When harvesting roundwood is produced, first of all they try to accurately calculate its cubature.
The measurement is made in the upper branch, where the diameter will be somewhat smaller. When measuring trunks having a cross-section different from a circular one, they try to measure on the narrowest section, passing through the center of the annual rings of wood.
This technique is used because it allows you to accurately estimate how much one of the logs will produce edged sawn timber, which have the greatest value in woodworking. It is obvious that they will be cut according to the diameter of the upper cut.
For the same reason, the log portion of the trunk, where the difference between larger and smaller diameters of the cut is large, is preferred to be discarded and not used in the blank. Still, take on the sawmill will be the forest on the upper cut.
When determining the length, measurements are taken with an accuracy of 10 cm, while the length is rounded down. This accuracy is due to the fact that logs are usually made with two notches - one higher, one lower. First make the bottom, then the top - on the other side. falls to the side where his head is sloping. The cuts are made so that the bottom is on the side where the barrel should fall.
In this case, the upper cut is made on the other side, standing in the direction opposite to the most likely drop. At the subsequent sawing the whip is usually sawed with a saw for one propyl, however often the error of a cut is allowed at the same time - it can pass slightly obliquely, because of this, such a large error.
Calcutation by cubist
In accordance with it, it is possible to determine the volume of each log by making measurements and selecting a value from the table. In the table, the diameter of the trunk goes in 1-2 cm increments, and along the length it is 10 cm. Of course, it is not very convenient to use the entire table of the cubist.
This table shows the data for the most common diameters of the upper cut and length. Usually it is required to consider the volume for logs up to 6 meters long. It is logs of this length that get into most standard bodies of conventional, not specialized as timber trucks or timber trucks to tractors, it is in size up to 6 meters that the cross-cuts of the whips are made.
Naturally, when the forest is handed over to the sawmill, there are no "approximate" calculations, and it is necessary to apply the full GOST for the final calculation - these are the sawmills and the money of the scaffolders who love accurate counting.
Calculation using formula
V = πd²l / 4, where d is the diameter of the trunk in the upper span, l is the length of the log, π = 3.14 - for our calculations, the high accuracy of this constant is not needed.
This is convenient when there is no GOST available, but only. With a large amount of work, even from three to four machines, this method will take a lot of time to calculate, in addition, this technique is not standardized and is not an argument in financial disputes.
When building a house from round logs, you need to calculate the number of necessary materials
The construction of a house from rounded or, as it is often called, profiled log, always attracted a lot of attention. After all, in addition to aesthetic performance, such living quarters carry a naturalness, naturalness and solidity. That is why many future homeowners give this material their preference, thereby leaving without attention the profiled bar or log houses of manual cutting. But when planning the future of construction, many do not know how to calculate the cubic capacity of logs and how much you need to purchase materials for your house. Let's try today to understand this issue and solve the main problem of all beginning builders.
Round logs
The process of manufacturing round logs takes quite a long time, because in order to get the right cylindrical shape, the workers of the sawmill use special machines that remove the outer layer of wood (sapwood or rind), leaving only the core - the most solid part of the trunk. This is what distinguishes the profiled log from the timber. And if you take into account the fact that you use ultra-precise equipment in the process of processing, you will never see a cone shaped log, as it often happens in manual cutting.
Another advantage that a rounded log has is the degree of its shrinkage.
If the average shrinkage of the house continues for 3-4 years and during this time the tree can lose in height from 7 to 10%, then the profiled log for the same period can shrink no more than 3-5%.
Thanks to such data, round logs always had an advantage over their competitors, which is why many prefer building a wooden house from this material. But still, how to calculate the volume of round logs is the main task that we are setting today.
Forest cubic meter
Before you start calculating the cubic capacity of a log, you need to explain for yourself what a cubic meter of wood is.
After all, often many do not even suspect that the released building material, in particular rounded logs, is calculated in cubic meters.
So, a cubic meter is a unit of volume, having a length of edges of one meter. Simply put, the length, width and height of any material (concrete, wood, water) is equal to one meter. It is this volume called the cubic meter of building material. In our case, when a wooden house is built from a profiled log, we will only talk about the cubic meter of round logs.
Calculation formula
To build a house you can buy logs of different diameters
Round logs can be different in diameter. In each individual case, the owner of a future wooden house can purchase both thin logs, with a diameter of 150-180 mm, and thick ones - 300-350 mm. What kind of material to give preference depends on the region of residence. If the air temperature in winter in the southern regions of the country does not fall below -20C °, then thin profiled logs will fit for the construction. In other cases, when the temperature can drop and below -40 ° C, it is necessary to purchase thicker materials that will help keep the heat in the house. Depending on the diameter and length of the log, the value of the cubic meter will also change. How correctly to count a cubic capacity of a log in this case?
To help builders, the State Standard No. 2708-75 may come, which regulates the volume of round timber depending on the length and diameter of the upper end. With the help of this standard, where the round timber tables are given, it is easy to calculate the volume of logs required for construction. In cases where you do not have this document at hand, you can use the following calculation formula:
∏* R² *H,
where the value of Π (Pi) expresses the ratio of the length of the circle to the length of the diameter, R is the radius of the log, and H is the length of the log. Substituting the lengths (6 meters) and the diameter (200 mm) of logs under the formula, we get the following result:
3,14 * 0,1² * 3 = 0,188 m³.
In other words, the formula can be expressed so that in one rounded log - 0.188 cubic meters of building material. Thanks to this formula, you can easily calculate the cubic capacity of a log, namely: 1 cu. meter / 0,188 = 5,3 logs. In such a tricky way, you can easily calculate how many profiled logs are needed for building a wooden house.
Measurement of the amount of timber and sawn timber is made by measures of volume, in our case in cubic meters. In general, the calculation is carried out according to standard geometric formulas, but can have some nuances.
Consider how to calculate the cubic capacity of a log.
From the geometric point of view, the log represents a cylinder. Accordingly, the volume of one log is calculated by the cylinder volume formula, that is: the number Pi is multiplied by the square of the radius and the length. The number Pi we know (3,1415 - for those who forgot), the radius is determined by measuring the diameter and dividing by 2, the length is obtained by direct measurement. All measured values are taken in meters.
To calculate the total volume of logs, it is necessary to multiply the volume value obtained for one log by their total number. As you can see, there is nothing particularly complicated here, if not for a couple of "buts":
- Logs should be more or less close to the ideal cylinder;
- They should have approximately the same radius;
- They should be the same length;
Otherwise, this method of calculating the volume will give us the wrong result.
That is why, when examining the purchased logs, pay attention to their correspondence to each other in diameter and length.
This method is often used when measuring the volume of sorted timber, as well as rounded logs. The latter have undergone factory processing and have the same parameters of radius and length, which makes the calculation of the volume quite accurate.
The approximate volume of the unsorted log will be easier to calculate by eye by calculating the volume of a conventional cube. Logs are stacked in a pile, in which length, height and width are measured. Multiplying these figures, you get the volume of the stack. Make a correction for the voids between the logs and the difference in logs in diameter and length (just "by eye"), and you will get an approximate cumulative amount of logs.
With a bar or boards everything is much simpler.
Their volume is calculated by the method described above, only, in this case, the results of calculations will more accurately correspond to reality. The reason is that both the board and the beam fit tightly to each other in the stack and have the same length. Thus, the stack of the factory beam is a regular cube, and this greatly simplifies the calculation of its volume.
In addition, you can calculate the cubic capacity of logs with the help of special tables called cubatured . Your task is to measure the diameter and length of the log, after which it is necessary to look at the table for the relevant indicators. However, in order to obtain the aggregate volume, it is necessary to measure each log in the stack and summarize the individual values. On the other hand, this will give an accurate result.