Stihl 660 Specs (5 Pro Tips for Safe Large-Log Cutting)

Have you ever felt the raw, untamed power of a chainsaw in your hands, the earth trembling slightly beneath your feet as you prepare to fell a giant? There’s a primal satisfaction in transforming a massive log into manageable pieces, a connection to nature and a testament to human ingenuity. But with great power comes great responsibility. That’s why understanding your equipment, like the legendary Stihl MS 660, and mastering safe cutting techniques is absolutely crucial. This isn’t just about getting the job done; it’s about getting it done safely and efficiently, respecting both the wood and yourself.

Stihl MS 660: A Beast of a Chainsaw

The Stihl MS 660. The name itself evokes images of towering trees and demanding tasks. It’s a chainsaw that has earned its reputation as a workhorse, a go-to for professionals and demanding users who need serious power and reliability. But before you unleash this beast, let’s get acquainted with its specifications.

Key Specifications of the Stihl MS 660

Why these specs matter:

• Engine Displacement: The 91.6 cc engine is the heart of the MS 660. It’s what gives it the raw power to tackle large-diameter logs with relative ease. This is a significant jump from smaller homeowner-grade chainsaws, and it translates directly into cutting performance.
• Power Output: The 7.1 bhp speaks for itself. It’s a substantial amount of power, enabling the saw to maintain cutting speed even under heavy load. This is crucial when working with dense hardwoods.
• Weight: At 16.1 lbs (powerhead only), the MS 660 is not a lightweight saw. This weight contributes to its stability during cutting but also demands more physical exertion from the operator. This is why proper technique and physical conditioning are essential.
• Guide Bar Length: The recommended guide bar length range (20″-36″) provides versatility for different log sizes. Choosing the right bar length for the job is crucial for safety and efficiency.
• Chain Pitch: The .404″ chain pitch is designed for heavy-duty cutting. It offers aggressive cutting performance but also requires more power to drive.
• Oilomatic Chain Type: Proper lubrication is vital for chainsaw performance and longevity. Stihl’s Oilomatic system ensures consistent oil delivery to the chain, reducing friction and wear.

My Experience: I remember the first time I used an MS 660. I was tasked with felling a massive oak tree that had fallen during a storm. I had used smaller chainsaws before, but the MS 660 felt like a completely different animal. The power was immense, and it sliced through the oak like butter. However, I quickly learned that respecting its power was paramount. The weight and vibration could be tiring, and any lapse in concentration could be dangerous.

Understanding the Stihl MS 660’s Features

Beyond the raw specifications, the MS 660 boasts several features designed to enhance performance and user experience:

• Decompression Valve: This valve releases some of the cylinder pressure during starting, making it significantly easier to pull the starter cord. This is a godsend, especially when the saw is cold or you’re starting it on uneven terrain.
• Side-Access Chain Tensioner: Adjusting chain tension is a regular maintenance task. The side-access tensioner makes this process much easier and safer than having to reach around a hot muffler.
• Adjustable Oiler: The ability to adjust the oil flow to the chain allows you to optimize lubrication based on the type of wood you’re cutting and the bar length you’re using.
• Anti-Vibration System: Chainsaws generate a significant amount of vibration, which can lead to fatigue and long-term health problems. Stihl’s anti-vibration system helps to dampen these vibrations, reducing strain on your hands and arms.
• Master Control Lever: This single lever controls choke, start, run, and stop functions, simplifying the starting and stopping process.

Wood Anatomy and Properties: Know Your Enemy (or Your Friend)

Before you sink your chainsaw into a log, it’s crucial to understand the wood itself. Wood is not a homogenous material; its properties vary significantly depending on the species, moisture content, and even the part of the tree it comes from.

Hardwood vs. Softwood

The most basic distinction in wood is between hardwoods and softwoods. This classification is based on the tree’s botanical structure, not necessarily the actual hardness of the wood.

• Hardwoods: Typically deciduous trees (trees that lose their leaves seasonally), hardwoods are generally denser and more complex in structure than softwoods. Examples include oak, maple, cherry, and walnut. They tend to burn hotter and longer, making them ideal for firewood.
• Softwoods: Typically coniferous trees (trees that have needles and cones), softwoods are generally less dense and easier to work with than hardwoods. Examples include pine, fir, spruce, and cedar. They are often used for construction and paper production.

Data Point: Hardwoods typically have a higher BTU (British Thermal Unit) rating than softwoods. For example, seasoned oak can have a BTU rating of around 28 million per cord, while seasoned pine might have a rating of around 20 million per cord.

Grain Structure

The grain of wood refers to the arrangement of wood fibers. Understanding grain is crucial for predicting how wood will split, warp, and react to cutting.

• Straight Grain: Wood with straight, parallel grain is generally easier to split and work with.
• Interlocked Grain: Wood with interlocked grain has fibers that run in different directions, making it more difficult to split and more prone to warping.
• Knotty Wood: Knots are remnants of branches and can significantly affect the strength and workability of wood. They can also dull chainsaw chains quickly.

Moisture Content

The moisture content of wood plays a critical role in its weight, strength, and burning characteristics.

• Green Wood: Freshly cut wood has a high moisture content, often exceeding 50%. It is heavy, difficult to burn, and prone to rot and insect infestation.
• Seasoned Wood: Seasoned wood has been allowed to dry, reducing its moisture content to around 20% or less. It is lighter, easier to burn, and less prone to rot.

Data Point: Seasoning wood can take anywhere from 6 months to 2 years, depending on the species, climate, and stacking method. Proper seasoning can increase the BTU output of firewood by as much as 50%.

My Insight: I’ve learned the hard way that trying to split green oak is an exercise in futility. The wood is so dense and the fibers are so tightly bound that it’s almost impossible to split with a maul. Seasoning makes all the difference.

Identifying Wood Species

Being able to identify different wood species is a valuable skill for anyone working with wood. Different species have different properties, which can affect how you cut, split, and season them.

• Bark: The bark of a tree is often a good indicator of its species.
• Leaves: If the tree is still standing, the leaves can be used to identify it.
• Grain Pattern: The grain pattern of the wood can also be helpful in identifying the species.
• Smell: Some woods have distinctive smells that can aid in identification.

Resource: There are many field guides and online resources available to help you identify different wood species.

Logging Tool Selection and Maintenance Best Practices

The Stihl MS 660 is a powerful tool, but it’s just one piece of the puzzle. To safely and effectively cut large logs, you need a range of other tools, and you need to know how to maintain them properly.

Essential Logging Tools

• Chainsaw: Obviously, the MS 660 is the star of the show, but you might also consider having a smaller chainsaw for limbing and smaller cuts.
• Axes and Mauls: For splitting firewood and felling smaller trees.
• Wedges: Used to prevent the saw from binding when felling trees and to help split stubborn logs.
• Sledgehammer: Used to drive wedges.
• Cant Hook or Peavey: Used to roll and position logs.
• Measuring Tape: Essential for cutting logs to the desired length.
• Marking Crayon or Paint: Used to mark cut lines.
• First Aid Kit: A well-stocked first aid kit is essential for any logging operation.
• Personal Protective Equipment (PPE): This includes a helmet, eye protection, hearing protection, gloves, chainsaw chaps, and steel-toed boots.

Chainsaw Maintenance

Regular maintenance is crucial for keeping your Stihl MS 660 running smoothly and safely.

• Chain Sharpening: A sharp chain is essential for efficient cutting and safety. Learn how to sharpen your chain properly using a file or a chain grinder.
• Chain Tension: Proper chain tension is crucial for preventing the chain from derailing and for maximizing cutting performance. Check the chain tension before each use and adjust as needed.
• Air Filter: A clean air filter is essential for maintaining engine performance. Clean the air filter regularly with compressed air or soap and water.
• Spark Plug: A faulty spark plug can cause starting problems and poor engine performance. Replace the spark plug annually or as needed.
• Fuel Filter: A clogged fuel filter can restrict fuel flow and cause engine problems. Replace the fuel filter annually or as needed.
• Bar and Chain Oil: Use a high-quality bar and chain oil to lubricate the chain and prevent wear. Check the oil level regularly and refill as needed.
• Cleaning: Keep your chainsaw clean by removing sawdust and debris after each use.

My Tip: I always keep a spare chain on hand, sharpened and ready to go. There’s nothing more frustrating than having to stop cutting to sharpen a dull chain in the middle of a job.

Axe and Maul Maintenance

• Sharpening: Keep your axes and mauls sharp using a file or a grinding wheel.
• Handle Inspection: Regularly inspect the handle for cracks or damage. Replace the handle if necessary.
• Head Attachment: Ensure the head is securely attached to the handle.

Wedge Maintenance

• Inspection: Regularly inspect wedges for cracks or damage. Replace them as needed.

Firewood Seasoning Techniques and Safety Considerations

Once you’ve cut your logs into manageable pieces, the next step is to season them for firewood. Proper seasoning is crucial for maximizing the heat output and minimizing smoke.

Seasoning Methods

• Air Drying: The most common and cost-effective method of seasoning firewood. Stack the wood in a single row, off the ground, in a sunny and windy location. Allow the wood to dry for 6 months to 2 years, depending on the species and climate.
• Kiln Drying: A faster but more expensive method of seasoning firewood. Wood is placed in a kiln and dried using heat. Kiln-dried firewood typically has a moisture content of around 20% or less.

Data Point: Air drying can reduce the moisture content of firewood by about 2% per month in optimal conditions.

Stacking Methods

• Single Row: The most effective method for air drying firewood. Allows for maximum air circulation.
• Circular Stack: A visually appealing but less efficient method for air drying firewood.
• Crib Stack: A stable and space-efficient method for storing firewood.

My Stacking Secret: I always stack my firewood with the bark side up. This helps to shed water and prevent the wood from rotting. I also leave gaps between the rows to allow for better air circulation.

Safety Considerations

• Stack Stability: Ensure your firewood stacks are stable to prevent them from collapsing.
• Insect Infestation: Inspect your firewood for signs of insect infestation. Treat the wood if necessary.
• Fire Hazards: Keep firewood stacks away from buildings and other flammable materials.
• Personal Safety: Wear gloves and eye protection when handling firewood. Be careful when lifting heavy logs.

5 Pro Tips for Safe Large-Log Cutting with the Stihl MS 660

Now, let’s get to the heart of the matter: five essential pro tips to help you safely and effectively cut large logs with your Stihl MS 660.

1. Master the Bore Cut (with Extreme Caution)

The bore cut, also known as the plunge cut, is a technique used to cut into the center of a log without cutting in from the sides. This is particularly useful for removing sections of large logs or for felling trees with a lean. However, it’s also one of the most dangerous chainsaw techniques and should only be attempted by experienced users who fully understand the risks.

How to Perform a Bore Cut (Safely):

1. Preparation: Ensure your chain is razor-sharp and properly tensioned. Position yourself firmly and have a clear escape route.
2. Pilot Hole (Optional but Recommended): Before attempting the full bore cut, consider making a small pilot hole with the tip of the bar. This helps to guide the bar and prevent kickback.
3. Controlled Entry: With the saw running at full throttle, slowly and deliberately plunge the tip of the bar into the wood at a slight angle. Use the bumper spikes to maintain control.
4. Maintain Angle: As the bar penetrates the wood, maintain a consistent angle and avoid forcing the saw.
5. Watch for Pinching: Be extremely vigilant for signs of pinching, which can lead to kickback. If the saw starts to bind, stop immediately and use wedges to relieve the pressure.
6. Complete the Cut: Once the bar has penetrated the desired depth, carefully pivot the saw to complete the cut.

Why it’s Dangerous: The tip of the chainsaw bar is a kickback zone. If the tip contacts an object or the wood pinches the bar, the saw can violently kick back towards the operator.

Safety Precautions:

• Never perform a bore cut above shoulder height.
• Always use a chainsaw with a chain brake.
• Wear appropriate PPE, including a helmet, eye protection, and chainsaw chaps.
• Maintain a firm grip on the saw with both hands.
• Be aware of your surroundings and potential hazards.
• If you are not comfortable performing a bore cut, don’t do it. There are often alternative methods that are safer.

My Experience: I once witnessed a fellow logger suffer a serious injury from a kickback while performing a bore cut. He was lucky to escape with his life. That incident reinforced the importance of respecting the power of a chainsaw and understanding the risks involved in every cutting technique.

2. Wedges are Your Best Friends

When cutting large logs, especially those under tension, the saw blade can easily become pinched, making it difficult to continue cutting and increasing the risk of kickback. Wedges are your allies in preventing this.

How to Use Wedges:

1. Identify Potential Pinch Points: Before you start cutting, assess the log for signs of tension or compression. Look for cracks, bends, or other indications that the wood might pinch the saw blade.
2. Make Your Initial Cut: Start your cut, and as soon as you have enough space, insert a wedge into the cut behind the saw blade.
3. Drive the Wedge: Use a sledgehammer to drive the wedge further into the cut, opening it up and relieving the pressure on the saw blade.
4. Continue Cutting: Continue cutting, adding more wedges as needed to keep the cut open.

Types of Wedges:

• Plastic Wedges: Lightweight and durable, plastic wedges are ideal for general-purpose use.
• Aluminum Wedges: Stronger than plastic wedges, aluminum wedges are suitable for heavier-duty applications.
• Steel Wedges: The strongest type of wedge, steel wedges are used for the most demanding tasks. However, be extremely careful when using steel wedges near a chainsaw blade, as contact can damage the chain and potentially cause a dangerous kickback.

My Wedge Wisdom: I always carry a variety of wedges in different sizes and materials. Having the right wedge for the job can make a huge difference in safety and efficiency.

3. The Importance of a Sharp Chain (and How to Maintain It)

A dull chainsaw chain is not only inefficient, but it’s also dangerous. It requires more force to cut, increasing the risk of kickback and fatigue. A sharp chain, on the other hand, bites into the wood effortlessly, making cutting safer and more enjoyable.

Signs of a Dull Chain:

• Sawdust instead of chips: A sharp chain produces long, thin chips of wood. A dull chain produces fine sawdust.
• Excessive vibration: A dull chain causes the saw to vibrate more than usual.
• Burning smell: A dull chain can generate excessive heat, causing a burning smell.
• Difficulty starting the cut: A dull chain requires more force to start a cut.

How to Sharpen a Chainsaw Chain:

1. Secure the Saw: Place the chainsaw in a vise or on a stable surface.
2. Use the Correct File: Use a chainsaw file that is the correct size and shape for your chain.
3. File at the Correct Angle: File each cutter at the correct angle, following the manufacturer’s instructions.
4. Maintain Consistent Pressure: Use consistent pressure and stroke length when filing each cutter.
5. Check the Depth Gauges: Use a depth gauge tool to ensure the depth gauges are at the correct height.
6. Sharpen Regularly: Sharpen your chain regularly, ideally after every few tanks of fuel.

My Sharpening Secret: I use a chain grinder to sharpen my chains quickly and accurately. It’s a worthwhile investment for anyone who uses a chainsaw frequently.

4. Plan Your Cuts Before You Start

Before you even fire up your Stihl MS 660, take the time to carefully plan your cuts. This will help you to avoid mistakes, minimize waste, and ensure your safety.

Factors to Consider:

• Log Size and Shape: Assess the size and shape of the log and determine the best way to cut it into manageable pieces.
• Grain Direction: Pay attention to the grain direction of the wood. Cutting with the grain is generally easier and safer than cutting against the grain.
• Tension and Compression: Identify any areas of tension or compression in the log. These areas can cause the saw blade to pinch or bind.
• Obstacles: Be aware of any obstacles in the area, such as rocks, roots, or branches.
• Escape Route: Always have a clear escape route in case of a kickback or other emergency.

Cutting Techniques:

• Bucking: Cutting a log into shorter lengths.
• Limbing: Removing branches from a felled tree.
• Felling: Cutting down a standing tree.

My Planning Process: I always walk around the log and visually inspect it from all angles before I start cutting. I look for any potential hazards and plan my cuts accordingly.

5. Respect the Power (and the Weight)

The Stihl MS 660 is a powerful machine, but it’s also a heavy one. Its weight can contribute to fatigue, which can lead to mistakes and injuries. It’s crucial to respect the power and the weight of the saw and to take breaks when needed.

Tips for Managing Fatigue:

• Use Proper Lifting Techniques: When lifting the chainsaw, use your legs, not your back.
• Take Frequent Breaks: Take short breaks every 20-30 minutes to rest and stretch.
• Stay Hydrated: Drink plenty of water to stay hydrated.
• Eat Nutritious Food: Eat a balanced diet to provide your body with the energy it needs.
• Listen to Your Body: If you’re feeling tired or sore, stop cutting and rest.

Proper Posture and Grip:

• Stand with your feet shoulder-width apart.
• Maintain a firm grip on the saw with both hands.
• Keep your back straight and your knees slightly bent.
• Avoid overreaching or twisting.

My Fatigue Fighting Strategy: I always start my cutting sessions with a warm-up routine to prepare my muscles. I also listen to my body and take breaks when I need them. There’s no shame in admitting that you’re tired. It’s better to take a break than to push yourself too hard and risk injury.

Project Planning and Execution: From Tree to Firewood

Now that you’re armed with knowledge and safety tips, let’s talk about planning and executing a wood processing project, from felling the tree to stacking the firewood.

1. Assessment and Permitting

• Tree Assessment: Evaluate the tree for health, lean, and potential hazards.
• Permitting: Check local regulations regarding tree removal. Some areas require permits for felling trees, especially if they are on public land or are of a certain size.

2. Felling (If Applicable)

• Planning the Fall: Determine the direction the tree will fall, considering wind, lean, and obstacles.
• Notch Cut: Create a notch on the side of the tree facing the desired fall direction. The notch should be about one-third of the tree’s diameter.
• Back Cut: Make a back cut on the opposite side of the tree, slightly above the notch. Leave a hinge of wood to control the fall.
• Wedges: Use wedges to help direct the fall and prevent the saw from binding.
• Retreat: As the tree begins to fall, move quickly and safely away from the tree along your planned escape route.

Important Safety Note: Felling trees is a dangerous task that should only be attempted by experienced individuals. If you are not comfortable felling a tree, hire a professional arborist.

3. Bucking and Limbing

• Bucking: Cut the felled tree into manageable lengths for firewood. Use wedges to prevent the saw from binding.
• Limbing: Remove the branches from the felled tree. Be careful of spring poles, which are branches under tension that can snap back when cut.

4. Splitting

• Manual Splitting: Use an axe or maul to split the logs into smaller pieces.
• Hydraulic Splitter: Use a hydraulic splitter to split the logs more quickly and easily.

Comparison: Manual vs. Hydraulic Splitters

My Take: For small-scale firewood production, a manual splitter is often sufficient. However, for larger projects or for those with physical limitations, a hydraulic splitter can be a worthwhile investment.

5. Stacking and Seasoning

• Stacking: Stack the split firewood in a single row, off the ground, in a sunny and windy location.
• Seasoning: Allow the wood to dry for 6 months to 2 years, depending on the species and climate.

Case Study: From Storm Damage to Winter Warmth

Let me share a personal experience that highlights the importance of these techniques. A few years ago, a severe ice storm ravaged my property, downing several large oak trees. It was a daunting task to clean up the mess, but it also presented an opportunity to replenish my firewood supply.

I started by carefully assessing the situation, identifying the safest way to fell the remaining damaged trees. I used the bore cut technique (with extreme caution) to remove sections of the larger logs that were under tension. Wedges were my constant companions, preventing the saw from binding and ensuring my safety.

I spent weeks bucking, limbing, and splitting the wood. It was hard work, but the satisfaction of transforming storm damage into a source of warmth was immense. I carefully stacked the firewood in single rows, allowing it to season properly over the summer.

That winter, as the snow fell and the temperatures plummeted, I was grateful for the hours of hard work I had put in. The seasoned oak burned hot and long, keeping my family warm and comfortable. It was a tangible reminder of the power of nature and the resourcefulness of human effort.

Key Takeaways and Next Steps

Cutting large logs with a Stihl MS 660 is a demanding but rewarding task. By understanding the specifications of the saw, the properties of wood, and the importance of safety, you can tackle even the most challenging projects with confidence.

Key Takeaways:

• Respect the Power: The Stihl MS 660 is a powerful machine that demands respect.
• Prioritize Safety: Always wear appropriate PPE and follow safe cutting techniques.
• Maintain Your Equipment: Regular maintenance is crucial for performance and safety.
• Plan Your Cuts: Carefully plan your cuts before you start.
• Manage Fatigue: Take breaks and listen to your body.

Next Steps:

• Practice: Practice your cutting techniques in a safe and controlled environment.
• Seek Training: Consider taking a chainsaw safety course to learn from experienced instructors.
• Join a Community: Connect with other woodworkers and share your knowledge and experiences.
• Stay Informed: Stay up-to-date on the latest chainsaw safety and maintenance techniques.

The Stihl MS 660, coupled with the right knowledge and a healthy dose of respect, is a powerful tool that can help you transform raw logs into a valuable resource. So, go forth, be safe, and enjoy the satisfaction of working with wood.

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