How Does a Chainsaw Work? – The Complete Working Explained

How Does a Chainsaw Work? The Complete Working Explained

As I sit here on this pleasant Tuesday morning, coffee in hand, I find myself contemplating the roar of a chainsaw echoing through the crisp fall air. It’s a sound that transports me back to my childhood, when my father would break out his trusty Stihl to cut firewood for the coming winter. Even then, I was fascinated by the raw power contained in that orange and white machine.

Today, chainsaws remain an indispensable tool for countless workers and DIYers. But how exactly does this iconic power tool operate? What internal mechanisms allow it to rip through solid wood with such ease?

In this article, I’ll provide a comprehensive overview of chainsaw function and components. Whether you’re a casual user looking to better understand your equipment, or someone considering buying their first chainsaw, you’ll find the key facts and operating principles outlined below. Let’s rev up and dive in!

How Does a Chainsaw Work?

At its core, a chainsaw is an efficient wood-cutting machine. Using a gasoline engine, electric motor or battery pack, it rotates a metal chain lined with sharp cutting teeth around a guide bar. When the spinning chain contacts wood, it acts like a mechanical saw blade and creates a narrow kerf or slit in the material. With applied pressure, the operator can extend the kerf to cut all the way through logs and branches.

Do not operate a chainsaw that is damaged or has disengaged safety devices. Chainsaws come in three main varieties – gas, electric and battery-powered. Let’s explore how each achieves the high-speed chain rotation necessary for sawing.

Gasoline Chainsaws

As the original and most powerful design, gas chainsaws are preferred for heavy-duty use. At the heart of the machine sits a compact two-stroke internal combustion engine. Just like a lawnmower or string trimmer, it runs on a gasoline/oil mix fuel. When started via pull cord, the engine spins at high RPM, engaging a drive clutch that transfers power to the chain. Gas saws can operate for long periods without recharging, though they require more maintenance than other types.

Electric Chainsaws

Electric models provide a lighter, more affordable option for homeowners and occasional users. Rather than an onboard engine, they use an electric motor plugged into a standard wall outlet. An extension cord provides mobility around the yard. Electric chainsaws have less kickback and vibration and require little maintenance. However, cord length can limit their range, and they can’t match the power of gas saws.

Battery-Powered Chainsaws

The newest breed, battery chainsaws liberate users from both gas and extension cords. They operate using rechargeable lithium-ion battery packs – the same technology found in cordless drills and other tools. Offering great convenience and portability, battery saws are a smart choice for light jobs like pruning and firewood cutting. Run times per charge are relatively short though, and power output currently trails gas models.

Now that we’ve covered the basic power sources, let’s look under the plastic casing at the inner workings of a chainsaw.

Chainsaw Components

How Does a Chainsaw Work? - The Complete Working Explained
How Does a Chainsaw Work? – The Complete Working Explained

While chainsaw designs vary across brands, all share a set of core components that enable cutting:


On gas-powered models, the engine – usually a 2-stroke – drives the entire operation. It spins the clutch and chain at a speed of approximately 13,500 RPM, far faster than would be possible with manual muscle power. Chainsaw engines are designed for high power-to-weight ratio, though they produce substantial vibration and noise. Most now have built-in chain brakes for safety.

Chain and Guide Bar

Unquestionably the stars of the show, the spinning cutter chain and guiding bar are the business end of a chainsaw. The chain’s tooth-like cutters shear through wood as they rotate at high speed around the grooved guide bar. Together, the matched chain and bar form the cutting attachment that mounts to the saw body. Chains come in varying pitch, gauge, and tooth design for different purposes.

Clutch and Gears

The clutch connects the engine to the chain drive system. At idle, it disengages the chain to allow safe starting. When accelerated, centrifugal force activates the clutch, transferring power through a gear system that drives the chain. Gears reduce the engine’s raw RPMs down to optimal chain speed.

On battery models, the electrical components and geared transmission stand in for the gas engine and clutch. But the chain system remains essentially the same across all types of chainsaws. It’s this elegant yet brutal dance of tooth, chain, bar, and power source that enables the signature ripping cut of a chainsaw.

Chainsaw Maintenance and Troubleshooting

Given their high-speed nature and exposure to dust, dirt and weather, chainsaws need periodic maintenance to function properly. Here are solutions to two common issues users face:

Stihl Chainsaw Not Oiling Bar

One frustrating problem is when your Stihl (or other brand) chainsaw stops lubricating its bar and chain. Without oil, the chain will overheat, damaging components. Causes include depleted or incorrect oil, clogged passages, and failing oiler mechanisms. Solutions include replenishing Stihl bar and chain oil, cleaning passages, replacing oiler parts, and inspecting the oil pump worm gear.

Chainsaw Chain Sharpening

A dull chain makes cutting difficult and can increase kickback. Regular file sharpening restores the teeth’s sharp precision edge. This can be done manually or using specialty grinding tools. Always maintain each cutter’s specific filing angle. Chains should be sharpened every few hours of use, and replaced once extensively worn. A sharp chain is a safe and productive chain.

Chainsaw Safety

I’d be remiss not to mention safety when discussing these powerful machines. While very useful, chainsaws can also be quite dangerous, especially for amateur users. Some key tips include:

  • Wear protective clothing like chainsaw chaps, gloves, boots and eyewear.
  • Add a tip guard for stability, and employ two hands.
  • Plan cuts to avoid pinching or kickback.
  • Maintain your saw properly, keeping the chain sharp and system in good repair.
  • Operate at full throttle when actually cutting.
  • Clear the area of hazards and bystanders before sawing.
  • Take training courses to hone proper chainsaw techniques.

Following basic safety precautions will keep you in one piece and let you enjoy the full benefits of chainsaw use. Personal protection is a must when dealing with such an intense power tool.

Chainsaw Applications

While felling trees and bucking logs are obvious uses, chainsaws have many other creative applications, both practical and artistic.

In the lumber industry, chainsaw mills leverage the cutting power of gas chainsaws to rip boards and beams from ordinary logs. Special attachment bars allow the operator to guide the saw along the log for smooth lengthwise cuts. Portable chainsaw mills enable milling lumber right at the logging site.

In the art world, chainsaw carving uses special saws with shorter bars to sculpt wood. By making a series of adjacent cuts, artists can remove excess material to create decorative bears, eagles, totem poles, and more. It’s noisy work, but chainsaws lend themselves well to freehand large-scale sculpting.


In summary, chainsaws are motorized cutting machines that use a high-speed spinning chain to shear through wood quickly and efficiently. Their internal combustion or electric power source drives the chain via an engine or motor and transmission. With proper care and handling, chainsaws are indispensable tools that can enhance productivity and creativity for an array of applications.

I hope you’ve enjoyed this introductory overview of chainsaw function. Remember to emphasize safety and maintenance to get the most from your saw over the long run. Chainsaws are icons of rugged capability, but also require common sense and precaution when unleashing their brute cutting force. Now go forth and saw without fear!

Frequently Asked Questions

How often should I sharpen my chainsaw chain?

It’s recommended to sharpen your chainsaw chain after every 1-2 hours of use. More frequent sharpening is needed when cutting dirty or sandy wood. Regular sharpening maintains optimal cutting performance and reduces strain on the saw.

What type of oil should I use for my chainsaw?

Use a good quality bar and chain oil specifically designed for chainsaws. Regular motor oil is too thin and becomes flung off at high chain speeds. Bar oil sticks better and continuously lubricates the chain and guide bar.

How do I adjust the tension on my chainsaw chain?

First loosen the side cover nuts, then turn the tensioning screw clockwise to tighten a loose chain, or counter-clockwise to loosen an overtightened chain. The chain should have just enough sag or play to still be easily pulled around by hand. Refer to your owner’s manual for proper tensioning procedures.

What safety gear should I wear when using a chainsaw?

At minimum wear chainsaw chaps, steel-toed boots, hard hat, ear protection, eye protection, and cut-resistant gloves. Chainsaw-specific chaps are reinforced to clog the chain upon contact and prevent deep leg cuts. Additional gear includes a chainsaw-proof safety jacket and face shield.

How do I store my chainsaw when not in use?

Allow the saw to fully cool, then empty the fuel and run it dry to prevent gumming. Clean the saw body, bar, and chain. Apply lubricating oil and store indoors in a dry location away from any heat sources. Leave the chain tension loose and scabbard on. Refer to long-term storage procedures in your owner’s manual if needed.

Can I use a chainsaw to cut metal or other materials besides wood?

It’s not recommended. Chainsaws are designed to cut wood and can be severely damaged or dangerously jam if used on metal, plastics, masonry, etc. Use appropriate saws or cutters for non-wood materials. An exception is specialized concrete chainsaws using diamond chains.

How do I choose the right chainsaw for my needs?

Consider the typical project size, wood type, and frequency of use. Smaller electric or battery saws are great for occasional limb removal or firewood cutting. Bigger gas models provide more power for felling trees and milling lumber. Match the bar length to your cutting tasks. Getting the right chainsaw size and power prevents frustration and safety issues.

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