Cutting Edge Care: Keep Your Saw Sharp and Running Smooth
Chainsaws are among the most powerful and versatile tools used in forestry, agriculture, and construction. Whether you’re felling trees, pruning branches, or slicing through concrete, your chainsaw’s performance depends on more than just brute force – proper lubrication is critical to keep it operating efficiently and safely.
A Brief History of the Chainsaw
While the exact origins of the chainsaw are debated, the concept dates back to the early 19th century. In 1830, German orthopaedist Bernard Heine developed a chainsaw-like medical instrument called the osteotome, used for cutting bone during surgeries. It featured a chain with small cutting teeth, moved by a hand-cranked sprocket wheel – a mechanical ancestor to today’s modern chainsaws.
How Chainsaws Work
A chainsaw is a mechanical saw that cuts through material with a rotating chain, fitted with sharp teeth, that runs along a guide bar. Most chainsaws are powered by petrol-driven two-stroke engines, though electric models (corded or battery-powered) are also available. Two-stroke engines are ideal for chainsaws as they don’t require an oil sump, allowing operation at any angle – a key requirement in dynamic cutting environments.
Why Oil Matters
Two-stroke engines use a petrol and oil mixture for both combustion and lubrication. The lack of a separate oil reservoir means lubrication must be delivered via the fuel mix. This system allows the engine to run efficiently regardless of its orientation – upside-down, sideways, or upright.
However, tightening engine emission standards have led manufacturers to design engines that run on leaner fuel-oil ratios. As a result, modern chainsaws operate at higher temperatures, putting additional strain on lubrication systems. Using low-grade two-stroke oil in such conditions can result in poor protection, overheating, and damaging carbon deposits on critical components like pistons, cylinders, and exhaust ports. Over time, this can cause reduced engine performance and premature failure.
To ensure engine longevity and optimal performance, always use a high-quality two-stroke oil approved by the chainsaw manufacturer.
Fuel-to-Oil Mixing Ratios
As a general guideline, most modern two-stroke chainsaws operate with a 50:1 fuel-to-oil ratio (i.e. 2% oil). This equates to 100 ml of oil per 5 litres of petrol. However, older or larger saws (typically 70 cc and above) may require higher oil concentrations. Always refer to the manufacturer’s recommendations before mixing.
When preparing the fuel mix:
- Use a clean, airtight container approved for fuel storage.
- Mix thoroughly to ensure even oil distribution.
- Store away from direct sunlight and use the mixture within 30 days to prevent degradation.
Using proper containers not only prolongs the fuel mix’s shelf life but also minimises risks of spillage, evaporation, and permeation.
Chain and Bar Lubrication
Equally important to engine lubrication is maintaining the health of the chain and guide bar. These components endure constant friction and must be properly lubricated to avoid excessive wear or failure.
Most chainsaws are equipped with an automatic oiling system. A dedicated oil reservoir feeds chain and bar lubricant as the saw operates. If you notice your chainsaw slowing down, cutting less efficiently, or draining the fuel tank faster than usual, it might be time to top up the chain oil.
Operating a saw without adequate bar and chain oil generates significant friction, which can damage the chain, overheat the bar, and even warp components. Routine checks and maintenance prevent these issues.
Choosing the Right Chain Bar Oil
A good chain bar oil must:
- Control wear
- Resist throw-off at high chain speeds
- Protect against rust and corrosion
To achieve these qualities, chain bar lubricants are blended using:
- Highly refined base oils of suitable viscosity
- Anti-wear and/or extreme pressure (EP) additives
- Rust inhibitors
- Tackifiers (to make the oil stick to the chain and bar)
Depending on the operating conditions, advanced formulations may also include:
- Anti-foam agents
- Pour point depressants (for cold weather use)
- Solid lubricants (e.g. graphite or molybdenum disulphide)
These additives help maintain consistent lubrication across a range of temperatures, speeds, and loads.
Don’t Forget the Sprocket!
Some chainsaws feature a sprocket at the front end of the guide bar. This component should also be greased regularly. Use a grease gun to inject clean, high-quality general-purpose grease into the lubrication hole (after cleaning it). Once you see grease pushing out, stop and wipe off any excess to prevent dirt accumulation.
Final Thoughts
Proper lubrication is not just good practice – it’s essential. From selecting the right two-stroke oil to topping up chain bar lubricant and greasing the sprocket, these simple maintenance steps will keep your chainsaw running reliably and efficiently for years to come.
If you’re unsure about which lubricants to use or need technical advice, don’t hesitate to contact our expert team at info@bcl.co.za – we’re here to help.