Stihl MS251C Chain Size Guide (5 Pro Cutting Tips Inside)

I remember a time, not too long ago, when my woodpile was a chaotic mess. Uneven logs, varying lengths, and a general lack of organization made the simple act of grabbing firewood a frustrating chore. It was a stark contrast to what I envisioned: a neatly stacked, readily accessible source of warmth for those cold winter nights. Now, after years of honing my skills and understanding the nuances of wood processing, my woodpile is a testament to efficiency and preparedness. The logs are uniform, the stacks are stable, and the wood is perfectly seasoned. The difference? Knowledge, the right tools, and a methodical approach. And a good chainsaw, like the Stihl MS251C, properly sized and maintained, is at the heart of it all.

Stihl MS251C Chain Size Guide: 5 Pro Cutting Tips Inside

The Stihl MS251C is a popular chainsaw, and for good reason. It’s a powerful, reliable tool that’s perfect for a wide range of tasks, from felling small trees to bucking firewood. But like any chainsaw, its performance hinges on having the correct chain size and keeping it properly maintained. Choosing the wrong chain can lead to poor cutting, increased wear and tear on your saw, and even dangerous kickback. This guide will walk you through everything you need to know about selecting the right chain for your Stihl MS251C and offer some pro cutting tips to maximize your efficiency and safety.

Understanding Chain Size Specifications for the MS251C

Before diving into specific recommendations, it’s crucial to understand the three key measurements that define a chainsaw chain: pitch, gauge, and drive link count. These specifications are non-negotiable; using the wrong size can damage your saw and compromise your safety.

Pitch: The pitch is the distance between any three consecutive rivets on the chain, divided by two. It’s typically expressed in inches. The Stihl MS251C usually uses a 3/8″ pitch chain, but it’s always best to confirm this on your saw’s guide bar or in the owner’s manual.
Gauge: The gauge refers to the thickness of the drive links, which are the parts of the chain that fit into the groove of the guide bar. This measurement is also expressed in inches. The MS251C generally uses a .050″ gauge chain.
Drive Link Count: This is the total number of drive links on the chain. The correct number depends on the length of your guide bar. For the MS251C, common guide bar lengths are 16″ and 18″, requiring different drive link counts.

Why These Measurements Matter:

Using the wrong pitch can cause the chain to not fit properly on the sprocket, leading to slippage and damage. An incorrect gauge can result in the chain being too loose or too tight in the guide bar groove, causing excessive wear. And, of course, the drive link count must match the guide bar length for the chain to fit at all.

Finding the Right Specs for Your Saw:

Check the Guide Bar: The specifications for your chain (pitch, gauge, and sometimes drive link count) are often stamped directly on the guide bar. Look for numbers like “3/8 .050” near the base of the bar.
Consult the Owner’s Manual: Your Stihl MS251C owner’s manual is the ultimate source of truth. It will list the recommended chain sizes for your specific model and guide bar length.
Use the Stihl Chain Selector: Stihl offers a helpful online tool and mobile app that allows you to identify the correct chain for your chainsaw model. Simply enter “MS251C” and your guide bar length, and the tool will provide a list of compatible chains.

Personal Story: I once made the mistake of assuming all 3/8″ pitch chains were created equal. I bought a chain that was advertised as 3/8″ but had a different gauge than my saw required. The chain was too loose in the guide bar, leading to excessive vibration and poor cutting. I quickly learned the importance of verifying all the specifications before making a purchase.

Takeaway: Always double-check the pitch, gauge, and drive link count before buying a new chain for your Stihl MS251C. Consult your guide bar, owner’s manual, or the Stihl chain selector to ensure you get the right fit.

Choosing the Right Chain Type for Your Cutting Needs

Once you know the correct chain size, you need to consider the type of chain that’s best suited for your cutting needs. Chainsaw chains come in various designs, each optimized for different applications. Here are some of the most common types:

Full Chisel Chains: These chains have square-cornered teeth that offer the fastest and most efficient cutting. They are ideal for felling trees and bucking clean wood but are more prone to dulling in dirty or abrasive conditions.
Semi-Chisel Chains: Semi-chisel chains have rounded-corner teeth that are more durable than full chisel chains and less susceptible to dulling. They are a good all-around choice for general-purpose cutting, including firewood preparation and limbing.
Low-Profile Chains: Also known as safety chains, these chains have a reduced kickback tendency, making them a good option for beginners or those who prioritize safety. They typically have lower cutting speeds than full or semi-chisel chains.
Ripping Chains: These chains are designed specifically for cutting wood lengthwise, such as when milling lumber. They have a different tooth geometry than cross-cutting chains and produce a smoother, more accurate cut along the grain.

Which Chain is Right for the MS251C?

For most users of the Stihl MS251C, a semi-chisel chain is the best all-around choice. It offers a good balance of cutting speed, durability, and ease of maintenance. If you primarily cut clean wood and prioritize speed, a full chisel chain may be a better option. However, if you are new to chainsaws or work in dirty conditions, a low-profile chain can provide added safety and longevity.

My Recommendation: I personally prefer using a semi-chisel chain on my MS251C for most firewood preparation tasks. It holds its edge well, even when cutting wood that’s a bit dirty or knotty. I also keep a low-profile chain on hand for situations where safety is paramount, such as when working in close proximity to others.

Considerations for Wood Type:

The type of wood you’re cutting can also influence your chain choice. Hardwoods like oak and maple require a more durable chain than softwoods like pine and fir. If you frequently cut hardwoods, consider a chain with hardened cutters or a specialized coating to extend its life.

Takeaway: Choose a chain type that matches your cutting needs and the type of wood you typically work with. Semi-chisel chains are a good all-around choice for the Stihl MS251C, while full chisel chains offer faster cutting and low-profile chains prioritize safety.

Step-by-Step Guide to Replacing Your MS251C Chain

Replacing a chainsaw chain is a straightforward process, but it’s essential to follow the correct steps to ensure safety and proper chain tension. Here’s a step-by-step guide:

Tools You’ll Need:

Chainsaw wrench (often included with the saw)
Gloves
A clean, flat surface

Steps:

Safety First: Always engage the chain brake and remove the spark plug wire before working on your chainsaw. This will prevent accidental starting.
Loosen the Bar Nuts: Use the chainsaw wrench to loosen the bar nuts that hold the guide bar cover in place. Don’t remove them completely yet.
Loosen the Chain Tension: Most Stihl chainsaws have a side-mounted chain tensioner. Use the screwdriver end of the chainsaw wrench to turn the tensioning screw counterclockwise to loosen the chain.
Remove the Guide Bar Cover: Once the chain is loose, remove the bar nuts and the guide bar cover.
Remove the Old Chain: Carefully lift the old chain off the guide bar and the sprocket. Be mindful of the sharp cutters.
Inspect the Guide Bar and Sprocket: Before installing the new chain, inspect the guide bar for wear and damage. Check the groove for burrs or uneven wear. Also, inspect the sprocket for worn teeth. Replace these parts if necessary.
Install the New Chain: Place the new chain around the guide bar, making sure the cutters are facing in the correct direction (they should point forward on the top of the bar). Ensure the drive links are properly seated in the guide bar groove.
Position the Guide Bar: Place the guide bar back onto the chainsaw, aligning the tensioning pin with the hole in the guide bar.
Reinstall the Guide Bar Cover: Reinstall the guide bar cover and tighten the bar nuts finger-tight.
Adjust the Chain Tension: Use the chain tensioner to adjust the chain tension. The chain should be snug against the guide bar but still able to be pulled around by hand. A properly tensioned chain should have about 1/8″ of sag on the underside of the bar.
Tighten the Bar Nuts: Once the chain tension is correct, tighten the bar nuts securely with the chainsaw wrench.
Check the Tension Again: After tightening the bar nuts, check the chain tension one last time. It may need slight adjustment.
Reattach the Spark Plug Wire: Reconnect the spark plug wire.
Test the Chain Brake: Before starting the saw, test the chain brake to ensure it’s functioning properly.

Common Mistakes to Avoid:

Installing the Chain Backwards: This is a common mistake, especially for beginners. Always double-check that the cutters are facing the correct direction.
Over-Tightening the Chain: Over-tightening can put excessive stress on the chain, guide bar, and sprocket, leading to premature wear.
Ignoring Guide Bar and Sprocket Wear: A worn guide bar or sprocket can damage a new chain and reduce cutting efficiency.

Personal Tip: I always use a small brush to clean the guide bar groove before installing a new chain. This helps to remove dirt and debris that can cause premature wear.

Takeaway: Replacing a chainsaw chain is a simple process, but it’s important to follow the correct steps and pay attention to detail. Always prioritize safety and double-check your work before starting the saw.

5 Pro Cutting Tips for Optimal MS251C Performance

Beyond choosing the right chain and replacing it properly, there are several cutting techniques and maintenance practices that can significantly improve the performance and longevity of your Stihl MS251C. Here are five pro cutting tips I’ve learned over the years:

Maintain Proper Chain Tension: As mentioned earlier, proper chain tension is crucial for safe and efficient cutting. A chain that’s too loose can derail, while a chain that’s too tight can overheat and break. Check the chain tension frequently, especially when the chain is new. New chains tend to stretch during the first few uses. I typically check the tension after every few cuts, especially when working with hardwoods.
Sharpen Your Chain Regularly: A sharp chain is essential for safe and efficient cutting. A dull chain requires more force to cut, which can increase the risk of kickback. Learn how to sharpen your chain using a file and guide, or take it to a professional sharpener. I prefer to sharpen my chains myself, as it allows me to maintain the correct cutting angle and depth. I typically sharpen my chain after every tank of gas, or more often if I’m cutting dirty wood.
Use the Right Cutting Techniques: Avoid forcing the saw through the wood. Let the chain do the work. Use a smooth, controlled motion and maintain a consistent cutting angle. When felling trees, use proper notching and back-cutting techniques to control the direction of the fall. There are many great resources online and in print that demonstrate proper felling techniques. I highly recommend taking a chainsaw safety course to learn these techniques from a qualified instructor.
Keep Your Chain Oiled: Proper chain lubrication is essential for reducing friction and preventing wear. Use a high-quality bar and chain oil and ensure the oiler is functioning properly. Check the oil level frequently and refill as needed. I prefer to use a vegetable-based bar and chain oil, as it’s more environmentally friendly and less likely to damage the soil. I also make sure to clean the oiler port regularly to prevent clogs.
Clean Your Chainsaw Regularly: Sawdust and debris can accumulate in the chainsaw’s engine, air filter, and cooling fins, reducing performance and potentially causing damage. Clean your chainsaw regularly with compressed air or a brush. I typically clean my chainsaw after every use, paying particular attention to the air filter and cooling fins. I also remove the guide bar and clean the groove to prevent buildup of sawdust and oil.

Personal Experience: I once neglected to clean the cooling fins on my chainsaw, and it overheated and seized up. It was an expensive lesson that taught me the importance of regular maintenance.

Takeaway: By following these pro cutting tips, you can maximize the performance and longevity of your Stihl MS251C and ensure safe and efficient cutting.

Troubleshooting Common Chain Problems

Even with proper care and maintenance, you may encounter problems with your chainsaw chain from time to time. Here are some common issues and how to troubleshoot them:

Chain Dulls Quickly: This could be due to cutting dirty wood, using the wrong type of chain for the wood you’re cutting, or improper sharpening. Try using a more durable chain, sharpening your chain more frequently, or cleaning the wood before cutting.
Chain Keeps Coming Off the Bar: This is usually caused by a loose chain, a worn guide bar, or a damaged sprocket. Adjust the chain tension, inspect the guide bar and sprocket for wear, and replace them if necessary. Also, make sure the drive links are properly seated in the guide bar groove.
Chain Smokes or Overheats: This is typically caused by insufficient chain lubrication. Check the oil level and ensure the oiler is functioning properly. Also, make sure the chain is not too tight.
Chain Cuts at an Angle: This could be due to uneven cutter lengths or a bent guide bar. Sharpen the chain to ensure all cutters are the same length, and inspect the guide bar for damage.
Chain Vibrates Excessively: This could be caused by a loose chain, a worn guide bar, or a damaged sprocket. Adjust the chain tension, inspect the guide bar and sprocket for wear, and replace them if necessary. Also, check the balance of the chain and make sure all cutters are the same length.

When to Seek Professional Help:

If you’re unable to diagnose or resolve a chain problem yourself, it’s best to take your chainsaw to a qualified repair technician. They have the expertise and tools to properly diagnose and repair complex issues.

My Advice: Don’t be afraid to ask for help! There are many experienced chainsaw users and repair technicians who are willing to share their knowledge. I’ve learned a lot from watching videos and reading articles online, but I’ve also benefited from the advice of experienced loggers and arborists.

Takeaway: By understanding common chain problems and how to troubleshoot them, you can keep your Stihl MS251C running smoothly and avoid costly repairs.

Maintaining Your Chain for Longevity

Proper maintenance is the key to extending the life of your chainsaw chain and maximizing its performance. Here are some essential maintenance practices:

Regular Sharpening: As mentioned earlier, regular sharpening is crucial for maintaining a sharp and efficient chain. Sharpen your chain after every tank of gas, or more often if you’re cutting dirty wood.
Cleaning: Clean your chain regularly to remove sawdust, pitch, and other debris. Use a brush or compressed air to clean the chain after each use.
Lubrication: Keep your chain properly lubricated with a high-quality bar and chain oil. Check the oil level frequently and refill as needed.
Inspection: Inspect your chain regularly for signs of wear or damage. Look for cracked or broken cutters, worn drive links, and loose rivets. Replace the chain if you find any significant damage.
Storage: Store your chain in a clean, dry place when not in use. Consider using a chain case or a protective sleeve to prevent damage.

The Importance of a Sharp Chain:

I cannot overstate the importance of a sharp chain. A sharp chain not only cuts more efficiently but also reduces the risk of kickback and other accidents. A dull chain requires more force to cut, which can lead to fatigue and loss of control.

My Routine: I have a dedicated sharpening kit that I keep in my truck, so I can sharpen my chain whenever and wherever I need to. The kit includes a file, a file guide, a depth gauge tool, and a chain breaker/rivet spinner. I also have a bench grinder with a chainsaw sharpening attachment for more precise sharpening.

Takeaway: By following these maintenance practices, you can extend the life of your chainsaw chain, improve its performance, and ensure safe and efficient cutting.

Safety Precautions When Using a Chainsaw

Chainsaws are powerful and potentially dangerous tools. It’s essential to follow all safety precautions to prevent accidents and injuries. Here are some key safety guidelines:

Wear Appropriate Safety Gear: Always wear appropriate safety gear, including a helmet with a face shield, hearing protection, gloves, chaps, and sturdy boots.
Read the Owner’s Manual: Familiarize yourself with the operation and safety features of your chainsaw by reading the owner’s manual.
Inspect Your Chainsaw: Before each use, inspect your chainsaw for any signs of damage or malfunction. Check the chain tension, oil level, and safety features.
Start the Chainsaw Safely: Start the chainsaw on a flat, stable surface, away from your body. Use the correct starting procedure and never drop-start the saw.
Maintain a Safe Distance: Keep a safe distance from other people and obstacles when operating the chainsaw.
Be Aware of Kickback: Kickback is a sudden and forceful reaction that can occur when the chain catches on an object. Be aware of the kickback zone and use proper cutting techniques to avoid kickback.
Never Cut Above Shoulder Height: Cutting above shoulder height can be dangerous and increase the risk of loss of control.
Take Breaks: Chainsaw operation can be physically demanding. Take frequent breaks to avoid fatigue.
Never Use a Chainsaw Under the Influence: Never use a chainsaw if you are under the influence of alcohol or drugs.
Store the Chainsaw Safely: Store the chainsaw in a safe place, out of reach of children and unauthorized users.

The Importance of Training:

I highly recommend taking a chainsaw safety course to learn proper operating techniques and safety procedures from a qualified instructor. A safety course can teach you how to avoid common accidents and injuries.

My Commitment to Safety: I always prioritize safety when using a chainsaw. I wear all the necessary safety gear, inspect my saw before each use, and follow proper cutting techniques. I also make sure to take breaks and stay alert.

Takeaway: By following these safety precautions, you can significantly reduce the risk of accidents and injuries when using a chainsaw.

Optimizing Your Wood Processing Workflow with the MS251C

The Stihl MS251C is a versatile tool that can be used for a variety of wood processing tasks, from felling trees to bucking firewood. Here are some tips for optimizing your workflow with the MS251C:

Plan Your Cuts: Before you start cutting, take the time to plan your cuts. Determine the desired length of your firewood and mark the logs accordingly. This will help you to avoid waste and ensure consistent results.
Use a Sawhorse: A sawhorse can make it easier and safer to buck logs. Position the log securely on the sawhorse before cutting.
Buck Logs in Batches: If you have a large pile of logs to buck, consider bucking them in batches. This can save time and reduce fatigue.
Stack Your Firewood Properly: Once you’ve bucked your firewood, stack it properly to allow for air circulation and drying. Stack the wood in rows, with the bark facing up. This will help to prevent rot and promote faster drying.
Season Your Firewood: Seasoning your firewood is essential for burning it efficiently and cleanly. Allow the wood to dry for at least six months, or preferably a year, before burning it.
Consider a Log Splitter: If you’re processing a large amount of firewood, consider investing in a log splitter. A log splitter can significantly reduce the amount of time and effort required to split wood.

My Wood Processing Setup:

I have a dedicated wood processing area in my yard. The area includes a sawhorse, a log splitter, and a wood shed for storing seasoned firewood. I also have a variety of tools and equipment, including a chainsaw, a splitting axe, a sledgehammer, and wedges.

Personal Tip: I always wear a dust mask when processing firewood, as the sawdust can be irritating to the lungs.

Takeaway: By optimizing your wood processing workflow with the Stihl MS251C, you can save time and effort and produce high-quality firewood.

Conclusion: Mastering the Stihl MS251C for Wood Processing Success

The Stihl MS251C is a fantastic chainsaw that, when properly sized, maintained, and used, can be a cornerstone of your wood processing endeavors. From selecting the right chain to mastering cutting techniques and prioritizing safety, the knowledge and skills outlined in this guide will empower you to tackle any wood processing task with confidence. Remember that wood processing is a journey, and continuous learning and practice are key to achieving mastery. So, get out there, put these tips into action, and enjoy the satisfaction of transforming raw wood into a valuable resource.

The transformation from that chaotic woodpile to my current, organized stack wasn’t just about the tools; it was about the knowledge and the application of that knowledge. And I hope this guide empowers you to achieve a similar transformation in your own wood processing journey.

Stihl MS251C Chain Size Guide (5 Pro Cutting Tips Inside)