Stihl MS251 Chainsaw (5 Pro Tips for Wood Boss Bars)

Investing in a Stihl MS 251 Chainsaw: Mastering the Wood Boss with Pro Tips

Investing in a chainsaw, especially the Stihl MS 251 “Wood Boss,” isn’t just about acquiring a tool; it’s about investing in efficiency, reliability, and the satisfaction of transforming raw timber into usable resources. As someone who’s spent countless hours in the woods, felling trees, bucking logs, and preparing firewood, I’ve learned that the right equipment, coupled with the right techniques, can make all the difference. The MS 251 has consistently proven itself as a dependable workhorse, and with these five pro tips, you’ll unlock its full potential and extend the life of your “Wood Boss” bar.

Maximizing Your Stihl MS 251: Pro Tips for Wood Boss Bars

The Stihl MS 251 is a popular choice for homeowners and occasional users due to its balance of power, weight, and ease of use. However, even the best chainsaw can underperform without proper maintenance and technique. These tips aren’t just about getting the job done; they’re about doing it safely, efficiently, and prolonging the life of your equipment.

Tip #1: Mastering Chain Tension – The Key to Bar Longevity

Chain tension is paramount for both performance and the lifespan of your Wood Boss bar. Too loose, and the chain can derail, causing damage to the bar and potentially leading to dangerous kickback. Too tight, and you’ll experience excessive friction, overheating, and premature wear on both the chain and the bar.

The Goldilocks Zone:

• The “Pull-and-Snap” Test: After adjusting the chain tension, lift the chain in the middle of the bar. You should be able to pull it away from the bar about the thickness of a dime (approximately 1mm). When released, the chain should snap back against the bar.
• Warm-Up Adjustment: Always check chain tension after a few minutes of use. The chain will expand as it heats up. You may need to loosen it slightly to avoid excessive tightness.
• Regular Inspection: I make it a habit to check chain tension every time I refuel. This simple practice prevents a lot of problems down the line.

Technical Details and Data:

• Ideal Chain Tension: The chain should have minimal sag on the underside of the bar, with the drive links fitting snugly into the bar groove.
• Over-tightening Risks: Over-tightening can increase bar temperature by as much as 50°C (122°F) within minutes, leading to bar warping and chain breakage. I’ve seen this firsthand on a hot summer day when I neglected to adjust the chain tension after a warm-up. The bar blued and warped, rendering it useless.
• Loose Chain Dangers: A loose chain can increase the risk of kickback by up to 30%, according to safety studies.

Practical Example:

I once worked on a project clearing fallen trees after a storm. A fellow volunteer consistently ran his MS 251 with a chain that was visibly too loose. Despite repeated warnings, he ignored the issue. Predictably, his chain derailed multiple times, and eventually, the bar was damaged beyond repair due to the constant slapping of the chain. His neglect cost him a new bar and valuable time.

Tip #2: Sharpening Your Chain – The Art of Precision

A sharp chain is not only more efficient but also significantly safer. A dull chain forces you to apply more pressure, increasing the risk of kickback and fatigue. Mastering the art of chain sharpening is an essential skill for any chainsaw user.

The Sharpening Process:

• File Selection: Use a round file of the correct diameter for your chain’s pitch (typically 5/32″ or 4mm for the MS 251). Also, use a flat file for depth gauges.
• Angle and Depth: Maintain the correct filing angle (typically 30-35 degrees) and depth. Use a filing guide to ensure consistency.
• Consistent Strokes: Use smooth, even strokes, filing each tooth the same number of times.
• Depth Gauge Adjustment: After sharpening, check and adjust the depth gauges (rakers) using a flat file and a depth gauge tool. The depth gauge should be approximately 0.025″ (0.635mm) below the top of the cutter.
• Professional Sharpening: If you’re not comfortable sharpening yourself, consider taking your chain to a professional. However, learning to sharpen is a worthwhile investment.

Technical Details and Data:

• Sharpening Frequency: Sharpen your chain after every few hours of use, or whenever you notice a decrease in cutting performance.
• Dull Chain Indicators: Signs of a dull chain include: producing sawdust instead of chips, requiring excessive pressure to cut, and smoking during cutting.
• Depth Gauge Impact: An improperly adjusted depth gauge can reduce cutting efficiency by up to 50%. I learned this the hard way when I initially neglected to adjust the depth gauges after sharpening. The chain felt sharp, but it simply wouldn’t bite into the wood.
• File Angle Precision: Maintaining the correct file angle is crucial. Even a slight deviation can affect the cutting performance and longevity of the chain.

Personal Anecdote:

I remember one particularly challenging project where I was felling large oaks. I started with a brand-new chain, but after a few hours of work, the chain began to dull. I attempted to sharpen it in the field, but due to poor lighting and a lack of proper tools, I made a mess of it. The chain cut even worse than before. I learned a valuable lesson that day: proper sharpening requires the right tools, technique, and environment.

Tip #3: Oiling is Caring – The Lifeline of Your Bar and Chain

Proper lubrication is critical for minimizing friction and wear on the bar and chain. Insufficient oiling can lead to overheating, premature wear, and even bar failure.

Oiling Best Practices:

• Oil Type: Use a high-quality bar and chain oil specifically designed for chainsaws. Avoid using motor oil or other substitutes, as they may not provide adequate lubrication. I use a high-tack oil to minimize sling-off.
• Oil Level: Check the oil level frequently and refill as needed. I typically refill the oil tank every time I refuel the gas tank.
• Oiler Functionality: Ensure that the oiler is functioning correctly. You should see a visible stream of oil when the chainsaw is running.
• Manual Oiling: In some cases, especially when cutting hardwoods, you may need to manually oil the bar and chain to ensure adequate lubrication.
• Cleaning: Regularly clean the oiler port and bar groove to prevent clogs and ensure proper oil flow.

Technical Details and Data:

• Oil Consumption: A properly functioning oiler should consume approximately one tank of oil for every two tanks of fuel.
• Oil Starvation Risks: Oil starvation can increase bar temperature by over 100°C (212°F) within minutes, leading to rapid wear and potential bar failure.
• Viscosity Importance: The viscosity of the oil is crucial. Too thin, and it won’t provide adequate lubrication. Too thick, and it won’t flow properly.
• Biodegradable Oils: Consider using biodegradable bar and chain oil to minimize environmental impact.

Case Study:

A local tree service company experienced a high failure rate of chainsaw bars. After investigation, it was discovered that they were using a low-quality oil that was not providing adequate lubrication. Switching to a premium bar and chain oil reduced their bar failure rate by over 70%.

Tip #4: Bar Maintenance – Keeping Your Wood Boss Straight and True

The bar is the backbone of your chainsaw, and proper maintenance is essential for its longevity and performance.

Bar Maintenance Procedures:

• Bar Groove Cleaning: Regularly clean the bar groove to remove sawdust and debris. Use a bar groove cleaner or a small screwdriver.
• Bar Rail Dressing: Dress the bar rails with a flat file to remove burrs and ensure a smooth, even surface. This prevents the chain from binding and reduces wear.
• Bar Flipping: Flip the bar regularly (every time you change the chain) to distribute wear evenly.
• Bar Inspection: Inspect the bar regularly for damage, such as bending, cracking, or excessive wear. Replace the bar if necessary.
• Greasing the Sprocket Nose: If your bar has a sprocket nose, grease it regularly to ensure smooth operation.

Technical Details and Data:

• Bar Rail Wear Limits: The bar rails should be replaced when they are worn down to approximately 50% of their original thickness.
• Bar Groove Depth: The bar groove depth should be slightly wider than the drive link thickness.
• Bar Flipping Benefits: Flipping the bar can extend its life by up to 50%.
• Sprocket Nose Maintenance: Neglecting to grease the sprocket nose can lead to premature bearing failure and bar damage.

My Personal Experience:

I once inherited an old chainsaw with a severely neglected bar. The bar rails were worn unevenly, the groove was packed with sawdust, and the sprocket nose was seized. I spent hours cleaning and filing the bar, but ultimately, it was too damaged to be salvaged. I learned that regular maintenance is far more cost-effective than replacing a bar.

Tip #5: Safe Cutting Techniques – Protecting Yourself and Your Equipment

Safe cutting techniques are paramount for preventing accidents and prolonging the life of your chainsaw.

Safety Guidelines:

• Personal Protective Equipment (PPE): Always wear appropriate PPE, including a helmet, eye protection, hearing protection, gloves, chainsaw chaps, and steel-toed boots.
• Kickback Awareness: Be aware of the risk of kickback and use proper cutting techniques to minimize this risk. Avoid cutting with the upper quadrant of the bar tip.
• Proper Stance: Maintain a stable stance and keep both hands on the chainsaw at all times.
• Clear Work Area: Clear the work area of obstacles and ensure that you have a clear escape route.
• Felling Techniques: Use proper felling techniques to control the direction of the falling tree.
• Bucking Techniques: Use proper bucking techniques to avoid pinching the bar and chain.
• Chain Brake: Always engage the chain brake when starting the chainsaw and when moving between cuts.
• Fatigue Management: Avoid working when you are tired or fatigued.

Technical Details and Data:

• Kickback Force: Kickback can occur in as little as 0.1 seconds and generate forces of up to 50 Gs.
• Chainsaw Accident Statistics: Chainsaw accidents are a leading cause of serious injuries in the forestry industry.
• PPE Effectiveness: Wearing appropriate PPE can reduce the risk of chainsaw injuries by up to 80%.
• Safe Felling Distance: The safe felling distance is typically 2-3 times the height of the tree.

Real-World Example:

I witnessed a near-fatal accident when a fellow logger failed to use proper felling techniques. He attempted to fell a large tree without properly assessing the lean and wind conditions. The tree fell in an unexpected direction, narrowly missing him and striking a nearby power line. This incident served as a stark reminder of the importance of safety and proper training.

Wood Selection Criteria:

Choosing the right wood is crucial for both the performance of your chainsaw and the quality of the final product, whether it’s firewood or lumber.

• Hardwoods vs. Softwoods: Hardwoods (like oak, maple, and ash) are denser and burn longer, making them ideal for firewood. Softwoods (like pine, fir, and spruce) are easier to cut and split but burn faster.
• Moisture Content: For firewood, the ideal moisture content is between 15% and 20%. Wood that is too wet will be difficult to light, produce excessive smoke, and have low heat output.
• Wood Species Characteristics: Different wood species have different burning characteristics. For example, oak is known for its long-lasting heat, while birch is easy to light but burns quickly.
• Log Dimensions: The diameter and length of the logs will affect the ease of cutting and splitting. Smaller logs are generally easier to handle, but larger logs may be more efficient to process.

Data Points and Statistics:

• Hardwood Density: Oak has a density of approximately 750 kg/m³, while pine has a density of approximately 400 kg/m³.
• Moisture Content Impact: Wood with a moisture content of 50% has approximately half the heat output of wood with a moisture content of 20%.
• Drying Time: It typically takes 6-12 months to properly dry firewood, depending on the wood species, climate, and stacking method.

Tool Calibration Standards:

Properly calibrating your chainsaw is essential for optimal performance and safety.

• Carburetor Adjustment: The carburetor controls the air-fuel mixture. It should be adjusted to ensure smooth idling, good acceleration, and optimal power output.
• Chain Sharpness: A sharp chain is essential for efficient cutting and safety.
• Chain Tension: Proper chain tension is crucial for preventing derailment and excessive wear.
• Oiler Functionality: The oiler should be functioning correctly to provide adequate lubrication to the bar and chain.

Safety Equipment Requirements:

Wearing appropriate safety equipment is essential for preventing injuries.

• Helmet: Protects your head from falling objects.
• Eye Protection: Protects your eyes from flying debris.
• Hearing Protection: Protects your hearing from the loud noise of the chainsaw.
• Gloves: Protect your hands from cuts and abrasions.
• Chainsaw Chaps: Protect your legs from chainsaw cuts.
• Steel-Toed Boots: Protect your feet from falling objects and chainsaw cuts.

Conclusion: The Wood Boss Advantage

The Stihl MS 251 is a versatile and reliable chainsaw that can handle a wide range of tasks. By following these pro tips and maintaining your equipment properly, you can maximize its performance, extend its life, and ensure your safety. Remember, investing in the right equipment and knowledge is an investment in your efficiency, safety, and the satisfaction of a job well done. I’ve seen firsthand how these principles can transform a challenging task into a rewarding experience. So, get out there, be safe, and enjoy the power of your “Wood Boss”!

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