H To move on to a more detailed consideration of sawn timber processing, you need to familiarize yourself with the following terminology. These are the elements of lumber.
The lumber face is the longitudinal wide side.
Lumber edge is the longitudinal narrow side.
Lumber edge is the intersection of the edge and face.
Lumber end is the end cross-section.
For processing, lumber is divided into edged, unedged, one-sided edged. Edged lumber is called lumber with four processed sides. Wane is allowed in permissible dimensions (wane is the surface of the log).
Unedged lumber is called lumber with a side surface of a log instead of an edge. One-sided edged lumber is called lumber that has sawn faces and one edge. The shedding is admissible within the limits of GOST. They also distinguish between the degree of processing of lumber. They are planed and non-planed.
In addition, depending on the location in the log, lumber can be core, central, side. By the nature of processing, lumber is divided into unedged, edged and one-sided edged. Lumber that has a lateral surface of a log instead of edges is called unedged(Fig. 2 a); lumber, in which all four sides are sawn, and the amount of wane (part of the surface of the log remaining on the lumber) does not exceed the permissible dimensions, is called edged(Fig. 2 b). One-sided edged lumber has sawn faces and one edge, and the size of wane on the sawn edge does not exceed the permissible values. In the direction of the length of the board, a butt (wide) and apex (narrow) butt are distinguished. The flab occupying part of the edge width is called blunt (Fig. 2c), the entire width of the edge is sharp (Fig. 2d). According to the degree of processing, lumber is divided into non-planed and planed. Depending on the purpose, planed timber has a different cross-sectional shape. By the location of the lumber in the log (in relation to the longitudinal axis), core, central and side boards are distinguished. Pith lumber contains the largest number of knots and is prone to cracking. Such lumber is not of the highest grade. The central lumber cuts all annual layers and is therefore of a higher quality. Side boards are sawn between the core (or center) and slab. They have a cleaner surface, easy planing, and generally have better quality.
Today, logs sawn along the grain are one of the most demanded types of building materials. These types of lumber are used for the construction of foundations, the construction of temporary buildings, all kinds of floors and fences, as well as for the construction of houses.
The popularity of wood is due to the fact that at a relatively low price it is durable and reliable. Wooden boards lend themselves very well to processing, have low thermal conductivity and are not afraid of exposure to water.
Features and benefits of different types of lumber
There is a wide range of different types of lumber on the construction markets, and all this is due to the fact that most people in the construction industry prefer to use wood.
Lumber differ among themselves not only in cost, experts distinguish an additional factor of difference:
- wood species;
- type of processing;
- the form;
- the size.
Therefore, each person will be able to find an ideal look for himself, capable of arranging it in all respects. Modern manufacturers make lumber from deciduous or coniferous trees.
Among hardwoods, oak is popular and of high quality, but not every person is able to afford to use this kind of wood for construction, since the price of an oak board is very high.
Coniferous wood is more common, it is resistant to moisture and stress, and amenable to processing. The only drawback of such wood is that, due to the high content of resinous substances, it begins to rot rather quickly.
Main types
Since the largest factories use specialized equipment for the production of wood, it is easy to find various types of lumber on sale, differing from each other not only by the type of wood, but also by the size and shape:
- plates;
- boards;
- lagging;
- bars;
- sleepers;
- croaker.
Plates are very simple to make, but the process requires - to cut the log lengthwise into two parts. The plates have one side convex and the other straight. The plates can be of different sizes, but it directly depends on the size of the used log. The material is most often used for the production of boards, beams and sleepers.
Boards can be unedged and edged, made only from large logs. Planks remain one of the most popular materials and are used for wall, floor and furniture production.
Obapol is made from the side parts of the logs. A feature of this material is that only one part is processed, the second remains in its original form.
The bars, depending on the number of processed sides, can be 2, 3 and 4-edged. Often the width and thickness of the timber is about 100 mm, so the material is very strong and can withstand increased loads. It is thanks to this advantage that the beams are considered versatile lumber.
The sleepers outwardly resemble bars, only they are shorter, but they have an impressive width and thickness. Due to the specific dimensions
sleepers are mainly used for the construction of railway tracks.
Slab is a type of waste left after sawing logs. It is used only for the construction of small temporary structures.
Classification according to processing
Depending on the method of wood processing, materials can be edged or unedged. To understand the big picture, experts recommend that you familiarize yourself with this terminology: 
- edge - longitudinal narrow side of sawn timber;
- face - longitudinal wide part;
- rib - the area where the edge intersects with the face;
- butt end - cross section.
Edged types of lumber are most often processed from 4 sides. Since these logs are time consuming to manufacture, trim products are more expensive. A well-known type of such building material is.
Specialists distinguish a distinctive feature of unedged sawn timber that their edges are partially sawn or not sawn at all. Single sided products have one edge and sawed inserts.
On the sawn edge, the wane in size should not exceed the parameters permissible for a particular product. This type of lumber is used quite rarely in construction, most often it is used for cladding or flooring. The material is fragile, therefore it only performs an auxiliary function.
Modern building materials made of wood can be milled or planed, not milled. Most often, only one cavity is processed in planed wood.
It must be understood that it is rather difficult to make planed beams, since this requires a large number of logs with a suitable size. In order for the product to be of high quality, the logs must be pre-dried, which is why it takes much more time to produce the material.
Classification by size and shape
Since today modern equipment is used for the production of building materials, but if desired, it is easy to make a product of any geometric shape. But, despite this, classic types of sawn timber are still in greatest demand, such as:
- board;
- bars.
As practice shows, this form of products is convenient, it is suitable for the construction of walls of houses and various partitions.
Another characteristic by which such materials can differ is size. Depending on what exactly the boards will be used for, they can be thick or thin.
Thickness of thin boards varies from 15 to 32 mm - parquet board, thick boards exceed 35 mm in thickness. As for the length of such products, it also varies, it is easy to find products on sale from 1 to 6 meters long.
Variety by wood species
Such a building material differs not only depending on the cutting of lumber, the type of species used for the manufacture of wood is taken into account. It must be understood that different types of trees have different strength, moisture resistance and degree of decay.
Depending on these characteristics, the cost of the material will vary. Today the following groups of sawn assortments are distinguished:
Characteristics of coniferous wood
- products made from specific coniferous species;
- wood made from certain hardwoods;
- products made from any deciduous and coniferous species.
Modern GOST standards for wood materials are tied specifically to wood species. If it is planned to take coniferous tree varieties for the production of boards, then the choice often falls on the following types:
- fir;
- cedar;
- Pine;
- larch.
The following trees are often used as a deciduous base:
- Birch;
- aspen;
Principles for choosing lumber
In Russia and other countries with a similar climate, building materials made from coniferous trees are in great demand.
Many homeowners wonder why the choice falls on these types of trees and what is their advantage?
The main advantage of coniferous trees is that they are practically not susceptible to the harmful effects of moisture. Another significant advantage of conifers is their increased strength and very good hardness, which greatly facilitates the process of wood processing.
But if a person decides to opt for such boards, it must be borne in mind that, due to the high content of resins, they are more susceptible to fire. According to statistics, the common type of wood used in Russia is pine.
Of the deciduous trees, oak is the most preferred. It not only looks very noble and aesthetically pleasing, but it is also reliable, and with proper care it will last for several decades. The only drawback of such boards is the extremely high cost.
Experts warn that you need to choose one or another type of lumber depending on the purpose for which it will be used.
If the tree is used for, it is necessary to stay on the species with the minimum amount of resin. Softwoods are often used to withstand heavy loads, and hardwood lumber is more suitable for the construction of decor and various furniture.
But before acquiring a specific type of lumber, you need to think carefully about everything and objectively evaluate its advantages and disadvantages.
Video: Wood species
Lumber types and purposes, as well as raw materials for production, varieties 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. Ultimately, a product of a certain shape and size is obtained, having at least two (front and back) parallel sides. This type of material is produced in special enterprises equipped with band saws, circular saws and other equipment.
Raw materials for production
As the primary raw material for the manufacture of sawn timber, trunks of almost any tree, previously cleaned from branches and bark, are used. Coniferous wood is usually used for the construction of load-bearing structures. Hardwoods are most often used for all kinds of finishing work. It should be noted that the waste obtained during the production of sawn timber is used both in industry and in everyday life.
Poplar and birch are considered to be the most affordable timber for sawn timber production. Quite often, pine, spruce, linden, larch, ash and maple wood are used for these purposes. The timber of hornbeam, oak, cedar is of great importance for the industry.
The lightness of birch does not make wood less durable, and its beautiful structure and affordable price have made it even more popular. Larch is considered to be very moisture resistant, resistant to mold and mildew. Ash wood boasts good elasticity and impact resistance.
Beech is indispensable for the manufacture of floors, stairs and furniture. Incredibly strong and unusually beautiful oak wood, despite the rather high price, is in great 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.
Varieties of lumber
The characteristics of the finished sawn timber depends on the type of wood, the equipment used, the observance of the production and drying technology, as well as the cutting method. It is the latter factor that affects the texture of the board.
Sawing of wood is carried out in several ways, differing in the direction of sawing:
- transverse (across the fibers);
- rustic (at an acute angle to the fibers);
- radial (along the radius to the center of the log);
- tangential (tangential).
Cross-sawing is used for the production of decorative parquet, the rustic method is used for the manufacture of flooring. Radial sawn timber has a very attractive appearance, is durable, resistant to deformation and external influences. The tangential cut creates a beautiful pattern on the surface of the board in the form of interesting arches and rings.
However, on the surface of some boards, delamination may form over time. The most popular and expensive are radial sawn timber, since their surface has a uniform texture, constant dimensions, good mechanical characteristics, and the degree of shrinkage.
Drying of lumber is carried out both in the open air and with the help of special chambers, which are tightly closed rooms. The first type of product contains up to 20% moisture, the second lends itself to additional processing with protective agents, and the moisture content is up to 14%. Lumber cuts can be trimmed (cut along the entire length) and unbeamed.
Depending on the degree of processing, lumber is:
- unedged (although there are no knots, there are unprocessed sections of logs);
- edged (the profile of the materials has a rectangular shape due to cutting off the defective side parts of the log);
- planed (there is no roughness of one or more edges).
Classification
The shape, size and mechanical characteristics determine the division of sawn timber into several types.
Beams- this is a log, hewn from 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.
Bars- this is a "miniature timber", less than 100 mm thick, they are raw, planed (at least one side is processed) and calibrated (adjusted to a certain size). Scope of application - the manufacture of furniture, the manufacture of lathing, flooring, frames, gazebos and other objects.
Planks made from logs or beams. They are unedged, trimmed (having a smooth edge) and trimmed only on one side. In addition, the boards are calibrated, that is, they have given dimensions.
Sleepers- material with increased strength and minimum sensitivity to temperature fluctuations.
Croaker- These are boards obtained by sawing logs with a flat and semicircular surface.
Lagging- lumber produced from the side of a log that has only one flat side.
Advantages and disadvantages
Man at all times has 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 in our days. On the contrary, thanks to the positive qualities of wood, construction and finishing materials made of wood are becoming even more in demand.
Pros of lumber:
- have a high bearing capacity with a relatively low weight;
- despite sufficient strength, the material is simple and easy to process (pliable to drilling, easy to saw, allows you to produce 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, does not cause allergies;
- processing does not require expensive and time-consuming work;
- external attractiveness;
- pleasant smell of wood creates a favorable microclimate in the room;
- variety of shapes and sizes of products;
- affordable price.
Minuses:
- the ability to quickly ignite, maintain combustion;
- destroyed under the influence of fungus, mold, various insects;
- prolonged exposure to water and a humid environment often causes the process of wood decay.
In order to secure lumber, to make them more wear-resistant and durable, they are treated with special protective substances that can significantly reduce the above disadvantages.
Lumber grades
The division into grades is carried out by assessing the state of the worst side of the face, edge, and section.
Selected sawn timber should not have rot, mold, cancer and fungal stains, overgrowth and other foreign inclusions on the surface, as well as cracks from shrinkage. The admissibility of intergrown healthy knots is two per one meter of length, shallow edge and formation cracks - 16%, deep - no more than 10%. The scope of application of the products is mainly shipbuilding and automobile construction.
The field of application of the first grade sawn timber is the timber industry. This type of material should not have dry loose knots, healthy knots over 1 cm in size, through and cracks larger than 1 cm, wounds overgrown with bark on wood, young active layers of wood, mold, mechanical damage, various foreign inclusions, rottenness.
The scope of the fourth grade materials is the construction of change houses, utility structures, gazebos, the manufacture of boxes, loess, pallets and construction formwork.
Wood derivatives
A wonderful material for building a house is rounded log... Thanks to a well-thought-out system of locks, a completely flat 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 structures do not require strong foundations. Structures made of this lumber do not need additional finishing work.
Glued laminated timber made from solid boards or individual pieces. The material consists of lamellas that are firmly attached to each other. It is strong, durable and resistant to external influences.
Plywood Is a material consisting of several thinnest 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 wood waste at very high temperatures with the addition of a special binder. Quite hard fibreboards are called hardboard. The sides of such sheets can be either smooth, or one of them is corrugated, the other is smooth.
Chipboard Is a combination of fine wood particles and synthetic resins. MDF is produced from woodworking industry waste purified from all kinds of impurities. In the manufacture of this type of board, adhesives are not 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 sawn timber is the construction and furniture industry.
Block house is a material obtained from a rounded log by sawing according to the "square in a circle" principle. Due to its 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 has a small thickness, it is very strong, resistant to deformation, cracks and cracks. The external attractiveness of the lining, the simplicity and ease of installation made it even more popular.
Lumber is a unique product of wood processing, which is indispensable in construction, furniture and other industries.
Lumber- timber obtained as a result of longitudinal sawing of logs and ridges.
Depending on the type of wood, they are divided into coniferous and deciduous.
Lumber as a structural, finishing, cladding and roofing material, as well as a material for the manufacture of joinery and molded products and sleepers is used in residential, industrial and railway. construction.
Lumber includes: plates, quarters, planks, bars, beams, sleepers and slabs.
Plate
Plate obtained by sawing a log along the axis into two equal parts - halves. The plates have sawn off only one side. They are used for the manufacture of sleepers, joinery, boards, bars, etc. The sizes depend on the logs.
Quarters
Quarters obtained by sawing a log in two mutually perpendicular directions or by sawing a plate into two equal parts. They are used for the manufacture of joinery, moldings and other small products. The dimensions depend on the dimensions of the logs or plates.
Planks
a - edged; b - unedged; c - with sharp wane; d - with blunt wane; d - grooved
Planks - a type of sawn timber, in which the width is twice the thickness or more. Obtained by longitudinal sawing of logs along several parallel planes. The thickness of the boards is from 13 to 100 mm, the width is from 50 to 260 mm. Boards with a thickness of 13 to 35 mm are called thin, the rest are called thick. The wide sides of the boards are called planks, the narrow sides are called edges. According to the processing of the side edges, the boards are divided into edged ones, in which the edges are sawn and unedged, the edges of which are not sawn at all are sawn less than half the length. Hardwood boards are produced, as a rule, unedged. Edged boards, in which the lateral surface of the log remains on the edges, are called wane boards. Sagging is sharp when the edge is not completely sawn in thickness, and dull when the edge is partially sawn. By the nature of the surface treatment, the boards are divided into untreated and processed. Untreated boards after sawing the logs are not subjected to additional processing. The boards processed after sawing are subjected to additional processing (planing, grooving, etc.). They are divided into planed and grooved. Planed boards - the surface of which is planed on one, two, three or four sides. The boards are grooved - on one edge they have a tongue (groove), and on the other - a ridge (protrusion), which enters the tongue of another board. For planing, planing, thicknessing or four-sided planing machines are used. The planing machine is used for planing parts from two adjacent sides; thicknesser - for planing parts parallel to the planed side to a given thickness; four-sided planer - for simultaneous planing from two or four sides. Untreated boards, depending on wood defects and processing, were divided into varieties: from conifers - into selected, 1st, 2nd, 3rd, 4th and 5th; from hardwoods - on the 1st, 2nd, 3rd and 4th. Planed and grooved boards were divided into three grades: 1st, 2nd, 3rd. Defects in processing included: wane, mossy and wavy cut, curvature, non-parallelism of seams, edges, etc. The norms of defect tolerances by grade were regulated by GOST 8486-57 for boards made of coniferous species and 2695-56 for boards made of hardwood. Coniferous boards were used: selected, 1st and 2nd grades - for structures, manufacture of joinery, furniture, platbands, clean floors; 3rd and 4th grades - for the installation of subfloors, battens, interroom partitions; 5th grade - for temporary warehouse and outbuildings, for the manufacture of picket fence and other small products. Hardwood boards were used: 1 st and 2 nd grades - for clean floors, for the manufacture of moldings, joinery and furniture; 3rd and 4th grades - for interroom partitions and temporary structures. Planed and grooved boards of all grades were used for clean floors, wall cladding, ceilings; grooved, in addition, in cases where it is necessary to obtain a strong and dense non-translucent connection of individual boards. Thin boards were used for roofing, wall cladding, clean floors, between room partitions. On the front side of the roofing boards, there should have been grooves at the edges for water drainage.
Bar
Bars- lumber, in which the width is not more than double thickness, and the thickness itself does not exceed 100 mm. Available in the same thicknesses, lengths and types as the boards. The division into grades and quality requirements are the same as for boards. They were used for structures, for the manufacture of joinery, furniture, clean floors.
Beams
a - two-edged; b - four-bit; I am wane
Bars- lumber, the width and thickness of which is over 100 mm. Produced mainly from coniferous and hard deciduous trees (pine, spruce, cedar, fir, larch, oak, hornbeam, etc.). The thickness of the beams is from 110 to 240 mm, the width is from 110 to 280 mm, the length is from 1 to 9.5 m with a gradation of 0.25 m.By the nature of the processing, the beams are divided into two-edged - sawn from two mutually parallel opposite sides and four-edged - sawn from four sides. In terms of cleanliness, filings can be the same as boards, without wane and with blunt wane. According to the presence of defects in wood and processing, they are divided into 1st, 2nd, 3rd, 4th and 5th grades. Were used: 1st and 2nd grade - for agricultural. mechanical engineering and railway bridges; for supporting structures and parts, for racks, beams and intermediate floors; 3rd and 4th grade - for bar walls of residential and public buildings, floor logs, etc.; 5th grade - for processing into small workpieces and parts of products at the place of production of lumber.
Sleeper
a - edged "A"; b - squared and squared "B"
Sleepers- lumber of large width and thickness and short length. Produced from coniferous logs. They are used for the railway device. canvases. By purpose, they are divided into two types: for a wide track and for a narrow track. Sleepers for a wide track have a length of 270 cm (sometimes 250 cm), a width (along the bottom layer) from 215 to 250 mm and a thickness from 135 to 175 mm. There are two types: edged "A" - sawn off from four sides - sawn off from two opposite sides. Each of the types, depending on the type of rails for which it is intended, is divided into five types: edged - IА, IIA, IIIA, IVA and VA; squared - 1B, PB, P1B, 1B and VB. The types differ from each other in the thickness and width of the upper and lower edges. According to the quality of wood and processing, they were divided into three grades: 1st, 2nd and 3rd (GOST 78-40). Sleepers of the 1st grade of the first three types (I, II, and III) are used for main-line railways. lines; 2nd grade of the first three types and 1st grade of IV and V types - for station tracks, secondary lines and lines of industrial enterprises; 3rd grade of all types and 2nd grade. IV and V types - for railway industrial transport routes. Sleepers for a narrow track have a length from 150 to 180 cm, a width (along the bottom surface) from 19 to 26 cm and a thickness from 11 to 14 cm. They are divided into slabs, sawn from two or four opposite sides, and plate, obtained from plates. According to the cross-sectional shape and dimensions, they were divided into five types. Sleepers of types O, I and III - bar; II and IV - plate. For a track width of 750 mm, tapers of types I, II, III and IV are used; for 1000 mm track gauge - O, I and II types.
Croaker
Croaker- the side part of the log. It turns out in the form of waste when sawing logs into boards. The slab has sawn off only one side, on the other - the oval surface of the log is preserved. It was used for the installation of a lathing under the roof, for the construction of temporary and auxiliary buildings for the manufacture of picket fences, etc.
Sawing of logs and logs into lumber is carried out on saw frames, circular saws and band saws. The main working part of the LRB-75 sawmill frame is a frame in which the saws are vertically mounted. Up to 14 saws can be inserted into the frame, depending on the thickness of the log and the specified thickness of the lumber. The frame, receiving a vertical reciprocating movement along the guides from the electric motor, cuts the log along its entire thickness. Special trolleys are used to feed the logs into the sawmill and receive the lumber when leaving the frame. With one pass of the logs through the frame, unedged sawn timber is obtained; with two - edged. Sawing of logs is carried out mainly in two passes in succession on two adjacent timber frames; this increases the yield and improves the quality of the finished product. The productivity of the LRB-75 sawmill in an eight-hour working day with one pass (on unedged boards) is up to 200 m³ of logs; with two passes - it is almost halved. Circular saws have a saw in the form of a thick disc of large diameter (1 m or more) and are mainly used for making sleepers. Most often, a PDT-4 machine with a saw diameter of 1200 mm, a speed of 800 and a feed rate of up to 60 m / min was used.
Band saws have a saw in the form of a thin continuous band rotating on pulleys. The length of the saw band is 11.2 m, the width is up to 250 mm, the thickness is 1.47— 1.83 mm, the speed of the saw (cutting) is 46 m / s, the cutting height is 1220 mm, the feed speed of the log is 60 m / min. They were used for sawing thick logs and logs of valuable wood species because they give little waste (narrow kerf). In one pass, only one board was sawed off, which made it possible to more accurately regulate the thickness and monitor the quality.
Lumber was counted in cubic meters according to the tables of GOST 5306-50 with an accuracy of 0.0001 m³ of each assortment and up to 0.01 m³ of a batch. The width of unedged boards was calculated by the half-sum of the widths of the layers in the middle of the length of the board. The width of edged boards was determined by the width in the middle of their length, and boards with wane along the wide side in the edged part. The length of the lumber was expressed in meters; fractions less than 0.25 m for softwood and 0.1 m for hardwood are not taken into account. Lumber was marked individually or in packs with the indication of the grade and number of the braker. The variety was placed with a stamp or indelible chalk on one of the layers, with a jackhammer or indelible paint on the end. When marking with paint, the variety was indicated by the number of dots or vertical stripes (selected variety with a horizontal stripe at the end); when marking with a stamp, jackhammer or chalk - Roman numerals (selected grade with the letter "O"). Lumber for storage was stacked on pads separately by species, grade and nature of processing. The stacks were covered from above with a pitched roof.
Lumber is produced by sawing wood into separate parts - plates, quarters, bars and beams, boards, slabs. The types of lumber are very diverse.
Classification of lumber by appearance and method of processing.
The thickness of boards made in a production environment can be no more than 100 mm, the width is 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 subdivided depending on the processing
According to the method chosen for the processing of raw materials, lumber is divided into unedged and edged. For the latter, processing from four sides is characteristic, on the faces and edges, while the values \ u200b \ u200bwane should be allowed only those determined in accordance with the type of product. Scab is the part of the log surface that is preserved on the part after mechanical trimming. It turns out a piece of board that is not finished around the edges, which can be used in architectural structures or in carpentry finishing of buildings.
Uncut lumber has edges that are partially sawn or not at all. One-sided products have one edge and sawn edges, while on the sawn lump, wane is not allowed that is larger in magnitude than the parameters permissible for a particular product. This type is used in construction a little less often. It can be used for sheathing various parts of the structure, for making flooring, other options are also possible.
Types of lumber and cutting of 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 has been cut. In order to produce planed timber, timber is taken only with a certain diameter, so that the blanks for the timber are formed in accordance with the required size. The workpieces must be dried - this is done using steam chambers or in natural conditions. Products are obtained by processing raw materials on machines.
Classification of lumber by size, shape
When processing wood with the use of modern technologies, different types of products are made. The assortment includes bars and sleepers, boards and slats, quarters, slabs, plates and other products. The types of lumber can vary depending on the way the raw materials are handled. You can familiarize yourself with them in more detail.
Types of lumber
The timber, depending on the number of sides that have been processed, will be called two-edged, three-edged, four-edged. The thickness and width of the products is usually more than 100 mm. The main area of their use is the construction of load-bearing structures, cottages or summer cottages, since these products can perfectly withstand significant loads.
The bar is similar to the bar, but has different dimensions. It is made with a thickness of up to 100 mm, width - less than double thickness. It is used in the furniture and carpentry industry, for finishing buildings, for example, door frames and crossbars are made from them.
Shrinkage coefficient and mechanical strength table for sawn timber.
Boards are made of logs or beams of sufficient thickness. Boards are available uncut or trimmed. The thickness is possible no more than 100 mm, the width is more than double 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 kind of timber, in which the cross-sectional size differs in size. The most common use is for making railroad cloths.
A croaker is a piece of a log, sawed off from the side. In the process of sawing logs into various boards, waste is obtained, which is called slab. It is convenient to make temporary structures like sheds out of it; they are also suitable for the construction of lathing under the roof.
Quarters (obapol) are also obtained from the sides of the logs. One of the surfaces of the product is propylene, the other is not. It is convenient to use for making small joinery.
The plate is half of the log that is obtained by sawing it in the center. The plates have only one straight side. The length depends on the log used as raw material. They are mainly used for the production of the above products - sleepers, beams, sometimes - for the manufacture of massive boards.
How is lumber classified by wood species
For sawn timber, the grade will also depend on the tree species - they can be deciduous or coniferous.
Coniferous areas include larch, spruce, pine, cedar, fir. Deciduous arrays - oak, birch, beech, aspen, poplar, maple. For the construction of buildings, coniferous trees are more often chosen, 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 structural structures. But it should be borne in mind that conifers in their composition have a lot of resinous substances, which means that any types of lumber created from them are quicker and easier to catch fire.
Spruce wood is especially popular. It also contains the smallest amount of resins, therefore, the propensity to fire is reduced. Among hardwoods, oak is widely spread - it is very strong and durable. Lumber can be divided into four grades. So, the selected grade is used in the manufacture of parts in shipbuilding, in the lathing of automobile sides, in other significant areas.