Calculating BdFt and Cubic metres

Woodworking is great we all love to build things out of trees but while trees grow out of the ground money certainly doesn’t grow on trees so it’s important before we start our projects that we know what were up against financially and if we can afford to build that next project.  So I’m going to try my best to teach you how to work out the costs from the materials you’ll need to build that project.

Firstly I must admit I’m fortunate living in a metric society to me it makes more sense but the irony is I rarely use it.  I’m a cross between a kind of a hybrid when I need to work out how much material I need and the costs involved because I use both metric and imperial to get the job done.  You see in Australia many don’t know inches, the basics, some, maybe but this is a metric nation and so all the lumber yards work in metric and therefore when I go there I have to think in metric.  When I get back to my shop all my hand tools chisels, blades are in inches (imperial) so all my drawings I draw up are also in imperial.  I can’t make a 6mm mortise with 1/4″ mortising chisel because there is a 0.35″ of a difference and while that may not sound a lot try building an entire clock with all these differences and you’ll be sure to run into a lot of trouble.

So let’s get on with it.

First let’s talk metric.  One cubic metre equals 200 lineal boards.  To work out the cubic metre you multiply the length by the width by thickness then divide it by 1000,000,000 mm and you’ll get your cubic metres.

Sounds confusing here is an example:  10000mm x 2000mm x 19mm/1000,000,000 = 0.38

Let’s say your making a wall shelf  and I won’t include everything you need but let’s pretend this is all you need and BTW there is no right or wrong way to read this.

Length, width, thickness or thickness, width, Length.  The only difference is which you country you live in will determine how they are written.

2 sides  L = 406  x  W = 205  x  T = 19

1 top   915 x 71 x 19

1 bottom  915 x 205 x 19

1 centre shelf  890 x 205 x 19

1 Back  876 x 57 x 19

You’ll need in total 3493mm Length, 743mm width but you never calculate the width unless you are trying to work out cubic metres.  So how did I come by this figure you’ll kick yourself on how simple it is.

406 + 406 + 915 + 890 + 876 = 3493 mm

So as you can see metric is simple

Lumber yards will rarely tell you how much a board is in lineal metres unlike home centre where they do why because they are dealing with non tradesman and that is the reason why they like to rip a new hole in your backside when you buy from them.  So you go to the lumber yard with your fibulator and you see this beautiful timber that’s perfect for your next project but there are no prices written anywhere and you have to go to the main office and ask how much for such and such and he looks into his computer punching the keys as if they are made out of stone and he say’s with an unemotional stare as if money is pouring out of the sky $7,500 m3

and you return that unemotional stare with the added exception of that immense chest pain you suddenly got while you quietly walk away to compose yourself while reaching for your fibulator and calculator.  This dramatisation is not far from the truth.

Anyway all jokes aside this is how you work it out.

1 x .025 x .200 x $7,500 = $37.50

So as you can see working in metric isn’t that hard at all even though their prices are.

Ok so let’s have a quick look at board feet.

Let’s use only one example:

72″ x 8 1/4″ x 3/4″/144= 3.09375 or 4 Bd.Ft.

Now to know how much this 4 BdFt is going to cost you, you need to know how much the lumberyard is going to charge you per board foot.  So let’s say it’s $18 a board foot and you need 4 BdFt so you pull out your calculator and you type

4BdFt x $18 per BdFt = $72.00

So I think you get the picture now, well I hope you do.  That wasn’t hard either learn this and you’ll know exactly how much it will cost you to build your next project .

 

 

 

 

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7 thoughts on “Calculating BdFt and Cubic metres

  1. No Salko… I didn’t get the picture…. LOL
    After 3 year buying wood I still did not got it!
    Here in Portugal the decimal metric system was first introduced since (around) 1814 and all the other measurements were made illegal around 1852.
    But today If I got to any hardware store buy a water/sure pipe (and almost everything in plumbing) I need to ask in 1/2″ or 3/4″ – yes inches
    Today I went to buy rough sawn pine wood in small shop in town near me. Board up to 3cm thick are sold by square meters. More then 3,5cm thick is sold by cubic meter. And the price chances every 1 or 2 moths.
    So I gave up. I go to the store and simply give the man a list and ask the price before…
    And some times is cheaper to buy in a big box store
    Just to compare National Pine around 1100€ m3; Beech 2700€ m3

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  2. I too have noticed this to be the case with many hardware’s and dowel sizes as well in box stores, the packets read in mm but the contents are actually sized in inches. Masters who was part owned by Lowes in the US used to be a big offender in this especially in dowel sizes, someone must of said something or they just woke up to themselves and marked all the products that came out of the US to inches. Even though most of the worlds goods are manufactured in China they are done so in imperial and then advertised to the public in whatever system of measurement that nation uses mostly.

    It’s interesting to read that imperial was made illegal in your country can you elaborate on this a little more as to why.

    The prices you mentioned is what it used to cost 20 years ago here, in the two big box stores we have pine 1000 x 285 x 19 is about $18 at the lumber yard it’s $3 less so in reality it’s not a great deal of difference. The cost of materials and labour in this country are too high which has forced many companies to go overseas and has given rise to an opportunity for many immigrants to enter Australia stay a short while under cut everyone accumulate wealth and go back home. This is the price we pay for living in the worlds largest island.

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    1. Salko,

      It wasn’t just the imperial measurements that was made illegal back then.
      In the XVIII and XIX century we had all kinds of measurements for every thing and it even differers from town to town. So it was harder to trade goods. So the Queen in 1852 tried to put some order in the nation… We are a Republic since 1910….But almost 200 years later its common to use different systems specially in informal forms of trade (ex a bag of potatoes in the farmers market have 1 “arroba” = 14,688kgs or a Portuguese manufactured axe is marked in pounds). And we live ok with it! 🙂
      Maybe it can be explained for this:
      Since the X century we had the influence (you can read invaded by) of Celtic, Roman, Arab, Roman Christian, Spanish, French and British culture. Plus around 1500 we were a people of sailors (or invaders depending the perspective) in different places from Brasil, half of Africa, Japan or some Islands near you like East Timor.
      So as a Nation and a Contry we had lots outside influences and we accumulated in our own culture

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  3. I can really relate to this as I’m very much conflicted between the two measurements myself, one because the tools I have are manufactured in the US and the other I live in Australia a once British colony that used only imperial now use only metric. So I’m torn between the two worlds which is fine by me but if everyone switched to metric I just don’t know if it would make an iota of a difference to the world. Would we be better off, I don’t know but sometimes I talk in inches and then realise they haven’t a clue as to what I’m talking about. I don’t do it on purpose it’s kind of like living in a foreign land and sometimes you say a few words in your own mother tongue without realising it and I’m guilty of that too atleast that’s what my wife say’s.

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    1. Salko,
      At the beginning it was very hard for me. After I got a cheat rule with faction inches, decimal inches and milimetres I then memorise 1″ aprox 2,5cm and 1 foot aprox 30cm… And I was set to go sort off…
      A few weeks ago I get in “trouble”. I made a grove with a 6mm cutter. After I made my panel. Then a stop dado and got my french 6mm chisel (this came from my father-in-law set of tools and he is almost 90 years old)…. It didn’t match and I had never seen that…
      No the chisel isn’t 1/4″… After checked with callipers it is 5,4mm. So I used the cutter to finish the project as a chisel.
      You wrote something about tight tolerances some time ago, and Greg have his mortice gauges set for is chisels…

      So I learn my lesson… from now on my reference are my tools and the dividers. That’s never wrong

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  4. Very true as you know no two 6 or 1/4″ chisel widths are the same, I may draw up or read someone else’s plan but I always gauge my work against my own tools this way I’m never wrong. I like training myself to work to very tight tolerances I have pretty much everything spot on except for thicknessing and planing the edge. So far I’ve got it down to about 4 thou some spots are right on the money and others 2 – 4 thou so I’m getting there.

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  5. Here in Belgium, we learn the metric system in primary school ( at least it was so 55 years ago) . When you do exercises on a school notebook or on an A4 or A3 standard sheet of paper, measures would be given in cm not in mm. So the general population would be quite familiar with cm or m but not with mm. If you look in an IKEA catalog (Belgian edition at least) you would find furniture dimensions expessed in cm not in mm or in m.
    mm would only be used by people having done mechanical training.
    Engineers, to avoid mistakes in conversion while doing calculations, would stick with basic units, the m in this case. A length of “x” mm would be expressed in m as “x E-3” if small enough. I would never use mm for woodworking it is too small and I have no feeling of what is 200mm while I have a good idea of what 20cm is.

    So, don’t take it as an offense, but if people accustomed to Imperial system or US customary system have been taught to use mm, I am not anymore surprised they don’t want to change.
    (for the difference, Imperial/US see : https://pegsandtails.wordpress.com/2010/01/12/inch-by-inch/ ).

    As in Portugal, France and probably everywhere in Europe units where different in each town.
    Making a sole sytstem mandatory simplifies (other than local) business, prevent cheating the customer, and … allows for uniform taxation and statistics.
    Interesting reading: “The measure of all things. The seven-year odissey and hiddn error that transformed the world” – The Free Press, (c) 2002 by Ken Alder.

    P.S. Please use the same board througout the text for your various examples if your goal is to clarify the use of units (whatever they are).

    Sylvain

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