Stihl MS 251 Chain Size Guide (5 Pro Tips for Efficiency)

Stihl MS 251 Chain Size Guide (5 Pro Tips for Efficiency)

The Stihl MS 251 is a workhorse of a chainsaw, a tool I’ve personally relied on for everything from limbing trees in my backyard to bucking firewood for the winter. Its versatility is a big part of its appeal, but to truly unlock its potential, understanding the right chain size and how to optimize its performance is crucial. This guide will walk you through everything you need to know, and I’ll share some hard-earned lessons I’ve learned along the way. This is a timeless guide for anyone looking to get the most from their Stihl MS 251.

Understanding the Stihl MS 251 Chain: Key Specifications

Before diving into the tips, let’s solidify the basics. The Stihl MS 251, known for its balance of power and weight, typically utilizes a chain with these specifications:

• Chain Pitch: .325 inch
• Chain Gauge: .063 inch (1.6 mm)
• Drive Links: This varies depending on the bar length. Common bar lengths for the MS 251 are 16-inch and 18-inch, requiring 62 and 68 drive links respectively.

Important Note: Always verify the recommended chain specifications in your Stihl MS 251 owner’s manual. Using the wrong chain can damage your saw and create a safety hazard.

Pro Tip #1: Selecting the Right Bar Length and Corresponding Chain

The bar length dictates the number of drive links your chain needs. While the MS 251 can handle both 16-inch and 18-inch bars, choosing the right one depends on your typical cutting tasks.

• 16-inch Bar: Ideal for limbing, pruning, and cutting smaller diameter firewood. It offers better maneuverability and is lighter, reducing fatigue.
• 18-inch Bar: Better suited for felling small trees and bucking larger diameter logs. Provides more reach but can be slightly more challenging to handle.

My Experience: I initially started with an 18-inch bar on my MS 251. While it was great for larger logs, I found it cumbersome for smaller tasks. Switching to a 16-inch bar for limbing made a world of difference in terms of speed and control. Now, I keep both bars on hand and swap them out depending on the job.

Chain Selection based on Bar Length

Cost Considerations: Chain prices vary based on brand and quality. Expect to pay between $20-$40 for a replacement chain for your Stihl MS 251. It’s a good idea to keep a spare on hand.

Pro Tip #2: Chain Sharpness: The Key to Efficiency and Safety

A dull chain is not only inefficient, but it’s also dangerous. It forces you to apply more pressure, increasing the risk of kickback. A sharp chain, on the other hand, bites into the wood effortlessly, making cutting faster, smoother, and safer.

How to Tell if Your Chain is Dull:

• The saw produces sawdust instead of chips.
• You have to force the saw through the wood.
• The saw pulls to one side while cutting.
• Increased vibration.

Sharpening Your Chain:

You have two primary options:

1. Hand Sharpening: Using a file and a guide is a cost-effective method, but it requires practice and patience.

   • Cost: A chainsaw file and guide kit typically costs between $20-$50.
   • Learning Curve: Moderate. It takes time to master the correct angle and pressure.

   • Electric Chain Sharpener: Offers faster and more precise sharpening, especially for beginners.

   • Cost: Electric sharpeners range from $50-$200 or more.
   • Learning Curve: Low. Easier to use than hand sharpening.

My Approach: I started with hand sharpening, but after struggling to maintain consistent angles, I invested in an electric sharpener. It’s saved me a lot of time and frustration, and my chains are consistently sharper.

Sharpening Frequency: How often you need to sharpen your chain depends on the type of wood you’re cutting and how often you use the saw. I typically sharpen my chain after every few tanks of gas, or whenever I notice a decrease in cutting performance.

Cost of Chain Sharpening

Cost Analysis: Professional sharpening is a good option if you don’t want to invest in the tools or time to sharpen your own chain. However, over the long run, investing in sharpening tools will save you money.

Pro Tip #3: Chain Tension: Finding the Sweet Spot

Proper chain tension is essential for safety and performance. A chain that’s too loose can derail, while a chain that’s too tight can cause excessive wear on the bar and chain.

Checking Chain Tension:

• The chain should be snug against the bar but still able to be pulled around by hand.
• When you pull the chain away from the bar in the middle, you should be able to see about half of the drive links.

Adjusting Chain Tension:

The Stihl MS 251 features a side-mounted chain tensioner, making adjustments quick and easy.

1. Loosen the bar nuts slightly.
2. Turn the tensioning screw until the chain has the correct tension.
3. Tighten the bar nuts securely.

Important Considerations:

• Always adjust chain tension with the engine off and the chain brake engaged.
• New chains will stretch, so check the tension frequently during the first few uses.
• Chain tension will change as the bar heats up, so adjust accordingly.

My Mistake: Early on, I overtightened my chain, leading to premature wear on the bar and chain. I learned the hard way that finding the “sweet spot” is crucial.

Pro Tip #4: Lubrication: Extending the Life of Your Chain and Bar

Proper lubrication reduces friction, extending the life of your chain and bar. Always use a high-quality bar and chain oil specifically designed for chainsaws.

Oil Types:

• Petroleum-based: The most common and affordable option.
• Vegetable-based: Biodegradable and environmentally friendly, but typically more expensive.

Checking Oil Level:

The Stihl MS 251 has a translucent oil tank, making it easy to check the oil level. Refill the oil tank whenever you refill the fuel tank.

Adjusting Oil Flow:

Some chainsaws allow you to adjust the oil flow. If you’re cutting dense hardwoods, you may need to increase the oil flow to provide adequate lubrication.

My Recommendation: I prefer using a vegetable-based bar and chain oil for environmental reasons, even though it’s slightly more expensive. I also make sure to clean the bar and chain regularly to remove sawdust and debris.

Cost of Bar and Chain Oil

Cost Analysis: While vegetable-based oil is more expensive upfront, the environmental benefits may outweigh the cost for some users.

Pro Tip #5: Chain Maintenance: Keeping Your Chain in Top Condition

Regular chain maintenance is essential for maximizing its lifespan and performance.

Key Maintenance Tasks:

• Cleaning: Clean the chain and bar regularly to remove sawdust and debris. I use a wire brush and solvent for this.
• Filing the Rakers (Depth Gauges): The rakers control how much wood the chain takes with each cut. If they’re too high, the chain won’t cut effectively. If they’re too low, the chain will be too aggressive and prone to kickback. Use a raker gauge and a flat file to maintain the correct raker height.
• Checking for Damage: Inspect the chain regularly for damaged or worn teeth. Replace the chain if necessary.
• Bar Maintenance: Clean the bar groove regularly and file off any burrs on the bar rails. Flip the bar periodically to ensure even wear.

My Routine: I dedicate a few minutes after each use to cleaning and inspecting my chain. I also file the rakers every few sharpening sessions. This simple routine has significantly extended the life of my chains and bars.

Cost of Chain and Bar Maintenance

Cost Analysis: Investing in basic maintenance tools will save you money in the long run by extending the life of your chains and bars.

Additional Considerations: Wood Processing and Firewood Preparation Costs

Beyond the chainsaw itself, it’s crucial to understand the broader context of wood processing and firewood preparation costs. This includes everything from the cost of the wood itself to labor and equipment.

1. Timber Purchase or Harvesting Costs:

• Standing Timber: If you’re harvesting your own timber, you’ll need to factor in the cost of the timber itself. Timber prices vary widely depending on the species, quality, and location.
  • Data Point: According to the USDA Forest Service, the average stumpage price (price paid for standing timber) for sawtimber in the United States in 2023 ranged from $20 to $100 per thousand board feet (MBF), depending on the species and region.
• Purchased Logs: If you’re buying logs, the price will depend on the species, size, and quality of the logs.
  • Data Point: The price of hardwood logs can range from $100 to $500 per MBF, while softwood logs are typically cheaper.
• Harvesting Costs: If you’re harvesting your own timber, you’ll need to factor in the cost of labor, equipment, and permits (if required).
  • Labor: Logging labor rates can range from $20 to $50 per hour, depending on experience and location.
  • Equipment: The cost of renting logging equipment (e.g., skidders, loaders) can range from $100 to $500 per day.
  • Permits: Logging permits can cost anywhere from a few dollars to several hundred dollars, depending on the location and regulations.

2. Tool Maintenance:

• Chainsaw Maintenance: As discussed above, regular chain maintenance is crucial. You’ll also need to factor in the cost of other chainsaw maintenance tasks, such as cleaning the air filter, replacing the spark plug, and lubricating the bar.
• Splitting Equipment: If you’re splitting firewood, you’ll need to factor in the cost of splitting equipment, such as a maul, wedge, or log splitter.
  • Manual Splitting: A maul and wedge can cost between $50 and $100.
  • Log Splitter Rental: Renting a log splitter can cost between $50 and $100 per day.
  • Log Splitter Purchase: Purchasing a log splitter can cost between $1,000 and $5,000, depending on the size and power.

3. Labor Wages:

• Firewood Handlers: If you’re hiring someone to help you process firewood, you’ll need to factor in their wages.
  • Data Point: The average wage for firewood handlers in the United States is around $15 to $25 per hour.

4. Permits:

• Firewood Permits: In some areas, you may need a permit to collect firewood from public lands.
  • Cost: Firewood permits typically cost between $20 and $50 per cord.

5. Variable Factors Affecting Project Costs:

• Wood Type: Hardwoods are generally more expensive than softwoods.
• Location Accessibility: If the wood is difficult to access, the harvesting costs will be higher.
• Seasonality: Timber prices and labor rates can fluctuate depending on the season.

Cost Breakdown Example: Preparing One Cord of Firewood

Let’s break down the costs associated with preparing one cord of firewood from purchased logs:

• Log Purchase: $150 (assuming a mix of hardwoods)
• Chainsaw Fuel and Oil: $10
• Log Splitter Rental (1 day): $75
• Labor (8 hours at $20/hour): $160
• Total Cost: $395

Industry Benchmarks and Statistical Data:

• Average Price per Cord of Firewood: The average price per cord of firewood in the United States ranges from $200 to $400, depending on the region and wood type.

Practical Tips for Cost Optimization and Budget Management:

• Harvest Your Own Timber: If you have access to timber, harvesting your own can save you money.
• Season Your Firewood: Properly seasoned firewood burns more efficiently, reducing your overall fuel consumption.
• Shop Around for Logs: Compare prices from different suppliers to find the best deal.
• Maintain Your Equipment: Regular maintenance will extend the life of your equipment and reduce repair costs.
• Consider a Wood-Burning Stove: If you heat your home with wood, a wood-burning stove can be more efficient than an open fireplace.

Relevant Calculations and Formulas:

• Estimating Volume of Logs: The Doyle Log Scale is a common method for estimating the volume of logs in board feet.
• Estimating Drying Time: The drying time for firewood depends on the moisture content, wood species, and climate. A general rule of thumb is that it takes 6-12 months to properly season firewood.

Global and Regional Sources for Timber Prices and Equipment Rental Fees:

• USDA Forest Service: Provides data on timber prices and forest resources in the United States.
• FAO (Food and Agriculture Organization of the United Nations): Provides data on global forest resources and timber trade.
• Local Equipment Rental Companies: Contact local rental companies for information on equipment rental fees.

Actionable Takeaways and Next Steps

By understanding the nuances of chain selection, maintenance, and the broader costs associated with wood processing, you can maximize the efficiency and lifespan of your Stihl MS 251 and save money in the long run. Here’s what to do next:

1. Review your owner’s manual: Double-check the recommended chain specifications for your specific MS 251 model.
2. Assess your cutting needs: Determine the appropriate bar length for your typical tasks.
3. Invest in sharpening tools: A sharp chain is essential for safety and efficiency.
4. Establish a maintenance routine: Clean and inspect your chain regularly.
5. Budget wisely: Consider all costs associated with wood processing, from timber purchase to labor.

I hope this guide has provided you with the knowledge and confidence to get the most out of your Stihl MS 251. Happy cutting!

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