How To Square File Chainsaw Chains?  [Do It Yourself]

People ask a lot about filing square-ground chainsaw chains. Many users enjoy the performance of the square-ground chain and want an inexpensive method to hone it. Most believe that square filing and round filing are similar and that they can simply grasp it with a few newly-learned additional skills. But this is not the case.

Although the knowledge and experience gained from other types of chain filing tasks help you develop some new skills, square filing is a way more difficult job than round filing. But with an efficient set of working modules, know-how, and a little bit of patience, you can get a satisfactory result in terms of square filing your chainsaw chain. 

This article is going to provide you with a pro-level DIY method to accurately square-file chainsaw chains. So, let’s get started. 

8 Steps To Follow To Square File Chainsaw Chains 

DIY method to square file a chainsaw chain is step-by-step instructions on how to do it in your workshop or garage. Square filing may be performed in the field, but it is best learned under adequate lighting and stable cutting teeth. 

If you have access to a workshop with enough lighting as well as a working bench, this is an ideal location for learning. It is recommended to avoid using an old chain, especially if that’s been filed anytime in the past.

So now, let’s move on to discussing the step-by-step DIY method to square file a chainsaw chain. 

Step-1: Pick The Right File Size 

Specialized files are used to sharpen chainsaw chains. Chainsaw files are typically available in three sizes – 5/32, 3/16, and 7/32. Choose the appropriate size for your chainsaw chain. For instructions regarding the right file size, see the owner’s guide or the label put on the original packaging. 

The chain specifications are displayed on the side of the majority of guide bars. Utilize this information to select a suitable chain and to obtain the required file information. 

Step-2: Strip Away The Power Supply

Before you begin sharpening the cutting teeth, you must disconnect the saw from its respective power source when servicing the chain. A chainsaw that is linked to the power supply may start accidentally, resulting in severe injury.

Working on chainsaws with the batteries installed or perhaps an electric cable connected is identical to that of a running gas-powered saw. Before beginning servicing, detach the electric power connection, be it a battery or a cable. Always bring a gas saw to a complete stop whenever it is running. 

Chainsaws are available in three different power configurations: battery, wired, and gas. The saw mustn’t start unintentionally during maintenance. Take off the battery or disconnect the device to achieve this.

Gas chainsaws need a multi-step manual start-up procedure, making them far safer in terms of inadvertent starting. Always check the instructions and become accustomed to your saw’s start-up mechanism. 

Step-3: Clean Up Your Chainsaw

After disconnecting the power supply, the next step in servicing the chainsaw is to cleanse the machine of debris, dust, etc. Chainsaws are devices that are more prone to get oily. Cutting lubrication aids in the chain’s smooth travel throughout the bar. 

This lube coats the chain as well as the bar extensively, and also any particles that the device gathers up during operation. It is essential to clean the device of debris and excessive grease. An Air compressor, a brush, or a cloth are all effective ways to clean waste from the machine.

If operating indoors, ensure that the use of lubricant is accounted for by putting plastics or towels beneath the device before performing maintenance.

Ensure that the motor housing as well as, in particular, the handles are free of grease, oil, dust, and debris.

Step-4: Configure The Guide And The File 

Having filehandles is an absolute necessity, and a guide happens to be quite beneficial. Luckily, complete sharpening kits for chainsaws are available in the market. Instructions are included with the kits on installing the file, guide, and handle. Pay heed to the file’s user directions.

The guide works to secure the file at the precise level in the teeth and assist you in angling the file accurately. The guide would often include markings for multiple angles. In most cases, matching the 30-degree markings on the guide would work.

If you’re unsure of the correct angle, examine the chain. Each tooth ought to have a fine line towards the basal of the cutter indicating the optimal angle for the chain. To avoid injury, always use heavy-duty working gloves whilst sharpening your chainsaw chain. 

Step-5: Set Up The Chain Tension

This step is vital to assist you to sharpen the chain whilst it is on the machine. As pressure is exerted on the cutter, a  loose chain may cause the teeth to rock rearward. A correctly fastened chain would also improve the cutting performance of the saw. It should be checked every time the chainsaw is operated.

The optimal tension would be if the chain goes enough far from the bar when pulled away, revealing the points of the driving teeth situated in the rail. When you are not pulling the chain away from the bar, the driving teeth should remain hidden.

To examine the tension, hold the chain along the upper middle of the bar (wearing thick gloves is recommended) and then swiftly release it. A correctly fastened chain would automatically snap back into place. If the chain remains loose, it must be fastened properly. 

To set the chain to the correct level of tension, follow these 3 steps – 

  • Slacken the holding nuts on the guide bar.
  • Raise the guide bar, then clockwise rotate the tensioning screw. These can be found on the chainsaw’s front or side.
  • After adjusting, screw the retaining nuts tightly. 

Step-6: Fasten The Chainsaw Bar

Secure the chainsaw in either a bench vise or a stump vise once your chain is prepared for sharpening. Maintaining control of the saw is essential to achieving consistent results from one tooth to another. 

A chain can be filed several times until the cutters get dull. When they get too tiny to file, they must be replaced by a similar chain using the following steps: 

  • Loosen the brake on the chain and detach the nuts, or unscrew the nuts or screws that secure the plate in the bar to the saw’s side.
  • After removing the plate, push the bar forward to disengage it from the fastener. This causes laxity in the chain, allowing it to be conveniently removed. 
  • On the inner edge of the bar, a tension screw can be found – loosen it a little to facilitate inserting the new chain smoothly. 
  • Thread the new chain onto the clutch drum of the saw, ensuring that the drive links in contact with the sprocket. 
  • Ensure that the chain’s direction matches the direction of the piece you previously removed. 
  • Thread the remaining chain carefully onto the bar as well as across the nose. 
  • Remove the bar from the saw to increase chain tension, then reinstall the plate. 
  • Fasten the nuts just halfway, since the bar would need to slide somewhat while the chain is set to the ideal tension. 
  • Adjust the tension screw till the chain could be pulled approximately half an inch off the center point of the bar, then fasten the bar plate of the guide. 

Additional info for you – To facilitate chain removal smoother, most chainsaws feature a wrench/screwdriver combined technique known as a “scrench.” 

Step-7: Begin Sharpening One Side Of The Chain

Make sure the chain is clean before you start. Having debris on the teeth will make it hard to sharpen them. When ready, follow these steps – 

  • Mark the tooth where you want to start using a marker or crayon. 
  • From the inside out, start to file the teeth. Make sure the tip of your file always points away from the motor. 
  • The file should be held at an angle of 90 degrees to the sides of the bar that have flat sections on them. Angle the file 30 degrees away from the chain’s straight line. Keep both angles the same during the stroke. Be cautious not to start changing towards the end of the movement, thus, rounding the edge you already produced.
  • Using a file, you can sharpen the chainsaw. Keep filing every other tooth on the chain. Then, turn around and start sharpening every other tooth in the other direction.
  • After sharpening a few teeth, release the brake on the chain and move the chain forth to keep sharpening.
  • If there’s a burr on the tooth’s edge on the other side, the tooth has successfully been sharpened. You can feel the burr with your fingernail. Be careful when you look for burrs. Unprotected skin can be cut by them, and can be very painful. 

Step-8: Sharpen The Reverse Side

After completing one side of the chain, reverse the chainsaw within the vise and start sharpening the remainder of the teeth. Keep in mind that filing should come outwards starting at the inside. Note that files, unlike abrasives, are cutting equipment. The file would eliminate unnecessary metal while leaving a cutting tip sharp enough to chop down lumbers.

Only the push stroke is cut by files. Put no pressure upon returning, or draw stroke. A file employed on metal will have a shorter lifespan if pressure is put on the return. 

Things To Consider Before Using Square Filing Chainsaw Chains: 

Square-chainsaw chains using a grinder have several inherent perks. Users can generate well-sharpened cutting teeth by merely aligning the edge with the edge of the grinding wheel. After sharpening a cutter tooth, stops are put in which restrict feed or travel. 

These stops enable the operator to conveniently replicate the results of the first sharp cutting tooth on the remainder of the gear.

The basic rules for sharpening are pretty much the same for square-grinding and square-filing:

  • The file’s or the grinding wheel’s edge must remain in alignment with the tip of the chain’s cutting teeth.
  • Sharpening angles within the cutting teeth have to be maintained.
  • You have to repeat this precisely on each tooth since all of the cutting teeth must be the same.

Safety Measures To Take When Using Chainsaw Chains:

It’s time to discuss chainsaw safety because now your chainsaw chain is sharp. Most people just don’t think chainsaws are dangerous, especially the small chainsaws meant for homeowners who use them only a few times a year. 

The reality is that any saw capable of cutting through a tree can cause significant injury to a human body.

Chainsaw safety gear comprises – safety goggles or a face mask, protective hearing devices, pair of thick work gloves, chainsaw chaps, steel boots, etc. Use a helmet too if you happen to work with your limbs overhead. 

Routine maintenance of your chainsaw’s chain guarantees that the cutting teeth are sharp before your next endeavor.

FAQs Regarding How To Square File Chainsaw Chain 

How Do You Sharpen A Chain With A Square File? 

Begin by positioning your filing tool next to the cutting tooth’s face. Decide which file edge should match the cutter tooth edge. Realign the file on another axis to match the other surfaces. Then, try a few strokes. Examine the cutter teeth without the filing.

You will see the file’s markings on the steel. Utilize what you can see to make changes to the file. Continue filling until the tooth resembles the sharp edge on the reference chain you have with you. 

What Kind of Square File Should You Use?

You are recommended to consult your chainsaw dealer for files intended for square-ground cutters. Square files come in three varieties – double bevel, hexagonal, and “goofy”.

The most commonly used file shape is a hexagon. It comprises six sides as well as three filing edges. When it comes to files, the hexagonal-shaped file is usually the smallest in size. It fits into a 3/8″ pitch chain properly.

The double bevel as well as “goofy” files feature two sharpening edges. These files have surfaces along their top and bottom to decrease depth gauges.

How Can You Make My Chainsaw Cut Faster? 

If you want to cut quickly, you could use a chainsaw chain that runs as fast as possible. A saw chain featuring full chisel cutters or teeth indicates that you’ve been cutting at a high rate of speed. It’s evidently important since speed is one of the fundamental precepts of an efficient chain.

In the professional sphere, experts typically use full-chisel chains on large chainsaws. Semi-chisel teeth generally have a round shape, which reduces the chance of kickback and keeps teeth sharper for longer. Semi-chisels usually do the cutting relatively slowly than full chisels yet are a superior option in dirty lumber. 

What Is A Square File Tool? 

Square files are tools used by machinists and can be employed inside slots and grooves. These tools are essential for roughing (fast material removal) while converting round drill holes to square slots. 

The cross-section of these files is square. It means they are suitable for rectangular or square notches within a piece of work. Moreover, they can be used for cutting right-angled notches generated by rotating the file while cutting with the edge. 

They have double cuts on all the sides, which means they can remove substances with different faces at the same time. It further allows them to do the task fast. Generally, square files come in lengths ranging between 100mm (4 inches) and 350mm (14 inches). 

How Do You Know That Your Chainsaw Chain Needs Sharpening?

A razor-sharp chain cuts swiftly and in a nearly straight line. Sharp chains can increase the lifespan of the chainsaw. A dull or rusty chainsaw can be potentially deadly. Use chainsaw files or electric sharpeners to sharpen the chain.

You know your chainsaw chain needs sharpening in the following scenarios – 

  • Your chainsaw is cutting at a snail’s pace. 
  • It is smoking or burning as it cuts. 
  • You are coming into contact with metal while chopping timbers 
  • You are tapping the dirt while removing debris. 

How Do You Know What Size File I Need For My Chainsaw?

The chainsaw file size you require is directly proportional to that of the chain pitch you have. If you are unsure about your chainsaw pitch, you might determine it by the distance across three rivets. 

It is essential to remember that if all the cutting teeth are not similar, you may require multiple files. Given the variety of chisels available for chainsaw chains, each sort of chisel would need a unique file for itself. 

The various file sizes available in the market are as follows – 

Pitch SizeFile Size 
3/8″5/32″ or 7/32″
          0.404″        7/32″

Final Remark:

Square filing your chainsaw chains may seem an overwhelmingly difficult task. But the procedure and outcome can get somewhat rewarding with proper knowledge and enough practice. Specifically, when you witness your chainsaw chain performing clean, competent, and effortless cuts. Hopefully, this article can come in your support in this regard.

Masud Rana

This is Masud Rana. I run this blog. My Tools Guide is a blog where I share product reviews of different tools. Stay tuned to get more helpful articles!

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