Since the age of this thread is rather old, I assume it's a moot point. However, just to contribute for anyone else who land on this page with the same question, here is some useful info:
http://www.evergreenscalemodels.com/conversions.htm
http://www.hamuniverse.com/antfrac.html
http://mdmetric.com/tech/cvtchtfdm.htm
http://www.rapidtables.com/convert/length/inch-to-mm.htm
Granted that all measurements seem to be based on some ridiculous arbitrary standard (I think that that other appendage was the source of the firkin) : my tongue-in-cheek point is that the metric measurements we use may be handy in some respects, but they're mostly ill-suited to many of the situations we encounter in day-to-day living. When we went metric (yeah, I'm a Canucklehead too), the English measurements on consumer goods were converted for a brief period to metric, but as stocks of Imperial-sized containers ran out, manufacturers invariably introduced metric-sized containers smaller than the previous Imperial container, yet the price stayed the same. Ditto for gasoline, which used to rise in penny-a-gallon increments - now it rises in dime-a-litre increments, the equivalent of $.48 a gallon. I think that we've been had. If you check, now most products sold by-volume in containers are marked in metric units, but they convert readily to U.S. measurements - where we once bought an Imperial gallon of paint (4.5 litres), then a four litre pail, now it's a 3.78 litre pail. If your car needs oil (remember add a quart?) even though your owner's manual advises you to add a litre, check the container - you're still adding a quart, only now it's a smaller American quart. And to offset so-called global warming, we now use Celcius temperatures, so when the guy on TV tells you that it's minus ten, you'll feel a lot colder than if he had said it was 14 degrees Fahrenheit. I don't know if it's still common practice, but machinists divide the inch into decimal increments, which is easy to work with.
Anyway, for the scale lumber, I use Evergreen styrene strips, which are available in HO scale dimensional lumber sizes (and also expressed in thousandths of an inch, for those wishing to convert to other scales). For building stuff like trestles, coaling towers, etc., I think that in most cases, 1/8" square stock is "close enough" to represent 12"x12".
Wayne
Yes the metric/English combination that HO is afflicted with causes no end of difficulties.
Having said that, I know of some very good HO modelers who are strict about scale measurements but do use the 1/8" = 1 foot for the very largest structures as a sort of automatic selective compression. The one thing that needs adjusting is the doors because a scale figure looks like Wilt Chamberlain [does that show my age?] next to a 1/8"=1 ft door opening.
Over the years I have purchased many "on sale" and "odd lot" leftovers of scale lumber and plastic and metal shapes as well so that I have a large selection available when I start a project. I also own a very useful tool made by General, No, 1401. This is a dial caliper where the readout is in HO -- down to a scale half inch and up to 42 scale feet. It also comes with a useful conversion chart and is marked so you can also work off of 1/4" scale plans or parts. There might be a digital readout version available but I am happy as a clam with my "analog" dial. It ain't cheap (mine was cheap but that is because I got it at Walthers' show room store and the plastic box was cracked -- there are advantages to living in Milwaukee!). When you first get one you find yourself walking around measuring everything in HO scale sizes. An Xacto knife blade for example is 2 1/2 inches wide in HO, which is something to think about when cutting.
One thing I have learned by the way, in using this caliper to measure scale lumber and other parts, is that one manufacturer's "scale foot" is not the same as anothers. And likewise, one manufacturer's "actual" 1/16" is different than another's. This is true for wood, plastic, and metal.
Dave Nelson
tatans wrote:Hooray, great responses, great answers, I do see the difficulty in transposing scales in 1:87, I'm going to take ALL your advice and proceed, I just may take the "very close enough theory" , unless some of you out there want samples of my wood to scrutinize in your electron microscopes. I even had to explain to a scale lumber manufacturer what MY problem is, he agreed. I'm taking all the above advice and information to heart and your info explains a lot about scale sizes, thanks, this forum comes through again. please consider converting to the metric system, please, please, I beg of you, please.
Hooray, great responses, great answers, I do see the difficulty in transposing scales in 1:87, I'm going to take ALL your advice and proceed, I just may take the "very close enough theory" , unless some of you out there want samples of my wood to scrutinize in your electron microscopes. I even had to explain to a scale lumber manufacturer what MY problem is, he agreed. I'm taking all the above advice and information to heart and your info explains a lot about scale sizes, thanks, this forum comes through again. please consider converting to the metric system, please, please, I beg of you, please.
I'm glad you found our posts helpful. As for converting to the metric system, RIGHT ON! We should have done that years ago.
tatans wrote: please consider converting to the metric system, please, please, I beg of you, please.
please consider converting to the metric system, please, please, I beg of you, please.
The problem with the metric system that's currently in use in much of the world is that the measurements are too puny for North American sensibilities. On the highway, I'm driving at a hundred and barely moving - with the English system of measurement, doing 100 is movin'! Similarly, what use is a millimetre or centimetre in real life - good maybe for measuring rainfall, but the next useable measurement of length is a metre. How much easier to have inches (divided into fractions, which can be expressed as decimals, if that's your preference), feet, and yards. A set of measurements tailored to match the situations one would normally encounter in everyday life, not some abitrary fraction of the length of an arc on the Earth's surface. Sure, the decimal system is easy to learn, but for practical purposes, not very useful. What's needed, in my opinion, is a decimal version of the foot, and a kilometer that's a mile long. And for our scale models, use a scale ruler (does anybody make a metric version of a scale ruler?) or express things like lumber and pipe sizes as thousandth of an inch. You could also take what I've said with a grain (480 grains equal 1 ounce) of salt, as I'm one of those people who still run my trains using DC.
tatans wrote: It seems I'm not expressing myself properly, what I need are dimensions such as 12'' x 12'' (1ft.x1ft.) in H O scale, that would be 1/8'' x 1/8'' --right??? Now I need other size lumber such as HO 12''x14''=...........'' HO 6''x10''=.........'' HO 3''x10''=....... I NEED TO FILL IN THE BLANKS WITH THE ACTUAL SIZE OF THE LUMBER IN THE PACKAGE, (IN FRACTIONAL NUMBERS) So I'm looking to find the actual fractional size of the lumber in the package, as the package contains 8 pieces of HO 12''x12'' --11'' in length, so what I have, is in reality, 8 pieces of 1/8'' x 1/8'' x 11'' Now if I can just find the dimensions for other sizes, I shall be happy. I have a feeling I'm still not explaining my problem properly.
It seems I'm not expressing myself properly, what I need are dimensions such as 12'' x 12'' (1ft.x1ft.) in H O scale, that would be 1/8'' x 1/8'' --right??? Now I need other size lumber such as HO 12''x14''=...........'' HO 6''x10''=.........'' HO 3''x10''=....... I NEED TO FILL IN THE BLANKS WITH THE ACTUAL SIZE OF THE LUMBER IN THE PACKAGE, (IN FRACTIONAL NUMBERS)
So I'm looking to find the actual fractional size of the lumber in the package, as the package contains 8 pieces of HO 12''x12'' --11'' in length, so what I have, is in reality, 8 pieces of 1/8'' x 1/8'' x 11'' Now if I can just find the dimensions for other sizes, I shall be happy. I have a feeling I'm still not explaining my problem properly.
You explained the problem fine.
But the answer isn't as simple as you want it to be. No harm there, I'm in the exact same boat, spooling up my shop to build lots of wood structures. I wish it was simpler too.
Some complicating problems:
Prototype lumber isn't the size it claims to be. That has changed over time.
Model lumber sellers often take shortcuts, for good reason. Their machines don't cut to hundred thousandths of an inch. They round off. They often round "up" to give you a little more to work with in tiny, fragile 'timber". They pick a size that's close, so the thickness of lumber versus it's width is a certain multiple, critical in actually building square, plumb buildings. They pick a size so that "two by fours" have a certain relation to "two by eights", for similar reasons. They pick a size that allows them to get the most out of cost effective stock THEY purchase.
They use decimal figures to describe what they sell, because decimal inches are much, much more precise than common inch fractions like 1/4" and 1/16".
Here are your options:
1. Place a calculator on your workbench.
2. Live with what they sell you, as labelled.
3. Make your own.
No matter which you choose, you have to decide how big your lumber is supposed to be in real life, then divide by 87, OR, just blindly accept what it says on the package.
No matter which option you choose, decimal inch figures will be more exact than common inch fractions.
That's just how it is.
Believe it or not, you HAVE a fraction that PERFECTLY describes what's in the package. If the package says it is 0.357 inches, then the wood inside is 357/1000ths of an inch thick.
If that fraction doesn't work on your table saw, then you can pick one that's close.
How close? How much error are you willing to accept?
To see what the errors will be, and to see what common fractions will do to your error levels, and to see what common fractions apply to which sizes of lumber, go back and read my earlier post, especially the bold text part at the bottom.
I can tell you EXACTLY how big a modern, or 50 year old, or 100 year old 3x10 will be in real life, AND how big in HO.
But then you'll be in a pickle when you need a dimension for a 4x16, and I might not be around that day.
Best bet, read my earlier post, assimilate it, decide how much error you are willing to accept, THEN install a calculator at your workbench and learn how to convert decimal fractions to common fractions, and you can meet any situation that comes up.
Give a man a fish, he eats dinner tonight. Teach a man to fish, he eats every night.
tatans wrote:It seems I'm not expressing myself properly, what I need are dimensions such as 12'' x 12'' (1ft.x1ft.) in H O scale, that would be 1/8'' x 1/8'' --right??? Now I need other size lumber such as HO 12''x14''=...........'' HO 6''x10''=.........'' HO 3''x10''=....... I NEED TO FILL IN THE BLANKS WITH THE ACTUAL SIZE OF THE LUMBER IN THE PACKAGE, (IN FRACTIONAL NUMBERS) So I'm looking to find the actual fractional size of the lumber in the package, as the package contains 8 pieces of HO 12''x12'' --11'' in length, so what I have, is in reality, 8 pieces of 1/8'' x 1/8'' x 11'' Now if I can just find the dimensions for other sizes, I shall be happy. I have a feeling I'm still not explaining my problem properly.
NO. An HO 12"x12" is NOT 1/8x1/8. The actual fractional size of an HO 12"x12" is 4/29"x4/29" which in decimal inches to three places is 0.138 x 0.138. The prepackaged HO scale lumber from firms such as Kappler is exact to three decimal places - Kappler's HO 12"x12" measures out to 0.138 x 0.138 actual inches (0.138" * 87 = 12 HO inches). By the way 1/8 " in HO is excatly 10 7/8 inches. (1/8 * 87 = 10 7/8)
HO 6"x10" is 2/29" x 10/87"
HO 3"x10" is 1/29" x 10/87"
The common fractional sizes of stripwood such as 1/8, 1/16, 1/32, etc do not scale up to integral numbers in HO scale.
Tatans, consider:
If a scale 12x12 is 1/8"x1/8" then it would follow that a scale 6x6 would be 1/16"x1/16", a 3x3 would be 1/32"x1/32", a 1.5x1.5 would be 1/64"x1/64".
I gather this is what you are trying to determine --- a 12x14 would be 1/8"x9/64" plus a hair using the above.
Hope this helps. John T. in the fractionalized cow pasture
Check this page on Kapplers site http://www.kapplerusa.com/y2k/p-ho-12.htm
Enjoy
Paul
tatans wrote: there some law that prevents scale lumber makers from putting on exact measurements???
there some law that prevents scale lumber makers from putting on exact measurements???
I think they just didn't think to do it. Did you ever notice that the name Walthers uses for their own products on their web site is not always the exact same name they use on the product boxes? Confusing!
There are some problems with trying to mark "scale" lumber stock.
A "2x4" today is 1.5 inches by 3.5 inches. Fifty years ago, it was 1.75 inches by 3.75 inches. A hundred years ago, it was either 2 inches by 4 inches, or "'purt' near as close as I kin reckon".
Then you have problems where cutting machines like rounded off decimal dimensions better than dimensions measured in hundred thousandths of an inch, and where designers wished for a simple decimal measurement to represent a basic dimension, like two inches, whether that "two inches" be 2 inches, 1.75, 1.5, or "dadburn close".
In HO scale, two inches, divided by 87 is just a fuzz more than 0.0229885057471264367816091954022989 decimal inches. To the closest thousandth of an inch, that rounds to 0.023 inches.
Some manufacturers round this to 0.024, for a certainty, and I'd be surprised if none of them round to 0.025.
0.0229885057471264367816091954022989 decimal inches is equal to 0.367816091954022988505747126436782 sixteenths of an inch.
0.0229885057471264367816091954022989 decimal inches is equal to 0.735632183908045977011494252873563 thirty seconds of an inch.
0.0229885057471264367816091954022989 decimal inches is equal to 1.47126436781609195402298850574713 sixty fourths of an inch.
If you round the last figure off to 1.5 sixty fourths of an inch, you will be less than three one hundredths of a sixty fourth of an inch wrong with a two inch HO scale measurement. A 12 inch HO scale measurement, using this conversion factor of 1.5 sixty fourths equals two inches, will be about one tenth of a sixty fourth of an inch wrong.
So...two real inches, in HO, is 1.5 sixty fourths of an inch, within the limits of most consumer grade table saws.
BUT...a real "2x4" today is only 1.5 inches thick.
1.5 real inches, in 1:87 HO scale, is 0.0172413793103448275862068965517241 decimal inches.
0.0172413793103448275862068965517241 decimal inches is 0.275862068965517241379310344827586 sixteenths of an inch. (Can you see where this is going?)
0.0172413793103448275862068965517241 decimal inches is 0.551724137931034482758620689655172 thirty seconds of an inch.
0.0172413793103448275862068965517241 decimal inches is 1.10344827586206896551724137931034 sixty fourths of an inch.
If you fabricate an HO 2x4 that is 1/64th of an inch thick, you will be just a fuzz more than one tenth of a sixty fourth of an inch wrong.
BUT...that doesn't get you home either. Two by fours, two by sixes, two by eights, etc., are NOT multiples of their 1.5 inch thickness, in width. Two by fours and sixes are their stated dimension minus a half inch. Two by eights and bigger vary from their stated dimension minus five eighths of an inch, to their stated diemnsion minus three quarters of an inch.
Soooo...a key figure would be the HO decimal and fraction for half an inch.
Half a real inch, in HO, is 0.00574712643678160919540229885057471 decimal inches.
(cut to the chase)
0.00574712643678160919540229885057471 decimal inches is one third of a sixty fourth of an inch, within table saw limits.
Three quarters of an inch, in HO, is half a sixty fourth of an inch, within table saw limits.
Sooooo...all your modern HO scale, "two-by" lumber should be one sixty fourth of an inch thick.
Modern "two by fours" and "two by sixes" are their stated dimension divided by two, times 1.5 sixty fourths, minus one third of a sixty fourth inch, wide. Two by six, six divided by two, times 1.5 64ths, minus one third of a sixty fourth, the two by six is 4 sixty fourths wide, or 1/16 inch wide.
One sixteenth inch is 0.0625 decimal inches. A real 5.5 inches scaled to HO is 0.0632 inches, less than one one thousandth of an inch error between the two.
Modern "2x8s" and wider, are their stated dimension, divided by two, times 1.5 sixty fourths, minus half a sixty fourth inch wide.
2x12, 12 divided by 2, times 1.5 sixty fourths, minus half a sixty fourth, equals 8.5 sixty fourths inch wide in HO.
8.5/64 equals 0.1328 decimal inches, while a real 11 and 1/4 inches, in HO, is 0.1293 decimal inches, an error of about three one thousandths of an inch.
To heck with metric measurements, my head hurts.
Key numbers:
All "two by" material is 1/64" thick in HO.
Two real inches, in HO, is 1.5 sixty fourths of an inch.
Half a real inch, in HO, is 1/3 of a sixty fourth of an inch.
Three quarters of a real inch, in HO, is 1/2 a sixty fourth of an inch.
(Are you glad you asked?)
:-)
cacole wrote: If you have a copy of the Walthers 2008 HO scale catalog, look on page 919 at the Northeastern Scale Lumber Company products -- they are listed in scale dimensions, such as 2"x4", 1"x2", etc.THAT"S THE PROBLEM, those are the dimensions of the real lumber sizes, I need the actual fractional sizes ( eg: 1/4" or 3/8'' of the wood in the package) No one does this.
If you have a copy of the Walthers 2008 HO scale catalog, look on page 919 at the Northeastern Scale Lumber Company products -- they are listed in scale dimensions, such as 2"x4", 1"x2", etc.
THAT"S THE PROBLEM, those are the dimensions of the real lumber sizes, I need the actual fractional sizes ( eg: 1/4" or 3/8'' of the wood in the package) No one does this.
I printed out a decimal chart and pasted in on the wall in the train room. I sure can't remember those numbers.
I cut some scale lumber out of Walnut. It looks real good for trestles and outside uses. It is a little too hard for internal structures.
I'm building some buildings from some old plans in H O scale, so I need scale lumber, I ordered some 1/8"x1/8" (actual:12''x12'') on the package was HO 12''x12'', now the plans are in fractional dimensions,(1/4", 1/8", 1/32" etc etc) but scale lumber makers will not put actual fractional numbers on the package, so now I have to convert every dimension from fractional to actual size: HO12''x''12''=.1250x.1250, who buys wood by the decimal system???? Why would the package not indicate ENGLISH:(American) 1/8''-----METRIC:0.3175cm -----DECIMAL:.0125" See the confusion, a scale rule will not help. Is there some law that prevents scale lumber makers from putting on exact measurements??? I'm also in the process of making my own scale lumber and with a fair bit of success using a jig saw and a guide and lots of patience, it's working well, I use hemlock , will try basswood next.