High-quality lumber after wood processing. Wood is a natural construction material. Lumber and wood materials Type of raw materials and their preparation for cutting
None of the building materials available on the market today have such unique qualities as natural wood. It is very convenient and easy to process, so that you can make anything, even a spoon, even an airplane fuselage. The wood has excellent strength, it is light and has a pleasant smell. Working with wood is a real pleasure if you understand the types of wood and the characteristics of lumber.
Types of wood cuts
If you look closely at any block of wood, you can see on it a textured pattern formed by growth rings. Its appearance depends on the direction in which the tree trunk was cut. It is customary to saw it in three directions: along and across the grain, as well as at an angle of 45 degrees. If the cut is made at an angle, then it is called tangential. It forms a texture similar to cone-shaped lines.
If the cut is made along the fibers, then it is called radial. The parallel lines formed by the fibers are clearly visible on it. A cross section shows us the annual rings of a tree trunk in all its glory. The pattern is important for the external beauty of wood products, therefore, before making a wooden blank, you need to clearly imagine yourself in which direction we want the patterns.
Internal structure of wood
In order to understand the structure of a tree trunk, it is necessary to make a complete cross-section. The top layer is called the bark. It is of no interest, so it is removed. The next thin layer is the so-called growth zone. It is difficult to see, but if the tree is young, then after removing the bark you can see green fibers that are damp to the touch. They are also called cambium. After it, the wood itself begins with pronounced annual rings. Professionals call it sapwood. In the center of the trunk there is a darker core or one that merges with the sapwood. It depends on the type of wood, which can be sapwood or heartwood.
Sound tree species are represented by all conifers (cedar, pine, spruce, larch, yew) and some common deciduous species such as oak, poplar, ash. The vast majority of deciduous trees are sapwood: birch, alder, hornbeam, maple.
The density of wood cells affects the strength and other physical qualities of wood, but the creation of artistic compositions and the possibility of using this or that raw material in work is influenced by the pattern of growth rings and heart-shaped vessels. These are macrostructural elements, and they also include knots, growths, undeveloped shoots that deflect growth rings and form various curls.
Wood with a pronounced macrostructure is the most interesting for processing, therefore, without exception, all conifers are used for crafts
Physical characteristics of wood
Like any building material, wood has a number of physical properties:
- Density is measured in g/cm 3 and depends on the type of wood and its moisture content. The higher this indicator, the stronger and heavier the material, it is more durable and less susceptible to rotting. The most dense wood is considered to be oak, ash, maple and larch, and the least dense is aspen, spruce and fir.
- The moisture content of wood indicates the degree of its quality and durability. Room-dry has 8 - 12% moisture, air-dry from 12 to 18%, and atmospheric-dry 18 - 23%. If the humidity is even higher, then such wood is called damp.
- Sound conductivity and thermal conductivity are important qualities. High-quality dry wood perfectly retains heat and sound in the transverse direction. Thermal conductivity along the fibers is reduced, but sound travels perfectly along the trunk. This is even an indicator of quality and dryness.
- Resistance to corrosion, which is higher in coniferous wood, due to the presence of resin in it.
- Texture, color, smell and shine allow us to determine the type of wood and determine its decorative value.
All of the listed physical properties are very important for the use of a particular tree species.
Mechanical characteristics of wood
The mechanical properties of different types of wood are more important. After all, they influence the strength and durability of buildings or wood products. Mechanical strength is the ability to resist various static and dynamic influences from the outside. The strength of a material depends on the direction of the load. In this regard, it is customary to distinguish between shear or shear strength, bending strength and compression strength. Any wood has greater strength along the grain than across it.
It is worth noting that damp wood becomes less durable. The same is observed in light and loose breeds.
Plasticity is the property that allows you to create bent parts from wood. More plastic rocks retain the shape obtained under a certain long-term exposure. Humidity and temperature greatly increase this indicator, so to make curved parts, wood is exposed to hot water or steam. Beech, elm, oak, and ash boast high plasticity. This cannot be said about conifers, since the structure of their fibers is too linear.
The hardness of wood is the ability to resist various penetrations of foreign bodies into it. There are hard tree species, such as: beech, maple, larch, oak, ash, elm (the hardest are boxwood and acacia) and soft ones, such as: linden, alder, spruce, pine. The level of wear resistance of wood directly depends on its hardness.
Characteristics of various types of wood
One type of wood or another is used for different purposes. All of them are divided into coniferous and deciduous. The former have a sharp resinous odor and a pronounced macrostructure. The most common coniferous species are: cedar, pine, fir, spruce and larch.
- Pine is the most common building material. Its color varies from pale yellow to reddish yellow. The wood is quite light and durable. The main thing is that it is very convenient for processing. It contains a lot of resin, so it rots poorly and is not particularly afraid of precipitation. Because of its softness, it easily accepts various dyes and varnishes. Warping during drying almost does not occur in pine. The disadvantage is the impossibility of high-quality finishing and painting. However, it is successfully used for the production of furniture and plywood.
- Spruce can be placed in second place after pine in terms of use. There is not much resin in it, so it is more susceptible to rotting and exposure to precipitation. Spruce wood is strong and light, but at the same time it has a large number of knots, which significantly reduces its consumer qualities. The advantages include the white color of the wood and low resin content. It holds various fasteners well. In construction, not the most important parts are made from it.
- Cedar, or correctly Siberian pine, is in no way inferior to spruce in its construction qualities, and is far superior to it in resistance to rotting. Despite the softness of cedar wood, it has good density and strength, and is easy to process.
- Fir is no different from spruce: it can be easily processed and does not tolerate caustic chemicals. It contains quite a bit of resin, which is why the wood rots too quickly without the use of special treatment.
- Larch is valued for its hardness and strength. Its density is such that the trunk of this tree sinks in water. But larch wood practically does not rot.
Hardwoods are usually divided into soft and hard. Their wood is odorless. It is only found on fresh saw cuts. Hardwood species include oak, ash and birch, and softwood trees include aspen and alder.
- Oak has very high strength and resistance to rotting. Its wood has a beautiful color and texture. It does not crack or warp, which is why furniture, luxury items and art are made from oak. Tannins have powerful antiseptic properties. The most durable and beautiful oak wood is obtained when it is kept in running cold water for 1.5 years. Her color turns black. Expensive furniture is made from such stained wood. This is an ideal material for furniture production, but it is very inconvenient to process due to its density and strength.
- Birch wood has medium density and hardness. It is strong and quite viscous, does not have a very pronounced texture, but is homogeneous. The disadvantages of this material are susceptibility to severe cracking and warping, too much shrinkage, low resistance to rotting, and quite frequent damage to diseases such as wormholes. However, it can be easily processed with hand tools, glued into plywood, easily polished and painted, and makes it possible to produce very fine relief carvings.
- Aspen has a fairly soft wood, with so few knots that it lends itself well to any processing. However, its porous structure does not allow making small parts.
- Linden is highly valued in the manufacture of various carved parts for furniture production. It does not warp and does not crack at all when dried. Linden wood has a fairly strong structure that is very resistant to rotting.
- Maple has a strong, dense and low-drying wood. It hardly warps, but rots quickly and is highly susceptible to wormholes. This wood is well processed, glued, finished and painted. It is used in carving work and the manufacture of solid wood parts.
- The mahogany tree, which grows in evergreen tropical forests, has red-colored wood. This is not just one species, but many with similar properties. Mahogany wood is very soft and lends itself well to processing, is easy to polish, and also absorbs varnish. Some pieces of furniture are made from such wood. Its high cost does not allow making the entire product out of it.
Lumber and its varieties
Mostly dry wood is sold at the lumberyard and in the store. Raw is rarely sold. If you decide to build something or make a piece of furniture, then you will come across the names of types of lumber, the meaning of which is worth understanding:
- The ridge is essentially solid tree trunks without bark or pieces of them of sufficiently long length. It is important that their diameter exceeds 25 cm.
- Podvyaznik is the same ridge, but with a diameter of less than 25 cm.
- A pole is a solid trunk without bark with a diameter of less than 9 cm.
- A plate is half a ridge that is sawn along the grain.
- Quarter - half of a plate sawn along the grain.
- A log, or in other words a beam with a wane, is a log hewn on both sides that can be placed on one of two planes.
- I call a beam a log that is hewn on four sides with a cross-section of at least 100x100 mm. If it is smaller, then the product is called a bar.
- The board can be very different depending on the method of its processing and size: unedged, edged, slab, planed on four sides, tongue-and-groove, folded.
All lumber that is commonly used in construction has its own specific name. They differ in the thickness of the product, as well as the ratio of width to this thickness. For boards, this ratio should never be more than 2. The maximum permissible board thickness is 100 mm. The length of any hardwood material does not exceed 5 m, and that of coniferous trees does not exceed 6.5 m.
After reading this article, you have become familiar with the basic concepts and characteristics of wood. Therefore, with such knowledge, you can safely purchase lumber, using terms no worse than sellers. Today, almost no major construction or renovation can be done without the use of wood to one degree or another, so such knowledge will be very useful.
Wood is a universal material used in capital construction, the manufacture of 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 components 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 tree being opened.
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 with 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 of many building structures and is used in the assembly of 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 cutting of 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 beams 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 obapola can vary along its length, due to which the longitudinal section along the sawn face 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.
Photos of different types of 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 the additional processing required 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 lowest quality material from naturally dried wood. 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 materials, so wooden coverings require maintenance 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 the wood is not very difficult to process, its finishing is quite difficult;
- 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.
Lumber types and purposes, as well as raw materials for production, types of lumber, varieties and derivatives of wood.
Lumber is a material obtained by longitudinal sawing of logs, followed by longitudinal and transverse (if necessary) division of the resulting parts. The end result is a product of a certain shape and size, with at least two (front and back) parallel sides. This type of material is produced at special enterprises equipped with band saws, circular saws and other equipment.
Raw materials for production
The primary raw material for the production of lumber is the trunks of almost any tree, previously cleared of branches and bark. Coniferous wood is usually used for the construction of load-bearing structures. Hardwood is most often used for all kinds of finishing work. It is worth noting that the waste obtained during the production of lumber is used both in industry and in everyday life.
The most affordable wood for lumber production is poplar and birch. Quite often, pine, spruce, linden, larch, ash and maple wood is used for these purposes. Hornbeam, oak, and cedar wood are important for industry.
The lightness of birch does not make the wood less durable, but its beautiful structure and affordable price have made it even more popular. Larch is considered very moisture resistant, resistant to fungus and mold. Ash wood boasts good elasticity and impact resistance.
Beech is indispensable for making floors, stairs and furniture. Incredibly durable and incredibly beautiful oak wood, despite its fairly high price, is very much in demand. Pine contains a large amount of resins, so it is most prone to rapid combustion. Although spruce wood is less durable, it is quite flexible and soft, so it can be easily processed.
Types of lumber
The characteristics of finished lumber depend on the type of wood, the equipment used, adherence to production and drying technology, as well as the cutting method. It is the last factor that affects the texture of the board.
Wood sawing is carried out in several ways, differing in the direction of sawing:
- transverse (across the fibers);
- rustic (at an acute angle to the grain);
- radial (along the radius to the center of the log);
- tangential (tangent).
Cross-cutting is used to produce artistic parquet, while the rustic method is used to produce flooring. Lumber obtained by radial sawing has a very attractive appearance, is durable, resistant to deformation and external influences. Tangential cutting creates a beautiful pattern on the surface of the board in the form of interesting arches and rings.
However, some boards may develop flaking on the surface over time. The most popular and expensive are radial lumber, since their surface has a uniform texture, constant dimensions, good mechanical characteristics, and a degree of shrinkage.
Drying of lumber is carried out both in the open air and using special chambers, which are tightly closed rooms. The first type of product contains up to 20% moisture, the second can be additionally treated with protective agents, and the moisture content is up to 14%. Lumber cuts can be trimmed (cut along the entire length) or uncut.
Depending on the degree of processing, lumber is:
- unedged (although there are no knots, there are untreated sections of logs);
- edged (the profile of the materials has a rectangular shape due to sawing off the defective side parts of the log);
- planed (no roughness on one or more edges).
Classification
The shape, size and mechanical characteristics determine the division of lumber into several types.
timber- this is a log, hewn on all sides, used in the construction of houses, as well as for the manufacture of individual large elements of windows, stairs and others. The thickness of the timber is 100 mm.
Bruschi- this is a “timber in miniature”, less than 100 mm thick, they can be untreated, planed (at least one side is processed) and calibrated (adjusted to a certain size). Scope of application: furniture production, lathing, flooring, frames, gazebos and other objects.
Boards made from logs or beams. They come in unedged, edged (having a smooth edge) and edged only on one side. In addition, the boards can be calibrated, that is, they have specified dimensions.
Sleepers– a material with increased strength and minimal sensitivity to temperature fluctuations.
Gorbyl– these are boards obtained by sawing logs, having a flat and semicircular surface.
Lagging- lumber produced from the side of a log, having only one flat side.
Advantages and disadvantages
Man has always been surrounded by objects and wood products. This material was used for the construction of houses and churches, baths and all kinds of outbuildings. The man was surrounded by wooden windows, doors, tables, chairs and other furniture. Wood has not lost its popularity even today. On the contrary, thanks to the positive qualities of wood, construction and finishing materials made from wood are becoming even more in demand.
Advantages of lumber:
- have a high load-bearing capacity with a relatively low weight;
- despite its sufficient strength, the material is distinguished by its simplicity and ease of processing (it is malleable for drilling, easy to saw, and allows the production of figures of various shapes and complexity);
- ease and speed of installation;
- due to its natural origin and environmental friendliness, the material is considered completely safe for human health and the environment and does not cause allergies;
- processing does not require expensive and time-consuming work;
- external attractiveness;
- the pleasant smell of wood creates a favorable indoor microclimate;
- variety of shapes and sizes of products;
- affordable price.
Minuses:
- ability to quickly ignite, maintain combustion;
- are destroyed under the influence of fungus, mold, and various insects;
- Long-term exposure to water and a humid environment often causes wood to rot.
To protect lumber, make it more wear-resistant and durable, they are treated with special protective substances that can significantly reduce the above-mentioned disadvantages.
Types of lumber
Division into grades is carried out by assessing the condition of the worst side of the face, edge, and section.
Selected lumber should not have rot, mold, cancerous and fungal stains, growths and other foreign inclusions on the surface, as well as cracks from shrinkage. The permissibility of fused healthy knots is two per one meter in length, shallow edge and face cracks are 16%, deep ones are no more than 10%. The scope of application of the products is mainly shipbuilding and automotive construction.
The area of application of first grade lumber is the wood manufacturing industry. This type of material should not have dry wobbly knots, healthy knots larger than 1 cm, through and cracks larger than 1 cm, wounds on the wood overgrown with bark, young active layers of wood, mold, mechanical damage, various foreign inclusions, and rottenness.
The scope of application of materials of the fourth grade is the construction of cabins, utility buildings, gazebos, the production of boxes, loess, pallets and construction formwork.
Wood derivatives
An excellent material for building a house is rounded log. Thanks to a well-thought-out system of locks and a completely even, rounded shape of the material, fairly strong and reliable structures are obtained. This material is considered the most expensive today, and buildings made of rounded logs do not require additional finishing.
No less popular material is profiled timber. There are two ways to produce it: milling and planing. During the construction of houses, the elements are connected very firmly, ensuring a high degree of reliability of the building. In addition, such buildings do not require powerful foundations. Structures made from this lumber do not require additional finishing work.
Glued laminated timber made from whole boards or individual pieces. The material consists of lamellas firmly fastened together. It is distinguished by strength, durability and resistance to external influences.
Plywood- This is a material consisting of several thin layers of wood, tightly glued together. Due to its strength and good flexibility, this material is in demand in the production of furniture, decorative elements and many other products.
Fiberboard obtained by pressing waste wood at very high temperatures with the addition of a special binder. Fairly hard wood fiber boards are called hardboard. The sides of such sheets can be either smooth, or one of them is corrugated, the other smooth.
Chipboard is a combination of small wood particles and synthetic resins. MDF is produced from waste from the woodworking industry, free of all impurities. In the manufacture of this type of slabs, no adhesives are used. In this case, the binding element is lignin, which is released from wood under the influence of high temperatures. The area of application of such lumber is construction and furniture industry.
Block house is a material obtained from rounded logs by sawing according to the “square in a circle” principle. Thanks to good noise and heat insulation, strength and attractiveness, this lumber is highly valued in the exterior decoration of houses.
Lining- lumber used for all kinds of finishing work. Although the material is small in thickness, it is very durable, resistant to deformation, cracks and crevices. The external attractiveness of the lining, simplicity and ease of installation made it even more popular.
Lumber is a unique wood processing product that is indispensable in construction, furniture and other types of industry.
Types of wood and characteristics of lumber in photographs.
Lumber made from natural wood is often used for construction. They can be classified according to the type of wood, the shape of the workpiece and other parameters. The characteristics of lumber depend on a number of properties of a particular type of tree.
Table of lumber characteristics.
Classification of lumber
Each type of wood has its own properties. That is why it is customary to follow a convenient and understandable classification. All natural wood materials can be divided into several groups:
Classification of lumber and characteristics:
Diagram of types of lumber.
Before purchasing one or another type of lumber, it is necessary to study their characteristics and areas of use. In this case, the selection will be correct, and the wood itself will last a long time.
Wood options
Lumber classification scheme.
Lumber used for construction can be made from various types of wood. The most popular material is pine needles; most beams and boards are made from pine and spruce, but there are other options.
Pine, unlike other types of wood, is lightweight; during construction, minimal loads are placed on the foundation. For example, aspen or birch are very heavy, but their strength characteristics are not so good. The boards are usually made of pine; this material is very durable, easy to process, and has numerous advantages.
Pine contains natural resin, which acts as an excellent antiseptic.
This ensures the absence of traces of rot and mold for a long time. Pine has a soft and delicate structure, which makes processing simple, pleasant and quick. The smell and color of pine add attractiveness to the material not only as a standard building material, but also as an option for decorative wall cladding and the construction of log houses.
The characteristics of lumber are not complete without such parameters as the number and presence of branches. Here you need to pay attention to the spruce.
This coniferous species has numerous positive characteristics, but its processing is complex. The problem is that the trunk contains many branches, and this is an obstacle to processing. .
Scheme of wood cutting options.
Wood such as cedar can also be used for boards. This option is not common, but is still used.
Cedar wood is strong and reliable, like spruce, but easier and more convenient to process. Fir can also be used to make lumber. It is rot-resistant, easily processed, and has numerous advantages.
Types of lumber
There are different types of lumber available, it is possible to choose the appropriate option. Products differ in shape, size, characteristics, and areas of use. Common materials include edged and unedged boards, which are suitable for almost any job, but there are other options that act as auxiliary materials.
Most often, edged and unedged boards are used for construction work; they differ in a number of parameters. These lumber are very popular; they are used for the construction of house frames, for the construction of strips, walls, partitions, for the installation of rafter systems, formwork and other works.
An edged board is a material obtained by cutting a log. In this case, all its edges are smooth, but a small amount of bark, that is, wane, may remain. Indicators of moisture resistance, strength, and mechanical stability vary greatly, as does the cost.
Edged board calculation table.
This makes it possible to choose exactly the material that is more suitable for the job than others, without overpaying. Pine or spruce are most often used to make edged boards. The cost of such boards is not so high, but strength and durability meet all parameters.
From such boards you can safely build not only outbuildings, but also carry out interior decoration. Lumber has a standard size of 6 m, but the thickness and width vary. The width of the boards can be 100 mm, 150 mm, 200 mm, for thickness - 25 mm, 40 mm, 50 mm.
The scope of application of edged boards is quite wide:
Unedged boards have bark edges and are used quite often in construction. The appearance of these lumber is attractive, as close as possible to natural, which makes them an excellent option for wall cladding.
Unedged boards do not have such a high density, so they can be easily processed. Finishing with such boards does not take much time. But if there are many cracks on the surface, this will significantly reduce the service life of the lumber.
Lumber can vary in price and quality. The cheapest include four-edged timber, which is produced in large quantities without requiring large, costly capacities.
The production of timber is carried out by sawing or hewing solid wood, but the quality of the surface will differ significantly. For example, when hewing, the sides end up torn, which is not always acceptable. When sawing, the edges and ends are more accurate; such timber is suitable for work where the appearance of the materials is important.
Clean-edged timber is a square-section material, planed on all sides. Its length is usually 4 m, thickness - from 100 mm, depending on the purpose. Such timber is usually made from pine.
It is processed from all sides, including the end parts. It is most often used for the construction of house walls, beams, ceilings, and subfloors. It has high strength properties.
Semi-edged board and slab
The semi-edged board has uneven planes; traces of bark may remain at the ends. This board is used for technical work. Walkways are made from it; it can be used for technical and subfloors, as a basis for other products.
In appearance, the slab is very similar to the side of a log; part of it is sawn on one side, but not on the other. Such lumber is considered lump-type waste; it remains after cutting the base material.
But the dimensions of the slab are standardized; it has the same width at the ends and along the entire length. Today, two types of croaker are used - wood and business material. It is used for various purposes, as blanks for other products and building elements.
Lumber is blanks made from natural wood.
They all differ in shape, individual characteristics, size, appearance, and degree of processing. Lumber is used for construction and repair work of various types; it is often used in assembling furniture, fencing, and in the construction of subfloors. When choosing, you should focus on those properties that are necessary for specific conditions.
Overview Types of wood and characteristics of lumber.
None of the building materials available on the market today have such unique qualities as natural wood.
It is very convenient and easy to process, so that you can make anything, even a spoon, even an airplane fuselage. The wood has excellent strength, it is light and has a pleasant smell. Working with wood is a real pleasure if you understand the types of wood and the characteristics of lumber.
Wood building materials
If you look closely at any block of wood, you can see on it a textured pattern formed by growth rings. Its appearance depends on the direction in which the tree trunk was sawn. It is customary to saw it in three directions: along and across the grain, as well as at an angle of 45 degrees. If the cut is made at an angle, then it is called tangential.
It forms a texture similar to cone-shaped lines. Three different types of cuts depending on the direction. If the cut is made along the fibers, then it is called radial. The parallel lines formed by the fibers are clearly visible on it. A cross section shows us the annual rings of a tree trunk in all its glory. The pattern is important for the external beauty of wood products, therefore, before making a wooden blank, you need to clearly imagine yourself in which direction we want the patterns.
Internal structure of wood
In order to understand the structure of a tree trunk, it is necessary to make a complete cross-section.
The top layer is called the bark. It is of no interest, so it is removed. The next thin layer is the so-called growth zone.
It is difficult to see, but if the tree is young, then after removing the bark you can see green fibers that are damp to the touch. They are also called cambium. After it, the wood itself begins with pronounced annual rings.
Professionals call it sapwood. In the center of the trunk there is a darker core or one that merges with the sapwood. It depends on the type of wood, which can be sapwood or heartwood.
Sound tree species are represented by all conifers (cedar, pine, spruce, larch, yew) and some common deciduous species such as oak, poplar, ash. The vast majority of deciduous trees are sapwood: birch, alder, hornbeam, maple.
The density of wood cells affects the strength and other physical qualities of wood, but the creation of artistic compositions and the possibility of using this or that raw material in work is influenced by the pattern of growth rings and heart-shaped vessels. These are macrostructural elements, and they also include knots, growths, undeveloped shoots that deflect growth rings and form various curls.
Wood with a pronounced macrostructure is the most interesting for processing, therefore, without exception, all conifers are used for crafts
Physical characteristics of wood
Like any building material, wood has a number of physical properties:
Density is measured in g/cm3 and depends on the type of wood and its moisture content. The higher this indicator, the stronger and heavier the material, it is more durable and less susceptible to rotting.
The most dense wood is considered to be oak, ash, maple and larch, and the least dense is aspen, spruce and fir. The moisture content of the wood indicates the degree of its quality and durability. Room-dry has 8 - 12% moisture, air-dry from 12 to 18%, and atmospheric-dry 18 - 23%. If the humidity is even higher, then such wood is called damp. Acoustic conductivity and thermal conductivity are important qualities.
High-quality dry wood perfectly retains heat and sound in the transverse direction. Thermal conductivity along the fibers is reduced, but sound travels perfectly along the trunk. This is even an indicator of quality and dryness. Corrosion resistance, which is higher in coniferous wood, due to the presence of resin in it. Texture, color, smell and shine make it possible to determine the type of wood and determine its decorative value.
All of the listed physical properties are very important for the use of a particular tree species.
Mechanical characteristics of wood
The mechanical properties of different types of wood are more important. After all, they influence the strength and durability of buildings or wood products. Mechanical strength is the ability to resist various static and dynamic influences from the outside.
The strength of a material depends on the direction of the load. In this regard, it is customary to distinguish between shear or shear strength, bending strength and compression strength. Any wood has greater strength along the grain than across it.
Testing the strength of a wooden block in the direction of load
It is worth noting that damp wood becomes less durable. The same is observed in light and loose breeds.
Plasticity is the property that allows you to create bent parts from wood. More plastic rocks retain the shape obtained under a certain long-term exposure.
Humidity and temperature greatly increase this indicator, so to make curved parts, wood is exposed to hot water or steam. Beech, elm, oak, and ash boast high plasticity. This cannot be said about conifers, since the structure of their fibers is too linear.
The hardness of wood is the ability to resist various penetrations of foreign bodies into it. There are hard tree species, such as: beech, maple, larch, oak, ash, elm (the hardest are boxwood and acacia) and soft ones, such as: linden, alder, spruce, pine. The level of wear resistance of wood directly depends on its hardness.
Characteristics of various types of wood
One type of wood or another is used for different purposes.
All of them are divided into coniferous and deciduous. The former have a sharp resinous odor and a pronounced macrostructure. The most common coniferous species are: cedar, pine, fir, spruce and larch.
Pine is the most common building material. Its color varies from pale yellow to reddish yellow. The wood is quite light and durable.
The main thing is that it is very convenient for processing. It contains a lot of resin, so it rots poorly and is not particularly afraid of precipitation. Because of its softness, it easily accepts various dyes and varnishes.
Warping during drying almost does not occur in pine. The disadvantage is the impossibility of high-quality finishing and painting. However, it is successfully used for the production of furniture and plywood. Spruce can be placed in second place after pine in terms of use.
There is not much resin in it, so it is more susceptible to rotting and exposure to precipitation. Spruce wood is strong and light, but at the same time it has a large number of knots, which significantly reduces its consumer qualities. The advantages include the white color of the wood and low resin content.
It holds various fasteners well. In construction, not the most important parts are made from it. Cedar, or correctly Siberian pine, is in no way inferior to spruce in its construction qualities, and is much superior to it in resistance to rotting. Despite the softness of cedar wood, it has good density and strength, and is easy to process. Fir is no different from spruce: it can easily be processed and does not tolerate caustic chemicals.
It contains quite a bit of resin, which is why the wood rots too quickly without the use of special treatment. Larch is valued for its hardness and strength. Its density is such that the trunk of this tree sinks in water. But larch wood practically does not rot.
Hardwoods are usually divided into soft and hard.
Their wood is odorless. It is only found on fresh saw cuts. Hardwood species include oak, ash and birch, and softwood trees include aspen and alder.
Oak has very high strength and resistance to rotting. Its wood has a beautiful color and texture. It does not crack or warp, which is why furniture, luxury items and art are made from oak.
Tannins have powerful antiseptic properties. The most durable and beautiful oak wood is obtained when it is kept in running cold water for 1.5 years. Her color turns black.
Expensive furniture is made from such stained wood. This is an ideal material for furniture production, but it is very inconvenient to process due to its density and strength. Birch wood has medium density and hardness. It is strong and quite viscous, does not have a very pronounced texture, but is homogeneous.
The disadvantages of this material are susceptibility to severe cracking and warping, too much shrinkage, low resistance to rotting, and quite frequent damage to diseases such as wormholes. However, it can be easily processed with hand tools, glued into plywood, easily polished and painted, and makes it possible to produce very fine relief carvings. Aspen is a fairly soft wood, with so few knots that it lends itself well to any processing. However, its porous structure does not allow making small parts. Linden is very valuable in the manufacture of various carved parts for furniture production.
It does not warp and does not crack at all when dried. Linden wood has a fairly strong structure, which is very resistant to rotting. Maple has a strong, dense and low-drying wood. It hardly warps, but rots quickly and is highly susceptible to wormholes.
This wood is well processed, glued, finished and painted. It is used in carvings and the manufacture of solid wood parts. Mahogany, which grows in evergreen tropical forests, has red wood. This is not just one species, but many with similar properties.
Mahogany wood is very soft and lends itself well to processing, is easy to polish, and also absorbs varnish. Some pieces of furniture are made from such wood. Its high cost does not allow making the entire product out of it.
Rare wood species
Rare wood species
Lumber and its varieties
Mostly dry wood is sold at the lumberyard and in the store. Raw is rarely sold. If you decide to build something or make a piece of furniture, then you will come across the names of types of lumber, the meaning of which is worth understanding:
- The ridge is essentially solid tree trunks without bark or pieces of them of sufficiently long length. It is important that their diameter exceeds 25 cm. A ridge is the same ridge, but with a diameter less than 25 cm. A pole is a solid trunk without bark with a diameter of less than 9 cm. A plate is half a ridge, which is sawn along the fibers. A quarter is half a plate, sawed along fibres. A log, or in other words a timber with a wane, is a log hewn on both sides, which can be placed on one of two planes. A beam is a log that is hewn on four sides with a cross-section of at least 100x100 mm. If it is smaller, then the product is called a block. The board can be very different depending on the method of its processing and size: unedged, edged, slab, planed on four sides, tongue-and-groove, folded.
Cross sections of boards depending on processing.
All lumber that is commonly used in construction has its own specific name. They differ in the thickness of the product, as well as the ratio of width to this thickness.
For boards, this ratio should never be more than 2. The maximum permissible board thickness is 100 mm. The length of any hardwood material does not exceed 5 m, and that of coniferous trees does not exceed 6.5 m.
Main types of lumber
After reading this article, you have become familiar with the basic concepts and characteristics of wood. Therefore, with such knowledge, you can safely purchase lumber, using terms no worse than sellers. Today, almost no major construction or renovation can be done without the use of wood to one degree or another, so such knowledge will be very useful.
>>Technology: Lumber and wood materials
When longitudinally sawing tree trunks at sawmills, various lumber is obtained (Fig. 11): beams, whetstones, boards, plates, quarters and slabs.
timber- lumber with a thickness and width of more than 100 mm. If the beam is sawn on both sides, then it is called two-edged, and if on four sides, then four-edged.
Bruschi- lumber with a thickness of less than 100 mm and a width of less than double the thickness.
Boards- lumber up to 100 mm thick and more than twice the width.
Plates obtained by longitudinally sawing a log in half, and quarters - into four parts.
Gorbyl, or obapol, is the sawn side part of a log.
Lumber has the following elements: faces, edges, ribs and ends.
Plasyu The wide plane of the lumber is called the wide plane, and the narrow plane is called the edge.
Edge is the line of intersection of these two planes.
end- transverse (end) plane of lumber.
Plywood is widely used as a construction material. Plywood is made by gluing three (or more) thin sheets of wood - veneer - onto each other. “Venere” translated from German means “sliver” (shavings). The veneer is cut (peeled) with a sharp knife of a special peeling machine while rotating a log about 2.0 m long (Fig. 12). In this case, the log, like a roll, is rolled out into a veneer strip.
The veneer strip is cut into square sheets, which are dried in dryers, coated with glue and laid on top of each other so that the direction of the fibers in them is perpendicular to each other (Fig. 13). The sheets are glued together under a press. This is how plywood with a thickness of 2 to 20 mm is obtained. 
Plywood is stronger than wood, almost does not dry out or crack, and bends and processes well. Plywood is used in construction, furniture making, mechanical engineering and aircraft manufacturing.
Peeled veneer is used to make bent-laminated wood, from which furniture, sports equipment and other products are made.
Chipboards (chipboards) are produced by pressing and gluing crushed wood in the form of shavings, sawdust, and wood dust. For the production of particle boards, mainly wood waste and even bark are used.
The slabs are made with a thickness of about 10...26 mm. They are durable, almost do not warp, and can be processed well with cutting tools. They are used to make furniture, doors, partitions, walls, and saws. However, over time they release substances that are harmful to health, so they are not recommended for use in residential areas.
Fibreboards (Fibreboard) are pressed into sheets from wood pulp that has been steamed and crushed into individual fibres. They have a pleasant gray color, smooth surfaces, dull, like plywood. Used for interior decoration: cladding walls, ceilings, floors, in production
furniture, doors.
The disadvantage of plywood, particle boards and fibreboards is that they are susceptible to dampness. Under the influence of water and moisture, plywood delaminates, and the boards swell, lose strength and crumble.
PRACTICAL WORK
Study of samples of lumber and wood materials
1.Look at samples of lumber and determine their type (bars, boards, slabs, etc.). Determine the types of wood.
2. Find a face, edge, edge, end in the lumber samples.
3.Look at samples of plywood, chipboard and fiberboard, measure their thickness. Count the number of layers in the plywood samples.
4.Check whether the samples can be easily processed with any tool (file, hacksaw, etc.).
- Lumber (timber, board, whetstone, slab), lumber elements (face, rib, edge, end), veneer, wood materials (plywood, chipboard and fiberboard).
1. What types of lumber do you know?
2. Name the main elements of lumber.
3. What is veneer?
4. What and how is plywood made from? Chipboard? Fiberboard?
5. How do wood materials differ from wood?
6. What advantages and disadvantages do they have?
A.T. Tishchenko, P.S. Samorodsky, V.D. Simonenko, N.P. Shchipitsyn, Technology 5th grade
Submitted by readers from the website