What is chain saw?
A chain saw or motor saw is a portable saw blade, on which a chain with a set of indentations is rotated on a metal guide bar.
Saws usually have a small single-cylinder gasoline engine, although some saws have an electric motor that draws power from a power cable or battery.
The chainsaw is a bit like a bicycle chain, with around 30 very sharp stainless steel alloy gears mounted at certain intervals.
Inside the engine, a piston inside the cylinder makes a reciprocating motion that forces the rod to move. The connecting rod makes the piston linear in rotation and rotates the crankshaft.
The crankshaft is connected to one of the chains on the chain by a centrifugal clutch, which eventually causes the chain to rotate. We recommend that you watch the following video.
How a motor saw turns gasoline into sawdust!
Scientifically, in a motor saw, the chemical energy in gasoline is converted to mechanical energy. This energy conversion can create work. In this process, the energy of noise, heat and sawdust is also produced.We explain the steps of this energy conversion very simply.
1- The gas you pour into the fuel tank consumes all its chemical energy in cutting and crushing the wood. Most saw chain tanks are 0.5 liters.
2- The fuel enters the carburetor and mixes with the air.
3- The gas and air are then transferred into the cylinder after mixing. This stage is similar to the car engine mechanism, with the exception of the two-stroke saw engine, but the four-stroke engine is more complex.
Inside the cylinder and the top of the piston, the fuel-air mixture is ignited by the spark plug, burned and driven by the release of gasoline energy, causing the piston to reciprocate. The piston diameter of the motor saw is about 45 mm and its course is about 33 mm. So it can be said that the chainsaw piston size is less than half the size of a conventional car piston.
4- The piston-mounted connecting rod converts the piston movement to the crankshaft rotation.
5- At this point, the drive shaft transmits power to a centrifugal clutch.
6- The engine has been working full-time since the engine was started, but you don't want the chains to rotate until you have the intention of cutting the wood. In this case, both the machine operation is very dangerous and it will waste a lot of energy. The device clutch has solved this problem. As explained, the centrifugal clutch is connected to the motor and chains when the engine is high (when the operator switches on) and stops the chains when the engine is low.
7- The gears carry and transfer power from the clutch to the gears that hold the chain.
8- The chain revolves around the edge of a metal plate called the guide. This causes the wood chips to be thrown outwards.
Centrifugal Motor Saw Clutch:
A clutch is a device by which we can create or disconnect a mechanical connection between the motor and the actuator (disconnecting factor).
The clutch can be considered a type of switch with which the engine can be operated without turning on and off. Using a clutch in a motor saw means keeping the engine running at all times without moving the saw chain (non-movement of the blade will increase safety when working) and until you do not intend to use it. The momentum remains.
The motor saw uses an automatic centrifugal clutch to connect power when cutting wood that is high around the engine, and when the saw is not engaged with the wood, it cuts off the engine chains.
The centrifugal clutch structure is simple and consists of only a few pieces. An internal drive axle that is directly connected to the engine and is always rotating and has an outer frame and edge around the clutch that is attached to the saw chain gear.
Between them are mechanical joints that are attached to the inner drive axle and move outwards (clutch environment) at high speed.
(Using centrifugal force) In this case the inner and outer parts of the clutch are locked together. This type of clutch is similar to the centrifugal clutch used in the Yoyo Toy.
The advantages of chain saw:
The main advantage of the saw is its high speed. Cutting timber and trees with hand saws is a very difficult task that you can easily do with a motor saw. With a fingerprint calculation, you can see how cutting is done 5 to 10 times faster using a motor saw.
Do you think multiple wood boards can be obtained from one tree trunk?
Maybe 10 or 15? Now think about how difficult it can be to saw a tree from a tree trunk with a hand saw; cutting the entire tree trunk takes at least 10 times more time if your energy is constant and do not melt your blade. With this account, using a saw will save you 10 times more time and energy.
Let's examine a more complex assumption together. Let's say you have a tree about 30cm (about 1 feet) in diameter and an electric saw that generates 0.5mm of chains each time. This means that the chains must pass through the wood 600 times. Now, if you use a high-speed motor saw at 2800 rpm (to simplify 3000 rpm).
Theoretically, in just 20 seconds, this is done 600 times crossing the tree and cutting the tree completely. Of course, these calculations are theoretical and actually take a little more than a minute to cut.
Now how long does it take to use a hand saw? Suppose your hand saw has the same number of motor saws and is the same length and size. As in the previous example, you need to cut the wood 600 times.
Now if you work at a steady speed and each cut takes 1 second, you will end up working in 600 seconds (10 minutes). But in practice you will get tired and lose more time each time you stop sawing.
All two comparisons were based on speculation. But in any case, using a motor saw will make the cutting process 5 to 10 times faster.
Disadvantages of chain saw:
Two of the biggest disadvantages of saws are the safety and maintenance of the machine. Although a relatively strong adult can use motor saws after proper training, the device is generally very dangerous.
The biggest risk and danger of a motor saw is that it kicks the device where the chains are stuck on something but the engine is on and running. So the saw in this situation is kicked and thrown at the operator's head.
(This can be said to be in accordance with Newton's third law of action and reaction) so it can be concluded that there is always a potential danger when operating this device.
Another big problem with the saw is the amount of maintenance the machine needs. Hand saws are easy to use and do not require painting. So that every time the saw cut is produced and dropped from the groove on the cutting site.
In motor saws, the sawdust is very fine and can be easily stuck inside the machine and mixed with lubricating chainsaw oil to form a sludge layer.
This causes the machine to be cleaned regularly. In this regard, check the catalog of the device Check all the items that should be checked daily, weekly, monthly and yearly before launch.
It is true that using a saw to cut wood can save you a lot of time, but it also takes time to clean and maintain the machine.
Types of motor saw (chain saw):
Saws are divided into types of battery, electric, hydraulic and gasoline in terms of energy consumption. Here are the features of each to find out which one suits you.
Electric motor saw:
These saws are lighter and cleaner than gasoline. The disadvantages of this type of motor saw are the constant need for electricity and are not suitable for large and heavy projects.
Battery motor saw:
This saw does not require electricity but is limited in time and has lower power than other saws. This type of saw is the best choice for pruning or cutting small branches of trees.
This saw is powered by a gasoline engine and is manufactured in the range of 27 cc to 150 cc. This type of saw is suitable for cutting anything. From the small branches of trees to the thick trees can be cut with this saw.
The engine of this type is a two-stroke saw, and the operation of this type of engine was explained at the beginning of this article.
Hydraulic motor saw:
This type of saw is used to clean power lines from branches and even underwater cutters, but since it requires a hydraulic unit to power the saw, it is not used for any purpose and is less energy efficient.
This article will discuss safety tips when working with saws and maintenance of saws.
Repair and maintenance of motor chain:
It is essential to follow the maintenance recommendations to extend the life of the chain saw and ensure that the machine is operating properly. In this section we are going to tell you some of the most important things to increase the life of a motor saw.
Important tips in repair and maintenance of chain saw:
Periodically check the blade and chain surface and lubricate and grease them. It is best to lubricate the chains before using them every time.
Always keep the chainsaw sharp. This will not only increase the efficiency of the machine during the cutting operation but also ensure operator safety during the sawing operation.
Before each use, clean the chain saw blade thoroughly and remove any debris from it.
How to sharpen a motor saw blade:
Use an iron saw to sharpen the chain saw. Blade milling is not difficult and time consuming, but this is one of the important issues in grass maintenance that will have a great impact on proper cutting operations.
Securely fasten the saw with a clamp and make sure the saw does not move during sharpening.
Engage the saws brake.
First, sharpen the winning teeth, groove at a right angle to the chained joints.
Sharpen each of the winning teeth using a gentle motion, forward and backward.
Rotate the saw so that the path is reversed.
Chop and sharpen the rest of the chainsaws according to the method taught.
How to replace chainsaw blades:
When the longest part of the blade has been eroded to less than 4 mm, it is time to replace the saw chain. Here's how to replace a chainsaw.
Remove the chain blade, replace the new one, and adjust the chain tension.
The chains should be firm enough that you can draw your hand from the middle of the blade by 1 cm.
Note: When installing new chains for motor saws, keep in mind that the chains are firmly mounted on the blade. The looseness of the chain will lead to the risk of chaining during operation and the possibility of possible events. Also excessive chain stiffness will cause blade wear.
How to clean the motor saw:
Motor saw cleaning is an important part of sawing machine maintenance. Here are the most important things to keep in mind when cleaning a motor saw:
Remove the clutch cover first.
Check the chain saw brake.
Wipe the motor saw with a piece of wood or metal inside the track.
Remove the cylinder cover.
Wash the air filter.
Clean the air intake ports and engine coolants if the grooves are blocked, open them until the air reaches the chain saw motor completely.
Examine the air inlet holes in the engine to make sure they are not blocked at all.
Chain Saw Safety:
Be sure to check the safety of the saw and its proper operation without damaging the operator and its safety.
Motor saw brakes
Chain rotation should be complete and proper and there should be no abrasion.
The bolts should be fully tightened if loose.