11 Essential Chainsaw Parts

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11 Essential Chainsaw Parts

To the uninitiated, buying a chainsaw may seem like a daunting task. There are so many different chainsaws available, from petrol to electric to battery-driven, but choosing the right one for a given application need not be difficult. The user should first consider the use a chainsaw may be put to, whether simply cutting back a few smaller branches or bushes, or for performing major tree surgery or even felling. Following that, the user must consider whether a traditional petrol-driven machine is required, or whether a lower powered, quieter, and cheaper electric one is sufficient.

If a more powerful petrol-driven machine is required, then the user must evaluate the maximum size of the branches to be cut in order to ensure that they possess the correct size of cutting blade needed. There are 11 essential parts or components that make up a viable chainsaw and it is helpful to be familiar with all of these components before purchasing as well as afterwards for maintenance purposes.

1. Chain

The chain is the most obvious important feature of a chainsaw and, as such, should be the first thing that any operator checks before firing up a saw. Close examination of the chain reveals riveted sections with small, sharp, cutting teeth every few links. The cutting teeth are arranged such that a left - facing tooth is followed by a right-facing tooth, and so on. Each cutting tooth is a hard, chromium, or hardened steel tab with a curved or angular corner with two cutting edges. One of the cutting edges is on the top of the tab; the other is on the front side. In front of each cutting tooth is a depth gauge tooth. These depth gauge teeth are essential to the correct operation of the chainsaw. If the depth gauge teeth are cut too low, the cutting teeth will cut too deeply.

This results in excessive wear on the teeth and an increased risk of kickback, a significant safety risk. If they are set too high and the cutting teeth do not run deeply enough, the saw will be very slow to cut and will result in disproportionate chain wear and excessive vibration. When looking to buy a chainsaw, a careful inspection of the chain is essential. Failing that, the buyer should be able to source a new replacement chain if needs be. It is important to note that different chainsaw manufacturers design different styles and fits of chains, such that a chain from one chainsaw manufacturer will almost certainly not fit a chainsaw made by a different manufacturer.

2. Chain Oil

This is normally in a separate reservoir from the fuel-oil mix tank. Chain oil is much more viscous than normal oil to help prevent it from flying off due to the centrifugal force exerted as the chain rotates. When filling up the main fuel tank, the operator should always check the chain oil reservoir and top it up as necessary. The chain oil tank is typically large enough to hold sufficient chain oil to operate the saw between fill-ups of fuel mix. If the operator notes that the chain oil tank is becoming depleted too frequently, they should check the chain’s cutting and guide teeth settings to ensure they are correctly positioned.

3. Engine Oil

Electric chainsaws frequently feature self-lubricated bearings, which means that the electric motor should never require further lubrication. On two-stroke petrol-engined models, however, engine oil needs to be mixed with the fuel to keep the piston and associated components lubricated and running freely. This varies from model to model, but is typically between 2 to 5 per cent oil and 95 to 98 per cent fuel. The handbook should always be consulted to ensure the operator provides the precise recommended mix ratio. Some manufacturers specify and even supply their own recommended engine oil. Whilst this manufacturer’s oil may seem like an extravagance, particularly when other oils are priced more cheaply, many manufacturers will not honour warranty repairs unless their recommended oil has been used in the fuel mix.

When mixing fuel with oil, the user should always follow the manufacturer’s instructions, and mix the two very thoroughly in a recommended mixing bottle. Failure to properly mix the fuel will mean the engine risks repeatedly stalling as almost pure oil is fed through the carburetor.

4. Chain Catcher

Under the flap that lifts back to reveal the main drive and clutch wheel lies the chain catcher. This sometimes plastic, but more often metal, piece catches the chain, should it break or become unseated from the main drive wheel. This is a small but vital part of the safety system on a chainsaw.

5. Throttle Interlocking Levers

The throttle interlock levers mean that the throttle cannot be operated unless an opposing lever or button is pressed at the same time. This essential safety feature of the chainsaw prevents accidental throttle operation, such as if nudged by one’s foot when holding the chainsaw down to pull the starting cord. Also. if the chainsaw is dropped during operation, this will automatically stop the chainsaw and help prevent accidental injury to the operator.

6. Chain Brake

Legally required on every manufactured and sold chainsaw, the chain brake pushes the top bar forward, causing the chain automatically to instantly stop. This is an essential safety feature to help prevent injury during kickback. Manufacturers will often give the stopping time when applying this brake, normally in a few tens of milliseconds.

7. Clutch

The automatic clutch system, mounted on the main drive wheel, is a centrifugal force-driven device. When the saw is idling, the clutch is disengaged and the main cutting chain should be stationary. If the chain does move, then adjustment is most definitely required. When the throttle is depressed, the clutch springs into action, transferring power to the main drive wheel and hence the cutting chain.

8. Exhaust

The exhaust system should always be fitted and working. Without an exhaust, the engine will not reach full power, but, more important, the operator will be the subject of poisonous exhaust gases and high levels of noise pollution that, with prolonged exposure, are almost certain to permanently damage the user’s health.

9. Hand Guard

Fitted below the main throttle towards the rear of the chainsaw, the hand guard protects the user’s rear hand should the chain break or the user experience kickback. This is ideally manufactured of toughened steel or at least hardened plastic.

10. Decompression Valve

On modern chainsaws, the decompression valve prevents the engine from fully compressing during the compression stroke. This makes for much easier starting, though the user should always be alert to possible flooding of the engine with fuel when cold.

11. Shock-Absorbing Handle System

If the chainsaw user will be using the saw for long periods of time, adequate vibration reduction is essential to prevent vibration white-finger, an irreversible condition that affects long-term users’ hands and fingers. This vibration reduction may take the form of a rubber or plastic bush system that insulates the top handle from the main drive linkage, combined with a system of de-coupling the rear handle from the main drive linkage. If the user is looking to purchase an older, second-hand chainsaw, then particular attention should be paid to these systems, as they do tend to fail with age and often need replacement in older models.

How to Buy Chainsaw Parts on eBay

When buying parts for a chainsaw from eBay, it is imperative that the user should have the make and model number of the chainsaw to hand. While the same type of part from various manufacturers may initially appear interchangeable, close inspection may reveal subtle differences which would mean the new part will not fit. If the user is looking to buy a chain, for example, very careful attention must be paid to make sure the intended chain will fit the precise model of chainsaw in question.

It might also be worth checking the manufacturer’s handbook, particularly the guarantee section. This will indicate whether the manufacturer’s warranty would be void if parts are fitted that are not specifically made or recommended by the manufacturer. Some manufacturers insist that a specific kind of chain oil must be used with their model of chainsaw and/or a specific kind of two-stroke engine oil, for example. By using oils from other sources, this could also invalidate a manufacturer’s warranty.


Buying parts for a chainsaw need not be as daunting a task as the buyer may fear. When looking to purchase parts, particularly the cutting chain, the buyer should keep the make and model of the chainsaw handy to ensure that the part being purchased will, in fact, fit the saw. The buyer would also be wise to check any returns policy of the company or individual seller to make sure that, if the part is wrong, it may be sent back for replacement or refund. Also, because there are often thousands of parts for different brands and styles of chainsaws, it might be worth the purchaser who elects to buy parts online to insert the chainsaw brand into their search query. Finally, before purchasing a generic-style part, it is recommended that the buyer first read the owner’s manual, particularly the guarantee section, to make sure that the manufacturer will still provide a warranty repair or replacement if the replacement part, engine oil, etc., that was used wasn’t specifically named by the manufacturer as required to maintain the validity of the warranty.

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