How to cut a log lengthwise with a chainsaw yourself. Methods for cutting logs on a band sawmill Sawing birch on a band sawmill

Wood, like natural stone, is one of the most ancient building materials. Despite the huge selection of various artificially created materials existing on the construction market today, timber is still very popular. In order to obtain high-quality lumber, the log must be cut into boards. In this article we will talk about how to cut a log into boards.

Types of log cutting

Sawing logs into boards is carried out in two main ways:

• radial
• tangential.

In addition, additional methods are possible:

• mixed
• semi-radial (rustic)
• central.

Radial sawing is a type of sawing during which the axis of the cut runs through the core of the log and, as a result, the annual rings in the section of the board form an angle of 76 - 900. The lumber obtained by such a cut has a uniform color and texture. Timber almost does not undergo deformation during drying and does not swell when moistened, because the dimensions of the wood change mainly along the line of the rings (across the grain). In radial sawn timber, the annual rings are arranged according to thickness. Such materials are distinguished by the highest performance indicators in comparison with other types of lumber.

Tangential cutting is carried out along tangents to the lines of annual rings at a short distance from its core. The surfaces of the resulting boards are distinguished by a pronounced texture and a bright wave-like pattern of annual rings. Such lumber is characterized by higher coefficients of shrinkage and swelling from moisture compared to radial cut boards. As a result, they are greatly deformed when exposed to moisture. Such boards are in demand for use in dry conditions.

Rustic (semi-radial) and mixed types cuts have characteristics of two main types of cuts simultaneously: radial and tangential. Therefore, they exhibit average shrinkage and swelling coefficients. Rustic cut boards are distinguished by straight lines of annual rings, which are located at angles of 46 - 75 degrees. to the layers. Mixed sawn timber is distinguished by the fact that the lines change from straight at the edges (along the width) of the board to arched towards the middle.

The center cut is made right in the center of the trunk and contains its core. Taking into account the fact that the core of the trunk is the wood with the most low performance strength, center-cut lumber is characterized by a structure that is heterogeneous in strength.

Wood balance when sawing

Tools for sawing logs

Tools and cutting methods depend on the total volume of logs, such indicators as length and thickness. In addition, you need to take into account the quality of the future lumber. Cutting a log involves working with different instruments and specialized equipment. In order to obtain a small amount of lumber at home suitable conditions manual method processing logs using a chainsaw or traditional hand saws with teeth for longitudinal cutting.

The sawmill is perhaps the most famous type of sawmill equipment. This is a woodworking machine that contains frame saws. Lumber is produced at the sawmill longitudinal cut, For example, edged board or timber. Sawmills allow processing logs with a diameter of 15 to 80 cm and a length of up to 7 m.

Cutting logs into boards using circular saws (circular saws) is carried out using a circular saw. Such equipment can be single-saw (single-disc) and multi-saw (multi-disc). Devices containing one disk are suitable for working with small-sized and low-quality raw materials. Using multi-disc machines, you can cut round workpieces of large diameter.

Band sawmills are the most popular today. They come in two types: vertical and horizontal. The cutting tool in such equipment is a belt blade that is put on pulleys. Work for tape machines guarantees the production of high-quality longitudinal and mixed lumber, such as boards and timber. This produces the least amount of waste.

On large industrial enterprises wood sawing lines are used. They allow achieving very high surface quality and precise geometry of the final products. Such lines are characterized by the highest productivity.

In addition to all the equipment listed above, such types of highly specialized sawmill equipment as debarkers, edgers, band-dividers and other types of machines are also used.

Very often there are situations when you need to produce a very small volume of boards or beams for your own needs. Of course, buying machines in this case is absolutely not an option. Having certain knowledge and skills, it is much more profitable to cut logs with my own hands, using an electric or gasoline chain saw. Despite the fact that this work is quite labor-intensive, the result is quite justified.

Most experts believe that a chainsaw is better suited for this purpose. Such equipment has high power and can operate without interruption for a long time. In addition, the operation of a chainsaw does not require electricity, so you can work far from the power supply, for example, right on the plot.

In order to cut a log into boards using a chainsaw, you will also need special tools, such as a mechanism for securing the log, a frame attachment for the chainsaw, and a guide for making the cut. The attachment frame must be attached to the chainsaw bar so that it can be used to adjust the gap between it and the chain. This will make it possible to create boards of different thicknesses. It is worth purchasing a special chain for longitudinal sawing. It has a special tooth sharpening angle. A guide ruler can be made from metal profile the required length or a flat, rigid board.

Before starting work, you need to remove all the bark and remaining branches from the workpieces, and also carefully inspect the log for various flaws. This way, you can choose the most suitable cutting pattern and, therefore, reduce the amount of possible waste.

If you are longitudinally sawing trunks, you need to make sure that the resulting lumber is of the same density across the entire width. Since the density of wood from the northern part of the log is much higher than from the southern part, the cut is carried out in a plane directed from east to west (or in the reverse order).

The first step is to remove the slabs from two opposite edges of the log. As a result, a double-edged beam will be obtained, which is then cut into boards or other lumber of equal thickness, according to the intended sawing pattern. The final product is an unedged board, from which the edges must then be removed.

For many centuries, timber has been the most popular raw material for housing construction. Today, primitive processing methods have been replaced by modern equipment. For example, to cut timber and process it to the required size, craftsmen use a sawmill. The disadvantage of such a machine is the cost. For this reason, many people make mini sawmills based on chainsaws.

All photos from the article

Sawn logs are boards. The task of competent and efficient sawing of trunks is extremely important when logging independently or industrially; in addition, knowledge of 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 into band sawmill.

Log sawing

The main task

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

Sawing tool

Logging is carried out using 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: disk and belt. Disk use circular saws and are considered less effective, since they have a larger cutting thickness (from 6 to 9 mm), less accuracy and depth.

The band sawmill is equipped with a different system: the saw is a band mounted on rotating rollers. The cutting thickness is approximately 1.5 – 3 mm, which is quite economical in terms of waste to chips.

Modern models are different high accuracy and work productivity, they are automated and have a tilting mechanism for lifting and turning logs in the 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 cut the log into boards right in the forest.

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

Conclusion

Sawing logs is considered one of the most difficult and important tasks in logging and lumber production. The quality of the product and the income of the enterprise depend on the chosen scheme, well-designed work order and preparation of the tool.

The video in this article will tell you about the types of sawmills and methods of cutting wood.

For a small forestry industry specializing in sawing wood into boards and beams, the optimal equipment for use is. It has good productivity and allows large-sized trunks to be cut into lumber. But in order for the equipment to work to its full potential during the work, you need to know how to saw on a band sawmill. Taking into account certain recommendations and operating features of such a unit will allow you to avoid problems and obtain high-quality business material as a result.

The process of sawing timber with this sawmill comes down to the fact that the log is placed and fixed on a special frame, which also acts as a guide. The frame with the cutting tool, driven by an electric motor or internal combustion engine.

Preparatory stage

One of the main conditions for normal operation equipment is to carry out preparatory work before sawing on a band sawmill. And they include:

• cleaning the sawn log from dirt and sand;
• wood assessment (species, humidity);
• selection of a saw (shape, profile, tooth sharpening angles) depending on the material being cut;
• correct performance of adjustment work (tensioning of the cutting element, drive belts).

Proper preparatory work will allow you to quickly cut wood with the proper quality.

An important factor for normal sawing is correct sharpening and saw wiring. These works should be performed only on special machines. A well-sharpened saw with a correctly selected tooth profile will provide high speed work and cleanliness of the cut.

Attention should also be paid to adjusting the cutting blade. A properly tensioned tape will ensure an even cut. Any violation of the tension will lead to “waviness” of the surface of the boards, or to tearing of the cutting tool.

The more sand and dirt there is on the wood, the faster the saw will become dull, which will greatly affect the performance of the equipment. Therefore, it is better to prepare the material before sawing, and also sharpen and set the cutting tool in a timely manner.

Sawing process

During the sawing process, it is important to ensure a uniform speed of movement of the frame along the log. This will eliminate the possibility of idle belt movement and ensure maximum productivity.

Before sawing wood with a high resin content on a band saw, care should be taken to ensure the supply of water or cleaning solution to the cutting area. This will prevent the teeth from sticking and ensure good speed sawed.

After each pass, you should evaluate the quality of the cut and make sure there is no “waviness”, and only then cut the log further. This will allow you to immediately identify problems with equipment setup and eliminate them in a timely manner.

Periodically it is necessary to clean the moving elements of the sawmill from sawdust. This will eliminate unnecessary vibrations during operation of the unit, which can affect the quality of sawing, and will also extend the service life of the units.

In general, sawing on a band sawmill is not difficult; the main thing is to fully adhere to the manufacturer’s recommendations regarding operation. Don't neglect preparatory work, because the performance of the unit directly depends on them.

To process logs on a band sawmill, it is necessary to adhere to the accepted technology. In this way you can get the maximum amount quality materials- boards and timber. But first you should familiarize yourself with the basic cutting rules.

Types of wood cutting

At the first stage, a carriage is formed from a log. To do this, cuts are made on both sides of it. In some cases, processing is performed on four sides. A map of the band cut of the workpiece is first drawn up, on which the dimensions of the components are indicated.

The determining parameter when choosing a scheme is the direction of processing of the log. In particular, the movement of the cutting edge relative to the annual rings. According to this, lumber of various qualities is formed, with a unique appearance. Not only their aesthetic qualities, but also their price depend on this.

The following types of cuts are distinguished:

• tangential. The cut is made tangentially to the annual rings. As a result, oblong patterns in the form of arches and rings are formed on the surface;
• radial. To perform it, perpendicular processing along the annual rings is necessary. A special feature is the uniform pattern;
• transverse. Processing occurs across the fibers, the cut pattern is an even cut of annual rings;
• rustic. Can be made at any angle, contains a certain number of knots, sapwood or other similar defects.

The woodworking industry often uses waste band sawing logs - slab. On one side there is a flat plane, and the other remains unprocessed.

To create the most accurate cutting, it is recommended to use special programs. They take into account not only the dimensions of the source material, but also the type of wood.

Sawing on a sawmill with log rotation 180°

To form the maximum number of boards, it is recommended to use a technology in which some belt processing processes are rotated 180°. This allows you to achieve the maximum amount of lumber with various types cuts.

The principle of processing is to make initial cuts along the edges of the log, located at an angle of 90° relative to each other. They will serve as the basis for further tape cutting. The work is carried out on equipment with a vertical arrangement of cutting elements. The diameter of the trunk must be at least 26 centimeters.

Step-by-step order of work.

1. Processing the side with the cut-off edge. The result is two boards.
2. Rotate the workpiece by 90°. The cut is made from the opposite part. The number of products varies from 3 to 4.
3. Repeated turn 90°. The main part of the source material is processed. Depending on what you plan, you may end up with 7-8 pieces.

Despite all my positive traits, this method has one significant drawback - low production speed. It is recommended to use it on equipment that has a block for automatically changing the position of the log relative to the cutting part of the machine.

The detailed diagram is most often used for the production of rustic boards, which have lower quality requirements.

Sawing on a sawmill with log rotation 90°

For the manufacture of tangential and radial boards, it is recommended to use a different technique. It consists of systematic strip processing of logs with simultaneous analysis of defects. In this way, products of the required quality can be obtained.

After delimbing, the workpiece is placed on the feed bed of the sawing machine. Then you need to complete the following steps.

1. Removing the primary slab. This is carried out until the width of the base is 110-115 mm.
2. I'll eat unedged boards about 28 mm thick.
3. If the number of defects on the surface exceeds the required level, the material is rotated 90°. If the quality of the board is sufficiently high, the next one is cut.
4. Repeating the operation.

A similar technique is applicable for processing units that have one cutting surface or have the function of temporarily dismantling the rest.

If there is a sufficiently large number of defects, you can not put the workpiece aside, but rather process it by turning it 180°.

The above-described tape processing technique can be applied to create any configurations wooden products. Often the core area is used to form timber, and the remaining parts are used to make boards. But there may be exceptions - it all depends on the required shape of the blanks.

The quality of work is affected by the current state of the sawmill, the level of sharpening of the saws and the processing speed. These factors must be taken into account before starting production process. If necessary, preventive maintenance or repair of equipment is carried out.

The video shows the technique of sawing logs on a homemade band sawmill:

Choose the right coolant
Numerous experiments conducted by American researchers led them to the conclusion that it is wrong to use water as a lubricant when operating band saws. There is no need to use lubricant at all until the sawdust begins to “roll” onto the saw. If this happens, the optimal lubricant should be used: a mixture of 50% diesel fuel and 50% oil for lubricating chainsaw tires.
This mixture should be sprayed evenly on both sides of the band saw blade. Moreover, in in this case Ordinary car glass cleaners work excellently. There should not be a lot of cooling solution; the operator will easily notice by the characteristic sound when it is time to “cool down”.
Using such a lubricant instead of water will also allow you to reduce the number of bloomed boards and extend the life of the belts on the drive pulleys of the sawmill, since they will no longer “go limp” from sawdust and water falling on them.
Relieve tension from the band saw as soon as you stop cutting.
During the process of sawing wood, the blade heats up, and therefore stretches and increases in length. As they cool, the saws tend to shrink back to their original size. This is where overloads appear, in other words, excess voltage. The blade also “records in memory” the shape of both pulleys of the sawmill, which also does not make its life carefree long. Add to this the inevitable deformation of the belts on the pulleys, which leads to additional vibration of the blade, as well as the “hump” on the belt that becomes wrinkled over time, which ensures self-centering of the saw on the pulleys.
Band saws - correct wiring
The layout can be considered optimal when there is a mixture of 65-70% sawdust and 30-35% air between the cutting blade and the wood being processed. The ejection of 80-85% of sawdust from the cut indicates that your saw is set correctly.
If the saw spread is too large, it will remain on the cut. a large number of loose sawdust, and most likely, characteristic nicks and scratches will remain on the surface of the board.
With a small saw spread, tightly compressed, hot sawdust remains on the surface of the board. You simply can’t imagine anything worse for a saw. The sawdust should be warm to the touch, not hot or cold.
A saw that is set too far will most likely work jerkily, and a saw that is not set too far will leave “waves” on the board.
Example. When sawing a log with a diameter of 30 cm at a good feed, everything goes like clockwork. Don’t think that everything will work out just as well for you with a log with a diameter of 60 cm, because now you need to remove twice as much sawdust from the cut. Right! Divorce should be increased (by approximately 20%). Therefore, in addition to other recommendations, we allow ourselves the following: before sawing, you should sort the logs by diameter.
Remember that only the upper third of the tooth should be separated, and in no case under the “root”. After all, only the sharp corner at the very top of the tooth should participate in the sawing process. Don't forget also that softer wood, which you saw, the larger the divorce should be.
And, of course, the sequence of operations is extremely important: the blade is sharpened after setting, and not vice versa. Sharpening will remove 0.002-0.003 inches, so this should be taken into account when setting.
And finally, never turn off your intuition; formulas will not help here.
The importance of regularly checking the adjuster indicator
Do not forget about such a device on your adjustable device as an indicator. It doesn't cost anything to reset it. It works in an extremely intense mode, judge for yourself: your saw has approximately 220 teeth, you sharpen the saw 15 times, it turns out that during the life of the saw the indicator is triggered 3.5 thousand times. The indicator wears out over time, so you should check its installation more often.
Band saws - tooth shape
If the thought has occurred to you that the saw will work perfectly regardless of what shape the tooth has, drive that thought away. The tooth shape has been developed and verified over the years. Why would you try to reinvent the wheel?
Practical advice: when you go to buy linen again, ask for a piece of linen about 30 centimeters, make a hole in it and chain it to sharpening machine. Here is a standard by which you can copy the shape of a tooth!
Some problems encountered during work band saws problems and ways to solve them
When entering the wood, the saw “jumped up”, and then it worked smoothly until the end of the log, after which it fell down. This is the so-called “squeezing” or “squeezing”, that is, when the saw is wrung out. Most likely, the reason is that the tooth sharpening angle is too large. Try decreasing the angle by 2 degrees.
When entering the wood, the saw went up. The result is a board curved like a saber. The reason is that the sharpening angle of the tooth is too large with insufficient setting. Try decreasing the tooth angle by 2 degrees, and increasing the set point by 0.002-0.003 inches per side.
The saw dives and then goes straight. This behavior is due to several reasons, for example, the cutting blade has become dull. However, most likely the sharpening angle is small, or maybe the sharpener simply did not set the stone in time. Look at the blade carefully; if the shape of the tooth seems ideal to you, then you should increase the sharpening angle by 2 degrees.
The saw “dives”, and the resulting board is curved, like a saber. The sharpening angle is small and at the same time the setting is insufficient. You should increase the sharpening angle by 2 degrees and increase the spread by 0.002-0.003 inches per side.
There is too much sawdust left on the board that feels loose to the touch. The divorce is too big. If you look closely, you can see characteristic scratches across the board. Divorce should be reduced.
The sawdust on the board is compressed and hot to the touch. Divorce is not enough. Should be increased.
Wave-shaped cut. If the saw is sharp, then this is due to too small a gap, you should increase the gap by 0.006-0.008 inches per side. Remember, working with an undone saw is the most serious violation of technology, leading to blade breakage!
The fabric is cracking at the trailing edge. This is due to the fact that the rear stops of the guide rollers are too far from the rear edge of the web. This distance should not exceed 0.3 mm.
Sawdust is “rolled” onto the saw blade. The gap is small and there is not enough air left in the cut, excessive friction on the sawdust occurs, which leads to heating and “baking” of wood dust on the metal. Increase the spread by 0.005 inches per side.
The sawdust “rolls” on the inner surface of the tooth, but this does not happen on the surface of the saw. Poor quality of sharpening (too high feed or too much metal removal, and, consequently, poor quality of the surface on the tooth cavity), or too high a sharpening angle of the tooth. Or they continued to saw with the blade after it had already become dull.
After regrinding, the blade becomes covered with cracks in the tooth socket. This is usually due to a change in tooth geometry. Compare the tooth geometry with the original one. Last but not least note. Many problems are caused by the sharpening stone not being refilled frequently and accurately enough.
If you consider the recommendations mentioned above to be unimportant, you may not adhere to them. Remember, no matter how perfect the machine you purchase, it remains a device for “running” saw blade through wood. 90% of the result depends on the correct maintenance of the band saw and only 10% on the overall setting of the machine!

Myths and reality of band sawing

Part 4.1
Setting the teeth of band saws
Any timber merchant planning to purchase a sawmill naturally hopes to make a profit. But you need to remember that for stable operation of a sawmill it is necessary to prepare saws with high quality. Moreover, this will have to be done almost daily. In previous articles, we talked about setting up the process of preparing band saws, about a new method of sharpening saws, and also started talking about one of the most difficult processes in preparing saws for work - the process of setting the teeth. In this post we will talk more about this process.
Work on band saw machines, or, as they are more often called, band sawmills, however, like on any other equipment, consists of two main parts - organizational and technical. Many people neglect the first part, in vain thinking that all organizational issues can be resolved directly in the process of work. The result of such neglect is a barely breathing or closed production. In this article I will try to describe the problems that should be solved before purchasing equipment.
We are often asked: which band sawmill and which configuration is best for sawing? It seems to many that our wealth of experience in communicating with hundreds of sawmill owners and with almost all of their manufacturers, knowledge of the problems they face every day, will help give an accurate answer to this “simple” question. In fact, in the list of questions about sawing, this, although very important, question should be at the top. last place. Those who first bought a sawmill and only then thought about how to properly organize work on it, usually organized this very work for a very long time, and some were not able to organize production at all in order to receive 500-1,000, and not 50-100 rubles per sawn cubic meter of lumber. Moreover, most often they blame all the failures on the fact that they bought the wrong sawmill.
In order to make a good profit when cutting sawlogs with narrow (27-60 mm wide) band saws, you first need to solve several basic issues. Moreover, without solving at least one of the issues listed below, it is better not to take on such sawing at all, because otherwise you will get a lot of problems and a complete headache.
1. It is imperative to work independently as a machinist and sharpener at an operating sawmill. Just work for 1-2 weeks, and not look at work for 1-2 hours. If you don't do this, you will never be able to understand the intricacies of production. As a result, machinists and sharpeners will give many reasons why they cannot work better, and you will not be able to correctly assess the correctness of their arguments, which means you are unlikely to get the maximum profit.
2. Will you be able to be in production almost every day for 10-12 hours for at least the first year in order to control and debug the entire work process? Don’t think that you can entrust this to your partner or, especially, to a hired master. Unfortunately, a partner can rarely be trusted, and any hired craftsmen most often deceive entrepreneurs. I know more than one example where hired craftsmen live very well in poorly functioning industries without constant control of the owners.
3. It is necessary to decide how the sawlog will be cut:
a) to order, cutting the required sizes of lumber from the sawlog, that is, non-optimally, each time losing 10-15% of the possible output volume, saving a little on warehouse costs;
b) with optimal cutting of each log, obtaining the maximum yield of lumber, but at the same time partially sending the finished product to the warehouse, with a delay in the sale of slow-moving sizes, that is, with a slight freezing in time working capital, although in the end with greater profits.
4. At first, will you independently cut sawn logs with the optimal yield of lumber and train your assistant to work in this way so that you can then replace you, or do you already have an experienced machinist who will immediately work perfectly, and not just “drive cubes.” Almost all machinists are paid for the sawn cubic meters of lumber, and not for the edged lumber obtained from this lumber. Therefore, it is more profitable for them to quickly cut thick boards, timber and take another log. Large slabs and large parts usually go to waste when cutting an unedged board. And this is lost profit. Depending on how well the production is organized, the percentage of finished products can range from 50 to 75%.
5. Decide how machinists will receive saws:
a) you will simply issue them as needed, that is, the drivers will not be interested in long work saws and will be able to calmly tear them one after another, and you will only listen to their complaints that the framer does not know how to saw, and the sharpener sharpens the saws incorrectly, and count your losses;
b) interest everyone in caring for the saw and sawmill.
Here's an example. Payment to workers is calculated as follows: for cutting 1 m³ of lumber, the driver receives 76 rubles, two assistants - 62 rubles each. Only 200 rub. This includes the cost of a band saw based on cutting 40 cubic meters of lumber with one saw. If the saw cuts more before it breaks, the earnings are correspondingly higher. They began to cut more than 100 cubic meters with a saw. The only clarification: sawing is carried out with bimetallic saws. Deducted for a torn saw: from the driver - 450 rubles, from each assistant - 200 rubles. Only 850 rub. If the saw breaks on a nail, a new one is issued free of charge. The sharpener receives an average salary (if he serves several sawmills) from all machinists. Thus, they all have an interest in keeping their saws running for as long as possible. And now no one needs to monitor them.
Machinists monitor the operation of the sawmill more closely, since even small misalignments (beating of the pulleys, saw walking on the pulleys, changes in correct settings guide rollers, uneven supply of coolant, grinding of cleaning scrapers, etc.) lead, in addition to the formation of waves on lumber, to accelerated rupture of the saw, which is very disadvantageous for them. And any malfunction is easiest to eliminate at the beginning - there will be less defects, and subsequent possible large repair downtimes are practically eliminated. To avoid large waste, you can use various systems fines. As practice shows, drivers who have been fined once or twice cut much more competently. But all this works only when there are several teams and the driver, in extreme cases, can be replaced by an assistant. When the driver works alone, it is very difficult to cope with him.
6. Find a good mechanic in advance, that is, a person who will debug the operation of the sawmill and will constantly monitor it, maintaining it in good condition.
7. Solve the problem of the band saw preparation area, taking into account that any sawmill is only a device for pulling saws with a set of service functions. The quality of the lumber obtained during sawing (dimensional accuracy, straightness (without waves) of the surface) and the productivity of the sawmill (the amount of lumber sawn per unit of time, that is, the actual profit) depend almost entirely (with an adjusted sawmill) on the correct daily preparation of saws . There are two options:
a) find in advance a highly qualified sharpener who can try (most often unsuccessfully) to prepare saws daily using inexpensive, low-quality and outdated sharpening and setting machines. The result of such preparation is quickly torn saws, low-quality lumber (waves on the surface), low productivity;
b) you can buy right away, by paying a little more, good sharpening and setting machines, on which almost anyone can prepare saws with high quality every day and carry out sawing with maximum profit for themselves. How to choose the right sharpening and setting machines was described in previous issues of the magazine.
8. Decide how the sawing process will be organized:
a) with minimal costs, but also with minimal profit: sawing is carried out by one driver and one assistant, the saw unit works only 20-25% of the working time, the rest of the time is spent on feeding the log, preparing it for sawing (leveling, turning, etc.) and removing the finished product lumber;
b) with slightly higher costs, but in the end (due to increased productivity) an increase in real profits - the most common option. Sawing is carried out by one driver and two assistants, the saw unit is already working 25-35% of the working time;
c) with the highest possible productivity at minimal initial costs. Sawing is carried out by one driver with two assistants, but at the same time an additional 6-meter section is docked to the main rail track. Two logs are laid sequentially. Now, when one log is being sawed, the assistants make necessary operations with another. The saw unit operates 35-50% of the working time.
9. Decide which market you want to work in:
a) internal;
b) external.
When working for the domestic market, the productivity of the sawmill, due to a possible increase in the feed of the saw unit, can be 10-15% higher. The resulting small deviations of nominal sizes or a small wave on the surface are not of fundamental importance.
10. Decide what you want to cut at the sawmill:
a) sawing is not very fast, but very high quality ( furniture panels, valuable species of wood, etc.), sawn logs of mostly large (more than 40 cm) diameters;
b) cut mainly sawlogs with a diameter of up to 40 cm into edged lumber.
When working according to option a) you will need additional hydraulic or electromechanical devices, an electronic ruler, and an automatic return of the saw unit.
When working on option b) it is worth seriously considering how necessary these systems are. With all due respect to such systems, they improve working conditions at the sawmill, reducing its actual productivity by 10-20%, and they also constantly break down.
An experienced driver will tune in much faster than electronics. right size(the up and down movement control of the saw unit must be electromechanical) and will return the saw unit back after cutting. I know many who started working with these electronic units, but then they were simply turned off so as not to interfere. Two assistants perform all operations with a log much faster than hydraulics or electromechanics, and even when actually working with logs with a diameter of 25-35 cm they practically do not get tired. It is only necessary that the stops are not screw, but eccentric. Do you agree to such productivity losses, especially since the installation of these systems, as a rule, doubles the cost of the sawmill?
11. Decide what actual diameters of saw logs you will cut:
a) mostly diameters greater than 40 cm - when sawing such sawlogs, you need a sawmill with pulleys of at least 600 mm, allowing you to work with a band saw up to 60 mm wide and a saw length of more than 6 m;
b) more than 90% will have diameters less than 40 cm - it’s worth thinking about whether you need to overpay significantly for the opportunity to cut three to five large logs per month. In extreme cases, they can be sawn in circles. With pulley diameters of 520-560 mm, the cost of a sawmill is usually up to 30% less. When cutting with a saw 32-40 mm wide and 4-4.5 m long, while obtaining the same quality of lumber and the productivity of the sawmill, you will not constantly overpay almost one and a half times for the width and length of the band saw with almost the same cutting of each cubic meter of sawlog before breaking.
12. Decide if you need a debarker. In my opinion, this is really not the most expensive, but very useful device, since it allows the band saw to work much longer before it becomes dull, especially if cutting a dirty log.
13. Decide if you need a laser pointer. Also very convenient device, as it allows assistants to position the log faster and more accurately, thereby increasing the productivity of the sawmill and reducing waste, which often increases with suboptimal cuts.
Only when you have resolved all the issues listed above can you begin to choose a specific sawmill with the necessary equipment. Let's go back to the original to the question asked. So, which band sawmill is better than others: it breaks less, cuts efficiently and is not very expensive? The paradox is that I cannot answer this question. Almost all manufacturers existing today have been producing sawmills for 10-15 years or more. Rich experience has allowed the designers of these industries to develop and produce very good new modifications of sawmills, which in terms of parameters are practically not inferior to foreign analogues, and at a price that is an order of magnitude lower. You can get real profits much faster by building your production on the basis of Russian sawmills. But the problem with all our productions is that our manufacturers could always develop and produce a prototype and show a polished model at exhibitions, and receive diplomas for these design works. But, unfortunately, almost no one can constantly produce high-quality products. Making a high-quality weld, manufacturing components for precise compliance with all necessary parallelisms and perpendicularities only in special conductors, the concept of tolerances when connecting components of 0.01 mm or 0.1°, high-quality electrical wiring connections and much more, that is, everything that can be called in one capacious expression - production culture is still an almost impossible requirement for many of our manufacturers. Therefore, when purchasing a sawmill from a Russian, Belarusian, or Ukrainian manufacturer, you must always remember that you are buying a construction set that you will assemble and bring to a greater or lesser extent to normal condition the first 1-3 months. There's nothing scary here. It’s just that at the initial stage you definitely need either good personal experience or the presence of a competent mechanic. But then these sawmills will work no worse than imported ones, and the money saved can be used in the form of working capital or used to purchase additional equipment.
They talk and write a lot about the low productivity of sawing sawn logs with band sawmills operating narrow saws 27-60 mm wide.
As a guide, I will give the following figures: with a well-functioning sawmill, high-quality preparation of the saw and organization of the sawing process according to option 8b, the average yield of edged lumber should be 1 m³ per hour with a real yield of 70-75% of the finished product from the log. With proper organization of production, working in several shifts, it is realistic to receive 400-600 m³ of finished edged lumber per month from only one sawmill.
Now, if you independently calculate all the initial costs, productivity, and the actual output of finished products from one log, you can be convinced that sawing up to 3 thousand m³ of sawn logs per month with band sawmills operating narrow saws 27-60 mm wide will be the most economically feasible compared to all other cutting methods.
I’m sure all the talk is about the inability to work productively and get lumber good quality sawmills of this type are operated by those who simply failed to properly organize the work of their production.

How to work correctly on band sawmills

Advice from professionals
1. GENERAL INFORMATION ABOUT THE MACHINE
The horizontal band saw machine is used for sawing wood of any hardness into boards, beams, and slats. Sawing occurs by moving the saw frame with the 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 quality surfaces made of material
get 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 capable of sawing short workpieces (from 1.0 meters) and producing products up to 2 millimeters thick.
The band sawmill operates under UHL 4 conditions (GOST 15150-69). The band sawmill is equipped with an electromechanical saw unit lift.
2. “Band sawmills” - operation and design:
2.1 Main components and parts of the band sawmill:
A bed that moves along rail guides in a horizontal direction;
Saw frame;
Saw frame lifting mechanism;
Electrical cabinet;
Log clamp;
Movable slider of the driven pulley;
Drive pulley;
Driven pulley;
V-belt drive;
Rail guides for band sawmill;
Band saw tensioning mechanism;
Band saw mounting connector;
Band sawmill pulley housing
Coolant reservoir
Fixed saw guide
Saw guide is movable
The bed 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 saw frame is lifted by two sliders located on the bed posts. 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 located parallel and connected to each other. The driving saw pulley is fixedly fixed on one end of the frame, and the driven one, which has the ability to move longitudinally, is fixed on the other. The saw blade of the band sawmill is tensioned by a spring-screw mechanism, the spring dampens the thermal expansion of the saw band. When making a band sawmill, the tension is calibrated for a saw 35 centimeters wide. The risks on the tensioner body and washer are equal to a 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 blade. On the brackets located in the middle of the frame there are two band saw guides (movable and fixed), which are equipped with support rollers and an adjustment system and bar. Torque is transmitted from the sawmill engine to the drive pulley by a V-belt drive. The coolant reservoir is mounted on top of the saw blade protection. The liquid supply is regulated by taps located on the tank. The control panel for the band sawmill is located on the top crossbar of the machine.
The guides are collapsible from 3 sections, which is convenient for transportation. At the bottom there are support plates into which the anchor bolts. On top of the guides of the band sawmill there are log supports. The log is fixed on the rail guides with four screw clamps and a stop that provides 90 degrees.
3. ADJUSTING THE SAW PULLEYS
3.1. The machine provides for adjustment of the position of both pulleys in relation 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/mm2. in cross-section, one branch did not come off the rims of the saw pulleys.
3.2. First of all, the pulleys are adjusted in the vertical plane, setting them at right angles to the saw frame. To do this, on the slider of the driven pulley, a bolt Ml0 is screwed from below to its axis, and on the drive pulley, adjustment is carried out by installing spacer washers or plates. This operation is carried out by the manufacturer.
3.3 To regulate the position of the horizontal plane saw pulleys, two bolts Ml2 are screwed into the ends of the frame from the side of the driving pulley, and one bolt is screwed into 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 power supply circuit breaker on the control panel.
3.3.2 Open the protective covers of the saw pulleys.
3.3.3 Place the band saw on the pulleys so that it protrudes beyond the edges of the pulleys by the height of the tooth plus 2-5 mm.
3.3.4 Close the movable connectors (locks).
3.3.5 Tension the band saw by turning the tension mechanism nut to the optimal value for this type of band saw (at the rate of 6-8 kg/mm2).
3.3.6. By rotating the driven pulley with your hand as you cut (counterclockwise), you need to see what position the band saw will take on the pulleys. If the belt runs outward by an equal amount from both pulleys, then, without weakening the tension of the saw, release the lock nut Ml6, which secures the axis of the driven pulley to the saw frame (saw frame slide).
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 M16 lock nut.
3.3.8 Repeat point 3.3.6 and if the tape runs out, repeat the adjustment until the correct result is obtained.
3.3.9 If the tape runs inward by an even amount, then it is necessary to loosen the tension of the band saw.
3.3.10. Loosen the lock nut Ml6, the lock nut M12 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 has been performed correctly.
3.3.12 If the band saw immediately runs away from the drive pulley when rotating, then adjustment should begin with it.
3.3.13 To do this, depending on the direction of the belt running (outward or inward), loosen the left or right lock nuts Ml6 and make adjustments 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 housings.
3.3.16 Turn on the automatic power supply. energy on the control panel.
3.3.17 Briefly turn on the drive of the saw pulleys and make sure that the saw blade is in the correct position. The machine is ready for use.
4. REQUIREMENTS FOR SAW BLADES
1. During the operation of the band sawmill, 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 using a “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 freely for at least 24 hours to relieve fatigue stress.
2 Use the correct lubricant for the band saw blade.
In most cases, simply water or water with the addition of detergent(“Fairy”, etc.). However, when low temperatures It is best to use a mixture of 50%-80% diesel fuel or kerosene and 50%-20% motor oil or oil for lubricating chainsaw tires. Good results when sawing coniferous species The use of turpentine also gives.
If water is used as a coolant, it is necessary to wipe the pulleys and belt with oil after completion of work.
3. Always loosen the band saw tension.
When you are finished, release the tension from the saw. During operation, the blades heat up and stretch, and then as they cool, they contract by tenths of a millimeter during each cooling period.” Therefore, belts left on pulleys under load overload themselves and develop an imprint from the two pulleys, which causes cracks to appear in the spaces between the teeth.
4. Use correct tooth set.
The alignment is correct if in the space between the saw blade and the wood being processed you have 65-70% sawdust and 30-35% air. If your tooth set is too wide for the weight or thickness of the wood available, there will be too much air and not enough sawdust in the cut. You will have excessively large losses due to sawdust, and as a result, greater roughness of the processed wood. If the clearance is insufficient, you will not get a strong enough air flow to remove sawdust from the cut. A sign of this is hot sawdust. This can cause the most devastating damage to the saw: operating intervals will be short and the saw will fail prematurely. The sawdust should be cool to the touch. And finally, if the cut is insufficient and the sharpening angle is incorrect, the saw will cut a wave on the board. From our point of view, you cannot work with logs of different diameters, timber and beams using the same tooth set.
You must sort the timber.
For every 20-25 centimeters increase in size, it is necessary to increase the wiring by approximately 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 test cuts on a specific log. Increase the setting by 5-8 hundredths of a millimeter on each side until tooth marks become visible. This means that you are working with a 50/50 mixture of air and sawdust. After this, reduce the tooth set by 8-10 hundredths on each side, and you will achieve desired result. Please note: You should only spread the top eighth of the tooth, not the middle or bottom. You don't want the gap between the teeth to be completely filled when sawing. When you work with softwood, whether wet or dry, the chips expand in volume to 4-7 times their cellular state. Hardwoods, wet or dry, only expand 1/2 to 3 times in volume. This means that if you are sawing 45cm pine logs, you will need to set the teeth 20% wider than when cutting 45cm oak logs. Always space your teeth before sharpening.
5. Sharpen your saw correctly.
There is only one way to sharpen band saw blades. The stone should go down the surface of the tooth, around the base of the cavity between the teeth and up along reverse side tooth in one continuous movement.
You must maintain the profile of the tooth and interdental cavity.
The space between the teeth (gallette) is not a sawdust bin. The power flow of air, cooling of steel and removal of sawdust depend on it.
If you have the correct teeth set, air is supplied along the log at the same speed as the saw, as a result of which sawdust is sucked into the gallet. The sawdust cools it significantly 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 operating time of the saw.
6. Set the correct sharpening angle.
Thanks to the deep gallets, we can use reduced sharpening angles, which transfer less heat to the tip of the tooth. The tape series uses a 10 degree hook angle that is capable of penetrating 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 sharpening machine!
The pins and guides on it wear out. During the work process, the profile of the stone changes.
To check the correct sharpening angles, use a protractor. Attention; We recommend changing saws every two hours of continuous operation, allowing them to rest for at least a day.
During the operation of the machine, there is a need to regulate individual components in order to restore their normal operation.