In the woodworking industry, there are carefully drawn up instructions according to which types of lumber are sorted. The complexity of this system is that the gradation is carried out according to:
- Type of wood;
- Method of processing;
- Dimensions and geometric parameters finished products.
That is, for complete identification of lumber, it is required to link it to all three criteria. And the lumber itself is a product of the woodworking industry, corresponding certain parameters and in which there are at least two flat parallel surfaces.
There are two types of industrial wood:
- Deciduous;
- Coniferous.
Deciduous trees are generally considered to be hard, and coniferous trees are soft. But in fact, linden, aspen or alder, although deciduous trees, have soft wood. But larch, yew or cedar, on the contrary, are extremely hard.
To a greater extent, they differ in the presence of resinous substances in the wood mass. It is for this reason that coniferous wood boards are not used in rooms where a microclimate is created that is favorable for the release of resin to the surface.
The steam room and showers are not finished with coniferous wood just because of this.
But here there is an exception - yew. Although yew boards are not so often presented on the building materials markets, its wood is not considered valuable.
Special category
It is impossible to find products made from it in common use. Sometimes it is used as inlay, or veneer is made from it to decorate pieces of furniture.
Such wood almost always has a unique combination different properties, making it original and truly valuable.
Tree cutting
For example, wood rosewood growing only in Brazil and Paraguay, it exudes the scent of roses for several decades. In addition, it has a beautiful textured pattern and yellow-pink color. But the price for a 6-meter board, 3 cm thick and 9 cm wide, exceeds $2,000.
Pattern and texture
These parameters manifest the ontological qualities of wood. The ability of fibers to intertwine or follow strict parallel courses, to be twisted or cross-layered, is present to one degree or another in every tree species. But they are combined in an extremely narrow-profile combination, which helps to accurately determine the type of wood.
Moreover, the texture of wood is particularly influenced by the place where the tree grows and the concentration of certain elements in the soil. In particular, the presence of iron-containing minerals in the soil increases the cross-layering of some tree species.
Greater importance is attached to the pattern and texture of wood if these types of lumber are intended for finishing work.
But in this case, some defects of wood, which disqualify it from the category of structural materials, increase the value of the product from such a piece. For example, curling sharply reduces the strength characteristics of lumber, but with skillful processing and sawing, it is possible to produce finishing boards with an exclusive pattern. Birch and Norway elm are valued for this property.
The color palette also characterizes the type of wood, but in some cases it may change during processing or use. Moreover, these changes may indicate the beginning of destruction, for example, rotting. But changes in the shade of wood may be due to changes in the physicochemical parameters of lignin and oily or resin fractions, which sometimes, on the contrary, increases performance characteristics products. For example, larch heartwood has a resin with a unique high-quality composition. Upon contact with water, this resin polymerizes, and the material from the sound larch can no longer be damaged or processed. It is easier to file.
Strength characteristics
These parameters also have a lot of gradations that are rarely known to the average consumer. For example, strength is measured using the following criteria:
- For compression;
- For bending:
- Static;
- Dynamic;
- Tangential;
- Longitudinal.
- Tensile;
- For break:
- Along the fibers;
- Across the grain;
- For twisting;
- Chip;
Plus, the hardness of the wood is also measured.
In everyday practice, boards made of oak, hornbeam, larch, and beech are considered durable lumber. But they, with the exception of larch, are almost always used in interior decoration or carpentry.
As a construction material, lumber from coniferous trees is almost always used.
Soft wood is found in linden, poplar and aspen. It weakly resists the damaging effects of atmospheric factors when outdoors, which is why these types of lumber are used in interior decoration and artistic creation.
Processing methods
The gradation, although complex, is more systematized.
Lumber elements
Depending on the surface treatment, lumber can be:
- Faced;
- Uncut;
- Edged;
- Unedged;
- Single-sided cut;
- Planed;
At the same time, depending on the grade, some flaws are allowed in the finished product, for example wane.
There are two main options regarding the orientation of the lumber in the workpiece:
- Radial;
- Tangential.
The remaining options, to one degree or another, rely on these two.
Log cutting options
Difference in yield when sawing logs in different ways does not differ much, and significantly affects the yield of the timber. To a much greater extent, this affects the manifestation of certain characteristics of the boards.
Diagram of the dependence of the yield of finished products on the type of sawing of logs
In particular, it is possible to achieve a more obvious manifestation of the pattern, or an increase in the strength characteristics of the longitudinal fracture of the beam.
Classification by size and shape
In this gradation the sequence is quite simple:
But when sawing logs, by-products are also formed, such as croaker and obapol.
Although they are similar, there is a difference between them. If the slope of the log was higher than normal, then both floors are removed during the first cut. This is a woodworking product that has only one face.
Sawing diagram
The next cut, if the croaker. For this product, one of the faces will only be partially processed.
Further cuts are made, depending on the thickness and width, of the following types of lumber: timber, timber or boards. Depending on the depth of processing, they can be edged or unedged.
There is another type of lumber that is included in this classification, but stands apart: sleepers.
The scope of their intended use is very limited, and their dimensions and strength characteristics are regulated internal documents Russian Railways
Others building materials made of wood, such as: slats, strips, glazing beads, etc., are already created from lumber.
Scope of application
The scope of use of lumber is limited to two areas:
- Industrial and construction direction;
- Furniture and finishing direction.
But these two categories include almost all types of human activity. At the same time, in the production of furniture and decorative finishing, much deeper processing of lumber is carried out.
In addition to planing and grinding, the following can be used:
- Thread;
- Etching;
- Edged boards;
- Coloring;
- Varnishing, etc.
Separately, I would like to mention the work on imparting plasticity to lumber. This is necessary for the formation of products of unusual shapes.
At correct selection even such fantastic designs can be made from lumber
These technologies are very labor-intensive and require good technological equipment. In principle, this is reminiscent of warming up in a huge microwave oven operating in a special mode.
What is attractive about this technology is the ability to re-process lumber using this method - if you don’t like the shape, you can change it.
Solid wood plates are called. Types of lumber vary, but they all have common feature- at least two faces are parallel to each other.
Their sizes are determined by their purpose, and six varieties are distinguished by shape. To describe them, let's first get acquainted with two concepts. The thickness of the lumber is the length of the smaller edge. The width is the length of the larger edge.
Main types of lumber
timber. It has a thickness of 10 cm, the edges are equal to each other, in cross section the timber, processed on all sides, gives a square. Depending on the number of processed edges, it can be two-, three-, or four-edge.
Bar. It has a thickness of 1.9 to 10 cm. The width can be no more than twice the thickness.
Board. Its thickness can reach up to 10 cm, and its width should be more than twice the thickness. Depending on whether the side edges are processed, there are unedged, single-edged and edged boards. The relief at the ends, which allows you to avoid gaps during installation, distinguishes tongue and groove boards.
Sleeper- This separate species lumber. They also come in edged, unedged and semi-edged varieties. The length of wooden sleepers is from 270 to 300 cm.
Lagging represents the sawn outer part of the log. At the same time, there is sleep with inside, and from the outside it is either absent or makes up no more than half the length of the obapole.
Gorbyl almost no different from obapole, except that for this lumber there are no standards for size and proportions. Both of the latter types are waste. It is almost never used in construction: it is used for the construction of scaffolding and for fuel.
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Tree - universal material, used in capital construction, manufacturing decorative coatings and furniture production. There are various forms of wood, differing in structure and method of production. The most durable and aesthetic material, which was used long before the advent of glued and pressed wood pulps, is the product of sawing a solid tree trunk.
By longitudinally unraveling a log into long component parts that have at least one flat side (face). Most lumber has two flat edges parallel to each other.
Two methods of sawing logs are used - radial and tangential. With a radial approach, the cutting directions are oriented towards the center of the growth rings. The resulting boards or beams have different sizes, and their width is limited by the diameter of the blossoming tree.
Tangential sawing is designed to produce long boards and is directed tangentially to the growth rings. In this way, a large number of fragments are obtained that have the same dimensions and cross-sectional shape.
Further processing and appearance depend on. The more work is carried out to improve the surface and protect it from external influences, the higher the cost of the final product will be.
It is very important to choose high-quality lumber; which ones you should not buy can be seen in the video:
What are there
There are several approaches to classifying lumber. Directions are distinguished according to the method of receipt (preparation), degree of processing and purpose.
By method of preparation
With this approach, the final moisture content of the material is taken into account. The most common concept is absolute humidity, which is the ratio of the mass of moisture to the mass of dry wood (per unit volume).
Based on the absolute water content, the following are distinguished:
- dry lumber(air-dry or natural moisture) - contain no more than 20% water and are widely used in construction and construction. The obtaining of an air-dry state of a tree is preceded by its prolonged exposure to air;
- kiln-dried wood– obtained by drying in a closed box at elevated temperatures. The moisture content of the material can be 10-14% or less, depending on the consumer's requirements. Absolutely dry wood must be treated protective compounds to prevent moisture absorption.
When stored for a long time in a humid environment, the wood becomes wet (contains 100% or more moisture). Boards made from freshly cut wood have a moisture content of about 50-100%.
By purpose
The following types of lumber are distinguished according to size and shape, as well as mechanical properties:
- timber– characterized by a thickness and width of more than 100 mm, is the main load-bearing element many building structures and is used when assembling the base;
- boards– have a thickness of less than 100 mm, and their width is more than two thickness sizes. Along with beams, boards are the most common lumber and are widely used for industrial, household and other purposes. Boards are produced by longitudinal cut logs and beams;
- bar– made of boards, which explains its small size. The thickness of the bar should be no more than 100 mm, and the width should be less than twice the thickness;
- sleepers – short bars, used for railway purposes as supports for rails. Sleepers are usually treated with a persistent mixture of petroleum or coke-based antiseptic, which is highly toxic. It is highly not recommended to use impregnated sleepers at home;
- lagging– is an “unfinished” version of the board, in which only one face is flat. The width of the obapole can vary along its length, due to which longitudinal section along the sawn surface it has a pronounced irregular shape;
- croaker– refers to an intermediate option between the board and the floor, which has one flat face. The untreated surface on the opposite side has a regular cylindrical shape (truncated), therefore, in a longitudinal section, the slab is a rectangle.
Photo various types lumber
Beam Boards Beam Sleepers Obapol Gorbyl
By degree of processing
The simplest version of lumber has two parallel faces and two untreated wanes (side edges) of a semicircular shape (the outer roundness of the tree). Two layers are often not enough to implement a number of construction and design tasks. Wane processing improves the aesthetics of wood and makes it more expensive.
According to the degree of processing, the following types of lumber are distinguished:
- unedged– have unprocessed wane, freed from bark and rough knots;
- edged– the wanes are cut parallel to each other, giving the transverse profile a rectangular shape;
- planed– the surface of at least one of the faces (face or wane) is planed to reduce roughness. Such boards or beams are used to create floor and wall surfaces, seats and other outdoor structures.
What trees are lumber made from?
Coniferous and deciduous wood, including their valuable varieties, is used for the production of lumber.
The most common species whose trunks are used to produce boards and beams are:
- larch– resistant to water and virtually undamaged by insects and fungi. Even without additional processing, obligatory for most other species, hardwood is resistant to rot and is widely used in damp areas;
- beech– used in the manufacture of furniture, stairs and wooden floors. Due to its high wear resistance, beech lumber is often used to make seats for benches in public places;
- pine– is highly environmentally friendly, supported by the resins included in its composition. Pine wood is less durable than hardwood and is more prone to fire, producing acrid tar smoke. They try not to make benches from pine lumber, so as not to spoil clothes with protruding resins;
- oak– is one of the most popular trees for the construction of houses and structures, it has high strength and beautiful texture. Oak products swell slightly with increasing humidity, but are less common due to their high cost;
- ash– has mechanical properties close to oak. The shades of its wood are not always attractive, which is caused by a violation of the integrity of cellulose fibers as a result of diseases. High bending tendency and impact strength are among the main advantages of ash;
- cedar– is used much less frequently than other pine species due to its high cost, but is distinguished by its aesthetics, resistance to decay and the ability to disinfect the air of the room in which it is located. In terms of mechanical properties, cedar is close to pine and has a more pronounced and rich texture;
- dead wood– used to obtain the least quality material from the dried naturally tree. Lumber from dead wood is usually cut into small pieces and used as auxiliary material;
- linden– has become widespread in the manufacture of quiet and heated floors, as well as walls of warehouse and industrial utility rooms (not damaged by rodents). The relative softness of linden lumber simplifies its processing when assembling composite structures;
- aspen– most often, aspen lumber is used for the construction of baths and saunas. Low performance qualities reduce the value of solid aspen, a significant part of which is used for the production of plywood or chipboard;
- birch– used to produce light and durable lumber. There are practically no resins in birch wood, and its lumber is most widely used in furniture production due to its beautiful texture and ease of processing.
The video will tell you about the types of larch lumber:
Let's evaluate lumber, comparing them with stronger and more durable stone materials for construction:
- price – 5. A wide range of wood allows you to choose lumber to suit any financial capabilities. In addition to expensive wood species, there are cheaper analogues. They are inferior in terms of texture, but not performance;
- practicality – 4. Wood is easier to damage than stone building material, so wood coverings require care and additional processing;
- appearance – 5. Wood surface is considered the most aesthetic. Even artificial surfaces are often disguised as wood to give the room more flavor;
- ease of manufacture – 3. Although wood is not very difficult to process, its finishing poses many difficulties;
- labor intensity when using – 4. It is better to work with wood in pairs to hold structural elements when marking, cutting or fixing;
- environmental friendliness – 5. Wood is one of the most environmentally friendly materials. To increase the safety and durability of wood, treatment with special antiseptic compounds is used.
All types of lumber belong to the group of sawn wood products, which have two flat surfaces, certain quality and dimensions. Lumber is obtained by cutting logs crosswise and lengthwise.
All types of lumber products are usually divided into lumber itself, wooden blanks, wooden parts. The differences between the groups are determined by the purposes for further use of the products.
From the beginning of the lumber formation processes, only 65% of the volume of processed wood reaches the final state. For this reason, lumber with any characteristics is an expensive raw material.
TO components lumber include:
- ribs;
- edge;
- plastic;
- ends.
To distinguish between different groups of lumber, several types of lumber classifications have been adopted, depending on various kinds parameters.
Classification by cross section
In this classification, the leading factor in classifying materials as one type or another is the cross-sectional shape. In accordance with this classification, the following are distinguished:
- bars;
- boards;
- bars;
- lagging;
- sleepers.
The bars have a thickness of up to 10 cm and a width of less than the thickness parameter multiplied by two. Bars are used in all branches of the construction segment and are the most popular lumber.
Boards
The boards have a width greater than the thickness multiplied by two. The range of board widths is 1.6-10 cm. Use this type lumber is used in the manufacture of flooring and furniture.
If the lumber has a width of more than 1 cm, then it is classified as beams. There are 2-, 3-, 4-edged beams depending on the number of sawn sides. Due to their ability to handle heavy loads, beams have become especially in demand during the construction load-bearing structures in construction.
Lagging
Obapol is lumber that has only one sawn surface.
Sleepers
Sleepers include lumber-shaped lumber that is laid on railway rails.
Classification by type of processing
According to the type of processing, the classification of lumber distinguishes samples:
- edged;
- edged one-sided;
- unedged.
Edged are lumber sawn in all directions. They have excellent visual parameters and are used for finishing.
Unedged - materials with the side surface of the log itself in place of the edges. Bark on the edge deprives the lumber of its impeccable appearance. This type of lumber is used in areas where visual parameters are secondary.
Classification by processing quality
Based on the quality of processing, lumber is divided into planed and unplaned. Planed options are of higher quality and more expensive. They may have different shapes cross sections, which is determined by further purposes of use.
Classification by location of sawn products
Depending on the location of the sawn products in the log, boards are distinguished:
- lateral;
- central;
- core.
The highest quality samples, free from knots and flaws, are side boards. They are formed after cutting the area of the log between the central boards and the slab. The clean surface is main feature this type of lumber.
The central boards have a central cut along the axis of the core. They are considered to be of lower quality than the side options, but are not as prone to cracking.
Core boards are low-grade lumber with the following characteristics: an abundance of knots, metic and peel-type cracks, and a tendency to crack.
Classification by wood type
To select lumber for solving specific problems, the type of wood that became its source is taken into account. All species are divided into coniferous and deciduous.
- Coniferous lumber is used primarily for load-bearing structures and building frames. They are strong, durable, and can withstand loads and atmospheric changes well.
- Hardwoods are considered soft. They are usually used for finishing and manufacturing small parts of building structures. If such rocks are used for the construction of frames, then only in the case of temporary structures.
In the case of each tree species, its individual characteristics are taken into account. For example, maple is known for its resistance to moisture. It is used for objects located in areas with variable humidity.
Larch is not suitable for nail structures. Oak is known for its high strength, which is why it is used in objects with heavy loads. This breed has found application in carriage building, shipbuilding, and is also actively used in furniture production.
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Lumber is produced by sawing wood into individual parts - plates, quarters, beams and beams, boards, slabs. There is a wide variety of types of lumber.
Classification of lumber by appearance and method of processing.
Thickness of boards made in production conditions, can be no more than 100 mm, the width has a value greater than the thickness value multiplied by two. The beams have a thickness of no more than 100 mm; the width should be less than twice the thickness.
How lumber is divided depending on processing
According to the method chosen for processing raw materials, lumber is divided into unedged and edged. The latter are characterized by processing on four sides; on the faces and edges, wane values should only be allowed as determined in accordance with the type of product. Wane is the part of the log surface that remains on the part after mechanical trimming. The result is a piece of board, untreated at the edges, which can be used in architectural structures or for carpentry finishing of buildings.
Uncut lumber has edges that are partially sawn or not sawn at all. Single-sided products have one edge and sawn edges, while the sawn lump is not allowed to have wane that is larger than the parameters allowed for a particular product. This type is used somewhat less frequently in construction. It can be used for cladding various parts of the structure, making flooring, and other options are possible.
Types of lumber and cutting logs.
Depending on the processing method, materials can be called unmilled or milled, that is, planed. The latter are a material in which at least one of the cavities is planed. In order to produce planed timber, timber is taken only with a certain diameter, so that the blanks for the timber are formed in compliance the right size. The workpieces must be dried - this is done using steam chambers or under natural conditions. Products are obtained by processing raw materials on machines.
Classification of lumber by size, shape
When processing wood using modern technologies perform different types products. The assortment includes bars and sleepers, boards and slats, quarters, slabs, plates and other products. Types of lumber may vary depending on the methods of working with raw materials. You can familiarize yourself with them in more detail.
Types of lumber
Depending on the number of sides processed, the beam will be called two-edged, three-edged, or four-edged. The thickness and width of products is, as a rule, more than 100 mm. The main area of their use is the construction of load-bearing structures, cottages or summer houses, since these products can easily withstand significant loads.
The bar is similar to the timber, but has different dimensions. It is made with a thickness of up to 100 mm, the width is less than double the thickness. It is used in the furniture and carpentry industry, for finishing buildings, for example, door frames and crossbars are made from them.
Table of shrinkage coefficients and mechanical strength lumber.
The boards are made from logs or beams of sufficient thickness. Boards can be uncut or trimmed. The thickness can be no more than 100 mm, the width more than double the thickness. Application: wall decoration, flooring, furniture production.
The sleeper is a product with a short length, but wide and thick. This is in some way a type of timber, the cross-sectional size of which differs in size. The most common application is for making railway tracks.
A croaker is a piece of log, a side cut. In the process of sawing logs into various boards, waste is produced, which is called slab. It is convenient to make temporary buildings like sheds from it; they are also suitable for constructing roof sheathing.
Quarters (obapol) are also obtained from the side parts of logs. One of the surfaces of the product is propylene, the other is not. Convenient to use for making small carpentry products.
The plate is half of a log, which is obtained by cutting it down the center. The plates have only one straight side. The length depends on the log used as raw material. They are used mainly for the production of the above products - sleepers, beams, and sometimes for the production of solid boards.
How lumber is classified by wood species
For lumber, the grade will also depend on the tree species - they can be deciduous or coniferous.
Coniferous forests include larch, spruce, pine, cedar, and fir. Deciduous trees - oak, birch, beech, aspen, poplar, maple. For the construction of buildings they often choose conifers trees, since they are less susceptible to moisture, are more convenient to process, have good hardness and are quite durable. They can be used to create load-bearing structures. But it should be borne in mind that coniferous species contain a lot of resinous substances, which means that any type of lumber made from them is faster and easier to ignite.
Spruce wood is especially popular. It also contains the smallest amount of resins, so the susceptibility to fire is reduced. Among deciduous trees, oak has become widespread - it is very strong and durable. Lumber can be divided into four grades. Thus, the selected grade is used in the manufacture of parts in shipbuilding, for sheathing car sides, and in other important areas.
