Stihl Hexa Saw Chain Sharpening (Filing Guide)

To sharpen a STIHL HEXA chain, first identify its chain code and confirm the matching HEXA file and guide in current STIHL instructions. HEXA file size and filing angle are not universal. File each cutter at the guide’s marked setting, then check depth gauges with the specified tool. Never substitute a conventional round file or guess at settings.

A chain that makes fine dust, burns wood, or needs pushing may be dull, but sharpening is only safe when the chain is correctly matched and still serviceable. Before picking up a file, check three fit details: pitch, gauge, and drive-link count. Those must agree with the bar and sprocket; a chain that only looks similar is not necessarily compatible.

I see a common garage mistake: someone remembers a file size from another chain and applies it to a HEXA chain. That can spoil the cutter shape or leave the depth gauges wrong. The reliable shortcut is to identify the exact chain first, then follow the instructions for that variant.

Identify the chain and find its sharpening settings

Start by confirming the chain’s identity, rather than choosing a file from the saw model or bar length. The chain marking or its packaging helps you locate the matching STIHL chart and HEXA instructions. Use those instructions to confirm the file, guide angle, and depth-gauge setting for that chain.

Check the chain code and fit

The chain code identifies the chain family or variant. Pitch is the spacing between the chain’s drive links, gauge is the thickness of those links, and drive-link count is the number of links that run in the bar groove. All three must match the bar and drive sprocket.

Look for chain and bar markings, packaging, or the saw’s parts information. If the chain code is hard to read, do not infer a replacement or sharpening setup from engine size. Use the model-specific STIHL manual or chain chart to confirm the approved combination.

Bar length alone does not identify the correct file. Nor does the wood species change the chain’s specified sharpening geometry. If you cannot confirm the chain variant, pause and check the STIHL chart or ask a STIHL dealer to identify it before filing.

Select the matching HEXA file and guide

A HEXA chain is designed for the matching STIHL HEXA file. A conventional round file is not an equivalent substitute. File diameter and filing angle depend on the chain variant, so use the current STIHL HEXA instructions or the markings on the matched guide to get those exact settings.

This is why there is no safe universal file-size or angle answer for every HEXA chain. Do not estimate from bar length, saw model, or a different chain you own. If the file or guide has no clear identification, compare it with the chain code and current STIHL guidance before use.

Confirm the depth-gauge tool and clearance in the same instructions. A generic raker setting may not match your chain. Keep the chain code and its sharpening information together; that simple habit prevents repeat guesswork next time.

Prepare the saw and work area safely

Preparation keeps the chain still while you file and prevents an accidental start. Work with the engine off and cool, or remove the battery from a battery saw. Wear eye protection and cut-resistant gloves, secure the saw on a stable surface, and keep hands clear of cutter edges.

Secure the saw before filing

For a gasoline saw, disconnect the spark-plug boot before working on the chain. On a battery saw, remove the battery. Secure the bar so it cannot shift. Engage the chain brake when repositioning the chain; release it while filing so the chain can move through the bar.

Move the chain with gloved hands and control it so it cannot roll unexpectedly. Keep the file, guide, and any depth-gauge tool within reach, but away from the chain until you are ready to use them. If you find cracks, damaged tie straps, loose rivets, or a cutter below the manufacturer’s wear limit, do not sharpen the chain for further use. Replace it.

Clean and inspect before sharpening

Remove dirt and oil buildup from the chain so the cutter edges and markings are visible. Check the bar groove, oil outlet, and chain for debris or damage. A file cannot repair a cracked link, loose rivet, or worn-out cutter; those are reasons to stop and replace the chain.

Before filing, mark one cutter with a marker. This gives you a clear starting point and helps you avoid filing the same cutter twice or missing one. Also note the shortest cutter that is still within the manufacturer’s service limit. The other serviceable cutters should be brought to that length, not filed shorter than necessary.

File the cutters and check the depth gauges

Work in a steady sequence and let the matched guide control the cutter geometry. Keep the HEXA file seated in its guide at the angle specified for your chain, and use consistent, smooth strokes. After the cutters are sharp, check the depth gauges with the correct STIHL tool and chain-specific instructions.

Sharpen each cutter consistently

Set the guide on the cutter and follow its marked filing angle. Keep the file seated as the guide directs, and apply steady strokes rather than forcing it. File cutters from the same side in one pass through the chain, then reposition as needed to work the cutters facing the other direction.

Use these steps:

• Begin at the marked cutter and file each cutter facing the same direction.
• Keep the HEXA file seated in its guide; do not change the angle by eye.
• Use smooth, even strokes and avoid pressing hard enough to distort the cutter.
• Move to the opposite-facing cutters and repeat with the same guide setting.
• Compare cutter lengths and bring serviceable cutters to the shortest serviceable one.

Do not assume every cutter needs the same number of strokes. The goal is consistent, sharp cutting edges without removing extra metal. If a cutter has damage that cannot be removed while staying within the maker’s wear limit, replace the chain rather than filing it down further.

Set depth gauges only with the correct tool

A depth gauge, also called a raker, controls how much wood each cutter can take. If it sits too high, the chain may cut slowly. If it is lowered too far, cutters can grab aggressively. Incorrect height can increase kickback risk, so do not grind or file depth gauges by eye.

Use the STIHL gauge or tool specified for the identified HEXA chain and follow its instructions for checking and lowering the gauges. Do not apply a generic clearance from another chain type. Remove material only as directed, and finish the gauges as the instructions specify. If you cannot confirm the right tool or setting, stop and look up the chain code first.

A practical garage example

Suppose a chain has started producing mostly fine dust and the saw pulls to one side. First, I would stop and identify the chain, then confirm pitch, gauge, and drive-link count against the bar and sprocket. I would not begin by reaching for the file used on another saw.

Next, I would check the matched HEXA file and guide information, inspect the chain for damage, and mark the first cutter. If the chain is serviceable, I would sharpen each cutter with the guide at its marked angle, compare cutter lengths, and check the depth gauges with the specified tool. This sequence addresses both dull cutters and uneven sharpening without guessing at settings.

Refit the chain, test the cut, and store it well

Sharpening is not complete until the chain is correctly tensioned, lubricated, and checked for free movement. Follow the saw manual for refitting and tensioning, then test the saw outdoors. Stop if the chain binds, runs loose, vibrates abnormally, or fails to receive bar oil.

Check tension, movement, and oiling

Refit and tension the chain according to the saw’s manual. With the power source still disconnected, wear gloves and check that the chain moves freely by hand. Remove all tools, confirm guards are in place, then reconnect the spark-plug boot or battery.

Start and operate the saw outdoors using the model’s starting instructions. In a controlled test cut, a properly sharpened chain should cut without being forced and should produce chips rather than mostly fine dust. Confirm that the chain receives bar oil. Stop at once if the chain is loose, binds, vibrates unusually, or appears poorly lubricated; correct the problem before cutting again.

Sharpening does not remove the need for safe cutting practices. Follow the saw maker’s limits and the safety rules for the work. Kickback, overhead cutting, and felling have hazards that require separate controls and training.

Clean and store the chain

After work, clear filings and debris from the chain, bar groove, and oil outlet. Check the bar rails and sprocket for wear. Keep the chain protected from moisture and contamination, and store its code or sharpening instructions with it so the correct file and settings are easy to find.

Bottom line: Identify the exact chain, use its matched HEXA file and guide, and check depth gauges only with the specified tool. If the chain is mismatched, damaged, or beyond its wear limit, do not try to sharpen it back into service.

Frequently asked questions

These answers cover the decisions that most often delay a sharpening job: file choice, angle, depth-gauge setting, and whether a chain is safe to reuse. For exact settings, the chain code and current STIHL instructions take priority over general advice.

Can I sharpen a STIHL HEXA chain with a regular round file?
No. Use the matching STIHL HEXA file. A conventional round file is not an equivalent substitute for the HEXA system.

What file size does a HEXA chain need?
It depends on the exact chain variant. Identify the chain code, then confirm the file in current STIHL instructions or the matching guide. Do not guess from saw model or bar length.

What filing angle should I use?
Use the angle marked on the matched HEXA guide or specified in the instructions for that chain. Do not assume an angle used for another chain type.

Can I use a generic depth-gauge setting?
No. Use the STIHL depth-gauge tool and chain-specific clearance specified for the identified chain. Do not grind depth gauges by eye.

Does hardwood require a different filing angle?
No. Wood hardness does not change the chain’s specified geometry. Sharpen to the chain instructions.

How do I know when to stop filing?
Stop if you find structural damage or a cutter is below the manufacturer’s wear limit. Replace the chain rather than filing it further.

Why does my chain make fine dust after sharpening?
Fine dust can indicate that the chain is still dull or that sharpening was uneven. Recheck the cutter edges and lengths using the matched HEXA guide, and inspect the chain for damage.

Why does the saw pull to one side?
Uneven cutter length or sharpening can contribute. Compare serviceable cutter lengths and check that both directions of cutters were filed consistently. Stop if the chain is damaged.

Should the chain brake be on while filing?
Engage it while repositioning the chain, then release it for filing so the chain can move through the bar. Keep the power source disconnected throughout the work.

What should I check before the first cut?
Confirm correct tension, free hand movement with gloves on, lubrication, and that all tools are removed. Test outdoors and stop immediately for looseness, binding, abnormal vibration, or poor oiling.

(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)