The correct chain tension on chainsaws is of great importance. It affects the life of the cutting headset and the entire chainsaw. over, with a critically improper stretch, working with a gasoline chain saw is simply impossible.
Tensioner device and principle of operation
The chain tension is adjusted by simply moving the tire:
- from the drive sprocket (from the chainsaw) to enhance the tension;
- to the drive sprocket (to the chainsaw) to loosen the tension.
The tire is moved using the simplest gear mechanism, which transfers force from the adjusting screw to the tire.
There is a spike on the adjusting shaft, which must necessarily fall into the hole on the tire when installing it. This engagement makes the tire move when adjusting.
The screw is located under the hole in the cover covering the drive sprocket, side or front, depending on the model of the chainsaw.
The screw in most models has a slot for a flat screwdriver. Turning it clockwise or counterclockwise moves the tire slowly, in millimeters, per revolution. This makes it possible to simply and accurately achieve the desired stretch.
The tensioner mechanism is simple, therefore reliable enough. Fails for the only reason. if the teeth of the drive gear are made of soft or brittle metal. Some unscrupulous manufacturers use parts made using powder metallurgy. The teeth on such gears quickly “slip together”.
In such cases, you have to change the entire assembly. You can tension the chain manually or with a vise. The tire is neatly, without pressure on the grooves, fixed in a vice, the chainsaw is pulled away from the vice until the desired chain tension is reached. This is a temporary measure. The chain has to be tightened often, and without an adjusting mechanism it is inconvenient to do this.
Adjustment is carried out with the tire with the chain fully installed in place, with a loose tightening of the fastening nuts, which, depending on the model, can be one or two.
Keyless tensioning system
It began to be used relatively recently, it is considered new, if not advanced. Differs from the classic wrench in the following:
- another tensioner mechanism;
- lack of an external tightening nut;
- adjustment without an additional tool.
Instead of a 13-turn-key nut, on the lid there is a wing (swivel cap) with a handle for tightening by hand. It also has a nut, but it is hidden inside. Instead of adjusting the screw for the screwdriver in this system, the tension is made using the tension wheel (adjusting knob).
Instead of a gear shaft there are an asterisk and a tension washer.
This system also has disadvantages:
- the mechanism itself is more complicated than a traditional wrench;
- installing a cutting headset causes additional problems, as complicates the process of pairing all the parts in the right order;
- the adjustment course is shorter, a slightly stretched chain will still serve with the traditional tensioning system, here it will sag and become unusable.
When to pull the chain
Working with a strongly sagging chain is strictly unacceptable.
The chain "jumping" during sawing can break a groove of the tire, damage the teeth of the driven sprocket.
A chain that has slipped off can damage the parts of the mechanism. But the most dangerous thing is operator injuries. Despite the brake and the catcher, a broken chain can whip along an unpredictable path, and this is extremely dangerous.
The tension must be checked before starting work. During operation, critical attenuation can be determined by two signs:
- chainsaw starts to jump and twitch in the hands;
- the sound of work changes, a metallic ringing, a knock appears.
In this case, turn off the engine and check the tension.
Why does the chain weaken on the chainsaw
The chain tension on any chainsaw weakens constantly. There are several physical and mechanical reasons for this.
- A chain is connected from a plurality of links that are held together by bushings through holes. Even with the most accurate factory fit between the bushings and holes, there is play, otherwise the chain will not fold into an ellipse. During operation, all backlashes are pulled together in one direction, which leads to an increase in length. Even a micron play of 52 or more links in total leads to tangible values.
- Under loads, especially strong, lamellar elements of the entire chain can stretch.
- Gradual sagging of chains occurs when parts wear. The teeth of the driving and driven sprockets are erased, the outer edge of the groove of the tire. Asterisks are reduced in diameter, the tire is getting shorter.
- When heated, the metal not only expands, but also lengthens. During operation, the heated chain becomes a little longer and sags.
Chainsaw chain tensioning algorithm
- A chainsaw is placed in a comfortable position on a table or workbench.
- Release the tire tightening, but not too much so that it does not dangle. On the contrary, with insufficient tempering the tire remains clamped, and this can lead to a breakdown of the adjusting screw or mechanism.
- The lower chain slack is clearly visible. When turning the adjusting screw (or wheel for keyless systems), the sag is tightened.
- The tension is checked. Correctness is determined manually. Around the middle of the tire, the chain is pulled with fingers with a little effort. It should come out of the groove by 3-5 mm. Guide chain segments that slide inside the groove of the tire during operation should never come out to the end. Their lower part should remain in the guide groove.
- The nut or lamb fastening is tightened.
- The ease of movement of the chain along the groove is checked. She must walk, both forward and backward. If with a little effort. this is acceptable. In operation, the stretch will quickly loosen.
- If the chain does not move by hand, the operation is repeated. The fastening nut is released and the tension is loosened.
A good example of how chain tension on a chainsaw occurs is presented in the following video:
New chains in the first hours of operation stretch more than the old ones. Therefore, the stretch must be checked after the first 12-20 minutes. work.
The constriction is fraught with excessive load on the engine with loss of power and accelerated wear of the cutting headset and parts of the chainsaw, especially the drive and clutch sprockets.
After 3-4 chains wear, replace the tire with a new one.
After wear of 6-8 chains and 2 tires, you need to evaluate the condition of the drive sprocket. On different models, they wear out after different service lives. The worn teeth of the sprocket have a non-standard size. Even if the chain does not slip along them, its service life is reduced.
Video: Do Not Stretch Chain On Saw
After each tension adjustment, it is recommended to lubricate the driven sprocket at the end of the tire. For this, there are special holes near it. Oil from the pump gets there according to the residual principle, and sometimes it does not get at all. Therefore, along with a key and a screwdriver for tensioning, you need to have a nipple on hand. 3-4 drops are sufficient for lubrication.
Inadequate lubrication speeds up wear on the cutting headset and chain stretching. The planned oil consumption for different chainsaws is different. On some models, 1 tank of oil is consumed almost simultaneously with 1 tank of gasoline. For others, 1 tank of oil is enough for 2 gas stations. A sign of good lubrication is the oil shine of the chain and its smooth running along the groove.
Do not use low-quality chains. They quickly stretch, disable the nodes in contact with them and require a more frequent tightening.
Why clamps a chain on a chainsaw
There may be several reasons for this:
- the chain is too tight;
- the groove of the tire is clogged with a mixture of sawdust and oil, the space around the sprocket under the tire mount cover, the clutch mechanism;
- the tire is completely incorrectly installed (the pin of the tensioning mechanism does not fall into the hole, the skew);
- one or more chain links jammed4
- the chain is deformed, the guide segments are bent;
- tire groove is damaged.
Adjusting the chain tension takes only a few minutes without experience, and with experience less than a minute. It’s easy to follow the right stretch, and not follow. it’s more expensive for yourself.
Tire installation on a saw
At one end of the tire web there is a slot and two holes on either side of it. When installing the tire with a slot, it is put on a special stud on the saw body, and one of the holes on the pin of the tension mechanism.
The second hole on the canvas serves to transfer lubricant from the oil channel into the groove of the tire.
The chain is pulled over the drive sprocket located on the saw body and the sprocket at the end of the tire. When installing the chain, you must take into account the correct direction of its rotation, which is usually indicated on the product itself.
After installing the chain, the saw’s drive sprocket is covered with a casing, the clamping nut of which is not tightened so that the tire is not completely clamped.
The chain tension control on Chinese saws is carried out using a special tension screw, the head of which has a slot for a screwdriver. It is located at the end of the device. For a stronger chain tension, it is rotated clockwise.
The tension screw is rotated until the chain slack disappears. After that, it is manually scrolled on the tire towards the saw body. This is necessary in order to "straighten" the teeth of the chain in the groove of the tire.
If the chain weakened after scrolling, then it is pulled again.
After that, the tire is taken at its free end, lifted up to the stop, and in this position, the chain slack is eliminated again.
At the last stage, the clamping nut on the casing covering the saw sprocket is completely tightened. In this case, the tire is held in the “raised” position.
A properly stretched chain should be freely pulled out of the grooves of the tire on both sides by about 3-4 mm, and when lowering, lie back in the grooves.
Checking tension after work
When the chain is tensioned, it is possible to finally check the quality of its tension only after a short operational test. For this purpose, several trial cuts are made with it.
Often after trial cuts, the chain on the saw bar weakens. This happens when its links were contaminated, and during operation these contaminants were dissolved by lubricant.
If this happens, the chain must be tightened again, first loosening the clamping nut on the casing and lifting the free end of the bar up. the saw, of course, must be disconnected from the mains before this.
At the end of the chain tension adjustment, it is always checked whether it goes in the right direction without tension, whether it is overtightened. To this end, it is unlocked by pressing the start button, and pushed for the teeth forward with a screwdriver. If she moves a little by inertia, then everything is fine.
And the last one. It is strictly impossible to adjust the tension of the saw chain when it is heated or not lubricated, otherwise there is a risk of it breaking during subsequent operation.
Full video version of the recommendations for pulling the chain onto the chainsaw and saw.
How to tension the chain correctly?
Constant chain pulling serves your safety and, in addition, reduces wear and tear and damage to the chain.
Most STIHL chainsaws have a convenient side chain tensioning device that is convenient to maintain. With it, you pull the chain with one motion of the hand. This is done as follows:
Release sprocket cover manually with wing nut. When the adjustment wheel located above is rotated to the left, the chain tension is miniaturized, while rotation adjusting wheel the chain is pulled to the right. When tightening the chain sprocket cover, the guide bar is locked automatically.
When you want to change the chain, it is necessary to carefully clean the groove of the guide bar from contamination in advance. In the case of heavy deposits of dirt in the groove, in an unpleasant case, the chain may simply slip off the tire. In addition, there is a danger that the adhesive chain oil is absorbed into the dirt before the time and does not get on the especially loaded lower side of the tire. We check the chain on let the saw is on the market. How. Strong heating and wear on the chain and tire may be the consequences of this. You can clean with, for example, a narrow screwdriver or other sharp object. The newest chain needed run in for a few seconds before approaching the tree species.
1. With the motor turned off, you must first release the fastening screws of the chain cover using a universal key. To tension the saw chain, it is quite enough to just loosen the fixing screws a little. Then twist the tension screw with a universal screwdriver.
How to pull the chain on saw
Setting the correct tension chains on a saw. Proper stretch chains on a saw is an important
How to install the chain on the saw
Chains and other components you can find at :.
2. Now check that the chain is free on the guide. Please use work gloves for this. If the chain sags at the bottom, then it is too loose, and you need to tighten the chain again with the tension screw.
3. If the chain on the underside of the tire does not sag, but it can still be easily pulled, then it is tensioned optimally. It should also be possible to pull it up a little. To avoid the risk of personal injury from contact with a sharp chain, you should always have work gloves.
You can conveniently and without tools tension the chain with the STIHL quick chain tensioner. many STIHL chainsaws are already equipped with this technique. You need to act like this:
Release sprocket cover manually with wing nut. Turning the adjusting wheel to the left to the left decreases the chain tension, while turning adjusting wheel the chain is pulled to the right. When the chain sprocket cover is tightened, the guide bar locks automatically.
When you want to replace the chain, you must carefully clean the groove beforehand. guide rail from pollution. The chain has stretched. Why does the chain on the chainsaw stretch so that the chain flies off the tire. In the event of heavy deposits of dirt in the groove, the chain otherwise could easily slip off the tire. In addition, there is a danger that the adhesive chain oil will soak up the dirt ahead of time and will not fall onto the especially loaded underside of the tire. Strong heating and wear on the chain and tire may be the consequences of this. You can clean using, for example, a thin screwdriver or other sharp object. New chain needed Break in for a few seconds before approaching the wood.
ATTENTION: since the chain shrinks again a little after cooling, the chain should never be pulled up or replaced while hot. Otherwise, it can cause severe damage to the guide rail or engine crankshaft. After completing work, it is recommended that the chain tension be relieved a bit again. This is important primarily in frosty weather.