff around the house".
Anyways - you asked why people use different separators and different conventions about how to write things. I have no idea. Accidents of history, I guess.
Doesn't matter, as long as most people make allowances - or just ask when things look weird :-)
Smile, Stein
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says...

Excellent response. I do wish we could all agree on one standard and stick to it. In my work I also have to be familiar with multiple time and date expressions. Personally, I would love to get rid of daylight savings time. I suggest the next time change it by 30 minutes, and stay that way. <G>
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wrote:

a little bit cool, 25C is just right.

no, just a bit on the warm side. 40C is getting hot, makes things a bit uncomfortable 45C is very hot, 48C is bloody hot! Marble Bar and other places to the north regularly have 100 or more consecutive days with temperatures over 38C/100F

We occasionally get ice on car windscreens in winter, but it is usually all melted by 8am - and that is cold enough for me! Other parts of WA get colder and we sometimes get snow in the Porongorup Hills near Albany.
Weather tomorrow, Friday - sunny, min12C max 24C Alan, in Gosnells, Western Oz. VK6 YAB VKS 737 - W 6174
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Ken Rice wrote: [...]

Back in the Olden Days, there was no consistent usage in Yurp. Then SI came along (systeme international). For reasons best known to themselves, the committee members who concocted this system decided on the comma as the decimal point marker. Most European countries used the comma, so that probably explains it.
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"> That's _102_ years ago - the number of people in Denmark old enough to

Greg you are way out on this one, the railway 50 meters from my flat (Apartment) is a Swedish narrow guage railway running on three swedish feet gauge there are others still measured in feet and inches (Fot and Tum) I can go to my local timber yard and order without anyone blinking an eye timber in feet and inches (yes yards too ....Aln) it is true that for most purposes metric is used but the old measurements are still in use even in France. By the way the imperial measurement of today is not that of 150 years ago or that of any other european nation, or indeed that of the USA, each has its own standards, time to stop this silly argument before you really put your foot in it:9 Beowulf
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Beowulf wrote:

I long since stopped - so how do your suppliers know which you're ordering of Swedish, British, French or any of the other pre-metric feet.
Years ago I started building a French loco from an 1850s French book I own (side view only) After a time it struck me that some dimensions like buffer height were wrong, and finally that _all_ the dimensions I converted were wrong. I never did have the heart to start that one again.
Regards, Greg.P.
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Greg Procter wrote:

In other words: Poor research.
We that live in Europe outside the UK know that a lot of different measuring systems have co-existed for a long time, and many of us grew up with them. We would have asked that question at first: Which measuring system?
I think in France there were more than one feet/inch-system in use, and as I recall the french were very early users of the metric systems (yes, there is more than one metric system).
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Erik Olsen
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