Why the chain on my chainsaw tightens and spontaneously

Care and use of the guide bar

The chainsaw is an important part of the chain saw. Its functionality is largely responsible for performance and quality of your appliance.

Chain lubrication system

Premature tire wear is most often caused by improperly functioning automatic lubrication system. There is a lot of friction in the saw zone, which causes the metal to become hot and deformed. The chain sprocket is usually the first one to break down. Also to prevent premature wear it is important to turn the bar frequently to evenly wear out the sprocket rollers.

Important: Use a tire with the parameters specified by the manufacturer of your chainsaw. This will extend the life of the bar and the life of your chain saw.

The following are some of the common problems with the guide bar:

  • Deformation or damage to the bar body;
  • Worn teeth or a complete breakdown of the sprocket;
  • Wear of the housing and the shank;
  • Critical damage to oil channels;
  • Broken or completely worn tensioner;


Never work with a badly slack chain.

A chain that “jumps” while sawing can break the bar groove, disrupt the teeth of the sprocket.

A loose chain can damage parts of the machine. But the most dangerous thing is injury to the operator. In spite of the brake and catcher, a broken chain can still whip around in an unpredictable pattern and that is extremely dangerous.

Always check the tensioning before starting work. There are two signs of critical looseness during operation:

In this case, turn off the engine and check the tensioning.

Chain tensioning principle

Chain tensioning is carried out by the following actions:

  • Loosen the nuts on the housing cover;
  • Tension the chain by turning it with a screwdriver in a special groove;
  • You have to control the tensioning by hand slowly and carefully;
  • After tightening the chain, put the cover back on.

How-To Properly Adjust The Chain Tension On Your Chainsaw. Video

chain, chainsaw

If carbide or carbide-tipped chain was used, it is better to have it sharpened by a professional, because it is almost impossible to sharpen carbide and carbide-tipped chain at home.

Can it be shortened

If the chain on your chain saw breaks, it is not a problem and you should not get upset. manufacturers have made sure that it is possible to repair and shorten chains. Spare links for chains of various kinds and sizes, rivets for the chain, riveting and riveting machines are available.

With the help of machines, chainsaw chain can be riveted at home even for those who have never done anything like this.

Important: Repairing a chain, even with the best quality, does not guarantee that it will last forever. The links wear evenly, so the chain can break elsewhere at any time.

On sale are chains in coils of 50-100 meters, which you can buy and rivet yourself.

Coils are beneficial to professionals who work with a chainsaw on a daily basis, such as woodcutters or sawyers.

Chain tensioning algorithm for chainsaws

A clear example of how the chain is tensioned on a chainsaw is shown in the following

Necessary accessories and tools for pulling a chain on a chainsaw

In order to perform tensioning correctly, you need to know some simple mechanisms and uncomplicated tools. STIHL chain saws are tensioned simply by the integrated chain tensioner. It is the easiest way to do it and it is very quick. For tensioning or adjusting the degree of slack in the chain, the manufacturer recommends doing the following:

  • unscrew the sprocket cover with a wing nut;
  • The chain is tightened to the required length by turning the adjusting wheel;
  • the sprocket cover is closed again and the chain is secured to the bar.

If it is impossible to tension the chain of a chainsaw with a built-in mechanism, use these tools (using a Sparky electric saw as an example):

  • An angle grinder with a metal disc;
  • hexagon socket wrench, 5 mm in diameter
  • A piece of wire;
  • A wooden stick or strong splinter;
  • flat screwdriver.

After having switched off the electric saw unscrew the screws with an allen key, remove the case cover, unscrew the tensioning screw with a screwdriver and take out the rod-nut. The side of the screw adjacent to the saw body is ground with a disc. Then the saw is assembled in the reverse order. The saw blade is needed to clean the sawdust from the body.

How to tension the chain on a chainsaw correctly:

Design of the tensioner and principle of operation

Adjustment of the chain tension is made by simply moving the bar:

The guide bar is driven by a simple gear mechanism, which transmits the force from the adjusting screw to the guide bar.

There is a cleat on the adjusting shaft that is sure to hit the hole on the tire when you install it. This is the meshing that makes the tire move when adjusting.

The screw is located under the hole in the drive sprocket cover on the side or front, depending on the chainsaw model.

Most models have a slot for a flat-blade screwdriver. Its clockwise or counterclockwise rotation moves the bar slowly, in millimeters per revolution. This makes it possible to achieve the correct tensioning simply and accurately.

The tensioner mechanism is simple, so it is quite reliable. Fail for only one reason: if the gear teeth are made of soft or brittle metal. Some unscrupulous manufacturers use parts made by powder metallurgy. The teeth on these gears will slip quickly.

In such cases, you have to replace the entire assembly. You can tighten the chain by hand or with a vice. Fix the bar carefully, without pressure on the grooves, in a vise, the chainsaw is pulled away from the vise until the desired chain tension is achieved. This is a temporary measure. You often have to retighten the chain and it’s hard to do without the chain adjuster.

Adjustment is carried out when the bar with the chain is fully installed in place, with the fastening nuts loosened, which, depending on the model may be one or two.

Tips for continued use of the saw after the chain has been tightened

To make the chain last longer and not sag, follow these recommendations of experienced owners:

  • Check that there is a constant supply of lubricant to the bar;
  • Mix the fuel and oil right when you fill up your chain saw;
  • If possible, keep the chainsaw straight when sawing, without leaning too much to the right or to the left;
  • Use chains with the right pitch and from reputable manufacturers;
  • Replace worn parts when necessary.
chain, chainsaw

Vladislav, Bucha:

“I have a piece of advice for all new chain saw owners: whatever chainsaw you own, you should tighten the chain in time! If there is a lot of slack or vice versa, a lot of tension, both are bad. Generally speaking after about 3-5 cubic meters of firewood I would advise to re-tighten it. And use saws that have a tensioner option. Such, for example, almost all Husqvarna, the Patriots also have such a function.

You should also be careful not to let the chain come off. it is very dangerous if it comes off when you are sawing! You can hurt yourself badly. Have a great job!!”

Causes of premature chain failure

The accelerated lengthening of the part occurs during the running-in phase and in the last quarter of the service life. During these time intervals, the headset requires particular care and maintenance.

  • The reason for the rapid stretching of the saw chain can be poor quality of the material of the budget model, inappropriate configuration of the rim and excessive wear of the drive sprocket, a faulty or ineffective lubrication system.
  • Complete chain chain performance also depends on the condition of the bar and drive sprocket, the quality of chain oil and performance of the lubrication system, timely and correct sharpening of the cutting links edges.

Professional sawyers believe that the operator’s lifestyle and the level of use influence the durability of a chainsaw set. The chains of the budget group are subject to stretching to a greater extent, the more expensive branded assortment has no remarks on the technical and working properties.