What Is The Correct Chainsaw Filing Direction (Filing Technique)
File each cutter from its inner face toward its outer edge on the forward stroke, then lift the file on the return. Keep the file at the chain maker’s specified angles and use the correct file size. Sharpen every cutter evenly, then check the depth gauges with the correct tool. The engine must be off whenever you file or move the chain by hand.
Does your saw cut slowly, leave fine sawdust, or pull to one side? A dull or uneven chain may be the cause, and the direction you file matters. The basic motion is simple once you know which part of the cutter is the inside and which is the outside. The exact angles and file size, however, depend on the chain.
What is the correct chainsaw filing direction?
The correct direction is from the cutter’s inner face toward its outer edge, using a smooth forward stroke. The file cuts as it moves forward; lift it on the return rather than rubbing it back and forth. Repeat this motion on each cutter, following the chain maker’s angles and file-size guidance.
The inner face is the side of the cutter nearest the center of the saw and chain loop. The outer edge is the cutting edge facing away from that center. Place the round file in the cutter’s gullet, the curved opening behind its cutting edge, and move it from inner face to outer edge.
The cutters alternate: some face left and some face right. Their direction of filing therefore alternates as you work around the chain. The rule stays the same for each cutter: file from its inside toward its outside, on the forward stroke.
Do not file with the engine running or use a powered chain to bring cutters around. Turn the engine off, let the chain stop, engage the chain brake, and secure the saw before sharpening.
Which angles and file size should you use?
The right file size and filing angles are set by the chain design, not by wood hardness or saw engine size. Check the chain markings and the saw or chain maker’s instructions before sharpening. A 30-degree top-plate angle and a 5/32-inch file are common examples, but neither is correct for every chain.
The top-plate angle is the angle formed as the file shapes the cutter’s top surface. Many chains use 30 degrees, but some call for a different angle. A filing guide can help you hold the file in the correct position.
As a general setup, hold the file level across the cutter and at 90 degrees to the sides of the guide bar, unless the chain maker specifies a different vertical filing angle. The chain’s filing instructions take priority over a general rule.
| Filing detail | Common example | What to do |
|---|---|---|
| Top-plate filing angle | 30 degrees | Check the chain specification |
| Round-file size | 5/32 in (4.0 mm) for many 3/8-in low-profile chains | Confirm the exact chain model |
| Depth-gauge setting | 0.025 in (0.65 mm) on some chains | Use the maker’s setting and matching gauge |
| File stroke | Inner face to outer edge | Cut on the forward stroke only |
Pitch describes the spacing of the chain’s rivets. Gauge describes the thickness of the drive links that fit in the bar groove. Confirm chain pitch, gauge, drive-link count, and cutter type against the saw and bar information. Do not guess a chain’s fit based only on bar length or engine displacement.
How do you file a chainsaw chain step by step?
A consistent sequence helps you keep cutters even and avoid missing any. Mark the first cutter, set up the saw with the engine off, then file each cutter using the same forward motion, file size, and specified angles. Check the depth gauges after sharpening and restore correct chain tension before use.
Prepare the saw and chain
Before filing, switch off the engine, let the chain stop, engage the chain brake, and secure the saw or bar so it cannot shift. Wear eye protection and cut-resistant gloves. Follow the saw maker’s instructions and any applicable workplace rules, including OSHA 29 CFR 1910.266 where it applies.
To advance the chain, release the brake only while the engine is off. Move the chain by hand, then re-engage the brake before filing. Never use the engine to rotate the chain during sharpening.
Inspect the chain before you begin. Look for cracked cutters, damaged tie straps, loose rivets, or cutters that appear too short to sharpen safely. If you find damage or are unsure whether the chain remains serviceable, stop and consult the chain maker or a qualified service provider.
File each cutter in sequence
Mark one cutter with a marker so you know where you started. Seat the correctly sized round file in the cutter’s gullet, at the specified top-plate and vertical angles. Use smooth, steady forward strokes from the inner face toward the outer edge, then lift the file on the return.
Use similar pressure and a consistent number of strokes on each cutter. The goal is to make the cutters uniform, not to remove as much metal as possible. Continue around the chain, following the left- and right-facing cutters in turn. Marking the first cutter makes it easier to see when you have completed the loop.
If a cutter is badly damaged or much shorter than the others, filing every cutter down to match may not be safe or practical. Follow the manufacturer’s sharpening limits; replace the chain or have it serviced if it is beyond those limits.
Check the depth gauges
A depth gauge, also called a raker, controls how much wood a cutter can take in each pass. If it is too low, the chain can grab aggressively and raise kickback risk. If it is too high, the chain may cut poorly, which can tempt you to push harder.
After sharpening, check the depth gauges with the matching depth-gauge tool and the chain maker’s setting. A 0.025-inch (0.65 mm) setting is common on some chains, but it is not universal. Lower a raker only as directed by the maker and with the correct tool. Do not estimate the height by eye.
| What you notice | Possible filing issue | Next step |
|---|---|---|
| Cutters have different lengths | Uneven filing or a skipped cutter | Recheck each cutter and follow the maker’s limits |
| Saw cuts to one side | Left- and right-facing cutters may differ | Compare cutter sharpness and length |
| Chain grabs too aggressively | Depth gauges may be too low | Stop and check with the correct gauge |
| Chain cuts poorly after sharpening | Cutters may be dull, or gauges too high | Inspect the angles, file size, and gauge setting |
How can you tell whether the filing technique is working?
A properly sharpened chain should cut smoothly when used as directed, without needing you to force the saw through the wood. Cutting problems can have more than one cause, so check the chain’s cutters, depth gauges, and condition before deciding that a filing angle alone is to blame.
For example, if a chain pulls to one side after sharpening, compare the cutters that face left with those that face right. Uneven cutter lengths or sharpness may contribute to the drift. If the chain grabs, stop using it until you have checked the depth gauges and chain condition.
A practical field example is a chain that still cuts poorly after a few strokes with a file. First confirm that the file matches the chain and sits at the specified angle. Then inspect the cutters for damage and check the depth gauges. Do not keep removing metal without finding the cause.
Keep the bar out of dirt and other abrasive material while cutting. Dirt can dull a chain quickly, making it harder to judge your filing work and shortening the time between sharpenings.
What should you check before using the saw again?
After filing, check the depth gauges, chain tension, brake, bar, lubrication, and controls before starting the saw. Confirm that the chain can travel freely by hand with the engine off, following the saw maker’s instructions. Keep bystanders out of the work area, wear required protective equipment, and start and operate the saw as its manual directs.
If the chain is too loose or too tight, correct its tension according to the manual. Inspect the bar condition and confirm the chain lubrication system is working as intended. These are operating checks, not filing specifications: engine RPM, bar-oil viscosity, and fuel mix do not tell you what angle or file size to use.
When work is done, stop the engine and let the saw cool. Clean the chain and bar groove, clear the oil holes, and inspect the bar rails and sprocket. Lubricate and store the chain as directed by the manufacturer. Follow the manual for fuel and seasonal storage as well.
Quick answers about chainsaw filing direction
- Which way do I push the file? From the cutter’s inner face toward its outer edge on the forward stroke. Lift the file on the return.
- Do I file both directions? No. File on the forward stroke only; lift the file as you bring it back.
- Do left- and right-facing cutters use the same rule? Yes. File each cutter from its own inner face toward its outer edge, even though the cutters face opposite ways.
- Is a 30-degree angle right for every chain? No. It is common, but the chain maker’s filing instructions set the correct angle.
- Can I use any round file that fits? No. Use the diameter specified for the exact chain. A file that is too large or too small can alter the cutter shape.
- Should the file be level? Hold it level across the cutter and at 90 degrees to the bar sides unless the chain maker specifies another vertical filing angle.
- Do I need to check rakers after filing? Yes. Check them with the matching depth-gauge tool and use the chain maker’s setting.
- Can I file while the chain brake is on? Secure the saw first. Release the brake only with the engine off when you need to move the chain by hand, then re-engage it before filing.
- What if the chain still cuts badly? Recheck the file size, filing angles, cutter uniformity, depth gauges, and chain condition. Replace or service a chain that is damaged or beyond its sharpening limits.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
