How to properly cut a log on a band sawmill. The work of a band sawmill: sawing logs into boards. Band sawmill Taiga T3 and its features How to cut boards on a band sawmill table

Boards and timber are one of the main building materials. But not everyone has the financial means to buy ready-made boards. In such situations, one of the ways out is to independently harvest wood on a plot taken from the forestry.

The advantage of a chainsaw as a tool for sawing logs

You can cut a log using a sawmill, a gas or electric saw and additional devices. When choosing one of these tools, the scope of the work ahead should be taken into account. The cost of the cheapest stationary sawmill, together with all components, is 150 thousand rubles. A chainsaw is much cheaper. It is more convenient than an electric saw for the following reasons:

• It does not require electricity to operate the tool - this makes it possible to use the chainsaw on the plots.
• It is more powerful than the electric saw.
• Starts smoothly and allows you to conveniently adjust the speed, which reduces the likelihood of chain breaks.
• The operation of the inertial brake is faster than that of an electric saw.
• Long working time without interruption - up to one hour.
• Can be used in high humidity conditions.

Types of working nozzles

When sawing logs with a chainsaw, various nozzles are used.

• Nozzle for longitudinal cutting. It is used for sawing logs along, the process takes place in a horizontal position. After work, the master receives the same thickness of the product. Finished materials are subjected to a drying process, after which the boards are used in construction. In appearance, the device is a frame small size, it is attached to the tire on each side.

• Drum debarker (rounder). With the help of such a nozzle it is easy to dissolve the log, it works due to the V-belt transmission. It is attached to the belts on both sides, for this purpose special pulleys are used. The speed of rotation of the shaft depends on the size of the pulleys, so the performance of the nozzle is easy to change. This technology forces the master to carefully monitor each stage of the process, some specialists use an assistant during this cut. But this option requires increased security measures.
• Sawing with a lightweight nozzle. The method is not very productive, but is used quite often. The element is fastened on one side, but the workpieces are slightly uneven. Such materials are necessary for the construction of sheds or fences.

Features of sawing with a homemade tool

You can easily cut a log into boards with the help of a self-made tool. It's easy to make. To do this, follow these steps:

• As a support, you need to use a frame from a school desk or a pipe with a section in the form of a square, its optimal size is 20x20, and more is allowed.
• It is necessary to build two clamps, mount a cross member with two holes for the tie bolts at one end, and make a protrusion for the tire in the middle.
• For longitudinal sawing of a log into boards, you need to make a support frame, its width should be seven to eight centimeters less than the length.
• Then two parts ten centimeters long are welded to both sides, holes are made for the bolts, a handle is attached in the middle for ease of operation.
• Then you need to insert the clamps into the grooves, install the tire, carefully fix everything.

It is not difficult to work with a home-made tool, this will require goats, they will serve as a support. In addition, you need to prepare a metal rail or board to use it as a guide. A log is laid from below, the required height for work is set.

The procedure for performing preparatory work

To cut a log lengthwise, you need to perform the following sequence of actions:

• Take two straight boards and attach one to the other at a right angle. The result is a strong leading ruler.
• To maintain the manufactured ruler, you need to make stops from the boards.
• The movement of the trunks must be performed using a tilter.
• The log should be placed on a comfortable base.
• On the chainsaw tire using nuts, you need to fix the frame.
• The supports of the leading ruler must be attached to the ends of the log, checking the horizontal position with a level.
• Self-tapping screws must be used to fix all brackets and structural elements. Nails are not suitable for these purposes, since it is difficult to remove them in the future without causing damage to structural details.
• The leading ruler must be attached to the supports with brackets and its height adjusted, taking into account that the cut will not go along it, but approximately one centimeter higher.
• The log must be rotated and the second board must be fixed in such a way that it rests on the ground and supports the log.

The procedure for performing basic work

• Now you need to start the chainsaw and make the first cut.
• Next, you need to free the log from the stops and boards and attach the leading ruler on the cut surface of the log in the direction of the next cut. The ruler is fastened directly to the surface or to the ends of the log using supports. The second cut is made perpendicular to the first cut.
• The log must be turned and fixed with a board point-blank to the ground.
• A guide ruler is not required to perform the following steps. One of the cut sides serves as a guide.
• It is necessary to adjust the thickness of the cut on the frame and saw off the log from the other side in such a way that you get a bar with bark remaining on only one side.
• This beam must be turned over and fixed in such a way that the fixing point of the fixing board is as low as possible.
• Then it is necessary to adjust the frame to the required thickness of the board and saw the timber into boards.

Safety rules when performing work

• Do not use the saw blade without the guard.
• Wear earmuffs, gloves, goggles, heavy clothing and a respirator.
• Do not pour fuel into the hot tank of the tool, you need to wait until it cools down.
• Children must not be allowed in the work area.
• It is necessary to start the tool on the ground with the chain brake applied, which must be released just before starting to cut.
• You should always have a first aid kit on hand.
• When working, you need to hold the chainsaw by the handle of the arc, moving it forward along the guide. Do not press hard on the chainsaw - it should move freely.
• Right-handers should place the log on their right side, left-handers on their left.

Pro Tips

1. GENERAL INFORMATION ABOUT THE MACHINE

The horizontal band saw machine is used for sawing wood of any hardness into boards, beams, rails. Sawing occurs by moving the saw frame with a cutting tool (band saw) along the fixed rail guides of the band sawmill.

The use of a band sawmill allows you to:

• produce boards with high surface quality from material
• receive a BOARD with an accuracy of 2 mm. with a length of 6 m;
• band sawmill allows you to reduce waste by 2-3 times,
• reduce energy costs;
• quickly adjust the sawing size,
• The band sawmill is able to cut short workpieces (from 1.0 meters) and obtain products up to 2 millimeters thick.
• the band sawmill works in the conditions of UHL 4 (GOST 15150-69). The band sawmill is equipped with an electromechanical type saw unit lift.

2. "Band sawmills" - work and device:

2.1 The main components and parts of the band sawmill:

• A bed that moves along rail guides in a horizontal direction;
• saw frame;
• Raising the saw frame mechanism;
• Electric cabinet;
• log clamp;
• Movable slider of the driven pulley;
• Leading pulley;
• Driven pulley;
• V-belt transmission;
• Rail guides of a band sawmill;
• Tensioning band saw mechanism;
• Band saw mounting socket;
• Band saw sheave cover
• coolant tank
• Saw guide fixed
• Saw guide movable

The frame of the band sawmill has a U-shape and soles with rollers for moving the saw frame along the rails and felt brushes that clean the guide from sawdust. The lifting of the saw frame is carried out by two sliders located on the racks of the bed. The movement is carried out by a two-way, synchronously connected chain transmission, driven by an electric motor, through a gearbox.

The frame is made of two channels, which are parallel and interconnected. On one end of the frame, the leading saw pulley is fixedly fixed, on the other end, the driven one, which has the possibility of longitudinal movement. Saw band sawmill tensioned by a spring-screw mechanism, the spring dampens the thermal expansion of the saw blade. In the manufacture of a band sawmill, the tension for a saw with a width of 35 centimeters is calibrated. The risks on the tensioner housing and washer are equal to the tension force of 525 kilograms. In the front beam of the band sawmill and on the slider of the driven pulley there are two locks for removing and installing the saw band. On the brackets located in the middle of the frame, two band saw guides (movable and fixed) are installed, which are equipped with support rollers and an adjustment system and a bar. Torque is transmitted from the sawmill engine to the drive pulley - V-belt transmission. The coolant reservoir is mounted on top of the saw pulley guard. The supply of liquid is regulated by taps located on the tank. The band sawmill control panel is located on the top jumper of the machine.

Guides collapsible from 3 sections, which is convenient for transportation. Below are the base plates into which the anchor bolts are screwed. On top of the guides of the band sawmill supports the logs. The log on rail guides is fixed with four screw clamps and a stop that provides 90 degrees.

3. ADJUSTING THE SAW PULLEYS

3.1. The machine provides for adjusting the position of both pulleys relative to each other in the horizontal and vertical planes. It is necessary to ensure that the band saw with a tension of 6-8 kg / mm sq. in cross section by one branch did not leave the rims of the saw pulleys.

3.2. First of all, the pulleys are adjusted in vertical plane, exposing them at right angles to the saw frame. To do this, on the slider of the driven pulley, the Ml0 bolt is screwed in from below to its axis, and on the driving pulley, adjustment is carried out by installing spacer washers or plates. This operation is performed by the manufacturer.

3.3 To adjust the position of the saw pulleys of the horizontal plane, two bolts Ml2 are screwed into the ends of the frame from the side of the driving pulley, and one bolt is screwed to the axis of the driven pulley.

It is necessary to adjust the pulleys of the band sawmill in the following sequence:

3.3.1 Turn off the automatic power supply on the control panel.

3.3.2 Open the saw pulley guards.

3.3.3 Install the band saw on the pulleys in such a way that it protrudes beyond the edges of the pulleys by the value of the tooth height plus 2-5 mm.

3.3.4 Close the movable connectors (locks).

3.3.5 Tension the band saw by turning the nut of the tension mechanism to the optimum value for this type of band saw (based on 6-8 kg/mm2).

3.3.6. Turning by hand on the driven pulley in the direction of sawing (counterclockwise), you need to look at what position the band saw will take on the pulleys. If the tape runs outward by an equal amount from both pulleys, then without loosening the tension of the saw, release the lock nut Ml6, which secures the axis of the driven pulley to the saw frame (saw frame slider).

3.3.7 Then loosen the M12 lock nut and screw in the Ml2 bolt a small amount, then tighten the M12 lock nut and the M16 lock nut.

3.3.8 Repeat point 3.3.6 and if the tape runs off, repeat the adjustment until the correct result is obtained.

3.3.9 If the band runs inward by an even amount, then it is necessary to loosen the tension of the band saw.

3.3.10. Loosen the Ml6 lock nut, M12 lock nut and unscrew the M12 bolt a small amount, then tighten the M12 and M16 nuts.

3.3.11 If the tape has taken the position according to the instructions, then the adjustment is correct.

3.3.12 If the band saw immediately runs off the drive pulley during rotation, then the adjustment should be started from it.

3.3.13 To do this, depending on the direction from which the belt runs (outward or inward), loosen the left or right lock nuts Ml6 and adjust in the same sequence as on the driven pulley.

3.3.14 After adjustment, tighten all nuts.

3.3.15 Close the doors of the saw pulley covers.

3.3.16 Turn on the e-mail dispenser. energy on the control panel.

3.3.17 Briefly switch on the drive of the saw pulleys and make sure that the saw blade is in the correct position. The machine is ready to work.

4. REQUIREMENTS FOR SAW BANDS

1. During the operation of the band sawmill, in order to increase the service life of the band saw, it is necessary to properly tension it on the pulleys.

1.1 The amount of tension, depending on its width, is determined by the "Tensometer" device.

1.2 Attention! The band saw should not be in operation for more than 2 hours. After this time, it must be removed from the machine and hung out in a free state for at least 24 hours to relieve fatigue stresses.

2 Use the correct lubricant for the band saw blade.

As a cutting fluid (coolant), in most cases, just water is enough, or water with the addition of detergent("Fairy", etc.). However, at low temperatures it is best to use a mixture of 50%-80% diesel or kerosene and 50%-20% motor oil or chainsaw tire oil. Good results when sawing conifers are also given by the use of turpentine.

In the case of using water as a coolant, it is necessary to wipe the pulleys and the belt with oil at the end of the work.

3. Always loosen the band saw tension.

When you're done, take the tension off the saw. In operation, the blades heat up and stretch, and then, when cooled, shrink by tenths of a millimeter during each cooling period. "Therefore, the belts left on the pulleys under load overload themselves, and they are imprinted by two pulleys, which causes cracks in the cavities between teeth.

4. Use the correct tooth setting.

The setting is correct if you have 65-70% sawdust and 30-35% air in the space between the saw blade and the treated wood. If your tooth setting is too wide for the weight or thickness of the wood, there will be too much air in the cut and not enough sawdust. You will have excessive sawdust losses, and as a result, a large roughness of the processed wood. If the spread is not sufficient, you will not get enough air flow to remove sawdust from the kerf. Hot sawdust is a sign of this. This can cause the most devastating damage to the saw: operating intervals will be short, the saw will fail prematurely. The sawdust should be cold to the touch. And, finally, with insufficient divorce and the wrong sharpening angle, the saw will cut a wave on the board. From our point of view, you cannot work with the same set of teeth with logs of different diameters, timber and cant.

You must sort the timber.

For every 20-25 centimeters increase in size, it is necessary to increase the wiring by about 18%, depending on whether the wood is hard or soft, wet or dry. The only way to achieve the desired layout is to carry out control cuts of a certain log. Increase the set by 5-8 hundredths of a millimeter on each side until tooth marks are visible. This means that you are working with a 50/50 mixture of air and sawdust. After that, reduce the setting of the teeth by 8-10 hundredths on each side, and you will achieve the desired result. Note: You should only breed the top eight, not the middle or bottom. You don't want the gap between the teeth to fill completely when sawing. When you work with soft wood, whether wet or dry, the wood chips increase in volume by 4-7 times compared to their state at the cellular level. Hard woods, wet or dry, increase in volume only 1/2-3 times. This means that if you are sawing 45cm pine logs, you will need to set your teeth 20% more than when sawing 45cm oak logs. Always set teeth before sharpening.

5. Sharpen your saw correctly.

There is only one way to sharpen band saws. The stone should travel down the surface of the tooth, around the base of the cavity between the teeth, and up along the back of the tooth in one continuous motion.

The space between the teeth (gallet) is not a sawdust bin. The power flow of air, the cooling of steel and the removal of sawdust depend on it.

If you have the correct set of teeth, the air is supplied along the log at the same speed as the saw, as a result, the sawdust is sucked into the gallet. The sawdust cools it considerably as it passes around the inside and outside of the next tooth. It is necessary that the space between the teeth be filled by 40%, which will provide the necessary cooling and increase the time of the saw.

6. Install correct angle sharpening.

Thanks to the deep gutters, we can use reduced sharpening angles that transfer less heat to the tip of the tooth. The series uses a 10 Degree hook angle that is able to penetrate most medium hard to medium soft wood surfaces.

The general rule is this: the harder the wood, the smaller the sharpening angle.

Warning: Do not trust the scales and measuring rulers on your grinder!

The pins and guides on it wear out. In the course of work, the profile of the stone changes.

To control the correct sharpening angles, use a protractor. Attention; we recommend changing saw blades every two hours of continuous operation, while allowing them to rest for at least a day.

During the operation of the machine, it becomes necessary to regulate individual constituent parts in order to restore their normal operation.

On fig. 1 shows some parameters of the canvas that determine its durability and performance where:

A - sharpening angle, this is the angle between the front surface of the tooth and the plane perpendicular to the back of the saw; B - tooth cavity; WITH - rear surface tooth

E - divorce, this is the deviation of the tooth from the vertical. The divorce line (the place where the teeth are bent) is located at a distance of 1/3 from the top of the tooth; R is the radius of the cavity;

P - tooth pitch, this is the distance between two teeth; H - the height of the tooth, this is the distance from the base of the tooth to its top.

Dependences of the saw parameters on the type of wood
wood type	Saw parameters
	Sharpening angle	Minimum Height teeth, mm	Divorce size, mm
Soft hardwoods	12-16	4,8	0,54-0,66
Soft conifers, medium resinous	12-16	4,8	0,52-0,66
Soft conifers, high resin content	12-15	4,8	0,52-0,60
Hardwoods	8-12	4,5	0,41-0,46
Soft hardwoods, frozen	8-12	4,5	0,46-0,56
Soft conifers, medium resin, frozen	8-12	4,5	0,46-0,56
Soft conifers of high resin content, frozen	10-12	4,8	0,41-0,51
Hardwoods, frozen	8-12	4,5	0,41-0,46

Problems encountered and solutions

Possible reasons	Solutions
Cracks in the cavity of the tooth
big feed
Incorrect belt tension	Set tension according to manufacturer's recommendations
Small root radius	increase radius
Small diameter pulleys	Set the saw to the correct thickness
Overheating of the tooth and interdental cavities	Correct grinding wheel, adjust the feed when sharpening
Saw band overheating	Increase the saw setting, hang the saw in the "inverted" state after every two hours of operation
Wrong wiring	Check the wiring, correct it according to the recommendations for the hardness of the wood being cut.
Incorrect selection of the front angle depending on the hardness of the wood	Change the rake angle according to the recommendations for the hardness of the wood being cut.
Blunt saw teeth	Sharpen
Belt wear on pulleys	Check the technical condition of the pulleys and the tension of the saw blade
Incorrect installation of rollers (damper)	Install the rollers according to the recommendations of the machine manufacturers
Wear of the working surface of the rollers (damper)	Replace
Imbalance of 1 pulleys, wear of the working surface of the pulleys	Perform pulley balancing and equipment maintenance
Installation of pulleys not in one PLANES	Adjust the position of the pulleys
Cracks on the "back" of the saw
Incorrect belt tension	Set the belt tension according to the manufacturer's recommendations
big feed	Reduce feed (feed should be even)
Runout of pulleys, installation of pulleys not in the same plane	Eliminate runout adjust pulleys
Pulley vibration	Replace bearing units, check balance
Incorrect installation or contamination of the guide rollers	Install according to manufacturer's recommendations, clean
Idler roller width does not match belt width	Set belt to desired width or replace rollers
Saw operation without rest, no blade tension release	Follow the manufacturer's recommendations. Loosen the tension of the belt at the end of the work
Variation in the thickness of the materials obtained, the wave of the tape (wave)
Incorrect wiring (different wiring on the sides of the tape)	Carry out the wiring according to the recommendations
Wear of rollers, failure of bearings	Replace
Burr on the side	Reduce feed when sharpening. Produce
belt surface after sharpening	deburring (after sharpening)
Insufficient cutting speed	Reduce feed or increase cutting speed
Incorrect belt tension	Install according to manufacturer's recommendations
Installation of the tape not in the same plane with the material being cut (as a result, a decrease in the set of teeth on one side)	Produce correct installation ribbons
Tape overheating	produce cooling, rest saw
Incorrect installation of rollers (damper)	Install the rollers according to the manufacturer's recommendations
big feed	Decrease
Loose, sawn material	Pin

5. PREPARING THE MACHINE FOR WORK

5.1 Before work it is necessary:

• check the reliability of the fastening of parts and the tightening of all threaded connections; lubricate rubbing parts in accordance with Section 7;
• check the installation of the band saw and, if necessary, adjust its position on the saw pulleys according to section 3;
• to ensure a stable position of the saw in the log at the time of sawing, as well as to align the band in the cutting zone and prevent it from coming off the pulleys under excessive load, install the support rollers of the movable and fixed guides of the band saw so that they press the saw band down. In this case, the deflection of the tape should be 2-5 mm. Then bring the bar with felt to the saw blade. To reduce the deflection of the tape, move the movable guide at a distance of 50-150 mm from the side surface of the wood;
• To avoid flaring of the rear edge of the belt and subsequent wear of the pulley plane, adjust the support rollers so that the belt does not constantly touch their stop collar. The gap should be 3 mm. using a level and a flat polished lining to prevent contact with the saw teeth, check the horizontal band saw, if necessary, adjust;
• adjustment of the guide rollers in the vertical plane eliminates the twisting of the saw in working area;
• check the reliability of fastening of the casings of the band saw and V-belt transmission.
• Make sure that the surfaces of the band saw and the rims of the saw wheels are clean and that the scrapers are tight against the rim of the wheels.
• turn on the electric motor and make sure that the band saw moves normally and correctly;
• when sawing, be sure to use coolants for cooling and lubrication (kerosene or diesel fuel diluted in half with engine oil, see section 4). The coolant is poured into the tank;
• the reverse (idle) run of the machine is carried out by first raising the saw blade above the plane of the log (by pressing the "up" button on the control panel) by 10-15 mm.

6. MAINTENANCE

At maintenance it is necessary to tighten the fasteners and, if necessary, replace the lubricant in the bearings, measure the insulation resistance for dielectric strength.

During operation, the following adjustments must be made:

• the tension of the drive belts, which is provided by the tension screw of the electric motor with the bolts previously loosened and then tightened; (ATTENTION! Do not overtighten the belts, thereby increasing the load on the bearings).
• band saw tension adjustment;
• parallelism adjustment of the saw pulleys!
• sharpening of teeth of band saws (sharpening is recommended to be done with corundum circles of a flat profile (p) with a grain size of 16-25 on a bakelite (b) bond with hardness C1 (C-medium hardness, 1-volume abrasive content 60%) or CT1 (medium hard). 6-8 mm. Good quality is ensured by the circumferential speed of rotation of the circle of 20-25 m / s. To lubricate the bearings, use Litol-24 grease. Change the grease after four months when working in one shift.
• replacement of worn scrapers:
• carry out the impregnation of felt scrapers-brushes every shift with mining, salaria, etc.

7. SAFETY INSTRUCTIONS.

The machine is made in accordance with safety requirements in accordance with GOST 25223, GOST 12.2.026.0, and GOST RMEK602041.

The machine must be properly grounded during installation. For this, there are grounding bosses on the sole of the frame, as well as on the track rails.

During the operation of the machine, it is necessary to regularly, but at least once a week, clean the electric motor and electrical equipment from dust and dirt. The presence of moving parts and electrical equipment in the machine requires strict adherence to safety regulations during its operation.

When working on band sawmill- be sure to follow the following rules:

• monitor the integrity of the insulation of conductive cables and the reliable connection of their ends;
• check the integrity and reliability of ground wires;
• adjust, replace the band saw and troubleshoot when it is necessary to disconnect the machine from the mains;
• in the event of a band saw break or a power outage, the machine must be immediately disconnected from the mains;
• while working on the machine strangers, as well as the machine operator should not be in the working area, as well as near the chip ejection pipe, because. when it breaks, the band saw can slip out in this direction;
• it is impossible to work on the machine with open doors of the casings of the saw pulleys;
• do not open the doors of the casings of the saw pulleys until they stop completely;
• it is impossible to work under the saw frame of the machine without first substituting a solid support under it;
• it is impossible to saw a log that is not fixed on the railroad tracks.
  

On the quality of the machine, in addition to those factors that are indicated in the passport (correct adjustment of the saw pulleys, correct wiring and sharpening of the saw teeth), the quality of the installation of the rail track plays an important role. So, with poor-quality installation, various defects can be observed on the layer of the sawn material, namely, the “waviness” of the surface, “tapering”, “stepping”, “non-parallelism”, etc.

The rails are leveled in the transverse and longitudinal directions. For normal operation of the machine, a solid foundation is required.

At the same time, the straightness of the rail guides is checked using a thin cord and a ruler. Steel strips of various thicknesses are placed under the plates and finally attracted to the foundation.

At correct installation and careful handling of the machine, the company guarantees the high quality of the sawn wood material, the deviation in the thickness of the cut over a length of 6 meters is no more than 2 mm.

9. FAULTS OF THE MACHINE, CAUSES OF THEIR APPEARANCE METHOD OF ELIMINATION

Faults	Reasons for the appearance	Solutions
Vibration of the saw in the cut	Poor welding quality and cleaning of the joint	Digest and clean the welding site
	Runout of saw pulleys	Repair
	Sticking of sawdust on pulleys and belt	Clean by first removing the saw. Adjust scrapers and coolant supply
Band saw slipping off pulleys	Pulleys not adjusted	Adjust the pulleys according to item 4
	Weak band saw tension	Adjust band saw tension
	Band saw guides incorrectly installed	Adjust band saw guides
Band saw rupture	Excessive band saw tension	Adjust tension
	Incorrect operation of the band saw	Monitor sharpening and wiring, remove the tape from the machine every 2 hours and hang it out for "rest" and relieve internal stresses according to the recommendations of manufacturers, relieve saw voltage during short and long breaks in work.
	Too much feed force	Reduce feed rate.
	Sticking of sawdust on the belt when working with softwood	Adjust scrapers and lubricant supply.
"Wavy" cut, not parallel to the processed surface to workpiece reference surface	Insufficiently installed rail track, not all supports are put on the site	Align the track correctly
	Saw pull up or down due to incorrect tooth setting	Set the teeth correctly
	Blunting (rounding) of the tops of the teeth	band saw sharpen
	Erroneous acceptance of an unsharpened and not set new saw for a fully prepared for work (bands supplied in coils with manufacturers come with pointed teeth from under the die, but not sharpened or set).	Sharpen and properly set a new saw
	Large belt deflection when sawing due to incorrect installation of the left movable roller.	Install the left roller 50-150 mm from the side surface of the wood

SAWING THE BIRCH

The main idea of ​​​​correct birch sawing is the ability to cut the maximum number of side boards from a log.

To increase the yield of high-quality lumber, we recommend using only the butt as a raw material (the first cut, 2.5 / 2.8 or 3.1 meters long), with a diameter of at least 26 cm, in the presence of a false core of no more than 1/3.

On a band sawmill, a birch is sawn only with the rotation of the log on 90 0 or 180 0 .

Sawing, (sawing through a half-beam) by rotating the log by 180 0

Sawing logs on a band sawmill with log rotation on 90 0

1. The slab is removed

(until obtaining a plate with a width of at least 110-115 mm.);

2. Unedged board No. 1 with a thickness of 28 mm is removed;

3. If there are flaws or a false core on the bottom of board No. 1 in an amount exceeding those allowed for grade 2C, the log is rotated by 90 0 . Board number 2 is removed. In the absence of defects, an additional board is removed.

4. If there are flaws or a false core on the bottom surface of board No. 2 in an amount exceeding those allowed for grade 2C, the log is rotated by 90 0 . Board No. 3 is removed. If there are no defects, an additional board is removed, etc.

After removing all the side boards, a beam of 110x110 mm remains. or sawn into 30mm fixed width boards for Grade 3C (110 / 135 / 165)

1. Place the end planks 28 mm thick on a semi-beam 110, 135 or 165 mm thick, depending on the diameter of the false core.

2. The half-beam is sawn into edged boards with a thickness of 28 mm.

Unedged boards are sawn on an edger with the maximum possible width without a fixed gradation or into a width dimension of 110 / 135 / 165 mm.

Birch lumber sorting

Birch lumber is sorted for two main markets: America and Europe

Grade 0 -Select - America orA3 - Europe

One face of boards of this grade should be free of knots and other wood defects.

On the other side, knots are allowed every 1 m.

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Grade 1 -Common 1 (1 Common) - America orAB - Europe

On both sides of the boards there may be knots every 1 m. in length.

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Grade 2 - BB - Europe

Any number of knots is allowed on both sides of the boards. false core is not allowed.

Grade 3 - BC - Europe

In grade 3, the number of knots is not limited on both sides.

False core on one side without restriction.

If the false core is on 2 sides, then no more than 50% of the board width

Marriage

false core (red core) on both sides more than 50% of the width

center board with core tube

The path to prosperity for your sawmill business

Wood is a versatile material. While wood is plentiful in Russia, we still need to make sure we don't waste this valuable natural resource when we turn it into lumber and when we turn lumber into furniture, houses, and other useful things.

Remember: only a tree should be cut good size. Your plan should be to cut as much high quality lumber from this tree as possible. You strive to do this with as little waste as possible, while at the same time wanting to achieve high value and utility in the product you produce. How to do it?

Raw material quality

The efficiency of sawing depends on knowledge about the quality of logs. It is very difficult to get good lumber from crooked, knotty logs of small diameter. Therefore, the first step, even before starting sawing, is to evaluate and sort the logs according to their quality.

Sorting is done according to appearance logs. The main criteria are the diameter, curvature, the presence of knots and the amount of false core. It is believed that the log has four faces, each face consists of 1/4 of the circle and occupies the full length of the log. These four faces do not overlap. A clean edge is free from knots, bark scars, cracks, chips, rot, insect damage, etc. The cleaner the edge, the higher its value, and the higher quality lumber produced from this log can be.

We have data on sawing thousands of cubic meters of wood. Based on these data, it is possible to estimate the volume (total and by grade) and the cost of lumber produced from logs. different sizes and varieties.

Curved logs of small diameter produce less valuable lumber than straight and large diameter logs. Therefore, when choosing raw materials, you should buy logs with a diameter of at least 26 cm in the upper part, optimal length and with the least distortion.

Logs used for sawing must be properly stored. In warm weather, they can spoil after a few weeks. It is best to start working on a tree as soon as it is cut down. The ends of the logs will immediately begin to dry out, and, as a result, the wood here will first change color, and then cracks will appear. For several months of storage, cracks can penetrate into the log by 15-20 cm, and the crack spreads up to 1 m. from the ends to the depth. In addition, dry ends are difficult to cut. In such material, the saw gives a wave and boards of variable thickness are obtained.

Sawing

Getting started with sawing is the key to getting the most profit and the most good quality lumber from each log. The sawmiller must keep in mind the full range of potentially useful products in order to manipulate the log to achieve maximum yield. This requires a sixth sense or even "X-ray" vision to "see" what is inside the log before sawing.

For a sawmiller to be efficient, he must receive logs that have been felled and stored properly. Logs should not have large bulges, bends, dirt and cracked, burst ends. The ends of the logs should not be dry. In short, the sawmill is not a magician: the way trees are cut, length-selected, and sorted before sawing affects the potential volume of lumber.

To optimize production volume, the sawmiller must consider how the lumber will be trimmed. If the sawer is not engaged in trimming, then the trimmer and sawmill should closely communicate with each other, exchange experience. They must work as a team. At a minimum, these people should match the required plank dimensions with the current volume of wood.

Clean, without knots, the most valuable wood is in the outer part of the log. The quality decreases as you start sawing closer to the center of the log. The most valuable are wide, long, clean boards.

Wood sawing methods

Which sawing operation to use (the sawing operation includes decisions about board thickness, log flipping and log taper compensation) depends on many factors: the type of wood, the quality of the log, its dimensions, the design of the machine and the grade of lumber to be obtained. There are 3 standard cutting patterns.

Sawing in a circle
A cut is made and the log is flipped to a new edge, sawn and flipped 90 or 180 degrees again, until the center of the log is gone. From a financial point of view, this the best way for medium to high quality logs, although some sawmills will find it difficult to turn the log and daily productivity will be low. Of course, a machine with hydraulics solves this problem.

Simple sawing (or loose sawing)
The log is sawn into unedged boards without overturning to the end. While this may be the fastest and easiest method of sawing, each board must be cut at the sides. In addition, lumber sawn in this way is of lower quality, has a lot of waste and is extremely susceptible to cracking at the center boards. In short, loose sawing is justified only in the case of very low quality logs, when all the above disadvantages are no longer particularly important.

Sawing timber
In this case, the log is first sawn as when sawing in a circle, but the central part of the log can have any dimensions, or it is transferred for processing to another machine along the production line. Cant Sawing Maximizes Productivity sawing machine. Mostly logs of medium and low quality are sawn in this way, when it is impossible to obtain valuable lumber from a log. Thus, time and effort are saved in the production of a product of not very high quality and therefore not very high price.

First cut

Of all the problems a sawmiller faces, deciding on which side of the log to start sawing (and therefore which side of the cut to open first) is the most important. (As already mentioned, we divide the log into 4 faces, each of which extends along the entire length of the log and occupies 1/4 of its circumference). The choice of the first face is determined by the position of all others. Before sawing begins, a log can be sawn in a million ways, but only a hundred of them will actually bring benefits! Having decided on the first cut, the sawmiller has only a few thousand other decisions to make.

In the case of sawing in a circle and sawing a bar, two basic rules apply.

Rule 1 The worst side of the log is sawn first, regardless of the taper of the log. (Accounting for log run means raising or tilting the log so that the saw runs parallel to the bark.) Since this is the worst part of the log, it will make short boards and a lot of slabs. Since we do not take into account the taper of the log, this gives us the opportunity to saw from the opposite, better side of the log parallel to the bark, without lifting or tilting the log. This means that more boards of high quality will come out of this best part of the log, moreover, the same length as the length of the log.

Rule 2 First cut the best edge of the tree, taking into account the taper of the log. This means that the log must be raised or tilted so that the first cut is made parallel to the bark.

The end result of both methods will be about the same, but the second method has one advantage: in this case, it is easier for the sawyer to position the log (i.e. rotate it), because the open edge is the cleanest, there are no defects on it. In the case of rule 1, the best part of the tree is opposite the open face. It is not visible, and it is impossible to accurately position the log. Usually, if the wood is of good quality, rules 1 and 2 work pretty much the same. However, if you encounter a worse log, adopt rule 2.

Large high-quality logs (these are logs from the bottom, butt of the tree) provide the most valuable lumber.

Remember: you won't make money just sawing boards - the boards still need to be sold. For this reason, the critical factor for you is not the sawing process itself, but the product - its grade, value and usefulness.

If the log is good, it is unwise to produce large lumber and railroad ties to say the least. Because the price of a bar is always less than the price of a board.

For logs of high grades, sawing in a circle is recommended. In fact, sawing with the taper of the log (i.e. slanting the log so that the cut is parallel to the bark) is recommended for all "good" edges. The result will be clean wood throughout the length, more valuable pieces of lumber. When you get to the low grade part of the log, go to the shape of the cant and minimize the operation of cutting the cant on the sides.

From logs of small diameter, from which it is impossible to obtain a wide and knotless material, the profit is very small, or none at all. So they need to be cut as quickly as possible. Any method of sawing is suitable here. Most often they are sawn into a beam (this is good from a financial point of view), or they are simply sawn “in collapse”. Remember that every minute of sawing costs money, so you need to find a compromise between production costs and the prices of the final product. In this case, it is generally better to reduce log flips to zero.

Logs with small diameters from 16 to 22 cm give such an insignificant profit that it is better not to deal with them at all. Invest money in good wood instead of going for the cheap stuff is my top tip.

Logs of large diameters - this is a real challenge for the sawmill. I say this because such logs can produce a significant amount of good lumber, and here a lot depends on the sawyer, on how he will turn the log over. Here the decision to rotate the log is critical to profit.

To begin with, the sawyer, guided by rule 1, selects the worst part of the log and cuts it without taking into account the run-off. But don't saw too much on this side. For small logs, you generally need to cut one board, and then turn the log over to the opposite side.

Another way is that the sawyer, guided by rule 2, chooses the best side of the log and starts cutting taking into account the taper of the log. After that, this particular part is sawn for a long time before the log is turned over.

log flip

Lumber is sawn from one side until the sawmill expects the next board on that side of the log to be at least as good as the boards that can be obtained from the other side. (Exception: if you started sawing from the worst side of the log, then cut until you have a perfectly smooth cut surface to flip the log onto). In other words, the good side of the log needs to be cut deep, and the slab or slab and one board are simply removed from the bad side.

Usually, when sawing, the log turns over 180 degrees. Because many sawmills do not have a log turner, the benefits of turning the log need to be discussed in detail.

When sawing with a 180 degree turn, we get several unedged boards, which need to be additionally cut on the sides, and the half-beam is sawn into finished edged boards. When flipped by 90 degrees (always turning to the adjacent edge), we will get unedged boards and additionally several semi-edged boards that need to be cut on one side. This circumstance alone can already be a significant argument in favor of turning a log 180 degrees, especially for small enterprises. In addition, this way of sawing produces more wide boards, and they are usually more valuable. However, if the edging machine has only one blade, the 90 degree flip sawing method may be more convenient.

In addition, turning over to the adjacent edge at a sawmill with manual tilting of the log can be more difficult due to the need to accurately "catch" the angle of 90 degrees, and from an economic point of view and from the point of view of sawing speed, it is more profitable to rotate the log by 180 degrees.

After sawing two opposite sides of the log, you need to move on to the third and fourth. Usually the worst of these edges is sawn first, regardless of the taper of the log. However, a good quality edge should always be sawn parallel to the bark to increase the yield of good lumber from the log.

With any turn of the log, the internal stress of the wood is removed, which, as a result, avoids bending of the log, cracks and cracks.

Lumber size decision

The width of the first board when sawing from all four sides of the log is critical.

Edge of good quality
If the sawmill believes that the first sawn board can be classified as good grade, then the minimum width of sawn lumber should be 11 + 1 cm. Why? Because the board of natural humidity must have a width of at least 11 cm. To take into account the further processing of the board (cutting on the sides), it is recommended that 11 + 1 cm, and not 11 cm, but still it is not recommended to specifically produce a lot of this size, because the quantity narrow boards per batch is limited.

Variety definition

Since our company is focused on the export of lumber to the United States, there are five main types of hardwood in their market:

FAS, Select, 1 Common, 2 Common and 3 Common. Briefly describe these varieties:

FAS means lumber that is at least 85% clean on 4 sides. Clean - it means without knots, rot, loose core, cracks, wane, stains and other defects. The clean surface should be extensive in both length and width of the lumber. The size of the lumber in this case is not less than 165 mm. x 2.45 m.

Select- this is actually the same as FAS, but one face of such lumber can be like Grade 1 Common. The size of the lumber in this case is at least 11 cm x 2.15 m.

1Common- at least 70% clean from the worst edge. (no more than 1 knot per 1 meter of length). The size of the lumber in this case is at least 11 cm x 1.85 m.

2 common- only 50% clean on the worst side (no more than 2 knots per 1 meter of length)

3Common- this is lumber, which, on the worst side, is only 33% pure.

Of course, this is only a general description of sorting. In fact, there are rules issued by the American Hardwood Association (NHLA rules) that explain individual cases in detail.

Currently, US buyers are limited to only two varieties -

it's a variety Select&btr. - mixture of FAS and Select grades

and grade 1Common

The rest of the material, lower grades, is in demand among European buyers.

conclusions

• Sawing logs can be profitable business if done wisely and safely.
• Storage of logs in a warehouse should be minimal in time.
• Logs must be protected from the ends from drying out.
• Logs should be sawn from the worst edge without compensating the log taper or from the best side, but taking into account the log taper.
• Logs need to be turned over on the bed every time the other side of the log promises to produce better quality boards than the one you are currently sawing.

All photos from the article

Sawn logs are boards,. The task of competent and efficient sawing of trunks is extremely relevant for independent or industrial logging, in addition, knowing the basics will help you choose the right lumber.

We will look at the main points regarding this topic and tell you how to properly cut a log on a band sawmill.

sawing logs

The main task

Important! The sawing scheme is selected in accordance with the quality of raw materials, the purpose of the board and the capabilities of the equipment.

Sawing tool

Logging is done with a special tool. For normal work by today's standards, you need a special machine for cutting logs with your own hands, which is called a sawmill.

There are two types of sawmills: disc and band sawmills. Disk use circular saws and are considered less effective, since they have a large cut thickness (from 6 to 9 mm), lower accuracy and depth.

The band sawmill is equipped with a different system: the saw is a band worn on rotating rollers. The cut thickness is approximately 1.5 - 3 mm, which is quite economical in terms of chip removal.

Modern models are characterized by high accuracy and productivity, they are automated and have a tilting mechanism for lifting and turning logs in case of circular sawing or sawing timber.

Using a chainsaw, you can only cut a log in half, but if you use a special frame, you can dissolve the log into boards right in the forest.

Important! Band sawmill is considered the most efficient and cost-effective.

Conclusion

Sawing a log is considered one of the most complex and important tasks in logging and lumber production. The quality of products and the income of the enterprise depend on the chosen scheme, well-designed work procedure and tool preparation.

The video in this article will tell you about the types of sawmills and how to cut wood.

Find out from which part of the trunk they are cutboards or timberit is possible according to the pattern of growth rings, looking at their end, as well as by the number of knots on the boards or bars. The butt part of the trunk is always thicker than the top part and, as a rule, does not have branches, that is, it contains better quality wood.

From the middle part of the whip, the so-called technological wood raw material is obtained - wood supplied to the mechanical (for chipboard production, fiberboard) or chemical (for example, for hydrolysis production) processing. The remaining butt part of the whip is sawn into two or three parts, which are fed to sawmills.

At sawmills, lumber is produced from logs by sawing them parallel to the longitudinal axis.

Among lumber, there are:

timber (width and thickness more than 100 mm)

segmented timber or quarters (obtained from a log sawn into four pieces)

bars (thickness up to 100 mm and width no more than double thickness)

Boards (thickness up to 100 mm, width more than double thickness)

obapol - side parts of the log

slats - thin boards and bars cut during longitudinal sawing

In addition to the listed basic lumber, there are also so-called semi-finished products, in particular, grooved and profiled boards, plinth and other molded products.

The thickness of the boards coming out of the saw frame is determined by the distance between the blades of the saw frame

1 - a beam is cut out of logs from heartwood;
2 - upon receipt of half beams, the log is sawn along the longitudinal axis;
3 - upon receipt of segmented bars, the log is sawn along the longitudinal axis crosswise;
4 - during group sawing (tossed), unedged boards are obtained in one pass of a log through a sawmill frame;
5 - with individual sawing with a bar, during the first pass through the frame, a two-edged beam, slabs and side boards are obtained;
6 - the most difficult is the radial sawing of a log, in which floorboards with vertically arranged growth rings;
7 - during the second pass, the two-edged timber is rotated by 90 ° and sawn into

Edged boards, separating side wane from it;
8 - for boards with horizontally arranged growth rings, the front side is called the side facing the core (core), and the back side is the side facing the sapwood (peripheral part of the trunk)

1. The outer layer of the bark, which protects the tree from cold and heat, and therefore from intense evaporation of moisture.
2. Through the inner layer of the bark (bast), the tree receives the necessary for its development nutrients. In the process of tree growth, the bast dies off, joining the outer layer of the bark.
3. Between the bast and the actual wood there is a cambium, which ensures the growth of the tree in thickness and the formation of growth rings.
4. Sapwood - external, a layer of active wood adjacent to the cambium and nourishing the tree with moisture. The older inner layers of sapwood are gradually receding towards the heartwood.
5. The internal dead layers of wood, no longer nourished by moisture, form the core (core), which, due to its strength, is the bearing and supporting core of the tree