Stihl MS 660 Specs (5 Pro Tips) For Handling Large Logs Safely

My old Labrador, Buster, used to love basking in the sun near the woodpile. He’d watch me for hours as I wrestled with logs, his tail thumping a steady rhythm against the earth. Buster is gone now, but his memory fuels my commitment to safety, especially when dealing with powerful tools like the Stihl MS 660. Large logs demand respect, and this chainsaw is more than capable of delivering some serious cutting power. However, with great power comes great responsibility. This guide is designed to equip you with the knowledge and skills to wield the MS 660 safely and effectively when tackling those behemoth logs. I’ll share my hard-earned lessons, practical tips, and essential safety advice to help you master the art of large log processing.

Understanding the Stihl MS 660: A Beast of a Chainsaw

The Stihl MS 660 is a legend in the logging world. It’s a powerful, robust chainsaw designed for felling large trees and processing massive logs. This isn’t your average backyard saw; it’s a professional-grade tool that demands respect and a thorough understanding of its capabilities and limitations.

Technical Specifications: Power Under the Hood

Engine Displacement: 91.6 cc (5.6 cu in)
Engine Power: 5.2 kW (7.1 bhp)
Weight (powerhead only): 7.3 kg (16.1 lbs)
Guide Bar Length (Recommended): 25″ to 36″ (though some users go longer)
Fuel Tank Capacity: 0.825 L (27.9 oz)
Oil Tank Capacity: 0.360 L (12.2 oz)
Sound Pressure Level: 103 dB(A)
Sound Power Level: 115 dB(A)
Vibration Level (left/right): 6.9/5.6 m/s²

These specs tell a story of raw power. The large displacement engine provides the torque needed to power through dense hardwoods. The weight, while significant, is balanced to allow for reasonable maneuverability, provided you have the strength and technique.

Why Choose the MS 660 for Large Logs?

I remember the first time I used an MS 660. I was helping a friend clear some storm-damaged oaks. The sheer power of the saw was astounding. It sliced through the thick trunks with ease, something my smaller saws struggled with.

Power: The MS 660’s engine provides ample power for cutting through large diameter logs, reducing the risk of stalling or bogging down.
Longer Bar Length: It can accommodate longer bars, allowing you to cut through thicker logs in a single pass. This reduces the need for multiple cuts, saving time and effort.
Durability: Built for professional use, the MS 660 is designed to withstand the rigors of demanding logging operations.
Efficiency: Despite its power, the MS 660 is relatively fuel-efficient compared to other saws in its class.

Understanding the Limitations

Despite its impressive capabilities, the MS 660 is not a magic wand.

Weight: It’s a heavy saw. Prolonged use can lead to fatigue, increasing the risk of accidents.
Cost: It’s a significant investment.
Maintenance: Requires regular maintenance to keep it running smoothly.
Skill Required: It demands a high level of skill and experience to operate safely and effectively. This isn’t a beginner saw.

Takeaway: The Stihl MS 660 is a powerful tool best suited for experienced users who need to process large logs regularly. Understand its capabilities and limitations before you even think about firing it up.

Safety First: The Non-Negotiable Rules of Large Log Handling

Safety is paramount. Always. No log, no amount of firewood, is worth risking your health or life. I’ve seen too many accidents, and they are always preventable.

Personal Protective Equipment (PPE): Your Shield Against Injury

Chainsaw Chaps: These are essential. They are designed to stop the chain in the event of a kickback or accidental contact with your leg. I personally recommend full wrap chaps for maximum protection.
Eye Protection: Safety glasses or a face shield are crucial to protect your eyes from flying debris.
Hearing Protection: Chainsaws are loud. Prolonged exposure to high noise levels can cause permanent hearing damage. Earplugs or earmuffs are a must.
Gloves: Sturdy work gloves provide a better grip and protect your hands from cuts and abrasions.
Steel-Toed Boots: Protect your feet from falling logs and potential chainsaw contact.
Helmet: A hard hat is essential, especially when working in wooded areas where falling branches are a risk.

Pre-Operation Checklist: Ensuring a Safe Work Environment

Before starting the saw, always conduct a thorough inspection and prepare your work area.

Chainsaw Inspection: Check the chain tension, sharpness, and lubrication. Ensure the chain brake is functioning correctly. Inspect the bar for damage.
Work Area Assessment: Clear the area of obstacles, such as branches, rocks, and debris. Identify escape routes in case of an emergency. Ensure you have stable footing.
Fuel and Oil Levels: Make sure both fuel and oil tanks are full. Use the correct fuel-oil mixture as specified by Stihl.
First Aid Kit: Keep a well-stocked first aid kit readily available.
Communication: If working alone, inform someone of your location and expected return time. Carry a cell phone or two-way radio for emergencies.

Understanding Kickback: The Most Common Chainsaw Hazard

Kickback occurs when the upper quadrant of the bar nose contacts a solid object, causing the saw to suddenly and violently thrust backward. This is the most common cause of chainsaw injuries.

Avoid Contact: Never allow the upper quadrant of the bar nose to contact a log, branch, or any other object.
Maintain a Firm Grip: Keep a firm grip on the chainsaw with both hands.
Proper Stance: Stand to the side of the cut, not directly behind the saw.
Use Low-Kickback Chain: Consider using a low-kickback chain, especially if you are less experienced.
Be Aware of Buried Objects: Be extra cautious when cutting near the ground, where rocks or other buried objects may be present.

Takeaway: Safety is not an option; it’s a necessity. Invest in quality PPE, conduct thorough pre-operation checks, and understand the dangers of kickback. Your life depends on it.

Pro Tip #1: Mastering the Art of Bucking: Safe and Efficient Log Cutting

Bucking is the process of cutting a felled tree into shorter, more manageable lengths. It’s a fundamental skill for anyone working with logs.

Assessing the Log: Understanding Tension and Compression

Before making any cuts, carefully assess the log to determine how it is supported and where the points of tension and compression are located. This will help you avoid pinching the bar and chain.

Supported on Both Ends: The top of the log is under tension, and the bottom is under compression.
Supported on One End: The top of the log is under compression, and the bottom is under tension.
Supported in the Middle: The top and bottom are under tension, and the sides are under compression.

The Three-Cut Method: Preventing Pinching

The three-cut method is a proven technique for preventing the bar and chain from getting pinched during bucking.

First Cut: On the compression side of the log, make a cut about one-third of the way through the log.
Second Cut: On the tension side of the log, make a cut slightly above the first cut, going about two-thirds of the way through the log.
Third Cut: Carefully complete the cut from either side, avoiding pinching.

Using Wedges: A Lifesaver for Heavy Logs

Wedges are invaluable tools for preventing the log from pinching the bar and chain, especially when dealing with large, heavy logs.

Placement: Drive wedges into the cut as you progress to keep the kerf open.
Material: Use plastic or aluminum wedges to avoid damaging the chain. Never use steel wedges.
Number: Use multiple wedges for larger logs.

Avoiding “Barber Chairing”: A Dangerous Splitting Hazard

“Barber chairing” occurs when a log splits prematurely due to excessive tension, creating a dangerous, uncontrolled split that can injure the operator or damage the chainsaw.

Assess the Log: Carefully assess the log for signs of tension, such as cracks or bends.
Relieve Tension: Make relief cuts to relieve tension before making the final cut.
Use Wedges: Use wedges to support the log and prevent it from splitting prematurely.

Takeaway: Bucking safely requires understanding the forces at play within the log. Use the three-cut method, wedges, and relief cuts to prevent pinching and barber chairing. I’ve had a few close calls with barber chairing in my early days, and trust me, it’s not something you want to experience.

Pro Tip #2: Felling Techniques: Precision and Control

While this guide primarily focuses on processing logs, understanding basic felling techniques is crucial for ensuring a safe and efficient supply of logs.

Assessing the Tree: Planning Your Felling Strategy

Before felling any tree, conduct a thorough assessment of the tree and its surroundings.

Lean: Determine the direction of the tree’s natural lean.
Obstacles: Identify any obstacles in the tree’s path, such as other trees, power lines, or buildings.
Wind: Consider the wind direction and its potential impact on the tree’s fall.
Escape Routes: Plan your escape routes.

The Hinge: Controlling the Fall

The hinge is the most critical element of a controlled felling. It’s a strip of wood left uncut that guides the tree’s fall.

Width: The width of the hinge should be about 80% of the tree’s diameter.
Thickness: The thickness of the hinge should be about 10% of the tree’s diameter.
Placement: The hinge should be placed perpendicular to the desired felling direction.

The Felling Cut: Completing the Fall

The felling cut is made behind the hinge to complete the fall.

Angle: The felling cut should be made at a slight angle to create a “Dutchman,” which helps to control the fall.
Wedges: Use felling wedges to help push the tree over in the desired direction.

Using a Felling Lever or Winch: For Difficult Trees

For trees that are leaning in the wrong direction or are otherwise difficult to fell, a felling lever or winch may be necessary.

Felling Lever: A felling lever provides mechanical advantage to help push the tree over.
Winch: A winch can be used to pull the tree over in the desired direction.

Takeaway: Felling is a complex and dangerous task that requires careful planning and execution. Always assess the tree and its surroundings, create a proper hinge, and use wedges or a felling lever to control the fall. I’ve seen trees fall in unexpected directions due to poor planning, and the results can be catastrophic.

Pro Tip #3: Chainsaw Maintenance: Keeping Your MS 660 in Top Condition

Regular maintenance is essential for keeping your MS 660 running smoothly and safely. A well-maintained saw is a safer saw.

Daily Maintenance: Before and After Each Use

Chain Sharpening: Keep the chain sharp. A dull chain is more likely to kick back and requires more force to cut, increasing the risk of fatigue. I use a file and guide for field sharpening and a grinder for more thorough sharpening.
Chain Tension: Check and adjust the chain tension. A loose chain can derail, while a tight chain can overheat and break.
Bar Lubrication: Ensure the bar is properly lubricated. A dry bar will wear out quickly and can cause the chain to bind.
Air Filter: Clean the air filter regularly. A dirty air filter can reduce engine power and increase fuel consumption.
Spark Plug: Inspect the spark plug and replace it if necessary. A fouled spark plug can cause starting problems.
Fuel Filter: Check the fuel filter and replace it if necessary. A clogged fuel filter can restrict fuel flow and cause engine stalling.

Periodic Maintenance: Longer-Term Care

Carburetor Adjustment: Have the carburetor adjusted by a qualified technician periodically. A properly adjusted carburetor ensures optimal engine performance and fuel efficiency.
Chain Sprocket: Inspect the chain sprocket for wear and replace it if necessary. A worn sprocket can damage the chain and bar.
Bar Rails: Check the bar rails for wear and dress them if necessary. Worn bar rails can cause the chain to bind.
Cooling Fins: Clean the cooling fins on the cylinder head to prevent overheating.
Exhaust Port: Clean the exhaust port to prevent carbon buildup.

Proper Storage: Protecting Your Investment

Drain Fuel: Drain the fuel tank before storing the saw for extended periods.
Clean Saw: Clean the saw thoroughly.
Store in a Dry Place: Store the saw in a dry place.
Bar Scabbard: Use a bar scabbard to protect the bar and chain.

Takeaway: A well-maintained chainsaw is a safer and more efficient chainsaw. Follow a regular maintenance schedule to keep your MS 660 in top condition. I’ve learned the hard way that neglecting maintenance can lead to costly repairs and dangerous situations.

Pro Tip #4: Handling Large Log Sections: Safe Lifting and Moving Techniques

Large log sections are heavy and awkward to handle. Proper lifting and moving techniques are essential to prevent back injuries and other musculoskeletal problems.

Assessing the Weight: Don’t Overestimate Your Abilities

Before attempting to lift or move a log section, accurately assess its weight. Err on the side of caution.

Diameter: The larger the diameter, the heavier the log.
Length: The longer the log, the heavier it is.
Wood Density: Hardwoods are denser and heavier than softwoods.
Moisture Content: Wet wood is heavier than dry wood.

Using Mechanical Aids: Taking the Strain Off Your Body

Whenever possible, use mechanical aids to lift and move large log sections.

Log Splitter: A log splitter can be used to split large logs into smaller, more manageable pieces.
Log Lifter: A log lifter can be used to lift logs onto a trailer or truck.
Skidding Tongs: Skidding tongs can be used to drag logs across the ground.
Come-Along: A come-along can be used to pull logs into position.
Tractor with Loader: A tractor with a loader is the most efficient way to move large log sections.

Proper Lifting Technique: Protecting Your Back

If you must lift a log section manually, use proper lifting technique.

Bend Your Knees: Bend your knees and keep your back straight.
Keep the Load Close: Keep the log section close to your body.
Lift with Your Legs: Lift with your legs, not your back.
Avoid Twisting: Avoid twisting your body while lifting.
Get Help: If the log section is too heavy, get help.

Rolling Logs: A Safer Alternative to Lifting

Rolling logs is often a safer alternative to lifting.

Log Peavey: A log peavey is a tool used to roll logs.
Leverage: Use leverage to your advantage.
Stable Footing: Ensure you have stable footing.

Takeaway: Handling large log sections can be physically demanding. Use mechanical aids whenever possible, and always use proper lifting technique to protect your back. I’ve learned the importance of this through personal experience. A back injury can sideline you for weeks, or even months.

Pro Tip #5: Understanding Wood Properties: Optimizing Your Cutting Strategy

Understanding the properties of different types of wood can help you optimize your cutting strategy and improve your efficiency.

Hardwoods vs. Softwoods: Knowing Your Wood

Hardwoods: Hardwoods, such as oak, maple, and ash, are generally denser and more difficult to cut than softwoods. They also tend to burn longer and produce more heat.
Softwoods: Softwoods, such as pine, fir, and spruce, are generally less dense and easier to cut than hardwoods. They also tend to burn faster and produce less heat.

Grain Direction: Cutting with the Grain

Cutting with the grain is generally easier than cutting against the grain.

Straight Grain: Wood with a straight grain is easier to split and cut.
Knotty Grain: Wood with a knotty grain is more difficult to split and cut.

Moisture Content: The Key to Efficient Burning

The moisture content of wood affects its burning characteristics.

Green Wood: Green wood has a high moisture content and is difficult to burn. It also produces a lot of smoke.
Seasoned Wood: Seasoned wood has a low moisture content and burns easily. It also produces less smoke.
Ideal Moisture Content: The ideal moisture content for firewood is between 15% and 20%.

Drying Wood: The Seasoning Process

Stacking: Stack the wood in a single row, allowing for good air circulation.
Elevation: Elevate the wood off the ground to prevent moisture absorption.
Sunlight: Expose the wood to sunlight to speed up the drying process.
Time: Allow the wood to season for at least six months, or preferably a year.

Takeaway: Understanding the properties of different types of wood can help you optimize your cutting strategy and improve your efficiency. Seasoning wood properly is essential for efficient burning. I always test my firewood with a moisture meter before burning it to ensure optimal performance.

Conclusion: Respect the Saw, Respect the Log, Respect Yourself

The Stihl MS 660 is a formidable tool, capable of tackling the largest logs with ease. However, it demands respect and a thorough understanding of safe operating procedures. By following the tips and advice in this guide, you can harness the power of the MS 660 safely and efficiently. Remember to prioritize safety above all else. Invest in quality PPE, maintain your saw regularly, and use proper techniques for lifting, moving, and cutting logs. With practice and patience, you can master the art of large log handling and enjoy the satisfaction of transforming massive trees into usable lumber or firewood. And always remember Buster, and the importance of making sure you make it home safe to your loved ones every day.