How do you file a chainsaw with a flat file?

Quick Answer

Filing a chainsaw with a flat file is a process that requires some specific steps and considerations to do correctly. The key things to know are: use a file guide, file the cutters side to side, use light pressure and avoid overheating the chain, file from the inside of each cutter to the outside, maintain the original angle, file enough to remove damage but not excessively, and finish with a depth gauge tool. With patience and care, a flat file can be used to effectively sharpen chainsaw teeth and restore cutting performance.

What Tools Do You Need to File a Chainsaw?

The basic tools you need to file a chainsaw by hand include:

• Flat file – Use a file sized for the chain pitch, such as 5/32″, 3/16″, or 7/32″. Look for a file labeled for use with chainsaws.
• File guide – This tool mounts to the bar and ensures the file is held at the correct angle to sharpen the cutters.
• Depth gauge tool – Used to establish proper depth gauge height after filing the teeth.
• Gloves – Protect your hands when handling the chainsaw.
• Eye protection – Filing creates metal shards that can fly into your eyes.

Optional items include a vise to securely clamp the bar and chain, and a raker gauge tool for measuring depth gauge heights.

Step-by-Step Filing Instructions

Here are the basic steps to properly sharpen chainsaw teeth with a hand file:

1. Secure the bar – Clamp the chainsaw bar horizontally with the chain attached in a vise or other fixture. The chain needs to be held steady but still able to be rotated.
2. Mount the file guide – Slip the guide over the nose of the bar and tighten the clamp so it is held in place. This will ensure the file stays at the correct angle relative to the bar and chain.
3. Find cutting direction – Look for the arrows etched into the side of each cutter. This shows the direction the cutter needs to be filed.
4. Position the file – With light pressure, place the file against the inside base of the cutter. Maintain the original angle of the tooth.
5. File side-to-side – Use steady, full length strokes from one side of the cutter across to the other side. Apply light pressure on each pass. Let the file do the work.
6. Avoid overheating – The metal will turn blue if the chain gets too hot. Dip the cutters in cool water to draw off the heat.
7. File to shape – Remove any damage on each tooth by filing just until the flat top of the cutter is restored. Follow the existing angle.
8. File all cutters – Systematically work your way around the entire chain, filing all the left cutters first. Then go back and file all the right cutters second.
9. Set depth gauges – Use a depth gauge tool to establish proper clearance behind each cutter after filing. This is crucial for fast cutting.
10. Clean chain – Use a wire brush to remove any metal fragments. Add bar oil to prevent rusting.

Filing Tips for Best Results

Follow these tips when filing a chainsaw chain to help get the best performance:

• Use the right size file – Match the file diameter to the chain pitch for a proper fit in the tooth gullet.
• Maintain original cutter shape – Closely follow the existing angles of the cutter. Don’t change the profile.
• Remove the minimum – Take off just enough material to eliminate nicks and restore sharpness.
• Lubricate the file – Use chainsaw bar oil to lube the file. The oil reduces friction and clogging.
• Steady hand – Brace your hands together to make smooth, consistent filing strokes.
• Rotate chain often – Frequently turn the chain while filing to avoid lopsided wear on the cutters.
• Check angles – Use a filing angle checker tool to verify you have maintained the correct cutter angle.

Proper filing technique will keep the chain cutting like new through multiple sharpenings. Take your time and focus on consistency for best results.

When to Replace a Chainsaw Chain

Here are some signs that indicate it is time to replace a chainsaw chain:

• Missing cutters – The chain is too worn if entire cutter teeth are broken off.
• Deep gouges – Major gashes or chunks of missing metal can’t be repaired through filing.
• Stretching – If the chain sags and feels loose on the bar it is past its usable lifespan.
• Rusting – Heavy oxidation that pits the metal calls for a new chain.
• Reduced cutting – Excessive filing has shortened the teeth too far to cut efficiently.
• Cutter length – Teeth have worn down to 1/8″ or less in length and no longer cut well.

As a general rule, replace your chainsaw chain after sharpening it 5-8 times. Watch for signs of excessive wear and don’t try to overextend a worn-out chain. A new chain will restore the chainsaw’s cutting performance.

Maintaining Your Chainsaw

Proper chainsaw maintenance helps maximize the working life of both the saw and the chain. Here are some key maintenance tips:

• Keep chain sharp – Regularly file the chain to maintain razor-sharp cutters. This also prevents overstraining the saw.
• Check chain tension – Ensure the chain is tightened to the manufacturer’s specification to prevent slack and slippage.
• Lubricate the chain – Oil ports and guide bar grooves need to be clear so oil can reach the chain while running.
• Clean the bar – Keep the guide bar free of debris so the chain rides smoothly without obstruction.
• Replace worn sprockets – The drive and nose sprockets should be replaced if the teeth become pointed or jagged.
• Monitor wear items – Check the chain, guide bar, and drive sprocket for excess wear and replace as needed.

Well-tuned chainsaws cut wood more efficiently, last longer between repairs, and are safer to operate. Invest a few extra minutes in regular chainsaw maintenance for best performance.

Safety Tips for Filing Chainsaws

While essential for optimal performance, chainsaw maintenance carries some inherent hazards. Use extreme caution when filing a saw chain:

• Unplug electric models – Disconnect the power before working on an electric chainsaw to avoid accidental startup.
• Allow cooling – Let gas chainsaws cool fully before beginning any maintenance to prevent burns.
• Secure the bar – Use vise clamps or a special clamping stand to fix the guide bar and chain.
• Wear protection – Use heavy gloves, eye shields, sturdy shoes, and hearing protection when using files.
• Point file down – Keep the file tip angled toward the ground, away from your hands and body.
• Maintain tools – Replace worn files that become small or develop ragged edges.
• Handle sharp chain carefully – Support the underside of the chain when handling to avoid contact with the cutters.

Focus your full attention on the task at hand. Also be sure to file chainsaws in a clean, well-lit area so you can see the angles clearly. Working carefully protects both you and your equipment.

Conclusion

While chainsaw chains are made to withstand heavy use, periodic sharpening is required to maintain optimal cutting performance. Filing by hand with a flat file is an effective method to reshape the cutters and remove nicks from the hard steel. Paying attention to details like using a guide, maintaining original cutter angles, and taking care not to overheat or remove excess material will provide the best results. File carefully, lubricate generously, and replace chains before they become excessively worn for a saw that cuts efficiently project after project.