Good day! We bring to your attention an article that should definitely help you in determining how many cubes of a board for building, for example, a wooden bath, you need to order. In the article, we will give a not easy final result for boards of a certain size, but we will also tell you what percentage of your overpayment from one cube of such a board, we will show an example of independently calculating the number of boards in a cube.
What is a cube and volume
Let's start with the fact that the boards are measured in cubic meters (abbr. cube). Cubic meter is the product of three quantities: the first of them is the length, the second is the width, the third is the height. In the case of a figure such as "cube", the value of "volume" will be equal to the length of the edge to the power of "3". Another definition of a cubic meter:
“Cubic meter (m³, cubic meter) is a unit of volume; equal to the volume of a cube with an edge length of 1 meter"
How to find the volume of a cube is shown in the video below (video in English):
Let's get back to your future boards, namely their size. The size of the board is indicated as follows: 25x150x6000. The first number is the height (thickness), the second number is the width, the third number is the length. The length of the board is usually either 4 meters or 6 meters.
Important! In fact, the length of the board will be greater than its nominal size. For example, a board 4 meters long actually has 4.1 or even 4.2 meters, and a board 6 meters long will have up to 6.25. As for the first two values, width and thickness (height), they must exactly match the specified parameter.
Calculation example for a board 25x150x6000
Consider the above board with a size of 25x150x6000. Dimensions here are in mm, but to determine the cubature, you need a different unit of measurement - meter. Let's translate mm into meters and get a board of 0.025x0.15x6.0. Let's apply the volume formula V= L* h* b, where L- length, h- height, b- width. L=6.0; h=0.025; b=0.15. Thus, 6.0 * 0.025 * 0.15 \u003d 0.0225 cubic meters. What does this mean? And this means one thing: if you know the price for 1 cubic meter of such a board, then freely determine the price of one board. Let's say if the price of a cubic meter is 100 rubles, then for one board you will have to pay 100 * 0.0225 = 2.25 rubles.
Attention! Often, the sellers of boards, one might say, "weld" on their customers, rounding the value of the volume of the boards. For example, instead of 0.025 cubic meters, a size of 0.023 is indicated. Of course, this is an insignificant deviation if you buy less than 1 cubic meter of boards worth 100 rubles, but when a cubic meter costs, for example, 300 rubles, and you need 10 cubic meters, then the overpayment will be significant.
That is why you should learn to independently determine the cubic capacity of the board. So, we managed to determine the volume of one board. But how to determine how many unedged boards are included in 1 cubic meter with dimensions of 25x150x6000. And to make it even easier, using the formula:
1 cubic meter / (L*h*b) = N pieces.
We substitute the available data and get the number of boards 25x150x6000 in 1 cubic meter:
1 / (6.0 * 0.025 * 0.15) \u003d 1 / 0.0225 \u003d 44.4 pcs.
Important! When ordering one cubic meter 25x150x6000, in fact, you take 44 boards, and you simply overpay for 0.4. Thus, 1% of the cost of a cubic meter is your overpayment.
Calculation of the volume and number of boards for different sizes
Below, together with you, we will determine the volume of one board and the number of boards for different sizes.
25x150x4000 (length - 4000, height - 25, width -150)
First, we determine the volume of one such board. We apply the formula and get 4 * 0.025 * 0.15 \u003d 0.015 cubic meters. meters.
Now we determine the number of boards 25x150x4000 in a cubic meter: 1 / 0.015 = 66.7 pieces. As a result, 1 cubic meter of board 25x150x4000 contains 66 pieces.
40x150x4000 (length - 4000, height - 40, width - 150)
Let's determine the volume of one such board: 4 * 0.04 * 0.15 \u003d 0.024 cubic meters. meters.
And the number of boards will be calculated as follows: 1 / 0.024 \u003d 41.6 pieces. Actually - 41 boards.
20x100x6000 (length - 6000, height - 20, width - 100)
Let's start by determining the volume of one such board, 20x100x6000 in size. 6*0.02*0.1=0.012.
The number of boards in 1 cubic meter: 1 / 0.012 = 83.3 pieces. We get 83 boards.
25x100x6000 (length - 6000, height - 25, width - 100)
We calculate the volume of one board using the formula: 6 * 0.025 * 0.1 \u003d 0.015 cubic meters. meters.
If you were careful, then a board measuring 25x150x4000 has exactly the same volume, and based on this we can immediately calculate the number of boards in 1 cubic meter: 66 pieces.
40x100x6000 (length - 6000, height - 40, width - 100)
We calculate the volume of one board 40x100x6000. We substitute the parameters into the formula and we have: 6 * 0.04 * 0.1 \u003d 0.024 cu. meters.
The number of boards will be 1 / 0.024 = 41.6. Thus, paying for 1 cubic meter 40x100x6000 you will receive 41 boards.
50x100x6000 (length - 6000, height - 50, width - 100)
First, we determine the volume of one such board. We apply the formula and get 6 * 0.05 * 0.1 \u003d 0.03 cubic meters. meters.
Now we determine the number of boards 50x100x6000 in a cubic meter: 1 / 0.03 = 33.3. As a result, 1 cubic meter of board 50x100x6000 contains 33 pieces.
25x150x6000 (length - 6000, height - 25, width - 150)
Let's determine the volume of one such board: 6 * 0.025 * 0.15 \u003d 0.0225 cubic meters. meters.
And the number of boards will be calculated as follows: 1 / 0.0225 = 44.4 pcs. Actually - 44 board.
30x150x6000 (length - 6000, height - 30, width - 150)
Let's start by determining the volume of one such board, 30x150x6000 in size. 6*0.03*0.15=0.027.
The number of boards in 1 cubic meter: 1 / 0.027 = 37.04 pieces. We get 37 boards. Perhaps, it is for a cubic meter of such a board that you will have to overpay the smallest percentage.
40x150x6000 (length - 6000, height - 40, width - 150)
We calculate the volume of one board using the formula: 6 * 0.04 * 0.15 \u003d 0.036 cubic meters. meters.
So how many boards 40x150x6000 in 1 cubic meter? It equals 1 / 0.036 = 27.8 cubic meters. meters. Attention! As you can see, if you round the number of such boards down, then you will overpay decent money, almost 3%!
50x150x6000 (length - 6000, height - 50, width - 150)
We calculate the volume of one board 50x150x6000. We substitute the parameters into the formula and we have: 6 * 0.05 * 0.15 \u003d 0.045 cu. meters.
The number of boards will be 1 / 0.045 = 22.2. Thus, paying for 1 cubic meter 50x150x6000 you will receive 22 boards.
25x200x6000 (length - 6000, height - 25, width - 200)
The volume of one board 25x200x6000 is 0.03 cubic meters. meters. The number of boards 25x200x6000 in 1 cubic meter is 33.3 pieces.
40x200x6000 (length - 6000, height - 40, width - 200)
The volume of such a board is 6 * 0.04 * 0.2 \u003d 0.048 cubic meters. meters. And the number of boards 40x200x6000 in one cube is 20.8 pieces.
IMPORTANT that when rounding down, the overpayment will be significant!
50x200x6000 (length - 6000, height - 50, width - 200)
The last size that we will consider in this article. We calculate the volume of one such board: 6 * 0.05 * 0.2 \u003d 0.06 cubic meters. meters. The number of such boards in 1 cubic meter will be equal to 1 / 0.06 = 16.7, which means a large overpayment when rounded towards 16 pieces!
In order for you not to get confused, below is a table with the results obtained:
Board size, mm | Volume 1 board, cube meters | The number of boards in 1 cubic meter, PCS | Amount of overpayment when rounding down, % with rounding |
|---|---|---|---|
Almost everything in our world has its own measurement value. We measure oil in barrels, coal in tons, the population of countries in thousands, millions.
We take as a basis a value that can specifically designate the object that we measure. When the question arises of how to calculate the cubature of a board, we are no longer talking about the mass of an object, since wood has a completely different density, and one tree has differences from another. In addition, boards of the same breed will have different weights depending on their moisture content.
For the convenience of calculating the cubature of the board, volume measurement formulas are used.
It is enough to recall school mathematics and the necessary formula by which to multiply the width, length and height. For the calculation to be correct, it is necessary to adjust all parameters to one value, for example, in centimeters or decimeters. It is most convenient to take meters as a basis. Thus, having multiplied three times in meters, we get m³ or cubic capacity.
Note. To calculate the cubature of the board, special formulas are used.
cubature boards
Boards may have differences in width, length, thickness. In addition, they are sold unedged and edged. Often, lumber has its own generally accepted standards, which make it easier to calculate cubic capacity.
For ordinary material sizes, there are already calculated volumes, which are systematized in tables for measuring the cubature of boards. Therefore, to determine the volume of the material, you simply need to open the table with the indicated dimensions and calculate the volume.
But, in order to do this, you must have these tables with you. Otherwise, in the absence of such, the cubature of the edged board is calculated, having previously determined the thickness and length. These are the main dimensions that meet the requirements for lumber. Each individual material is different. For example, a board with a thickness of 25 mm is used to create a crate, and 50 mm for subfloors. Next, you need to measure the width of the board.
In the case of a cut board, everything is simple, since the material is cut to give one width. Further, using a calculator, all values \u200b\u200bare multiplied among themselves. With a board length of 5 m, a thickness of 50 mm and a width of 25 cm, the volume of the material will be:
5 x 0.050 x 0.25 = 0.0625 m³
After multiplying the resulting number by the number of boards, we get the total volume of material.
The formula for calculating the cubature of boards
V = L x h x b
L - length
h - height
b - width
Determination of the number of boards in a cubic meter
1 m 3: V = N
In order to determine the cost of a particular type of board, with known volume values: V x price 1 m 3.
There is one more point that you need to pay attention to when determining the cubature of boards - the nominal length is exactly 6.1 - 6.2 m, but this is not taken into account when selling. Often this is important in the case of buying a large amount of material. For example, let's take a board with dimensions of 150 x 20 mm.
Having made simple calculations, we get the number of boards in 1 m 3 - 55, 5 pieces. So, in the cubature of the board 6 m there are exactly 55 pieces, in total, when calculating, we get the value of 0.99 m 3. In essence, the overpayment for the cubature of the board will be 1% of the exact price. For example, at a cost of 4,995 rubles, we pay 5,500 rubles.
Unedged board
Calculation features
The calculation of the cubic capacity of an unedged board is somewhat complicated, since the material does not have the same width between different boards, but also in each board individually. This is explained quite simply - the tree does not have the same diameter.
It is clear that it is wider at the bottom, narrower at the top. Thus, the width of the edged board does not fall under any standards. How to be in this case? Use different formulas to calculate. The width of the board is measured for convenience in the middle of the length. This is how you get the average width. This counting method works well if the batch of material is small.
For industrial volumes
This method is not suitable, because the work will be very slow, and this is not profitable. For such cases, experts have developed the so-called unedged board cubature. The volume in it is obtained by measuring and experimenting, in other words, using many measurements and calculating the average value of the width.
Of course, this cannot be called a super accurate way, but the deviations are so small that they should not be paid attention to.
Some wood processing companies use the stack measurement method in practice. To do this, it is not necessary to pre-sort the wood according to width. Specialists take measurements of the length of the board, the average width and height of the stack. The obtained values are multiplied among themselves, and the result is multiplied by a coefficient for calculating the cubature of the board, which has an average value of 0.67.
Weighing Method
In order to measure the cubic capacity of an unedged board, obtaining the most accurate result possible, the weighing method is used.
Before doing this, it is necessary to measure the moisture content of the material and dense wood. Considering that the edged board is the cheapest material used on objects with the least degree of responsibility, complex calculations are not very justified.
Also, it should be noted that the result that you get will not be very different from the one that can be obtained using the cube.
During the construction of residential buildings
Here, professionals in their field are required to perform many tasks, including: calculation and budgeting before finishing the premises. In addition, you need to calculate the required amount of building materials. It should be noted that this task is quite difficult. Given this, determining the cubature of the board is an important point.
Note. A cubic meter of lumber is calculated using a single method. The type of board does not affect the result.
To non-grooved types wood include: edged board, unedged board.
tongue-and-groove types- these are those that have special grooves for the perfect joining of the boards: flooring, lining,. Please note that when purchasing a tongue and groove board, the calculation is carried out using the working width of the material, without spikes.
Regarding the calculation of the cubature of an unedged board, with a width of one end of 25 cm, and 20 cm of the other, the average value will be 22 cm. To calculate a large amount of material, it is laid out in such a way that the wide part does not differ from the narrow one by more than 10 centimeters.
The main length of the board in the unfolded bundle should be approximately the same. Then, using a tape measure, measure the height of the stack of boards and the width in the middle. The result obtained during measurements is multiplied by a coefficient with a value of 0.07 - 0.09, which depends on the air gap between the boards.
When building a cottage or a house, the master, by necessity, performs many different tasks. He thinks through all the construction processes, draws up the necessary estimate for each of them. Calculating the correct amount of materials needed is not easy. This requires knowledge of mathematics. He must know: how many boards are in 1 cube, how many and so on. If he has such knowledge, then it's great! He is a real master!
And for an ignorant person, “how many boards are in a cube” is an abstract concept. In order for him to understand it, he should know exactly what building materials made of wood are. What are they, how are they measured? Without knowing this, he will not be able to adapt in these calculations.
Edged or tongue-and-groove, as well as other types of lumber
The first thing to learn is that it is not so important from which wood exactly this or that material was made. Let the boards are not the same, but their calculations will completely coincide. Let them have different varieties, different sizes, the calculation is still made according to the same principle. It's still wood, and it will be measured the same way! It can only determine how many boards are in 1 cube each time it will be different. Regardless of whether edged or tongue-and-groove, cylindered, etc. calculation will be the same.
Grooved lumber- different beams, edged materials, their non-edged counterparts, this is the case when their cubic capacity is calculated in a completely different way! These products have grooves, spikes. They are intended for docking between forest units among themselves. Such products include:
- blockhouses;
- floor material;
- imitation of various timber.
When purchasing such a grooved one, the circumstance should be taken into account. When calculating the cubic capacity, only the working width of the beam should be taken. The spike is not taken into account here. And when calculating the cubic capacity of a blockhouse, which can imitate a log, one should take into account its thickness, which it has at a high point.
Examples of calculations using formulas for the volume of 1 m3 of wood, as well as price comparison
Since the time of school, any specialist has known exactly how to calculate the cubic capacity or how many boards are in 1 cube. To do this, you need to find the product of 3 quantities: height, length, width. The same method is used to calculate the cubic capacity of a unit. Making calculations more convenient to immediately translate the parameters into the value of "Meter".
For example, the cubature of a unit of material having a length of 6 m and a cross section of 150x25 is calculated as follows: 0.15 m x 0.025 m x 6 m;
The formula we are going to calculate is: V= L*h*b (where L is length, h is height, b is width)
As a result of calculations, 0.0225 m3 is obtained. This is the cubic capacity of one product. If you want to know the cost, then 0.0225 must be multiplied by the cost of 1 cubic meter. After the calculations, it turns out that if we skip it, the cube will cost 6500 rubles. And the price of one of them will be 146 rubles. 25 kop. Here, for ignorant people, there is a little trick of sellers.
Usually, cubature can be rounded up to 0.023. And this means that lumber will cost 149 rubles for the buyer. 50 kop. Sometimes unscrupulous sellers can round off a cubic capacity with a size of 150x50 mm to about 0.05 m3. But if all calculations are performed correctly from the very beginning, it turns out that with a correct calculation, the result is only 0.045 m3.
It seems, so what, someone will say! The numbers are small, but the result is stunning! Such rounding will unwittingly lead only to the fact that the unit price will already be 325 rubles. instead of 292 rubles. 50 kop. And these calculations are performed considering that the price of a cube is 6500 rubles.
In addition, it is also necessary to know and take into account that boards having a nominal length of 6 m actually have a length of 6.1-6.2 m. This should not be taken into account when selling lumber! Sometimes customers may ask to know: how many boards are in a cube. This applies to the acquisition of more boards.
Everything is perfectly visible on the example of purchasing boards with dimensions of 150x25 mm, where their number in a cube is 44.4. But still, most often only 44 boards are considered a cube. And with the correct calculation, this amount is listed as 0.99 m3. In reality, an overpayment is obtained for 1 cubic meter. It is approximately 1% of its initial cost. It will look like this: that instead of 6435 rubles. for 1 cubic meter there will be a cost of 6500 rubles.
The volume of unedged wood is calculated in a completely different way. If you buy one of them, then measurements of its thickness and length are performed just as accurately as for edged lumber. But here its width is taken as an average. That is, it is between the smallest and the largest. Example: at one end it is 30 cm wide, and at the other about 15 cm, then to calculate the cubature, this parameter will be 22-23 cm.
If you need to find out the volumes of a large number of timber or determine how many boards will be in volume, they should be laid out in piles. But so that the widest of them would not differ from the narrowest by more than 10 cm. In such a pile, their length should match. But this is only an approximation! After that, with a tape measure, you need to measure the height of the stack and its width. These measurements are taken somewhere in the middle, the same applies to length.
The result of the calculation should be multiplied by the coefficient. It ranges from 0.07 to 0.09. It depends on the air gap that exists between the material. When performing calculations, the larger the gap, the smaller the coefficient is taken. If it has the same dimensions, then you can determine the number of boards in the cube.
By the way, for such calculations there are special tables in the textbooks of builders. Similar tables exist for almost all lumber, from and ending. In them, the cubature of common types of timber or other types is indicated. And it is not difficult to calculate the volume of boards, for example, for a fence! You can use the above formula yourself!
Performing a calculation according to the table of timber of standard length 6 meters
Determine how many pieces of boards in a cubic volume according to a special table
| The size | Volume of 1 piece | Pieces per 1 m³ | m² to 1 m³ |
|---|---|---|---|
| 20×100×6000 mm | 0.012 m³ | 83 pcs. | 50 m² |
| 20×120×6000 mm | 0.0144 m³ | 69 pcs. | 50 m² |
| 20×150×6000 mm | 0.018 m³ | 55 pcs. | 50 m² |
| 20×180×6000 mm | 0.0216 m³ | 46 pcs. | 50 m² |
| 20×200×6000 mm | 0.024 m³ | 41 pcs. | 50 m² |
| 20×250×6000 mm | 0.03 m³ | 33 pcs. | 50 m² |
| 25×100×6000 mm | 0.015 m³ | 67 pcs. | 40 m² |
| 25×120×6000 mm | 0.018 m³ | 55 pcs. | 40 m² |
| 25×150×6000 mm | 0.0225 m³ | 44 pcs. | 40 m² |
| 25×180×6000 mm | 0.027 m³ | 37 pcs. | 40 m² |
| 25×200×6000 mm | 0.03 m³ | 33 pcs. | 40 m² |
| 25×250×6000 mm | 0.0375 m³ | 26 pcs. | 40 m² |
| 30×100×6000 mm | 0.018 m³ | 55 pcs. | 33 m² |
| 30×120×6000 mm | 0.0216 m³ | 46 pcs. | 33 m² |
| 30×150×6000 mm | 0.027 m³ | 37 pcs. | 33 m² |
| 30×180×6000 mm | 0.0324 m³ | 30 pcs. | 33 m² |
| 30×200×6000 mm | 0.036 m³ | 27 pcs. | 33 m² |
| 30×250×6000 mm | 0.045 m³ | 22 pcs. | 33 m² |
| 32×100×6000 mm | 0.0192 m³ | 52 pcs. | 31 m² |
| 32×120×6000 mm | 0.023 m³ | 43 pcs. | 31 m² |
| 32×150×6000 mm | 0.0288 m³ | 34 pcs. | 31 m² |
| 32×180×6000 mm | 0.0346 m³ | 28 pcs. | 31 m² |
| 32×200×6000 mm | 0.0384 m³ | 26 pcs. | 31 m² |
| 32×250×6000 mm | 0.048 m³ | 20 pcs. | 31 m² |
| 40×100×6000 mm | 0.024 m³ | 41 pcs. | 25 m² |
| 40×120×6000 mm | 0.0288 m³ | 34 pcs. | 25 m² |
| 40×150×6000 mm | 0.036 m³ | 27 pcs. | 25 m² |
| 40×180×6000 mm | 0.0432 m³ | 23 pcs. | 25 m² |
| 40×200×6000 mm | 0.048 m³ | 20 pcs. | 25 m² |
| 40×250×6000 mm | 0.06 m³ | 16 pcs. | 25 m² |
| 50×100×6000 mm | 0.03 m³ | 33 pcs. | 20 m² |
| 50×120×6000 mm | 0.036 m³ | 27 pcs. | 20 m² |
| 50×150×6000 mm | 0.045 m³ | 22 pcs. | 20 m² |
| 50×180×6000 mm | 0.054 m³ | 18 pcs. | 20 m² |
| 50×200×6000 mm | 0.06 m³ | 16 pcs. | 20 m² |
| 50×250×6000 mm | 0.075 m³ | 13 pcs. | 20 m² |
Video on calculating lumber in a cube using formulas and tables
Construction works require the solution of many different issues, among which the most important task is the selection and purchase of lumber. It is not difficult to calculate how many linear meters of boards and timber will be needed during the construction process. That's just the price of commercial wood is indicated for 1 cubic meter, and this often causes difficulties for novice home craftsmen. The ability to correctly select and calculate the amount of edged or unedged lumber in a cube will save money and avoid a situation where, after completion of construction work, a pile of unused boards remains on the site.
Classification and characteristics of lumber
The very name "lumber" suggests that this type of construction raw material is obtained by longitudinal sawing of tree trunks on circular or band saws. For the production of boards and timber, several sawing methods are used:
- tangential (in a circle),
- radial.
Tangential sawing involves the movement of the saw tangentially to the annual rings of the tree, which reduces the amount of waste, and hence the cost of building materials. The boards obtained in this way have a beautiful, pronounced pattern, therefore they are often used for finishing purposes. Disadvantages of circular sawing include the wood's tendency to shrink and swell, and a significant difference in texture as the cutting tool approaches the center of the log.
In the sawmill industry, several methods of sawing the trunk are used.
With radial sawing, the cutting line passes through the core of the tree, so the output of boards will be less and their price will be higher. However, if it is necessary to obtain high quality wood, this method is used. This is due to the fact that, compared with the tangential method, radial sawing boards have halved swelling and shrinkage rates. In addition to the sawing methods discussed above, a mixed method is also used, which combines the advantages of the first two.
The concept of lumber actually includes not only the traditional molding, which is most often seen in the construction markets. A complete list of products that are obtained when sawing logs includes:
- board;
- timber;
- bar;
- lagging;
- croaker.
The last two types of lumber are waste, which absolutely does not prevent them from being used for certain types of construction work, as well as for finishing purposes.
Boards
Boards include rectangular lumber with a thickness of not more than 100 mm and a width to thickness ratio of at least 2:1. Depending on the degree of processing, the board can be edged and unedged. The first is a finished product without bark and with evenly sawn edges, while the second is a "semi-finished product" taken directly from the saw frame.
The edged board has even edges and a constant width along the entire length of the lumber
Most often in construction boards of such standard sizes are used:
- thickness - 25 mm, 40 mm, 50 mm, 60 mm;
- width - from 75 to 275 mm with gradation through 25 mm;
- length - from 1 m to 6.5 mm in 250 mm increments.
Boards of other sizes can be obtained by cutting or planing standard lumber, as well as by making an individual order for sawing round timber.
Unedged board has a lower cost, but without finishing, its scope is limited
The parameters of lumber used in construction are standardized and determined according to the current GOST 8486–86 for softwood and GOST 2695–83 for hardwood.
bar
Timber is called lumber, the cross section of which is a square with sides of at least 100 mm. The size of the beam in the diameter is unified and can vary from 100 to 250 mm in increments of 25 mm. The standard defines the length of products of this type from 2 to 9 m, but most often square-section lumber with a length of no more than 6 m is used. to sleepers.
The beam is an ideal material for the construction of frames and other wooden structures.
The bar differs from the bar considered above only in that its cross section does not exceed 100x100 mm. The typical length of the bar is also 6 m, and the size in diameter ranges from 40 mm to 90 mm in 10 mm increments. To simplify the classification, bars are often referred to as a rail, in which the cross section has a rectangular shape, and the ratio of thickness to width is at least 1:2. The standard range of edges of softwood slats looks like this: 16, 19, 22, 25, 32, 40, 44, 50, 60, 75 mm. For hardwood lumber, products of increased width are additionally provided, and the product line itself looks like this: 19, 22, 25, 32, 40, 45, 50, 60, 70, 80, 90, 100 mm.
A variety of bars and slats allow you to strengthen and make any wooden structure as stable as possible
Obapol and croaker
Obapol represents the very first cut of round timber, in which the outer surface remains untreated. Unlike obapol, the croaker can have a cut on half of the second side or an alternation of processed and unprocessed sections from the side of the bark. The value of obapol and slab in construction is secondary, since the unaesthetic appearance and reduced performance characteristics make it possible to use this type of lumber only for auxiliary purposes. Most often, slab and obapol are used as a fastening material, as well as for the manufacture of formwork, crates or flooring for scaffolding. This material is also interesting as a decorative material for decorating walls, fences and other vertical structures.
Despite external unsightliness, slab and obapol are widely used for secondary construction tasks.
Technology for calculating the number of boards in a cube
On the wood market, both edged lumber and unedged boards are presented, along the edges of which there is a wane. Depending on the type of wood products, several methods are used to determine the cubic capacity.
How to find out the number of edged lumber in a cube
The algorithm for determining the cubature of lumber is based on the formula known to every schoolchild for finding the volume of a rectangular parallelepiped. In order to find out the cubature of one board (V) in a cube. m, it is necessary to find the product of its length (a) by the width (b) and thickness (h) in meters V=a×b×h.
The desired figure will make it easy to calculate how many boards of this type will fit in one cubic meter of lumber. For this, 1 cu. m of lumber is divided by the volume of one product. For example, if you need to find out the cubic capacity of one board with parameters 6000x200x25 mm, then by substituting these numbers into the formula, we get V = 6x0.2x0.025 = 0.03 cubic meters. m. Therefore, in one cubic meter there will be 1 / 0.03 = 33.3 of such products.
The grooved board has a groove on one side and a ridge on the other. Since both of these elements are approximately equal to each other, their parameters can be neglected. That is why the size of tongue-and-groove lumber in diameter is measured without taking into account the locking part.
In the case of boards that have the same dimensions, the calculation can be simplified by substituting the dimensions of the lumber stack into the formula. Of course, at the same time, its laying should be as dense as possible, otherwise the gaps between the individual elements will affect the accuracy of the calculations. Given that the cost of individual types of wood reaches tens of thousands of rubles, such an error can result in a pretty penny.
To simplify the calculations, you can use special tables that allow you to quickly determine the cubic capacity or the amount of wood in 1 cubic meter. m lumber.
Table: the number of edged boards in 1 cu. m lumber standard length
| Board size, mm | The number of boards 6 m long in 1 cu. m | The volume of one board, cube. m |
| 25x100 | 66,6 | 0.015 |
| 25x150 | 44,4 | 0.022 |
| 25x200 | 33,3 | 0.03 |
| 40x100 | 62,5 | 0.024 |
| 40x150 | 41,6 | 0.036 |
| 40x200 | 31,2 | 0.048 |
| 50x100 | 33,3 | 0.03 |
| 50x150 | 22,2 | 0.045 |
| 50x200 | 16,6 | 0.06 |
| 50x250 | 13,3 | 0.075 |
The cubature of timber of standard sizes can also be determined using the table below.
Table: the amount of timber in 1 cu. m lumber
| Beam size, mm | The number of products with a length of 6 m in 1 cu. m | Volume of 1 bar, cu. m |
| 100x100 | 16.6 | 0.06 |
| 100x150 | 11.1 | 0.09 |
| 100x200 | 8.3 | 0.12 |
| 150x150 | 7.4 | 0.135 |
| 150x200 | 5.5 | 0.18 |
| 150x300 | 3.7 | 0.27 |
| 200x200 | 4.1 | 0.24 |
Very often it is required to determine the surface area (floor or wall) that can be covered with a board of one thickness or another with a volume of 1 cubic meter. m. To do this, you can use the formula S \u003d 1 / h, where h is the thickness of the lumber. So, one cubic meter of a 40 mm board will be enough to equip S = 1 / 0.04 = 25 square meters. m floor. To facilitate the process of calculating the area allows a table called a cubature. It contains data on the cross-section of boards, their number in 1 cu. m and the desired area that they can cover.
Method for calculating the cubature of an unedged board
Unedged lumber is not trimmed along the edges, so not only the size in the diameter of individual products varies, but also the width of different parts of one board. In this regard, it is possible to calculate the volume of a stack of raw lumber only approximately. The same applies to calculating the cubic capacity of a separate unedged lumber, although the error in this case will be much smaller.
So, to calculate the cubature of an unedged board, there are two constants - thickness and length, and one variable - width. To avoid complex calculations using differential algebra methods, the last parameter is simply averaged. To do this, the board is measured in several places and the arithmetic mean is found. For example, for a board with a diameter at the base of 400 mm, a width of 350 mm in the middle and 280 in the top, the calculated value will be (430 + 340 + 260) / 3 = 343 mm. Further calculations are carried out in exactly the same way as for edged lumber.
Most often, the width of an unedged board is determined only on the basis of measurements along the edges of the lumber. It should be noted that the accuracy of calculations directly depends on the number of measurements, therefore, in critical cases, their number is increased.
If it is required to find out the cubic capacity of a package of unedged wood, then the products are stacked on top of each other in such a way that the following conditions are met:
- stacks must be aligned along the front end;
- boards in a stack should not overlap;
- it is not allowed to change the width of the package along the entire length of the lumber;
- the protrusion of the outermost products beyond the stack should not exceed 100 mm.
By measuring the height, length and width of a package of unedged wood with a tape measure, the approximate cubic capacity is determined using the formula V=a×b×h. To find out a more accurate value, the result is multiplied by the stacking factor, which can be found in special tables.
When roundwood is harvested, first of all they try to accurately calculate its cubic capacity.
The measurement is made in the upper cut, where the diameter will be slightly smaller. When measuring trunks that have a cross section other than round, they try to measure along the narrowest section, passing through the center of the annual wood rings.
This technique is used because it allows you to most accurately estimate how much edged lumber will be obtained from one log, which is of the greatest value in woodworking. Obviously, they will be cut based on the diameter of the upper cut.
For the same reason, the ridged part of the trunk, where the difference between the larger and smaller diameters of the cut is large, is preferred to be discarded and not used in the workpiece. All the same, wood will be taken at the sawmill along the upper cut.
When determining the length, measurements are taken with an accuracy of 10 cm, while the length is rounded down. Such accuracy is due to the fact that when felling logs, two cuts are usually made - one higher, the other lower. First do the bottom, then the top - on the other side. falls in the direction where the top of his head leans. The cuts are made so that the bottom one is on the side where the trunk should fall.
In this case, the upper cut is made on the other side, standing in the direction opposite to the most likely fall. During subsequent sawing, the whip is usually sawn with a saw for one cut, but often a cut error is allowed - it can go a little obliquely, because of this, such a large error.
Calculation by cube
In accordance with it, it is possible to determine the volume of each log by taking measurements and selecting a value from the table. In the table, the diameter of the trunk comes in increments of 1-2 cm, and the length is 10 cm. Of course, using the entire cubature table is not very convenient.
This table provides data for the most common top cut diameters and lengths. Usually it is required to calculate the volume for logs up to 6 meters long. It is logs of this length that fit into most standard standard bodies of ordinary ones that are not specialized as timber trucks or timber trailers for tractors, it is in the size of up to 6 meters that the whips are crossed.
Naturally, when the forest is handed over to the sawmill, there is no question of any “approximate” calculations, and it is necessary to apply the full GOST in the final calculation - after all, these are sawmills and the money of foresters who love accurate counting.
Calculation by formula
V=πd²l/4, where d is the diameter of the trunk in the upper cut, l is the length of the log, π = 3.14 - for our calculations, the greater accuracy of this constant is not needed.
This is convenient when there is no GOST at hand, but only. With large volumes of work, even from three or four machines, it will take a lot of time to calculate in this way, in addition, this technique is not standardized and is not an argument in financial disputes.
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