Chainsaw Chain For Stihl MS250 (Expert Tips On Sprocket Care)

Let’s face it, we’ve all been there. You’re in the thick of splitting firewood, the satisfying thwack of the maul a rhythmic symphony against the backdrop of a crisp autumn day. Then, disaster strikes. Your trusty Stihl MS250 chainsaw, the workhorse you rely on, starts bucking and spitting. The cut is ragged, smoke billows, and the chain is duller than a butter knife. In my experience, more often than not, the problem isn’t just the chain itself; it’s often a neglected sprocket.

I remember one particularly brutal winter a few years back. I was behind on my firewood, and a surprise snowstorm was bearing down. Desperate, I pushed my MS250 harder than I should have. The chain was constantly getting pinched, and I spent more time filing it than cutting. Eventually, the drive sprocket gave way, leaving me stranded with a half-finished woodpile and a very cold house. That’s when I learned the hard way that neglecting the sprocket is like ignoring the foundation of your wood-cutting operation.

This article isn’t just about finding the right chainsaw chain for your Stihl MS250; it’s about understanding the entire system, with a special focus on sprocket care. We’ll dive deep into the types of chains, the importance of proper tension, and, crucially, how to maintain your sprocket to keep your saw running smoothly and safely for years to come. I’ll share tips and tricks I’ve learned over years of cutting, splitting, and stacking, ensuring you avoid the same pitfalls I stumbled into.

Choosing the Right Chainsaw Chain for Your Stihl MS250

The Stihl MS250 is a versatile saw, popular for its balance of power and portability. However, it’s crucial to select the right chain for the job. Using the wrong chain can lead to poor performance, increased wear and tear, and even dangerous kickback.

Understanding Chain Types

Chainsaw chains aren’t a one-size-fits-all affair. They come in various configurations, each designed for specific applications. Here’s a breakdown of the most common types:

Low-Profile Chains (Picco Micro): These chains, like Stihl’s Picco Micro series, are designed for smaller saws and users with less experience. They feature a rounded cutter design that reduces kickback potential, making them ideal for limbing and light-duty firewood cutting. I often recommend these to beginners, as they’re more forgiving.
Semi-Chisel Chains: A good all-around choice, semi-chisel chains offer a balance of cutting speed and durability. The cutters have a slightly rounded corner, making them more resistant to dirt and debris than full-chisel chains. These are my go-to for general firewood cutting and tackling moderately dirty wood.
Full-Chisel Chains: These chains are the speed demons of the chainsaw world. With their square-cornered cutters, they slice through clean wood with incredible efficiency. However, they dull quickly when exposed to dirt or abrasive materials. I reserve these for felling clean timber and processing wood that’s been carefully debarked.
Ripping Chains: Designed specifically for cutting wood lengthwise (with the grain), ripping chains have a unique cutter angle that produces smooth, consistent cuts. These are essential if you’re milling lumber with your MS250, though that’s not its primary purpose.
Carbide-Tipped Chains: These chains are a significant investment, but they offer exceptional durability. The carbide-tipped cutters can withstand significantly more abuse than steel cutters, making them ideal for cutting dirty wood, reclaimed lumber, or even roots.

Matching the Chain to Your Stihl MS250

The Stihl MS250 typically uses a 3/8″ low profile chain with a .050″ gauge (thickness of the drive links). The number of drive links will depend on the bar length. Common bar lengths for the MS250 are 16″ and 18″, requiring 55 and 61 drive links, respectively.

Data Point: Using the wrong gauge chain can damage your bar and sprocket. Always check your saw’s manual or the bar itself for the correct specifications.

Here’s a quick reference table:

Bar Length	Chain Pitch	Chain Gauge	Drive Links (Approximate)	Common Chain Type
16″	3/8″ Low Profile	.050″	55	Picco Micro, Semi-Chisel
18″	3/8″ Low Profile	.050″	61	Picco Micro, Semi-Chisel

Important Note: Always double-check your specific saw and bar before purchasing a chain. Bar length and drive link count can vary slightly.

My Preferred Chain for the MS250

For general firewood cutting with my MS250, I typically stick with a semi-chisel chain. It offers a good balance of cutting speed and durability, and it’s more forgiving if I accidentally nick the ground. I’ve had good luck with both Stihl’s own chains and Oregon brand chains.

Personal Experience: I once tried using a full-chisel chain on some seasoned oak that had been sitting in my yard for a while. The chain dulled incredibly quickly, and I ended up spending more time sharpening than cutting. Lesson learned: match the chain to the wood and the environment.

Chain Selection Considerations

Beyond the basic types, consider these factors when choosing a chain:

Wood Type: Softwoods like pine and fir are easier to cut and can be handled by most chain types. Hardwoods like oak, maple, and hickory require sharper chains and more power.
Wood Condition: Clean, debarked wood is ideal for full-chisel chains. Dirty or knotty wood is better suited for semi-chisel or carbide-tipped chains.
Cutting Frequency: If you’re cutting firewood regularly, invest in a durable chain that can withstand frequent use.
Sharpening Skills: Full-chisel chains require more precise sharpening than semi-chisel chains. If you’re not confident in your sharpening abilities, stick with a more forgiving chain type.

Sprocket Care: The Foundation of a Healthy Chainsaw

Now, let’s get to the heart of the matter: sprocket care. The sprocket is the toothed wheel that drives the chain around the bar. A worn or damaged sprocket can cause a host of problems, including:

Premature Chain Wear: A worn sprocket can stretch the chain, causing it to skip or derail.
Reduced Cutting Efficiency: A damaged sprocket won’t engage the chain properly, resulting in slower cutting speeds.
Increased Vibration: A worn sprocket can create excessive vibration, leading to operator fatigue and potential damage to the saw.
Kickback: A damaged sprocket can increase the risk of kickback, a dangerous situation where the saw suddenly recoils.

Types of Sprockets

There are two main types of sprockets used on chainsaws:

Spur Sprockets: These are one-piece sprockets that are typically found on older or less expensive saws. They are simple and durable but can wear out more quickly than rim sprockets.
Rim Sprockets: These consist of a separate rim that fits onto a splined hub. The rim is replaceable, which means you don’t have to replace the entire sprocket assembly when it wears out. This is more cost-effective in the long run. The Stihl MS250 typically uses a rim sprocket.

Identifying Sprocket Wear

Regular inspection of your sprocket is crucial for maintaining your chainsaw’s performance and safety. Here are some signs of a worn sprocket:

Rounded or Hooked Teeth: The teeth of a healthy sprocket should be sharp and square. If they are rounded or hooked, it’s a sign of wear.
Uneven Wear: Check for uneven wear patterns on the sprocket teeth. This can indicate that the chain is not tracking properly.
Cracks or Chips: Inspect the sprocket for any cracks or chips. These can weaken the sprocket and lead to failure.
Excessive Play: If the sprocket feels loose or wobbly on the shaft, it may be worn out.

Case Study: I once worked with a small logging operation in Oregon that was experiencing excessive chain wear on their Stihl MS250s. After inspecting their saws, I discovered that the sprockets were severely worn. The operators were unaware of the problem and had been simply replacing the chains more frequently. Replacing the sprockets immediately resolved the chain wear issue and saved them a significant amount of money.

Replacing the Sprocket

Replacing a worn sprocket is a relatively simple task that can be done with basic tools. Here’s a step-by-step guide:

Gather Your Tools: You’ll need a socket wrench (usually 19mm), a screwdriver, a new sprocket, and a pair of gloves.
Remove the Chain and Bar: Loosen the bar nuts and remove the chain and bar from the saw.
Remove the Clutch Cover: Use a screwdriver to remove the clutch cover.
Lock the Piston: Insert a piston stop tool into the spark plug hole to prevent the piston from moving. Alternatively, you can carefully feed a length of rope into the cylinder.
Remove the Clutch: Use a socket wrench to remove the clutch nut. Note that the clutch nut typically has left-hand threads, meaning you’ll need to turn it clockwise to loosen it.
Remove the Sprocket: Once the clutch is removed, the sprocket will slide off the shaft.
Install the New Sprocket: Slide the new sprocket onto the shaft.
Reinstall the Clutch: Reinstall the clutch and tighten the clutch nut. Remember to tighten it counter-clockwise.
Remove the Piston Stop Tool: Remove the piston stop tool or rope from the spark plug hole.
Reinstall the Clutch Cover: Reinstall the clutch cover.
Reinstall the Chain and Bar: Reinstall the chain and bar, ensuring the chain is properly tensioned.

Pro Tip: When replacing the sprocket, consider replacing the clutch drum as well. The clutch drum is the part that the clutch shoes engage with, and it can also wear out over time. Replacing both the sprocket and the clutch drum will ensure optimal performance.

Sprocket Maintenance Tips

Here are some tips for extending the life of your sprocket:

Regular Cleaning: Keep the sprocket clean and free of debris. Use a brush or compressed air to remove sawdust and grime.
Proper Chain Tension: Maintaining proper chain tension is crucial for preventing premature sprocket wear. A loose chain can skip on the sprocket, causing damage.
Proper Lubrication: Ensure the chain and sprocket are properly lubricated. Use a high-quality bar and chain oil.
Chain Rotation: Rotate the chain on the bar regularly to distribute wear evenly.
Sharpen Your Chain Regularly: A dull chain puts more strain on the sprocket. Keep your chain sharp. I prefer using a file guide to ensure consistent sharpening angles.
Avoid Cutting Dirty Wood: Cutting dirty wood can accelerate sprocket wear. If you must cut dirty wood, use a carbide-tipped chain.
Inspect Regularly: Inspect your sprocket regularly for signs of wear. Replace it as soon as you notice any problems.

Data Point: Studies have shown that replacing a worn sprocket can improve cutting efficiency by up to 20%. This translates to less fuel consumption, less operator fatigue, and faster firewood processing.

Chain Tension: The Goldilocks Principle

Chain tension is a critical factor in chainsaw operation, often overlooked. Too loose, and the chain can derail, causing damage and potential injury. Too tight, and you’ll experience increased friction, wear, and reduced cutting power. Finding the “just right” tension is key.

How to Check and Adjust Chain Tension

Safety First: Always turn off the chainsaw and engage the chain brake before checking or adjusting chain tension.
Location Matters: Check the tension on the underside of the bar, midway between the sprocket and the nose.
The Pull Test: With gloved hands, pull the chain away from the bar. You should be able to pull the drive links out about 1/8 inch (3-4mm).
Adjusting Tension: Most chainsaws have a tensioning screw located on the side of the bar. Loosen the bar nuts slightly, then use the tensioning screw to adjust the chain tension. Tighten the bar nuts securely after adjusting.
Warm-Up Adjustment: After running the saw for a few minutes, recheck the chain tension. The chain will expand as it heats up, so you may need to make further adjustments.

Common Idiom: Think of chain tension like a guitar string. Too loose, and it won’t play properly. Too tight, and it’ll snap.

The Impact of Temperature

Temperature plays a significant role in chain tension. On cold days, the chain will contract, requiring you to loosen the tension slightly. On hot days, the chain will expand, requiring you to tighten the tension.

Personal Experience: I once made the mistake of setting the chain tension on a cold morning and then running the saw hard on a hot afternoon. The chain became so tight that it started smoking and binding. I had to stop and readjust the tension to avoid damaging the saw.

Troubleshooting Chain Tension Issues

Chain Keeps Loosening: This could indicate a worn chain, a worn sprocket, or a problem with the tensioning mechanism.
Chain is Too Tight: This could be due to over-tightening, temperature changes, or a bent bar.
Chain is Skipping: This could be due to a worn chain, a worn sprocket, or improper chain pitch.

Lubrication: The Lifeblood of Your Chainsaw

Proper lubrication is essential for keeping your chainsaw running smoothly and preventing premature wear. The bar and chain oil reduces friction between the chain, bar, and sprocket, dissipating heat and preventing rust.

Choosing the Right Bar and Chain Oil

Viscosity: Choose an oil with the appropriate viscosity for your climate and cutting conditions. Thicker oils are better for hot weather and heavy-duty cutting. Thinner oils are better for cold weather and light-duty cutting.
Tackiness: Look for an oil with good tackiness, meaning it will cling to the chain and bar rather than flinging off.
Additives: Some oils contain additives that improve performance, such as anti-wear agents, rust inhibitors, and tackifiers.
Biodegradability: Consider using a biodegradable bar and chain oil, especially if you’re working in environmentally sensitive areas.

Data Point: Studies have shown that using a high-quality bar and chain oil can extend the life of your chain and bar by up to 50%.

Checking and Filling the Oil Reservoir

Regular Checks: Check the oil level frequently, especially when cutting for extended periods.
Refill When Necessary: Refill the oil reservoir whenever it gets low. Most chainsaws have a sight glass that allows you to easily check the oil level.
Use a Funnel: Use a funnel to avoid spilling oil when filling the reservoir.
Clean the Cap: Clean the oil cap before replacing it to prevent dirt and debris from entering the reservoir.

Troubleshooting Lubrication Issues

Chain is Smoking: This indicates that the chain is not getting enough oil. Check the oil level, the oil pump, and the oil passages.
Bar is Overheating: This also indicates a lack of lubrication. Check the oil level and the oil pump.
Oil is Leaking: This could be due to a damaged oil reservoir, a loose oil cap, or a faulty oil pump.

Real Example: I once had a chainsaw that was constantly running hot and smoking. After inspecting the saw, I discovered that the oil pump was clogged with sawdust. I cleaned the pump and the oil passages, and the saw started lubricating properly again.

Sharpening: The Key to Efficient Cutting

A sharp chain is not only more efficient but also safer. A dull chain requires more force to cut, increasing the risk of kickback and operator fatigue.

Sharpening Tools and Techniques

File and Guide: The most common method for sharpening chainsaw chains involves using a round file and a file guide. The file guide helps you maintain the correct sharpening angle and depth.
Electric Sharpener: Electric sharpeners are faster and more precise than hand filing, but they can also be more expensive.
Grinder: A bench grinder with a chainsaw chain sharpening attachment can be used to sharpen chains quickly and efficiently. However, this method requires more skill and experience.

Personal Experience: I used to rely solely on hand filing my chains, but I eventually invested in an electric sharpener. It has significantly reduced the amount of time I spend sharpening, and it produces more consistent results.

Sharpening Frequency

The frequency with which you need to sharpen your chain depends on the type of wood you’re cutting and the amount of use the chain receives. As a general rule, you should sharpen your chain whenever it starts to feel dull or when it produces sawdust instead of chips.

Common Idiom: A dull chain is like a dull knife: it’s more dangerous than a sharp one.

Sharpening Tips

Maintain the Correct Angle: Use a file guide to maintain the correct sharpening angle.
Sharpen Each Cutter Equally: Sharpen each cutter the same amount to ensure consistent cutting performance.
Remove Burrs: After sharpening, remove any burrs from the cutters using a flat file.
Check the Depth Gauges: Check the depth gauges (rakers) and file them down if necessary. The depth gauges control the amount of wood each cutter takes.

Wood Species and Processing Techniques

The type of wood you’re processing significantly impacts the tools and techniques you’ll need. Understanding the properties of different wood species is crucial for efficient and safe firewood preparation.

Hardwoods vs. Softwoods

Hardwoods: Typically deciduous trees (lose their leaves annually) like oak, maple, hickory, and ash. They are denser, heavier, and burn longer, making them ideal for heating. They also require more effort to split and process.
Softwoods: Typically coniferous trees (evergreens) like pine, fir, spruce, and cedar. They are less dense, lighter, and ignite more easily, making them good for kindling and starting fires. They are generally easier to split and process.

Data Point: Oak has a BTU (British Thermal Unit) rating of approximately 28 million per cord, while pine has a BTU rating of approximately 20 million per cord. This means that oak produces significantly more heat than pine.

Wood Seasoning

Seasoning is the process of drying wood to reduce its moisture content. Properly seasoned wood burns more efficiently, produces less smoke, and reduces creosote buildup in your chimney.

Ideal Moisture Content: The ideal moisture content for firewood is between 15% and 20%.
Drying Time: The drying time depends on the wood species, the climate, and the stacking method. Generally, hardwoods require at least six months to a year to season properly, while softwoods may only require three to six months.
Stacking Method: Stack firewood in a single row, off the ground, and in a sunny, well-ventilated location. Cover the top of the stack to protect it from rain and snow.

Splitting Techniques

Manual Splitting: Using a maul or splitting axe to split wood by hand. This is a good option for small quantities of wood and for those who enjoy the physical exercise.
Hydraulic Log Splitter: Using a hydraulic log splitter to split wood. This is a faster and easier option for large quantities of wood.

Real Example: I used to split all my firewood by hand, but after a few years, I invested in a hydraulic log splitter. It has saved me a significant amount of time and effort, and it has allowed me to process larger quantities of wood.

Safety Considerations

Personal Protective Equipment (PPE): Always wear appropriate PPE when processing firewood, including safety glasses, gloves, hearing protection, and steel-toed boots.
Safe Cutting Practices: Follow safe cutting practices when using a chainsaw, including maintaining a firm grip, keeping your feet planted, and avoiding cutting above your head.
Proper Stacking: Stack firewood safely to prevent it from falling over.
First Aid Kit: Keep a well-stocked first aid kit on hand in case of injury.

Conclusion: Mastering the Art of Chainsaw Maintenance and Wood Processing

Maintaining your Stihl MS250 chainsaw, particularly the chain and sprocket, is an ongoing process that requires attention to detail and a commitment to safety. By understanding the different types of chains, practicing proper chain tensioning, ensuring adequate lubrication, and sharpening your chain regularly, you can extend the life of your saw and improve its performance.

Remember my early struggles with the neglected sprocket? I learned that consistent maintenance is not just about saving money on replacement parts; it’s about ensuring your safety and maximizing your efficiency. The time you invest in caring for your equipment will pay dividends in the long run.

Wood processing, from selecting the right wood species to employing safe splitting techniques, is a craft that blends knowledge, skill, and experience. By understanding the properties of different wood species, mastering splitting techniques, and prioritizing safety, you can transform raw logs into a valuable source of heat and enjoyment.