Lumber is building wood materials that are obtained by sawing large timber. There are various sawing methods, the main purpose of which is to minimize the amount of waste in production. On sawing, we get a bar, the surface of which will be of high quality, as well as geometric dimensions that meet the requirements of GOST.
It is quite useful to know the standardized parameters wood. This will help both for homemade products with your own hands and for capital construction.
For the construction of supports, frames and other supporting structures, in most cases, coniferous materials are used.
There are several types of sawn timber:
In this case, conifers are dissolved into only 3 types:
The establishment of dimensional standards allows for the transformation of construction into a more versatile technology .
There are GOSTs that regulate a number of recommended parameters and sizes - length, width and thickness. When a timber log is sawn, the geometric dimensions are selected from a list of standard values. Moreover, the slab is a part obtained from the extreme regions of the log, it can be obtained of any non-standard thickness.
The standardized geometry of lumber simplifies the design of typical architectural structures, the preparation of technical documentation, and the control of the activities of construction teams.
Considering the type and size of the required products, the most suitable option is selected from several schemes for breaking up round timber.
Sawing to size can be radial and tangential. The radial pattern is a cut, the shear plane of which is cut through the center of the trunk, and the produced floorboards are obtained with the direction of the fibers (annual rings) parallel to the lateral edge, which is a guarantee of high quality.
When using radial sawing, the resulting bar is almost not warped and has a small coefficient of shrinkage and swelling. 10-15% of floorboards from the total volume of scaffolding are obtained from radial sawing at the exit. Everything else falls on the tangential cut.
The disadvantage of such rods is that the annual rings run along a wide surface (layer), and therefore there is a risk of warping and a large shrinkage coefficient.
The widest part of the board is usually called the face, and the sides are the edges.
By quality, deciduous species are divided into 3 varieties, and conifers into 5.
The best grade sawn timber is usually called selective - it is marked with a horizontal strip or the letter "O", other varieties are marked with numbers: 1-4 - marked with the corresponding number of vertical stripes, dots or direct number. The quality of the lumber is judged by the worst edge or side.
The grade is determined by the presence or absence of knots, cracks, rot, warping, wormholes, the quality of machining (non-parallel planes and edges are established by GOST 24454-80 "Sawn softwood. Dimensions").
First-class wood is used in the manufacture of structural elements, windows, stairs, doors, finishing of walls and floors. Grade 2 is allowed on floorings, supporting structures in construction, lathing, formwork, planed parts. Grade 3 is used for supporting structures.
And 4 is used for the manufacture of containers and blanks.
Recommended dimensions of lumber in GOST 24454-80 "Lumber conifers. Sizes "are summarized in the table for convenience. The standardized size of the width of the cut materials ranges from 75 to 275 mm. The standard width increases in 25 mm increments.
For example, after 75 millimeters, the subsequent width of the wooden floorboards will be 100 mm. , then 125, etc.
There are 3 main geometric groups into which wood material is divided:
It must be understood that, for example, 22 mm is the maximum for thin floorboards. The next thickness is already the middle class.
In width, the material is divided into 2 groups:
To find out the number of edged boards in 1m 3 , we multiply the number of boards from the third column of the table by the length of the board (in our table - 6m).
And thus, we get the number of running meters of boards in 1m 3 .
To calculate the weight of one cubic meter of a board, we will use the formula: M = V * P, where M is the weight, V is the volume, and P is the density.
It depends on the type of selected wood, the place of its growth, and the specific place in the trunk from which it was cut.
In conclusion, we will reveal a few secrets of how to buy lumber and at the same time save money.
, smaller in diameter. Moreover, the quality of the boards of the working section is not inferior to the first grade! But if you take it in the appropriate number, it will turn out to be 10-15% cheaper than the edged board according to GOST.
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