Chainsaws: basic principle of operation, a number of additional functions
The technical characteristics of the product are directly related to the design of the tool and the basic principle of its operation. For example, the size and type of motor depends on the power, as well as the permissible dimensions of the saw headset. Here are the designs and materials used. weight. In general, the construction of a chainsaw consists of a motor, torque transmission mechanisms and a saw blade. A gearbox (transmission system) and a clutch system are connected between the engine and the chain. The saw blade is a bar with a chain placed on it. Since the engine of the chainsaw is a 2-stroke engine, it has 2 tanks. oil (for chain lubrication) and fuel (for the fuel mixture).
The operation of this tool proceeds as follows: when the user pulls the starter “string”. The crankshaft spins. In the event that there is a sufficient amount of fuel mixture in the tank, then at one of the revolutions the spark plug is triggered, after which. The spark ignites the mixture. She, Burning, gives off gases increasing in volume, which push the piston. The latter, in turn, is connected through a connecting rod to the crankshaft, which by inertia goes to the second revolution, thus continuing the process anew without the participation of external forces. In the process of starting the chainsaw, the engine begins to spin the drive sprocket. A saw blade is attached to it, and the chain, driven by an asterisk, begins to “walk” in the grooves of the tire. The chain is lubricated automatically when driving. At the end of the work, turning off the chainsaw, you can see that a certain amount of lubricating oil flows out of it. This is the unused oil remaining in the grooves.
First of all, the active use of this system is very necessary on professional models of chainsaws, because Long-term work with a powerful vibrating instrument is quite detrimental to the joints and can lead to serious consequences. The simplest version is a set of rubber gaskets located between the handles and the body. However, such an anti-vibration system is practically not used in modern devices. As a rule, the principle of “two masses” is implemented: the engine block separates from the handle block and the fuel tank.
Dependence of impacts of chain elements into the material: less step. Less layer removed in one pass, respectively, and the resistance of wood is also less. As a result, the vibration level will naturally decrease. In the absence of a normal anti-vibration system in a chainsaw, several years of working with it can lead to sad consequences, ranging from poor circulation in the hands and ending with more serious diseases. However, some household chainsaws are not equipped with an anti-vibration system. Its absence is explained, firstly, by the short period of use of such tools, and secondly, by the fact that they DO NOT develop high power and chains on them with a smaller step.
In the process of purchasing a chainsaw, buyers often wonder about the speed of sawing wood with a separate instance of a chain saw (for example, whether it is necessary to “press” on the entire tool during operation). We will answer you to the question posed: first of all, it depends on the condition of the saw headset and, in particular, on the chain itself. When working with a blunt chain Not only will the sawing efficiency be low, but the likelihood of the saw breaking out increases, since the load on the engine increases significantly. Therefore, during intensive use, it is recommended to regularly “correct” the chain (for example, at the end of the working day). In addition, such indicators as the shape of the cutting tooth and the pitch of the chain make a significant contribution to productivity.
The main purpose of the air filter installed in chainsaws is to keep dust, sawdust and other small particles from unwanted entry into the engine or chassis. The protection system in this case is presented in a two-part form: the first barrier will be the impeller, fixed on the engine shaft, and the next. the air filter itself, nylon or Felt. This element retains most contaminants and is easy to clean or replace during maintenance. It can also be impregnated with special oils, which increase the coefficient of trapping microparticles and preventing their further “cementing”.
This function is a direct necessity, proceeding from the peculiarities of the chainsaw operation: in case of a “kickback” or accidental breaking of the chain, irreparable harm can be caused to the operator. Therefore, the best option in this case is to stop the chain. It occurs through a mechanism that is activated by the chainsaw flap. If the sawfly’s hand rests against it, then by means of the lever the force is transferred to the brake and the chain is blocked. This can happen automatically.
What other chainsaw classifications exist?
Chain with a pitch of 0.325 is used for household, semi-professional and low-power chainsaws.
The thickness of the chain saw is an important parameter for the quality of the tool. The grooves on the saw bar differ in width. There are five sizes that characterize the ponytail:
- 1.1 mm. Used on low power saws.
- 1.3 mm. Most often it is also used on low-power chainsaws.
- 1.5 mm. This thickness is widely used on semi-professional saws.
- 1.6 mm. Chains with this link thickness are also used on semi-professional machines.
- 2 mm. Chains of this thickness are used on chainsaws that operate under high shock loads.
I also follow the chain, taking into account the depth of its cut. Depending on the height of the profile, the depth of cut will change and, accordingly, the productivity of the tool. There are 2 types of profile:
- 0.635 mm.
- 0.762 mm.
Saw chain structure
Both profiles are used on semi-professional, household and professional chainsaws. As a rule, the tool passport should indicate which chain profile is right for your dust.
If you are using professional or semi-professional chainsaws. you should know what the cutting links can be. They are of 2 types:
The first type is commonly called the “seven”. The chisel profile is considered the best for use on powerful chainsaws, as the entire cutting edge is straight and able to provide good penetration into the wood. However, this profile has several disadvantages. The first of them is the difficulty of sharpening, since even with a slight deviation from the given angle, the profile will be unsuitable for work. Another significant disadvantage is the sensitivity of the chisel to dirt and sand.
The chipper type has a completely different shape from the chisel. This sectional profile resembles a sickle. It is no secret that the contact area of a chipper link is much smaller than that of a chisel one. As a result, working with it impairs the cutting ability of the chainsaw. However, operating the chipper cutter unit has its advantages. For example, it is easier to sharpen and is immune to dirt.
Most often saws are used for cross-cutting, and for longitudinal cuts it is more rational to use circular saws.
In order to find a suitable chain saw, it is worth Paying attention to the sequence of the chain links. As a rule, at least one cutting link should have two tails. However, these days you can easily find chains on which the number of links to cut is less. They come with a half-pass and a space. In the first type, at least one connecting link is inserted through each cutting tooth. In semi-skid chains, the cutting link is located between each cutting tooth.
During the operation of the chainsaw, do not neglect the sharpening of the chain. It can be produced both manually and using special machines. If you are working with a professional chainsaw, it should be sharpened at least once every 2-3 months.
You should also pay attention to the bus parameters.
How to choose a chain for a chainsaw?
Any professional knows that a quality chainsaw chain will help to achieve high cutting parameters.
The chain is the most important part of any chainsaw. It is she who takes most of the loads, and therefore wears out faster.
The first criterion that indicates strong wear is stretching. As a rule, the chain will wear out several times faster than the tire and drive sprocket. Be sure to pay attention to the type of chips. If the saw is working properly and is sharp enough, the sawdust will be the correct shape. And if the chips are small and have a large amount of wood dust, then the chain has become unusable or urgently needs sharpening.
What is the marking of saw chains by step?
The cutting link is the most complex of the saw chain elements and in fact consists of two parts. the cutting segment (with an L-shaped contour angle for cutting) and the cutting depth gauge.
The main parameter of marking is considered to be the step. It represents the distance between adjacent tool teeth. The steps are 0.325; 0.375; 0.404 in. Each of THESE types has its own purpose. The saw manual will usually indicate which chain is suitable for a particular tool. However, some semi-professional and professional saws can work with all types of chains at once.
- The chain for chainsaws with a pitch of 0.325 is the most common. It is suitable for saws with low power density (0.325-3.5 HP) If you are using a chainsaw for cutting small knots, this type is best suited.
- The 0.375 pitch chain is less popular than the 0.325 chain. It is rational to use it on gasoline-powered tools with a power of 4 hp. This type of chain is appropriate if you are working with thin wood. For semi-professional dust, step 0.375 is recognized as the best.
- The 0.404 pitch chainsaw chain should only be used if you are working with powerful chainsaws. The power of the tool must be more than 5 HP. Chainsaws made for a 0.404 chain usually have increased torque.
As a rule of thumb, the smaller the track pitch, the lower the productivity. In addition, the pitch of the saw chain affects what is called “aggressiveness”. It implies ease of control during operation. Simply put, as the pitch increases, the saw chain cuts into the wood harder and begins to “tear” it. Therefore, the force that a person must exert must also increase. Even with an increase in the step, the dimensions of the links will increase. This will cause the cut to be wider. Therefore, we can conclude: chains with a large pitch are NOT suitable for low-power and household saws.
Do I need to pay attention to the way of cutting wood?
In order to choose the optimal tracking chain, you should pay attention to the way you cut the wood. It can be longitudinal and transverse. The first type should be used if the wood will be sprayed along the grain. A cross cut is used when the wood will be cut across the grain. It is no secret that the resistance of wood in THESE two cases will be different. Therefore, a different angle must be used for cross and longitudinal cuts. For a longitudinal cut, the angle should be from 5 to 20 degrees, for a transverse cut. 20-35 degrees.
Belt: pros and cons
The main advantages of belt drives:
- If the engine is equipped with a timing belt, then such a product will run much quieter. The driver can hear only one sound when the power unit is operating. a weak knock of valves.
- Ease of replacement compared to chain drive. If you prepare, you can change the belt yourself.
- Low service life of the drive in comparison with chain transmission. Long-term use will cause the strap to break, and this can lead to serious malfunctions. Eight-valve engines practically DO NOT suffer from breakages. In the case of motors equipped with 16 valves, the elements themselves may bend as a result of breakage. This will lead to the need for overhaul, the cost of which will be significantly higher than replacing the strap. Sometimes a reduction in resource and a broken belt leads to the formation of cracks on the head or the cylinder block itself. The only solution to the problem would be to install a new cylinder head, while the gasket also changes.
- The need to replace the tension roller with the belt. In some cases, car owners also need to change the water pump and washer kit. The service life of the strap is on average about 60 thousand km. But given the difficult conditions of use and the presence of defects in many spare parts, experts recommend changing the belt earlier.
What is the belt used for?
The timing belt is a part, the purpose of which is to perform the function of a connecting link.
Let us examine several examples of the translation of decryption on the timing belt:
- ISO-58111×19. The first two digits (58) encode a series of teeth used on the product. In this case, the step and profile will be without a groove, the shape is semicircular, and the height is 3.5 mm. Then there are three numbers (111), which indicate the number of teeth. By number 19, you can determine the width of the product. There are belts on sale, the teeth of which are made in the form of a rounded trapezoid.
- 58127х3 / 4 HSN. Here, the first two digits also indicate a series of teeth. The numbers 127 indicate their number, but it should be noted that in the straps belonging to the 40 series, this number is conditional. The 3/4 numbers represent the width of the product in inches. In this case, it is also 19 mm. The HSN mark at the very end indicates that the product is made of strong, highly saturated nitrile. This material has proven its durability. If there are such letters at the end, then the strap is made of neoprene rubber.
This parameter is a value in millimeters, although it is customary to write inches in the documentation. It is calculated by dividing by 2 the distance between the three rivets. It is from this characteristic that it is customary to divide the canvases into several main groups:
- A pitch of 0.25 inches (6.35 mm) is used in devices with a minimum power, which are suitable exclusively for summer cottages. Dimensional logs with such a cut will NOT work. Chains for chainsaws with this pitch are not very common.
- The following two groups, where a pitch of 0.325 and 0.375 inches (8.25 and 9.3 mm, respectively) is used, are the most common of all, since approximately 70% of all chainsaws that are produced in the world are in these groups. Accordingly, they can be used for most of the existing household tasks. But there is one little trick! Since it is quite easy to confuse the numbers 0.325 and 0.375, chains with a pitch of 0.375 are marked 3/8, that is, 3/8 inches.
- The latter group is in increments of 0.404 and 0.75 inches (10.26 and 19.05 mm) for the most demanding applications. In this case, we are already talking about a logging tool than in the dust for domestic use. That is, chains with such a step can only be found on professional chainsaws.
There is a direct relationship between the step size and the performance of the tool, but it must also be borne in mind that a large step requires a more powerful motor. The cutting quality of devices with a large pitch is still inferior to devices from the first three categories, since the teeth are located there more densely. For a power of 2.5 liters, a step of 0.325 mm is suitable, and on a more productive chainsaw, it is better to put a saw blade and a 3/8 mm chain, as this will help to reveal the potential of the saw to the fullest.
Chainsaw chains. How to choose? How it works?
The difference between professional lumberjacks and novices in this business is that the first ones understand exactly how to determine the quality of a chainsaw. It makes little sense to take into account the power of the device alone, since the configuration of the cutting element is of decisive importance. In the case of a chainsaw, this element is a chain, which consists of cutting, driving and connecting links. The cutting link includes a depth stop and the cutting part itself, the operation of which is somewhat similar to a plane, that is, the thickness of the chips depends on how much the upper edge is extended. The driving link takes over the function of rotating the chain along the groove and distributing the lubricant, and the connecting links are designed to connect the rest of the chain elements together. Their design always takes place at a strict angle, the same applies to the subsequent sharpening, since the slightest change in the angle in one direction or another will lead to the fact that the chainsaw will not work.
The first time such tools were used back in 1920, but then the teeth were flat and straight, which could not but affect the final result of cutting, and it was quite difficult to work with such a saw. A definite breakthrough in this area happened in 1947, when a fundamentally new type of chain teeth was introduced. the L-shape made it possible to spray the material much faster, in addition, the process of sharpening the teeth was simplified, so it is not surprising that the invention of Joseph Cox, which suggested idea, became a sales leader in a short time. If we consider our days, then almost the same version of the chainsaw has reached us, which is based on a chain system with a sickle-shaped cutting profile, for which the type of wood does not play a significant role.
How to determine a chain for ripping or cross cutting?
- For cross cutting, the chain sharpening angle is 30 degrees.
- For longitudinal sawing, the angle of sharpening of the saw chain is 10 degrees.
Stihl’s rip saw chain is PMX. For example, STIHL 63 PMX 50.
Oregon will have an R in the chain model index. Example: 73RD100R
The main types of links
If we consider the most common types of links, then these are chisel links, which can most often be found on professional equipment, and chippers, which are supplied to simple chainsaws. The first option in the section is a bit like the number 7, and this design allows you to work with the saw as quickly as possible, since the link sticks into the material evenly. Cutting is more accurate, but it is extremely difficult to sharpen such links at home, since the slightest deviation from the permissible angle negates all the advantages of this design. In the case of the chipper, there is a need to maintain strict angles, and such a link is also less afraid of contamination, although there is a higher load on the tool. For home operation, the second option is more suitable, especially if there are skills in sharpening the saw. As for the material, chrome-nickel steel is mainly used, although if it is necessary, if you need to work with a particularly strong material, carbide brazing can be put on the teeth, as evidenced by the markings on them.
Rip and cross saw chains. Drive link thickness
In this case, splitting into several main categories is also used in accordance with this parameter. These are thicknesses such as 1.1; 1.3; 1.5; 1.6; 2mm (0.043“, 0.050 ”, 0.058“, 0.063 ”, 0.080“). This characteristic, measured in inches, affects how smoothly the cutting blade will move while the saw is running.
- Chains with a pitch of 1.1 mm are used on low-power household chainsaws, as well as on chainsaws designed for figure cutting (carving).
- Chains with a pitch of 1.3 mm or more are common. For example, the famous chainsaw. Stihl MS 180 is equipped with chains with just such a pitch. Anyway, this is the most popular step.
- The pitch of 1.5 and 1.6 mm have chains that are intended for professional and “semi-professional” (farm “chainsaws.
- 2 mm. This step is found exclusively on chains installed on very productive and powerful chainsaws of the professional segment.
What to look for when choosing a saw chain ?
The key characteristics of a saw chain are its pitch, shank or drive link thickness, depth of cut and profile size, and chain length. The direction of the cut should also be taken into account. It is from THESE parameters that you need to build on when you buy a chain instead of a worn out one, or when you need to buy a chain for some special needs. In order not to be mistaken, you can look at the device’s passport, where the manufacturer indicates the main parameters of the saw. If we are talking about the initial purchase of a tool, then these parameters themselves must correspond to the purposes of using the chainsaw.
Such chains are much more expensive, and they have a special purpose. work with frozen wood or with contaminated material. In all other situations, the money will be spent in vain, since for simple wood it makes sense in carbide drinks comments.
Low profile and high profile chains
What you need to know about the chain profile height? It determines how deep the saw will cut. Based on this parameter, the saw can be either low or high profile, respectively, in the first case, the chips will be removed thinner, but the work will be somewhat slower, while in the second case the depth and productivity will be greater. For a low profile tool, a parameter of 0.635 mm is used, and for a high profile tool, 0.762 mm. If we consider specifically devices for household use, then they are always low-profile, while professional equipment can be produced in two versions. At the same time, in order to stabilize vibration, which inevitably occurs during operation, manufacturers make a balance between the profile height and the number of steps. For a small step, make a high profile, and vice versa. Failure to comply with this rule will lead to the fact that it will be impossible to work with the chainsaw for a long time, although the wood will be cut very quickly. This balance must be observed if there is an intention to sharpen at home, in all other situations it remains only to choose dust for home or for professional cutting.
A chainsaw is one of the most essential tools in any summer cottage, as well as in construction and in the woodworking industry. Whatever model is used, whatever the high quality of production, it remains unchanged. nothing is eternal. All types of Husqvarna chainsaws break down sooner or later and require repair, which is sometimes impossible without the use of spare parts.
The general device of the chainsaw
In order to choose the right parts for replacement or repair, you first need to navigate the main elements of the chainsaw. Devices on the market may differ in technical characteristics, but their mechanism is almost identical and consists of the following structural elements:
- Chain with tensioners.
By design, the chainsaw is considered a classic mechanism, driven by an internal combustion engine. A fairly simple device uses a single-cylinder two-stroke internal combustion engine. The gearbox replaces the single-stage transmission that drives the chain.