What Size File for a .325 Chain: A Comprehensive Guide

What Size File for a .325 Chain: A Comprehensive Guide

Cutting wood with a chainsaw is an extremely satisfying experience. The roar of the engine, the smell of gasoline and oil, and the feeling of power as you slice through logs – it’s pure bliss for any weekend warrior. However, keeping your chainsaw running at peak performance requires proper maintenance and sharpening. And one of the most important aspects of chainsaw sharpening is using the correct size file. But what size file do you need for a .325 pitch chain, which is one of the most common sizes? Read on to find out!

I’ll walk you through determining the ideal file size for your saw, the different types of files, and the complete sharpening process. I’ll also touch on common mistakes, brands I recommend, and frequently asked questions. Whether you’re sharpening for the first time or looking to improve your technique, this guide has everything you need to master chainsaw chain maintenance. A properly sharpened chain cuts faster, requires less effort, and saves unnecessary wear on your saw. So let’s get filing!

What size file for a .325 chain?

What Size File for a .325 Chain: A Comprehensive Guide

For a standard .325 pitch chain, which is by far the most popular size, the ideal file size is 3/16 inch or 4.8mm. This matches the proportions of the chain’s cutters and allows you to sharpen them effectively. Using the wrong file size can damage the cutters and lead to poor performance.

It’s crucial to match the file size precisely to the chain pitch. Chainsaw chains come in different pitches, like .325, 3/8, and .404. The number refers to the spacing between the drive links, not the file size needed. So a 3/16 file is correct for a .325 chain, but would be too small for a 3/8 chain.

To visualize it, think about using a knife to spread butter. You need one that fits the grooves in the bread, not too big or small. Same goes for filing chainsaw teeth – the file has to fit in the cutter properly. Keep this in mind and you’ll be golden.

Types of Chainsaw Files

The two main types of files used for sharpening chainsaw chains are round and square. Let’s compare them:

Round Files

Round files are the most common for chainsaw sharpening. They fit nicely into the curved profile of the cutters and are easy to use with the right technique. Round files come in a range of sizes to match different chain pitches. For .325 chains, look for 4.8mm or 3/16 inch round files.

The circular shape allows you to smoothly file the top cutting edge and sides of the tooth in one motion. Round files are affordable and suitable for most homeowners or weekend warriors. Keep a few on hand so you always have a fresh sharp file ready to go.

Square Files

Square chainsaw files have a flat profile and squared-off edges. They are popular with professional loggers who need to quickly sharpen chains between felling trees. The flat section makes it easy to file the depth gauge on each tooth.

However, square files are less common for the average chainsaw user. They can be more difficult to use and are aggressive, so in inexperienced hands they increase the risk of making mistakes. Stick with a round file unless you require heavy-duty sharpening capabilities.

How to Determine the Correct File Size

To find the right file size, you’ll need to check two things – your chainsaw’s manual and the chain itself. Here’s how:

Check the Chainsaw’s Manual

The owner’s manual or guide that came with your chainsaw should specify the correct file size needed. For instance, the manual for my Stihl MS 271 states to use a 4.8mm round file for the included .325 pitch chain.

If you don’t have the manual, search online for a PDF version. Most manufacturers provide downloadable manuals on their websites. Or you can call their customer support line and ask. Getting the recommended file size directly from the source is the safest route.

Inspect the Chain’s Cutter

You can also determine the file size by examining the chain’s cutter teeth closely. Look for tiny numbers stamped into the metal drive links on the top or sides.

For .325 chains, you’ll see 325, 32, or 3/8. This indicates a pitch of .325 inches and that you need a 3/16 or 4.8mm round file. Make sure to use the metric measurement when purchasing a file.

If the number doesn’t make sense based on standard chain sizes, your chain may be specialty, custom, or worn out already. Start with the manual’s recommendation in that case.

Chainsaw Sharpening Process

Now that you’ve got the right file, let’s walk through the complete chainsaw sharpening process:

Preparing the Chainsaw

Safety comes first! Disconnect the spark plug before filing and wear protective gloves. Use a clamp or vise to secure the bar. Ensure the chain brake is on so the chain doesn’t spin during filing. Clean any debris, sap, or dirt off the chain.

Select an area with good lighting and a solid workbench or table. Secure the tip of the guide bar in the vise about 6 inches from the table. You want the chain to be stationary and accessible.

Sharpening the Chain

Insert the correctly sized round file into the tooth’s gullet – the curved part the cutter slides into. Keep the file level at a 30° angle to the side plate. Gently push forward 3-4 times. Use the same number of filing strokes on each tooth to wear the cutters evenly.

Apply minimal downward pressure – let the file do the work. Going too aggressively can take off too much material. File every other cutter tooth as you move around the chain in a clockwise direction.

After several passes with the round file, use a flat file to restore and lower the depth gauges. This helps optimize chip flow and sawdust ejection. Take care to file gauges uniformly so cutter length remains consistent.

File Brands and Recommendations

When purchasing a round chainsaw file, you can’t go wrong with either of these top brands:


Oregon is one of the leaders in chainsaw chains and accessories. For .325 pitch chain, they recommend their 3/16-inch round file. It has durable alloy steel construction and easily fits standard .325 chains.


Stihl, another trusted manufacturer, offers a 4.8mm round file specifically for their brand’s .325 chains. I’ve found the Stihl 4.8mm x 200mm file maintains a sharp edge for a long time.

Common Sharpening Mistakes and Myths

To wrap up, let’s review two common errors that compromise chain performance:

Using the Wrong File Size

It can’t be stressed enough – always match the file size precisely to the chain pitch. An improperly sized file, even 1/16 inch off, can rapidly eat away too much material. This permanently damages cutters, throws off their angles, and creates uneven sharpening.

Filing the Cutters but Not the Depth Gauge

Many folks sharpen just the cutting teeth but neglect the depth gauges. This prevents the cutters from penetrating deep into the wood. Make sure to lower depth gauges every couple sharpening sessions using a flat file. This restores maximum chip flow.


Let’s review some frequently asked questions:

How often should I sharpen my chainsaw chain?

In general, sharpen the chain after every 1-2 hours of use, or whenever performance starts to decline. Harder wood species may require more frequent sharpening.

Can I use a different file size if I don’t have the recommended one?

It’s best to use precisely the right size file for your chain. An incorrect round file can rapidly cause damage. Only use a different size in an emergency until you can get the proper file.

How do I know when my chainsaw chain is sharp enough?

A sharp chain will cut smoothly with minimal pressure and small, powder-like sawdust. Visually inspect that all cutters have an even bevel. Ease up on filing passes if cutters get too hot.

What is the difference between chain pitch and file size?

Chain pitch refers to the spacing between rivets, not the file size. File size is measured in inches or millimeters based on the chain’s pitch and cutter proportions. Always match file size to chain pitch.

Can I use a chainsaw file for other sharpening purposes?

It’s best to use a file solely for chainsaw chains. The specialized steel and precise size is designed for cutting teeth only. Using it elsewhere will wear the file down.

How do I maintain my chainsaw file?

Store files in the packaging or a hard case, away from moisture. Clean with a wire brush after each use and rub with lubricating oil to prevent rust. Toss files once the edges appear rounded, wavy, or uneven.

What are some safety tips for chainsaw sharpening?

Unplug the spark plug, use protective gloves, secure the bar in a vise, keep the chain brake on, file away from your body, clean the chain first, and wear eye/ear protection. Maintain a balanced stance and don’t force the file.


Whether you’re a homeowner or professional, keeping your chainsaw’s cutters razor sharp is crucial for safety and optimal performance. Matching the file size precisely to your chain’s pitch prevents cutter damage and accelerated wear. For the most common .325 chains, a 3/16 or 4.8mm round file is ideal. Use the manufacturer’s recommendation and take time to properly sharpen. Your chainsaw will reward you with buttery smooth cuts for years to come.

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