Building materials made from hardwood and softwood have a wide range of applications; they are used for the construction and cladding of houses, paving paths, interior design building. The lumber on the market is divided according to the cutting method; it can be tangential, radial, longitudinal, disk or mixed. Depending on the presence of edges, boards are classified into edged, semi-edged and unedged.
Mechanical processing of logs can be carried out using special machines or electrical appliances by cutting or splitting. Distinguish following methods cutting wood: planing, turning, drilling, grinding, they all involve removing chips. There are three types of cutting - longitudinal, transverse and straight. The first involves cutting along the fibers, the second and third – perpendicularly. Sawing is the main stage in the manufacture of all lumber; the operational and aesthetic characteristics of the finished product depend on the quality of the procedure.
Tangential sawing
This method of processing logs is considered one of the most popular. With a tangential cut, the plane of the cutter passes at a certain distance from the core of the trunk, tangentially to the growth rings. The result is practical and durable boards that are resistant to shrinkage and swelling. Such lumber has an attractive texture - an elegant wave-like pattern is clearly visible on them tree rings. Boards obtained by tangential cutting can be used for exterior decoration of buildings and creating a cozy interior.
High-quality parquet is also produced in this way. When cut perpendicularly, a natural pattern is visible on the boards - rings, arches, waves, curls. If the parquet is made from Siberian larch, it can be used for laying flooring in rooms with high humidity, since products made from this rock, when in contact with water and steam, not only do not collapse, but also become stronger. Wooden flooring, created as a result of tangential sawing, will last for many years without needing repairs or renovations.
It is customary to call a radial cut of a log, carried out perpendicular to the annual layers. Lumber produced by this method has a uniform texture, they are characterized by increased strength and wear resistance, and are practically not subject to deformation. Radial cut boards have minimal shrinkage and swelling coefficients, so they do not collapse due to negative influence environment and are great for external cladding buildings. With this processing method, lumber has virtually no flaws. Defects may be caused by a violation of sawing technology (displaced core, incorrect size).
Radial sawing is used for the production of edged boards, a sought-after lumber used for finishing houses, summer houses and cottages. If the cladding is made of Siberian larch, it is perfectly would be better suited for decoration of baths, saunas and bathrooms. Products from this coniferous do not require additional processing, have an attractive texture and have a long service life. Edged boards are widely used by interior designers; with its help, you can create a cozy atmosphere in a room. Lumber from Siberian larch contains resin, when released, it spreads a pleasant aroma.
Mixed wood cutting
Semi-radial sawing is a common method of producing lumber. It involves cutting logs at an angle of 45°. This technology allows you to save raw material and reduce the cost of the finished product. The only drawback this method cutting is that the resulting board may be subject to deformation due to improper drying. Therefore, special attention must be paid to preparing wood for processing.
Semi-radial sawn timber can be made from both hardwood and softwood. Products made from Siberian larch are especially popular today; their demand is due to their strength, resistance to mechanical damage and aesthetics. Coniferous cladding reliably protects the building from the effects of atmospheric phenomena, helps retain heat and create a comfortable microclimate indoors.
Equipment for cutting wood
For the production of lumber, modern high-tech equipment should be used, only in this case the finished product will have a minimum of defects. The amount of waste generated when cutting wood also depends on the characteristics of the special equipment. Today, angle sawing machines are used for the production of boards, beams, and parquet; due to their special design, they make it possible to produce high-quality products and reduce the amount of waste. Using equipment for radial sawing, you can produce not only radial, but also edged lumber. The basis for creating molded products is a log - a tree trunk freed from branches. Wood cutting can be done in various ways:
- at the sawmill;
- manually (using special sawing tools);
- on woodworking machines.
To use existing logs rationally, the craftsman needs to carefully study the sawing pattern (tangential, radial, longitudinal, mixed). Knowing how to distribute raw materials can reduce waste and significantly increase profits. Suitable for the production of wooden building materials at home manual method, which involves the use of chainsaws and hacksaws. However, homemade boards and beams, as a rule, have defects and look unaesthetic. It is advisable to buy attractive lumber from specialized companies. Large enterprises carefully control the quality of products.
Interested in the rules for industrial cutting of wood, as well as the differences and characteristics of wood in different ways sawing. So, if anyone is interested, read on. The knowledge will be useful when purchasing building materials and building a country house.
There is a radial cut, in which the cutting plane passes through the core of the trunk. The wood of such boards is quite uniform in color and texture, the inter-ring dimensions are minimal. Radial cut boards-2 are resistant to external influences, are practically not subject to deformation and have high wear resistance. The radial cut board has a shrinkage coefficient = 0.19% and a swelling coefficient = 0.2%. These indicators for radially cut lumber are twice as good as for tangentially cut boards. For a radial cut board, the process of shrinkage and swelling occurs along the width of the fibers - the thickness of the board, and for a tangential cut along the width of the board, because the fibers at the "tangent" are located along the width. Accordingly, at the floorboard, parquet board, imitation timber, block house, lining - radial cut - there are practically no gaps compared to similar tangential cut products. design features:
Since the yield of radial cut boards is 10–15% of the total volume, their cost is quite high. Sawing scheme for maximum production of boards with radial-2 and semi-radial cutting-3.
Tangential-1 is a cut in which the cutting plane passes at a distance from the core, tangentially to the annual layer of the trunk. Such boards have a pronounced texture and a rich wave-like pattern of annual rings. Tangential cut boards - 1 have higher shrinkage and swelling coefficients, but are more affordable.
Radial sawing-2 wood is a method of cutting a log in which all the fibers in the board run along the direction of the annual rings. When radially cut, lumber has the best physical and mechanical properties. The strength and hardness of wood with radial cutting is higher than with tangential cutting.
The yield of radial saw-2 boards is usually small (does not exceed 30%). On the UP-700 longitudinal sawing machines, the yield of radial cut boards reaches 60%. This high rate is achieved thanks to the cutting optimization system. By choosing among the optimization criteria the maximum yield of a radial cut board, the conditions of radial and semi-radial-3 cuts, the technologist determines the percentage of yield of the radial board.
Sawing lumber- a fundamental process in wood processing. First, we need to recall a few terms that are used in the woodworking industry and which are defined by GOST 18288-87 sawmill terms and definitions:
Lumber. Materials that have one or more straight sides. Depending on the ratio of length to width and quantity parallel sides distinguished by beams, beams, boards, obapol and sleepers.
- Bruschi- thickness less than 100 mm, width does not exceed double thickness. This category also includes slats, only linear dimensions there are significantly fewer of them.
- timber- thickness more than 100 mm, width does not exceed double thickness.
- Boards- the width exceeds two thicknesses, they can be trimmed (all four sides are trimmed) or unedged (the sides are not trimmed).
- Sleepers- this is a timber with strictly defined dimensions, used during construction railways, is rarely used nowadays.
- Lagging- the more common name is “croaker”, outer side the whip has only one flat surface. Most often used for further processing into wood chips.
Wood sawing methods
This is a very important factor; the overall yield of lumber and its quality largely depend on the chosen method. Depending on the direction of cutting to the annual rings, there are two methods:
- Radial. The highest quality lumber has an excellent structure and high levels of physical strength. The saw moves perpendicular to the annual rings.
- Tangential. It produces a significantly higher yield of lumber, but its quality is somewhat lower. The saw moves parallel to the annual rings or in a tangential direction.
The choice of a specific cutting method depends on the end use of the lumber and the condition of the log. On the Internet you can find “strange articles” about circular sawing and so on. In fact, the vast majority of the logs are in one position during sawing; as a result, some of the lumber has a tangential cut (about 2/3 of the total), and the rest of the lumber has a radial cut. The top and bottom of the log are sawn tangentially, only its middle is sawn radially.
According to customer's request or taking into account own production the whip can be sawed from the sides, then turned 90°, and sawing is done again. As a result, some of the boards are unedged, tangentially cut, and the rest of the boards will be edged with a radial cut. Let us repeat once again that cutting methods are selected in each specific case separately, taking into account the above factors. Currently, there are three types of sawmills, each of them has its own advantages and disadvantages. Let's talk about them in more detail.
Frame sawmills
These were the first mechanisms that began to be used for mechanical sawing of wood. Today, in our opinion, they have undeservedly gone out of fashion. Let's take an objective look at their advantages and disadvantages.
To make it clearer, you need to learn about the principles of operation. On a frame sawmill, several saws are fixed in a vertical position (from ten or more, it all depends on the size of the frame), the distance between the saws is set once, sawing is carried out vertical movement drank everyone with the simultaneous application of the whip.
pros.
- The entire process can be completely mechanized
- The sawmill is easy to set up and maintain
- Performance is at a very acceptable level
- Cuts the entire length of wood in one pass
- All received unedged boards can be trimmed simultaneously and also in one pass
- The edged board is of high quality
- Save time
Minuses
- It is believed that these sawmills are converted into sawdust a large number of wood. But this is only true for older models. Previously, saws were made from low-quality steel, the thickness of each saw was up to 3 mm, plus the spread of the teeth, the cut increased to 5 mm. Today, by reducing the thickness of the saw and the angle of the teeth, the thickness of the cut is significantly reduced. We will compare the thickness of the cut with the band sawmill below, you will find out what their manufacturers are silent about.
Band sawmills
They are considered the most advanced equipment, the most productive, the amount of sawdust is minimal. We will discuss this later, but first we will briefly describe their structure and principle of operation. The cutting is done with closed high-speed saws, the thickness of the saws is small, the width of the cut is reduced. The cutting occurs due to the forward/reverse movement of one saw along the blade. To be honest, we don’t notice any particular advantages (for the buyer), but there are disadvantages. In order not to be unfounded, we will talk about the intricacies of the cutting process.
Sawmills require a very careful attitude. Incorrect sharpening of the teeth, incorrect tension or selection of cutting speed (all of these parameters are selected taking into account the type of wood) lead to the fact that the lumber gets a wavy surface. The height of the waves can reach several centimeters. And such waviness of even one board negates all the “advantages of thin cutting.” A wave on lumber is a visible processing defect and reduces the grade of lumber. The classification of wood defects is described in detail in the article of the same name.
These sawmills have enough low performance, requires a lot of physical labor. For example, if your log has a diameter of 100 cm, then calculate how many passes back and forth you need to make to cut it into boards 2 cm thick, and the frame sawmill will cut it in one pass. In addition, each sawn board must be manually removed from the sawmill and stored in a separate place. In this case, after each cut you have to set the saw level again. Very high degree dangers during operation. The risk of injury while working at such a sawmill increases exponentially - this includes the breakage of the saw at high speeds, and the presence of metal objects in the body of the tree (and this happens not so rarely). Problems with sawdust removal. They scatter along the entire length of the sawmill, removing them is long and difficult.
Of course, manufacturers of band sawmills are “bashfully” silent about such “subtleties”. We advise you to take into account the maximum number of factors when choosing a sawmill: the required volume of lumber, the availability of qualified personnel, the characteristics of lumber and requirements for their quality. After all, professional workers band sawmill produce 1st grade lumber in accordance with GOST.
pros.
- Relatively inexpensive
- Sawing in both horizontal and vertical directions
- Large whip thickness, up to 400 mm
- Low waste percentage
- Clean saw
Minuses
- Poor performance
- Increased danger
- Complex setup
- Highly qualified personnel
- Mandatory "rest time" from 8 to 10 hours
- Cleaning
Disc sawmills
Circular saws differ from band and frame (multi-saw) sawmills in the quality of edges and parallelism of the face. Lumber produced at disk sawmill is rightfully considered the best, but only from the consumer’s point of view. The main fact that makes lumber produced on a circular sawmill unavailable for consumption is its high price. High price does not allow you to compete in the market building materials, despite the excellent quality of boards and timber produced by this method. This circumstance is connected with three facts that influence the increase in the cost of lumber from a circular sawmill:
Summarize: When choosing edged lumber, you need to take into account not only the method of sawing the lumber, but also the qualifications of the personnel servicing this equipment. Buy lumber good quality You can contact a trusted supplier by looking at the products using the photos offered on the manufacturer’s website or by visiting the warehouse finished products. The Elka-Palka company is ready to offer its services in accordance with the price lists listed on our website. We sell only high-quality products of our own production or purchased from trusted suppliers. Mandatory quality control.
TYPES OF CUTTING LOG
There are two main types of cutting wood (logs) into boards (lumber):- radial;
- tangential,
as well as three additional types:
- mixed;
- semi-radial (rustic);
- central.
Scheme of types of log cutting
DESCRIPTION OF TYPES OF LOG CUT
Radial cut- this is a cut in which the axis of the cut passes through the core of the log and, as a result, the lines of annual rings in the section of the board form an angle of 76 - 90 degrees. with its faces (two main planes of the board). The wood of radial cut boards is quite uniform in color and texture. Such boards practically do not deform when dried and do not swell when moistened, because the change in wood dimensions occurs mainly along the line of the rings (across the grain), and for radial cut boards they are located along the thickness. Radial cut lumber has the highest performance indicators compared to lumber of other types of cut.
Tangential cut- This is a cut that is made along tangents to the lines of the annual rings of the trunk at some distance from its core. The surfaces of such boards have a pronounced texture and a bright wave-like pattern of annual rings. For tangentially cut boards, the coefficients of shrinkage and swelling from moisture are twice as high as for radially cut boards, which causes their significant deformation when the humidity state changes. For this reason, tangential cut boards are less preferable for use in wet conditions than radial cut boards.
Rustic (semi-radial) and mixed cuts- these are cuts with signs of two main types of cuts at the same time: radial and tangential and, as a result, have indicators averaged between them. In a rustic cut, the lines of annual rings have the form of straight lines located at angles of 46 - 75 degrees. to the layers, and in a mixed cut these lines change from straight at the edges (along the width) of the board to arched in the middle.
Central cut- This is a cut made directly in the center of the trunk and including its core. Considering that the core of the trunk consists of the least durable wood, center-cut lumber has the most heterogeneous structure in terms of strength of all the types considered.Useful articles
The main products of sawmill production are sawn materials. Minor – sawdust and wood chips, which are used for the manufacture of particle boards, fuel pallets, etc.
Types of materials produced on a sawmill
If you follow the “letter” of GOST 18288-77, the materials that are produced at the sawmill include:
1) Lumber
Lumber– wood blanks with two plane-parallel layers and certain dimensions specified in the standards.
- Bars– lumber, the width and thickness of which is more than 10 cm, is widely used in the construction of houses, as load-bearing structures, for internal and exterior finishing, manufacturing stairs, windows, etc.
- Bruschi– lumber in which the width does not exceed double the thickness. By geometric parameters There are square and rectangular bars. Depending on the length, these lumber are used as floor joists, bases for wall cladding, in the construction of gazebos, bathhouses and other small architectural forms, in furniture production.
- Boards- lumber in which the width exceeds the size of double the thickness. Depending on the presence of bark on the side edges, they are divided into trimmed and unedged. Edged boards are more in demand for the manufacture of furniture, windows, doors, for various finishing works- in a word, where not only the strength qualities of wood are important, but also aesthetic parameters. Unedged material costs an order of magnitude cheaper, so you can buy it either for self-processing into edged board to reduce the cost of production, or is used in construction as auxiliary material(when lathing roofs, for making decking, etc.).
- Sleepers– bars established size and molds that are made as supports for railway rails;
2) Blanks
Blanks – edged lumber with wane and edges that are sawn perpendicular to the faces completely or partially. These include plates (half sections of logs) and quarters;
3) Obasexual
Lagging– material with an internal sawn and an external unsawed (or only partially sawn) face. Plank obapol - with a convex part sawn half or more, used for the production of fence pickets and in the construction of formwork, scaffolding, strengthening mine workings;
4) Croaker
Gorbyl– the outermost parts of the log that remain during sawing. The croaker differs from both sexes in that certain ratios of thickness, width and minimum requirements by lenght. Most often used as an environmentally friendly fuel or for the production of wood chips.
Lumber elements
Plast– wide longitudinal surfaces of the sawn log and any side of the lumber square section. The inner surfaces are those closest to the core of the log, and the outer surfaces are the surfaces that are farthest from the core.
Edges– narrow surfaces, the processing method of which determines the division of lumber into edged, partially edged and unedged;
Edge– the intersection of adjacent two sides of lumber;
Ends– surfaces perpendicular to the edges.
Classification of lumber according to sawing method
Depending on the location of the layers to the annual layers, lumber is divided into:
1) Made by radial sawing
A radial cut is a cut in which the cut passes through the core of the log, at right angles to the rings. In this case, the surface of the layers is uniform in texture and color, and the distances between the annual rings are minimal.
Boards made by radial sawing have excellent quality indicators (swelling coefficient 0.2%, shrinkage coefficient 0.19%). Therefore, radial lumber is in demand for the manufacture of parquet, timber, lining, block house - finished products There are practically no gaps in comparison with similar tangential saw products.
Lumber made by radial sawing is the most durable and expensive. They are used in construction, in the production of massive panels and window beams. The yield of radial boards is usually small (30% is already good indicator), and depends on the method chosen for cutting the log. The optimal cutting pattern for obtaining radial and semi-radial boards is considered to be the following.
2) Made by tangential sawing
When cutting a log tangentially, the saw passes tangentially to the annual layers of the trunk without touching the core of the tree. Such lumber has a wavy pattern, which clearly shows the patterns of annual rings and beautiful wood structure.
For tangential boards, the coefficient of shrinkage and swelling is at least twice as high as that of radial material, so their cost is more affordable and the quality of the products is lower. For basic building elements Such boards are not used - the wood can be deformed and the product will “lead”. But, nevertheless, due to its high aesthetic qualities and low price, the demand for tangential wood is high - it is used for decorative finishing furniture, doors, building elements.