The unique properties of wood - strength, long service life, environmental friendliness, pleasant aesthetic appearance, made it a popular building material, raw material for furniture production, decorative covering, folk art. People who work with wooden blanks after sawing them are called upon to have a good understanding of the types of lumber and know their technical characteristics.

Type of raw material and its preparation for cutting

When classifying wood according to the degree of preparation, the moisture content of the material is taken into account. Absolute humidity is determined by the ratio of mass - moisture and dry wood per unit volume.

There are several types of lumber

Exterior lumber with an air-dry or natural humidity more than 18–20%, obtained after prolonged exposure to air. Used in construction and for the construction of wooden structures.

A universal lumber with a moisture content of up to 15%, it is used for arranging skirting boards, platbands, and beams.

– in a special box at high temperature. Humidity – within 8–10%. Absolutely dry wood is treated with a protective compound to prevent it from absorbing moisture from the atmosphere.

Insufficiently dried or improperly stored wood is susceptible to deformation, rotting or destruction. To prevent this from happening, lumber needs additional processing in steam chambers.

All wood is divided into several types:

• trimming material, when the workpiece is processed from all sides;
• unedged pieces – processing on one side only.

By processing method:

• unmilled lumber;
• milled or planed.

There are different cutting methods in relation to the annual rings of wood:

• The radial cut is oriented towards the center of the rings. Blanks – with various sizes, width limited by the cross section of the log.
• Tangential - the cut is directed tangentially to these rings and helps to obtain long boards with the same dimensions and cross-sectional shape.

Each type of cutting lumber is used to create different shapes of products. It is the variety of sizes and shapes that allows processed wood to be used in all areas of human activity.

Classification of processed lumber

There are several types of lumber, depending on the degree of processing.

Plate- half a log obtained by cutting a tree down the center. It is used for the manufacture of sleepers, timber, and solid boards.

timber– a common result of woodworking. Used when arranging cladding and in the form self-constructed in buildings. The timber has a thickness not exceeding 100 mm, and a width less than twice the thickness.

Depending on the number of processed sides, there are two-, three- and four-edged timber. There are its varieties:

• simple timber;
• rounded timber.

The influence of part size on its classification

Bar- the same timber, but with smaller dimensions, standard size sections 40×40 or 50×50 mm. Used in the furniture industry and for the production of joinery.

Rail- a type of bar, flatter and narrower, found different sizes. Often such a product is sawn directly at the construction site, its width and height are adjusted to the required dimensions.

Board– edged products whose width ranges from 85 to 140 mm, and thickness ranging from 27 to 45 mm. Products are needed in capital construction, for finishing premises, and in the production of furniture.

The board is divided into 5 grades:

• Selective - applicable in shipbuilding, car side sheathing and creating luxury class interiors.
• First and second grade lumber is suitable for the production of furniture facades.
• The use of third-grade boards is construction projects.
• For fourth grade boards – production of boxes. They are used to pack large mechanisms for shipment.

Popular types of boards:

• Parquet - its bottom layer is made of roughly processed wood, and elite species are used for the top.
• – durable and light, it is made from the best wood.
• Window sill - well dried, with special impregnation.
• Engineering - with a top made of wood and a bottom layer of plywood.

Additional classification of materials by purpose

Lining is lumber used for interior and external cladding. In technical documentation it is called a cladding board. Street cladding is made exclusively from solid lumber.

Sleepers are made from wood valuable species, with excellent wood condition, as they are subject to the adverse influence of the external environment and heavy loads from heavy trains.

Lumber is selected that can reliably hold the rails and dampen the vibration of trains. Pine is often used to make railroad ties, and they are sometimes made from spruce, fir, red maple, and Siberian cedar. To prevent rotting and rapid destruction, they are impregnated with a special substance.

Small moldings - these products include corners, skirting boards, platbands, glazing beads - of various sizes to satisfy the need for selecting the optimal options.

Croaker – waste from sawing logs into boards, its side part. It is used for the construction of temporary buildings, as sheathing under the roof. Some designers advise customers to do decorative finishing using this lumber. The low cost of such wood has made croaker in demand.

Obapol (quarter) is an unfinished version of the board, only one side is flat, the width along the entire length is unequal, so the longitudinal section has an irregular shape.

A wide range of wood and an abundance of lumber, differing in - real opportunity choose all the interior details to your advantage.

Tree species for lumber

There are known types of lumber from various tree species; they can refer to two types of wood:

• coniferous;
• deciduous.

Almost all hardwood lumber, which has an aesthetic appearance and performance properties, is suitable for finishing premises.

Both coniferous and deciduous wood species of different price groups belong to environmentally friendly materials. They are now popular for interior finishing and exterior work in the construction of private houses.

But it is necessary to select the right wood and take into account performance qualities various types lumber.

Features of coniferous materials

Larch– resistant to water, not damaged by insects and fungi, rotting rarely occurs.

Pine– less durable, more prone to fire than other types of wood, due to the resins protruding on its surface.

Cedar– close in quality characteristics to pine and has a pronounced and rich wood texture, is resistant to decay and is able to disinfect the air in rooms where there are products made from it. Lumber is rarely used due to its high price.

Yew– the wood is red-brown in color with veins, is durable and hard, and has many knots. The material is not susceptible to wormholes and is insensitive to precipitation. Yew bars are good for carving, and veneer is good for mosaic work.

Fir– light and not too elastic wood, convenient for woodworking. It is made from roofing materials, lining for building cladding. The absence of the characteristic smell of resin allows the material to be used for the manufacture of food containers (barrels and boxes).

Deciduous range of materials

Acacia– hard wood of yellow color with pronounced growth rings. It does not crack or warp, has elasticity, high friction resistance, and can be easily polished. It is used to make parts for woodworking tools and carpentry workbenches, and veneer is good for mosaic work.

Oak– demanded wood in the construction of houses and buildings. It has a beautiful texture, high strength, rot resistance, bendability and durability. Oak blanks are used for the production of furniture and parquet, arts and crafts.

Ash– with mechanical properties close to oak. High bending ability and strength are the advantages of wood. But it is easily damaged by a wormhole and needs antiseptic treatment. Ash lumber is used to make furniture and gymnastic walls.

Aspen– made from deciduous lumber, it is easy to process and is used for, in different jobs. Most often, its wood is used for making plywood or chipboard.

Alder– soft wood does not rot, it is used for making furniture, building houses, storerooms and well log houses, the material does not smell and does not absorb third-party aromas.

Birch is a durable wood with a beautiful texture, easy to process, but not resistant to rotting. It is used to make plywood, chipboard and peel-cut veneer used for furniture production.

Hornbeam or white beech belongs to a tree species with strong and hard wood. After drying, this indicator increases, exceeding the quality of oak. Difficult to process with cutting tools, but finishes well.

Maple - with hard light yellow wood, it can be processed and polished, does not warp, and is easy to cut. Wood is in demand for arts and crafts, and carved items made from it are especially successful.

Video: Types of lumber

None of the building materials available on the market today have such unique qualities, How 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 nice 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, so before making wooden blank We need to be clear about ourselves in which direction we want the patterns to go.

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 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 than 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 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– this 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 a couple. 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 inability high-quality finishing and coloring. 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 terms of 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 a flowing water for 1.5 years. cold water. 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 lends itself well to processing hand tools, glued in plywood, easily polished and painted, 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. Maximum permissible thickness boards is 100 mm. Length of any material hardwood does not exceed 5 m, and from conifers 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.

Class: 5.

Lesson topic: Wood. Lumber and wood materials.

Lesson Objectives : to familiarize students with wood, its structure and scope of application, lumber and wood materials; to form and develop environmental thinking, outlook, interest in the subject; cultivate discipline and accuracy, respect for nature.

Lesson Objectives : teach students to distinguish between types of wood and types of lumber, to select required material for the product.

UMK : Tishchenko A.T. Technology. Industrial technologies: 5th grade: textbook for students of general education institutions / A.T. Tishchenko, V.D. Simonenko. M.: Ventana-Graf, 2012.

Equipment : samples of wood of various species, samples of lumber and wood materials (chipboard, fiberboard, plywood, veneer).

1.Organizing time.

Objectives: to prepare students for efficient work in class by preparing for the lesson (notebook, stationery, textbook).

Objectives: to familiarize students with the goals and objectives of the lesson; prepare to perceive new material.

Teaching methods: story.

At this stage of the lesson, the teacher organizes the students’ activities to work effectively. Students should prepare for class: everyone should have a textbook, workbook, and stationery on their desk. The teacher communicates the goals and objectives of this lesson.

2. Survey of students on the material assigned for home.

Objectives: to find out the degree to which students have assimilated previously studied material on the topic “Natural materials”.

Objectives: to ensure that all students master the material.

Teaching methods: frontal questioning, conversation.

Criteria for achieving goals and objectives: “++” – if the student gave a complete answer to the question; “+” – if the student’s answer was not complete; “-” – if the student could not answer the question.

The teacher prepares an assessment sheet in advance (Appendix 1), in which he evaluates the students’ answers on the topic covered.

1. How do you understand the expression “man-made world”? (Answer: many objects that surround us are made by human hands).

2.Which natural materials You know? (Answer: for example, clay, metals, wood, limestone, granite and others).

3.Give examples of clay products. (Answer: for example, pots, jugs, toys).

4.What products can be made from metal? (Answer: for example, nails, scissors, forks, spoons, knives).

5.What is paper made from? (Answer: made of wood).

6.What building materials do you know? (Answer: for example, bricks, cement, boards, logs and others).

Those students who received a “-” during the survey, having heard the correct answers, become aware of them and try to remember them; The teacher recommends that such students work through this material again at home. A positive assessment of students' answers will help stimulate their learning activity in the lesson. Students who receive a negative result during the survey also receive motivation to improve in the next stages of this lesson.

3. Studying new educational material.

Objectives: to familiarize students with wood, its structure and scope of application, lumber and wood materials; to form and develop environmental thinking, outlook, interest in the subject; cultivate discipline and accuracy, respect for nature.

Objectives: inform students about the topic of the lesson; teach students to distinguish between types of wood and types of lumber.

Teaching methods: demonstration of visual aids, conversation, story, work with a book.

Criteria for achieving goals and objectives: “+” - attentive, active work at this stage; “-” - inattentive, passive work.

The teacher announces the topic of the lesson (writes it on the board): “Wood. Lumber and wood materials." Students write down the topic in their workbooks.

Teacher: Wood is a natural structural material. It is obtained from the trunks of felled trees of various species. A tree species is a type of perennial woody plant.

There are the following tree species: deciduous, which have leaves growing on their branches, and coniferous, which have leaves in the form of needles.[ L3 ]

Teacher: Guys, what hardwood species do you know? (Answer: oak, birch, linden, aspen, beech, etc.).

Teacher: Give examples of coniferous species known to you. (Answer: spruce, pine, cedar, larch).

Teacher: Why is larch called that, although it belongs to the coniferous species? (Answer: because its needles fall off in the winter, like the leaves of deciduous trees).

Teacher: What are the main parts of a tree? (Answer: trunk, root, branches (boughs), leaves or needles).

The text of the first slide ends here (Slide 2).

Teacher: Let's look at the structure of a tree trunk.

Then you can discuss this material and clarify unclear points.

When demonstrating the structure of a tree trunk (on a piece of wood), you can ask schoolchildren to determine (calculate by tree rings) the age of the tree.[ L1 ]

Teacher: Wood as a structural material weighs less than metals, is easy to cut, glues well and is connected with nails and screws. Another advantage of wood is its beautiful appearance. Therefore, since ancient times, people have widely used this material in construction, in the manufacture of furniture, sports and gardening tools, musical instruments, artistic products and much more. But wood also has disadvantages: it deteriorates from dampness (it molds, rots), warps (becomes uneven) when dried, and easily catches fire. In addition, wood may have defects: knots, rot, wormholes, cracks, etc.[ L3 ]

Teacher: Texture is the pattern on a cut of wood, resulting from the intersection of growth rings, core rays and fibers.[ L3 ]

Next, the teacher needs to prepare and show to the students samples of deciduous wood: oak, birch, aspen, linden, maple, etc., as well as coniferous wood: spruce, pine, larch, etc. It is advisable to coat these samples with colorless varnish to preserve them for a long time colors and textures.[ L1 ]

At the same time, it is advisable to demonstrate products made from various types of wood, for example, birch wood - handles for carpentry tools, maple - block for a plane, aspen - matches, etc. [L1]

Teacher: Let's take a closer look at hardwoods.

The text of the second slide ends here (Slide 3).

Oak has hard wood yellow color with yellowish-brown veins. Oak is resistant to decay, is not afraid of moisture and does not warp. Its wood is used to make furniture, doors, and is also used in construction, carriage building, and arts and crafts.[ L3 ]

The text of the third slide ends here (Slide 4).

Birch also has hard, light wood (white with yellowish or reddish tint). It is used to make furniture, plywood, ax handles, and handles for carpentry tools. [L3]

The text of the fourth slide ends here (Slide 5).

Linden wood is soft, light, white-yellow in color, and cuts well. Frames, boxes, shelves, products with artistic carving. [L3]

The text of the fifth slide ends here (Slide 6).

Aspen wood has a light-colored fibrous texture. It is harder than linden and cuts with effort. It is used to make handles for garden tools, dishes, matches, and is used to decorate Russian baths, etc.[ L3 ]

The text of the sixth slide ends here (Slide 7).

Maple has a texture with a yellowish or pink tint and a silky sheen. This is a hard rock and is difficult to cut. Blocks for planes and jointers are made from maple. [ L3 ]

Teacher: Let's now consider coniferous species.

The text of the seventh slide ends here (Slide 8).

Spruce has white-yellow wood. Small knots are visible in its section. Furniture is made from spruce wood, musical instruments, it is used in the production of paper, etc.[ L3 ]

The text of the eighth slide ends here (Slide 9).

Pine has soft wood, slightly darker than spruce, with a reddish tint. Tree rings are clearly visible in the texture. Pine wood is widely used in construction and furniture production. [ L3 ]

The text of the ninth slide ends here (Slide 10).

Larch is the only European conifer tree with needles falling for the winter. Larch wood is hard, difficult to process, and resistant to decay. The texture is similar to that of pine, but brighter. Sleepers are made from larch railways, pillars, dams, piers; it is used in shipbuilding.[ L3 ]

Teacher: What is lumber?

When studying lumber, students should focus their attention on the names of such elements as face, edge, edge, end, since they will be mentioned in almost all woodworking lessons. [L1]

The text of the tenth slide ends here (Slide 11).

Teacher: Tree trunks, after trimming branches and twigs, are cut into logs. The logs are sawn lengthwise and lumber is obtained:

The text of the eleventh slide ends here (Slide 12).

a) edged boards,

The text of the twelfth slide ends here (Slide 13).

b) unedged boards,

The text of the thirteenth slide ends here (Slide 14).

The text of the fourteenth slide ends here (Slide 15).

c) bars,

The text of the fifteenth slide ends here (Slide 16).

d) bars,

The text of the sixteenth slide ends here (Slide 17).

d) plates,

The text of the seventeenth slide ends here (Slide 18).

e) quarters,

The text of the eighteenth slide ends here (Slide 19).

g) croakers.

The difference between a board and a block is that the width of the board is twice the thickness.

The text of the nineteenth slide ends here (Slide 20).

Lumber has the following elements: face, edge, end, edge. [L3]

Teacher: Let’s now find out the features of wood materials.

To demonstrate wood materials, prepare small samples of particleboard, fiberboard, veneer, plywood, etc. Explain how the cross arrangement of veneer fibers when gluing makes plywood a durable material. [L1]

The text of the twentieth slide ends here (Slide 21).

Teacher: Particleboards (chipboards) are made on special machines by pressing chips mixed with synthetic resin. [L3]

The text of the twenty-first slide ends here (Slide 22).

Fiberboards Fiberboard is pressed into sheets of crushed wood. [L3]

Chipboard and fiberboard are used for making furniture and in construction. [L3]

The text of the twenty-second slide ends here (Slide 23).

Veneer is thin layers of wood. It is produced on special machines: a special knife cuts a thin layer of wood from the surface of a rotating log. This process is called peeling (Fig. 7, page 14 [L3]).

The text of the twenty-third slide ends here (Slide 24).

Plywood is a wood material obtained by gluing three or more thin sheets veneer To produce plywood, birch, alder, beech, and pine wood is used. [L3]

4. Consolidation of educational material.

Goals: to develop skills in recognizing wood and wood materials, making an informed choice required material for products.

Objectives: to teach students to recognize wood and wood materials.

Teaching methods: laboratory and practical work, work with a workbook.

Criteria for assessing the quality of a student’s work:

1.correct completion of task 1 in the workbook:

a) there are no wrong answers – mark “5”;

b) incorrect answers 1-2 – mark “4”;

c) incorrect answers 3-4 – mark “3”;

d) incorrect answers 5 – the topic material has not been mastered;

2.compliance with safe work rules.

To carry out laboratory practical work No. 1 from the textbook, the teacher needs to prepare 15-30 samples of wood of various species, so that each student studies samples of two deciduous (hard and soft) species and one coniferous species. Sample dimensions approximately 6 x 4 x 1 cm 3 .

During practical work, students complete steps 1-4 of task 1 in the workbook. In conclusion – point 5 “Test yourself.” [L1]

Students open workbooks [L2] on pages 4-5 and complete task 1 (1, 2, 3, 4, 5).

Task 1 No. 1 (Appendix 2).

Task 1 No. 2 (Appendix 3).

Task 1 No. 3 (Appendix 4).

Task 1 No. 4 (Appendix 5).

Task 1 No. 5 (Appendix 6).

Correct answers to task 1 No. 5.

While students are doing their work, the teacher is constantly with them and advises them in the process of difficulties that arise.

The results of the lesson are summed up; students receive grades.

When grading a lesson, you must also take into account the correctness of completing tasks from the workbook.

The text of the twenty-fourth slide ends here (Slide 25).

5. Homework assignment.

Goals independent work for students: study paragraph 3 of the textbook, answer questions 1-5, p. 15 of the textbook; find on the Internet how Karelian birch wood differs from birch wood growing in middle lane Russia, and where it is applied; Prepare and bring drawing tools to the next lesson: simple pencils, ruler, compass, eraser.

The teacher’s goals: broadening the students’ horizons, developing interest in the subject, consolidating material on the topic studied.

Success Criteria homework:

1. conscious study of the material in paragraph 3;

2.correct answers to questions 1-5, p. 15 of the textbook;

3. finding interesting educational material about Karelian birch wood.

The text of the twenty-fifth slide ends here (Slide 26).

List of printed sources used.

1. Tishchenko A.T. Technology. Industrial technologies: 5th grade: methodological manual / A.T. Tishchenko. – 2nd ed., revised. – M.: Ventana-Graf, 2014.

2. Tishchenko A.T. Technology. Industrial technologies: 5th grade: workbook for students of general education organizations / A.T. Tishchenko, N.A. Buglaeva. – 2nd ed., revised. – M.: Ventana-Graf, 2014.

3. Tishchenko A.T. Technology. Industrial technologies: 5th grade: textbook for students of general education institutions / A.T. Tishchenko, V.D. Simonenko. M.: Ventana-Graf, 2012.

Annex 1.

Evaluation paper.

Appendix 2.

Task 1 No. 1.

List the main types of wood.

Table 1

Appendix 3.

Task 1 No. 2.

Mark with arrows which materials are classified as lumber and which are classified as wood.

Lumber Wood materials

Appendix 4.

Task 1 No. 3.

Get wood samples from your teacher. Carry out an experiment under the supervision of your teacher: by pressing an awl into the surface of each sample (without rotating it), determine which rocks are hard and which are soft. Fill out the table.

table 2

Number

sample

Breed

Texture

Color

Smell

Hardness

Appendix 5.

Task 1 No. 4.

Get samples of wood materials from your teacher and study them. Determine the number of layers in the plywood sample and measure its thickness with a ruler. Enter the results in the table.

Table 3

Appendix 6.

Task 1 No. 5.

Test yourself. Are the following statements true?

In your workbooks, fill out Table 2 (if the statement is true, then put “+” in the “Yes” column; if the statement is false, then put “+” in the “No” column).

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 a certain shape and sizes, having at least two (front and back) parallel sides. This type materials are 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. Deciduous trees are most often used for all kinds of finishing works. 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. Important The wood used for industry is hornbeam, oak, and cedar.

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 number of resins, therefore 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 sawing is used to produce artistic parquet, the rustic method is used to make 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 as per outdoors, and with the help of special chambers, which are dense closed premises. 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 (material profile has rectangular shape due to cutting down 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 positive qualities wood, construction and finishing materials made from wood are becoming even more in demand.

Advantages of lumber:

• have high bearing capacity with 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 environment, 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 varieties is carried out by assessing the condition the worst side faces, edges, and sections.

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 locking system, completely smooth rounded shape material, the resulting structures are quite strong and reliable. 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 is a material consisting of several thinnest layers 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 exterior decoration 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.

Obtained by cutting logs(blanks). In fact lumber- these are sawn products of certain sizes with two plane-parallel sides ( in layers). Sawing can be either radial or tangential. (Fig.1) are divided into plates, bars, boards, bars, croakers.

Plates receive at sawing logs along the axis into two equal parts.

Bars- This lumber thickness and width more than 100 mm; There are two-, three- and four-edged ones.

Boards They are no more than 100 mm thick and more than double the width.

Bruschi have a thickness of less than 100 mm, a width of less than double the thickness.

Gorbyl- side parts of the log remaining during sawing.

Lumber elements

IN lumber highlight the following elements: plastic, edges, ribs, ends.

Plast- longitudinal wide side lumber, as well as any side lumber square section. In the best plastic lumber the least number of defects, best quality processing. Lumber face, facing the core is called internal, and facing the sapwood is called external.

Edge- longitudinal narrow side lumber

Edge- line of intersection of two adjacent sides lumber.

end- end transverse side lumber.

Obzol optional lumber element, this is, so to speak, an element of marriage edged boards due to substandard source material ( logs or blanks).

Planed sections giving them shaped shapes are called planed molding (platbands, skirting boards, tongue and groove boards For flooring etc.).
Wood sheet materials and various additives - these are plywood, wood fiberboard (fibreboard) And chipboards (chipboards).

Manufacturing of lumber

Manufactured according to GOST 8486-86E:
1) From softwood - pine trees, ate, larches, fir
2) From hardwood - beech, birch trees, alders, linden trees, aspen And poplars.

Coniferous wood

Coniferous wood usually softer and lighter than wood majority hardwood; however, this is not always the case - yew wood heavier and denser than wood some deciduous trees. Fir trees that grow in cool or cold climates are usually processed. Wood they are light yellow, with resin passages and numerous knots. It's cheaper than hardwood, and easier to process. The wood was ate Used for almost all basic carpentry and construction. As a rule, they are on sale lumber as planed or unplaned boards of various thicknesses and widths from red And Canadian spruce . For outdoor use you will need either rot-resistant view wood, or spruce wood, pre-treated with a special protective compound. It is not enough to simply apply this substance to the surface of the wood with a brush - if possible, buy wood impregnated with an antiseptic under pressure: in this case protective composition penetrates deep into wood.

Table 1. Conifers

Wood species	Description
Thuja occidentalis	The wood is reddish-brown with a silky surface. Resistant to rot and insect damage. Used for cladding, construction of fences and greenhouse frames. Flaws: the color fades over time, the surface is easily damaged, and nails in such wood do not hold firmly
Larch	The wood is hard and difficult to process. Advantages: resists rot well, holds nails well. Used for posts and fence construction
Red spruce	Used for outdoor work. The wood is durable, easy to process, and suitable for staining and painting. Color varies from light yellow to red-brown. Rots quickly, requires antiseptic treatment
Canadian spruce	The wood is softer and finer grained than red spruce. Light yellow color does not fade over time. Used for interior decoration. They are not impregnated with antiseptic, so they are not suitable for outdoor use.

Hardwood

Trees that produce very hard wood are: oak, mahogany, or red, tree And teak. Wood these breeds denser and harder than softwood; it is heavy, resistant to rotting, has a denser structure and is more decorative than softwood. At the same time, it is more expensive and more difficult to process.
On a cross cut of a hardwood trunk deciduous trees grown in Europe or other regions with cool or frosty winters are clearly visible growth rings. Wood these breeds usually light and difficult to process. Coming to market tropical wood almost always darker, less textured and easier to work with. Important:
- Allowed application lumber from hardwood for parts of rafters, internal stairs, internal linings walls and partitions, ceiling lining, soffits, pediments, interior architectural details, carpentry and finishing wood.
- Not allowed application wood birch trees, linden trees And poplars for rafters; linden trees, alders, aspen And poplars for treads of wooden stairs; linden trees And poplars for clean floors.

Table 2. Hardwoods

Wood species	Description
Iroko	Grows in West Africa. Cheap wood from this plant is used instead teak for the manufacture of garden furniture. The color is rich brown, the texture is quite rough
Mahogany (red) tree	Wonderful, but too expensive for exterior finishing With ort of wood. African mahogany has a rich orange-brown color, American has a stronger gloss and costs more.
Meranti (shoreya)	Cheaper substitute mahogany from Malaysia. The color has pronounced red tones and is easier to process than Red tree. Used for making garden furniture
Oak	The strongest and most durable - sessile oak, but it is expensive, difficult to machine, and will splinter when nails are driven into it. Oak ordinary is somewhat softer
Teak	Traditional material for garden furniture: resistant to rotting, not afraid of water, difficult to ignite. Light brown color with darker stripes

Lumber sizes

Lumber length: coniferous species no more than 6.5 m, deciduous- no more than 5 m. Can be used for special structures lumber up to 9 m long, made to special order. Thickness and width of lumber determined assortment(Table 3, 4, 5, 6).

Table 3. Output standard edged lumber per cubic meter logs

Type of wood	Log diameter, mm	Variety	Output from 1 m³
			Lumber, m³	Wood waste, m³	Sawdust, m³
Conifers	140-240	2	0,591	0,269	0,14
Same	Over 260	2	0,637	0,223	0,14
Hardwood (including birch)	140-240	2	0,533	0,307	0,14
Same	Over 260	2	0,565	0,295	0,14
Aspen	140-240	2	0,481	0,379	0,14
Same	Over 260	2	0,512	0,348	0,14

Table 4. Thickness and width of softwood lumber in mm.

Name	Thickness	Width
		Least	Greatest
Boards	16	70	180
	19	70	180
	25	70	180
	30	100	180
	40	50	180
	50	50	220
	60	60	220
	70	80	220
	80	100	240
	100	100	240
Bruschi	120	120	---
	150	150	200
	180	180	220
	200	200	260
	220	280	280

Table 5. Thickness and width of hardwood lumber in mm.

Name	Thickness	Width
		Least	Greatest
Boards	16	50	160
	19	50	200
	25	50	220
	30	50	220
	40	50	200
	50	50	260
	60	60	220
	70	70	220
	80	80	260
	100	100	260
Bars	120	120	---
	150	150	200
	180	180	220
	200	200	260
	220	220	260

Table 6. Volume of one log, cubic meters

Log diameter, cm	Log length, m
	4,0	4,5	5,0	5,5	6,0	6,5
12,0	0,053	0,063	0,073	0,083	0,093	0,103
13,0	0,062	0,074	0,085	0,097	0,108	0,120
14,0	0,073	0,084	0,097	0,110	0,123	0,135
15,0	0,084	0,097	0,110	0,125	0,140	0,154
16,0	0,095	0,110	0,124	0,140	0,155	0,172
18,0	0,120	0,138	0,156	0,175	0,194	0,210
20,0	0,147	0,170	0,190	0,210	0,230	0,260
22,0	0,178	0,200	0,230	0,250	0,280	0,310
24,0	0,210	0,240	0,270	0,300	0,330	0,360
26,0	0,250	0,280	0,320	0,350	0,390	0,430
28,0	0,290	0,330	0,370	0,410	0,450	0,490
30,0	0,330	0,380	0,420	0,470	0,520	0,560

Characteristics of lumber

Lumber ends and rough blanks should be sawdusted at right angles to the longitudinal axis. Wane bars(with a partial absence of a cut in the edge) with a cross-section of 120 x 120 mm or more must have a cut width at the thin end of at least one third of the side of the beam.
Maximum permissible lumber moisture content for load-bearing structures - 25%, for glued structures - 15%.