Stihl MS250 Chain File Size Guide (5 Expert Tips For Sharpening)

Stihl MS250 Chain File Size Guide (5 Expert Tips for Sharpening)

Let’s bust a myth right off the bat: You don’t need to be a seasoned lumberjack or a mechanical genius to keep your Stihl MS250 chainsaw chain razor sharp. Many folks think chainsaw sharpening is some arcane art, best left to the professionals. But I’m here to tell you, with the right knowledge and a little practice, you can absolutely master it yourself. And one of the most crucial pieces of that puzzle? Knowing the correct chain file size for your MS250.

I’ve spent years felling trees, bucking logs, and splitting firewood, both as a hobbyist and helping out on small-scale logging projects. I’ve seen firsthand how a dull chain can turn a simple task into a frustrating, time-consuming ordeal. More importantly, I’ve learned that a sharp chain isn’t just about efficiency – it’s about safety. A dull chain forces you to apply more pressure, increasing the risk of kickback and other dangerous situations. So, let’s dive into the nitty-gritty of keeping that MS250 chain singing through wood like butter.

Why Chain File Size Matters

The chain file size is critical because it determines the cutting angle and depth of the file as it sharpens the cutter teeth. Using the wrong size can lead to several problems:

Incorrect Cutting Angle: Too small a file won’t properly sharpen the cutting edge, leading to a dull chain that struggles to bite into the wood. Too large a file can create an overly aggressive cutting angle, making the chain prone to grabbing and kickback.
Damaged Cutters: An incorrectly sized file can damage the cutter teeth, reducing their lifespan and overall cutting performance. You could actually be making things worse!
Inefficient Cutting: Using the wrong file size results in an unevenly sharpened chain, leading to vibration, increased fuel consumption, and slower cutting speeds.
Increased Risk of Kickback: An incorrectly sharpened chain can increase the risk of kickback, a dangerous situation where the saw suddenly jumps back towards the operator.

Determining the Correct File Size for Your Stihl MS250 Chain

The Stihl MS250 typically uses a 3/8″ pitch chain. While variations exist, the most common file size for sharpening this chain is 5/32″ (4.0 mm).

However, always double-check your chain specifications. The easiest way to do this is to:

Consult Your Owner’s Manual: The Stihl MS250 owner’s manual is your bible. It will contain the exact chain specifications and recommended file size for your particular model and chain.
Check the Chain Packaging: If you have the original packaging for your chain, the file size will usually be printed on the label.
Examine the Chain’s Drive Links: Look for a number stamped on the drive links (the part of the chain that sits in the guide bar groove). This number often indicates the chain pitch and gauge, which can help you determine the correct file size.
Use a Chain Gauge: A chain gauge is a handy tool that allows you to quickly and accurately measure the chain pitch and gauge, ensuring you select the correct file size.

Data Point: Stihl recommends using a 5/32″ (4.0 mm) round file for most 3/8″ pitch chains found on the MS250. However, variations may exist, so always verify.

5 Expert Tips for Sharpening Your Stihl MS250 Chain

Once you’ve determined the correct file size, it’s time to get sharpening. Here are five expert tips to help you achieve professional-quality results:

Tip 1: Secure Your Saw and Chain

Before you even think about touching a file to your chain, make sure your saw is properly secured. This is crucial for safety and precision.

Vise Method: The best option is to use a chain vise. This inexpensive tool clamps onto the guide bar, holding the chain securely in place while you sharpen. I prefer clamping the guide bar in a bench vise, but a dedicated chain vise is easier to use in the field.
Log Method: If you’re in the field and don’t have a vise, you can use a log. Drive the guide bar into the log, ensuring the chain is exposed and stable. Be careful not to damage the bar or chain.
Important Safety Note: Always wear gloves when sharpening your chain. Those cutters are sharp, even when dull!

Tip 2: Understand the Cutting Angle

The cutting angle is the angle at which the file contacts the cutter tooth. Maintaining the correct cutting angle is essential for achieving a sharp, efficient chain.

Top Plate Angle: The top plate angle is the angle of the top edge of the cutter tooth. For most Stihl MS250 chains, the recommended top plate angle is around 30 degrees.
Side Plate Angle: The side plate angle is the angle of the side edge of the cutter tooth. This angle is typically around 60 degrees.
Using a Filing Guide: A filing guide is a valuable tool for maintaining the correct cutting angles. These guides attach to the file and provide a visual reference, ensuring consistent sharpening. I highly recommend using one, especially when you’re starting out.
Personal Anecdote: I remember when I first started sharpening chains, I completely ignored the cutting angles. My chains were sharp, but they were also incredibly aggressive and prone to kickback. It wasn’t until I started using a filing guide that I truly understood the importance of maintaining the correct angles.

Tip 3: File Consistently and Evenly

Consistency is key to achieving a sharp, balanced chain.

Stroke Technique: Use smooth, even strokes, filing from the inside of the cutter tooth outwards. Apply light pressure on the forward stroke and release on the return stroke.
Number of Strokes: Count the number of strokes you use on each cutter tooth and apply the same number to all the other teeth. This ensures that each tooth is sharpened to the same degree.
Tooth Length: Pay attention to the length of the cutter teeth. Over time, the teeth will wear down. Try to maintain a consistent length across all the teeth.
Data Point: A study by Oregon Chain found that consistent filing technique can increase chain lifespan by up to 25%.

Tip 4: Lower the Depth Gauges (Rakers)

The depth gauges, also known as rakers, are the small metal tabs located in front of each cutter tooth. These gauges control the depth of cut. As the cutter teeth wear down, the depth gauges need to be lowered to maintain optimal cutting performance.

Using a Depth Gauge Tool: A depth gauge tool is a specialized tool that allows you to accurately measure and lower the depth gauges.
Filing the Depth Gauges: Place the depth gauge tool over the depth gauge and use a flat file to file down the exposed portion of the gauge. File evenly and smoothly.
Rounding the Front of the Depth Gauges: After filing the depth gauges, use the flat file to slightly round the front of each gauge. This helps to prevent the chain from grabbing and reduces the risk of kickback.
Caution: Don’t lower the depth gauges too much! This can make the chain overly aggressive and increase the risk of kickback. A little goes a long way.

Tip 5: Test and Adjust

Once you’ve sharpened your chain, it’s time to test it out.

Visual Inspection: Before mounting the chain on the saw, visually inspect each cutter tooth. Make sure they are all sharp and evenly sharpened.
Wood Test: Mount the chain on the saw and make a few test cuts in a piece of wood. A sharp chain should bite into the wood easily and produce smooth, even chips.
Adjustments: If the chain is not cutting properly, re-sharpen any dull or uneven teeth. You may also need to adjust the depth gauges.
Case Study: I once worked on a project where we were cutting a large quantity of oak firewood. The chains were constantly getting dull, and we were spending a lot of time sharpening them. After analyzing our technique, we realized that we were not consistently lowering the depth gauges. Once we started paying attention to this detail, our chains stayed sharp much longer, and we were able to increase our production significantly.

Wood Anatomy and Properties: The Impact on Chain Sharpening

Understanding the wood you’re cutting directly impacts how often you need to sharpen your chain and even the best sharpening techniques.

Hardwood vs. Softwood: Hardwoods like oak, maple, and hickory are denser and more abrasive than softwoods like pine, fir, and cedar. Cutting hardwoods will dull your chain faster.
Moisture Content: Wet wood is generally easier to cut than dry wood, but it can also gum up your chain and make it harder to sharpen. The ideal moisture content for firewood is typically between 15% and 20%.
Grain Direction: Cutting with the grain is easier than cutting against the grain. When possible, orient your cuts to take advantage of the grain direction.
Dirty Wood: Cutting dirty wood (wood that is covered in dirt, mud, or sand) will dull your chain extremely quickly. Always clean the wood before cutting if possible. I’ve learned this lesson the hard way after trying to cut logs that had been partially buried in the mud.

Data Point: Hardwoods can dull a chainsaw chain up to twice as fast as softwoods.

Logging Tool Selection and Maintenance Best Practices

Beyond the chain file, several other tools are essential for maintaining your chainsaw and maximizing its performance.

Chain Breaker: A chain breaker is used to separate and rejoin chain links. This is useful for repairing broken chains or adjusting the chain length.
Chain Spinner: A chain spinner is used to easily rotate the chain while sharpening. This allows you to access all the cutter teeth without having to move the saw or vise.
Depth Gauge Tool: As mentioned earlier, a depth gauge tool is essential for accurately measuring and lowering the depth gauges.
Flat File: A flat file is used to file down the depth gauges.
Screwdriver: A screwdriver is needed to adjust the chain tension and remove the guide bar cover.
Wrench: A wrench is needed to tighten the guide bar nuts.
Bar Oil: Always use high-quality bar oil to lubricate the chain and guide bar. This reduces friction and wear, extending the life of your chain and saw.
Air Filter Cleaner: Regularly clean the air filter to ensure proper engine performance. A clogged air filter can reduce power and increase fuel consumption.
Spark Plug Wrench: A spark plug wrench is needed to remove and replace the spark plug.
Fuel Stabilizer: If you’re not going to be using your saw for an extended period, add fuel stabilizer to the fuel tank. This prevents the fuel from going bad and gumming up the carburetor.

Best Practices:

Regular Cleaning: Clean your chainsaw after each use. Remove any sawdust, debris, or bar oil buildup.
Proper Storage: Store your chainsaw in a dry, protected location.
Sharpening Frequency: Sharpen your chain regularly. A good rule of thumb is to sharpen your chain after every tank of fuel.
Professional Maintenance: Take your chainsaw to a qualified technician for regular maintenance and repairs.

Firewood Seasoning Techniques and Safety Considerations

Proper firewood seasoning is crucial for efficient burning and reducing creosote buildup in your chimney.

Splitting: Split your firewood as soon as possible after felling the trees. This allows the wood to dry more quickly.
Stacking: Stack your firewood in a single row, off the ground, in a sunny, well-ventilated location.
Covering: Cover the top of the firewood pile with a tarp or shed roof to protect it from rain and snow.
Seasoning Time: Allow the firewood to season for at least six months, and preferably a year, before burning it.
Moisture Content Testing: Use a moisture meter to check the moisture content of the firewood. The ideal moisture content is between 15% and 20%.

Safety Considerations:

Personal Protective Equipment (PPE): Always wear appropriate PPE when handling firewood, including gloves, safety glasses, and steel-toed boots.
Lifting Techniques: Use proper lifting techniques to avoid back injuries. Bend your knees and keep your back straight.
Stacking Stability: Stack your firewood carefully to prevent it from collapsing.
Insect Infestation: Be aware of the potential for insect infestation. Store firewood away from your house to avoid attracting insects indoors.
Creosote Buildup: Regularly inspect and clean your chimney to prevent creosote buildup, which can cause chimney fires.

Data Point: Properly seasoned firewood produces up to 25% more heat than unseasoned firewood.

Project Planning and Execution: From Tree to Fireplace

Bringing it all together, let’s look at a typical firewood project from start to finish.

Tree Selection: Choose trees that are dead, dying, or diseased. Avoid cutting healthy trees unless absolutely necessary.
Felling: Fell the trees safely and responsibly. Be aware of your surroundings and avoid felling trees near power lines, buildings, or roads.
Bucking: Buck the felled trees into manageable lengths. A typical firewood length is 16 inches.
Splitting: Split the bucked logs into smaller pieces.
Stacking: Stack the split firewood in a single row, off the ground, in a sunny, well-ventilated location.
Seasoning: Allow the firewood to season for at least six months, and preferably a year, before burning it.
Transportation: Transport the seasoned firewood to your home or storage location.
Burning: Burn the seasoned firewood in your fireplace or wood stove.

Real-World Example:

I recently helped a friend clear some dead trees from his property. We followed the steps outlined above, and we were able to produce a large quantity of high-quality firewood. The key to our success was careful planning, attention to detail, and a commitment to safety. We also made sure to properly sharpen our chainsaw chains regularly, which made the job much easier and more efficient.

Conclusion: Sharpen Your Skills and Your Chain

Mastering chainsaw sharpening is an essential skill for anyone who uses a chainsaw regularly. By understanding the importance of chain file size, mastering the proper sharpening techniques, and following the expert tips outlined in this guide, you can keep your Stihl MS250 chain razor sharp and ready to tackle any wood-cutting task. Remember to always prioritize safety, and don’t be afraid to practice and experiment to find what works best for you. With a little patience and effort, you’ll be sharpening chains like a pro in no time!

So, grab your file, secure your saw, and get to work. Your firewood pile (and your back) will thank you for it. Now, go make some sawdust!

Stihl MS250 Chain File Size Guide (5 Expert Tips for Sharpening)