Step-by-step guide to sharpening chainsaw chains by hand and with an electric sharpener. Covers file sizes, angles by chain type, and when to replace instead of sharpen.
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Oregon 520-120 Bench Chain Sharpener
Step-by-step guide to sharpening chainsaw chains by hand and with an electric sharpener. Covers file sizes, angles by chain type, and when to replace instead of sharpen.
Best For: Best Electric Chain Sharpener
Check Current PriceTime Required: 15-20 minutes (by hand), 5-10 minutes (electric sharpener)
Difficulty: Easy to moderate
Tools Needed: Round file (correct diameter), flat file, file guide, stump vise or bar clamp
How to Tell Your Chain Is Dull
Sawdust instead of chips. A sharp chain throws wood chips. A dull chain makes fine sawdust. This is the most reliable indicator. You have to push. A sharp chain pulls the saw into the wood under its own feed. If you are pushing the bar to make it cut, the chain is dull. Smoke or burning smell. Excessive friction from dull teeth generates heat that burns the wood and can damage the bar. Chain pulls to one side. If one side of the chain is duller than the other (common if you hit a rock or nail on one side), the chain veers instead of cutting straight. Crooked cuts. The saw does not cut vertically — it drifts to one side. This usually means the teeth on one side are shorter or duller than the other. File Sizes by Chain Pitch
This is where most people get confused. The round file size must match the chain's pitch. Using the wrong file diameter grinds the wrong part of the tooth and makes the chain cut worse. Check your chain's pitch (stamped on the chain or listed in the saw's manual) and match it to this chart: Filing Angles by Chain Type
Different chain types use different filing angles. The angle determines how aggressively the tooth cuts. Steeper angles cut more aggressively but dull faster. When in doubt, file at 30 degrees. That is the standard angle for most chains and works well in most wood types. Step-by-Step: Sharpening by Hand
Step 1: Secure the Saw
Clamp the bar in a stump vise, bench vise, or bar clamp. The chain needs to be tight enough that it does not flop around but loose enough to advance by hand. If you are in the field, wedge the bar between two logs or use a stump vise that straps to a tree. Step 2: Identify the Starting Tooth
Find the shortest or most damaged tooth on the chain. Mark it with a dab of paint or a permanent marker. You will file every tooth to match this one's length — this ensures all teeth are the same length, which keeps the chain cutting straight. Step 3: Set Up the File Guide
A file guide (also called a filing gauge) clamps onto the file and rests on the top of the chain. It holds the file at the correct diameter position relative to the tooth and gives you a reference line for the filing angle. Set the guide to the correct angle for your chain type (usually 30 degrees). Step 4: File the First Direction
Start with the teeth that face one direction (every other tooth faces the same way). Place the file in the tooth's gullet, matching the angle marked on your guide. Apply pressure on the push stroke only — lift the file on the return stroke. Two to three strokes per tooth is usually enough for routine sharpening. For very dull teeth, take 4-5 strokes. Use the same number of strokes on each tooth to maintain consistent tooth length. Step 5: File the Opposite Direction
Rotate the saw (or walk to the other side) and file all the teeth that face the other direction. Same angle, same number of strokes. Step 6: Check the Depth Gauges (Rakers)
The depth gauge is the rounded nub in front of each cutting tooth. It controls how deep the tooth bites into the wood. After several sharpenings, the teeth get shorter but the depth gauges stay the same height — which means the chain takes a shallower bite and cuts slower. Place a depth gauge tool (a flat metal guide with a slot) over the chain. If the depth gauge protrudes above the tool, file it down flat using the flat file. Most depth gauge tools are set to 0.025 inches, which is correct for most chains. Step 7: Test Cut
Start the saw and make a test cut on a log. The saw should pull itself into the wood, throw chips (not dust), and cut straight without veering. Electric Sharpener Option
If you sharpen chains frequently (weekly or more), an electric bench-mount sharpener saves time and produces more consistent results. The Oregon 520-120 is a reliable, affordable option that handles all common chain pitches: An electric sharpener uses a small grinding wheel instead of a hand file. You set the angle on the sharpener, clamp the chain, and lower the wheel onto each tooth. Advantages over hand filing: - Consistent angle. The machine holds the angle perfectly on every tooth.
- Even tooth length. The adjustable stop ensures every tooth is ground to the same depth.
- Speed. A full chain takes 5-10 minutes versus 15-20 by hand.
- Damaged teeth. An electric sharpener can remove enough material to fix chipped or bent teeth that a hand file cannot.
The downside is that electric sharpeners remove more material per sharpening than hand files. A chain sharpened by hand gets 8-10 sharpenings before the teeth are too short. The same chain on an electric sharpener might only get 5-6 sharpenings. For a good file kit to get started with hand sharpening, the Stihl 5605 007 1027 file kit includes the round file, flat file, depth gauge tool, and file handle for most common chain sizes: When to Replace Instead of Sharpen
Replace the chain when: - Teeth are shorter than 4mm. Measure from the top of the tooth to the bottom of the gullet. Below 4mm, there is not enough tooth left to cut effectively.
- Multiple teeth are damaged. If 3 or more teeth are chipped, bent, or broken, replacing is faster and safer than trying to salvage the chain.
- The chain has stretched significantly. Pull the chain away from the bar at the midpoint. If you can lift it more than 1/4 inch away from the bar with the chain properly tensioned, it is stretched and will not track safely.
- You have sharpened it 8-10 times. After that many sharpenings, the teeth are at minimum length and the chain is near the end of its service life.
- You hit a rock, nail, or dirt. One solid hit on a rock can damage every tooth on the chain. If hand filing does not restore clean cutting in 3-4 strokes per tooth, replace the chain.
Common Mistakes
Wrong file size. This is the most common mistake. Using a file that is too large rounds over the top of the tooth. Too small grinds a hollow in the wrong place. Check your chain pitch and use the correct file diameter. Filing on the return stroke. Only apply pressure on the push stroke (away from you). Dragging the file backwards dulls the file and creates burrs on the tooth. Uneven stroke count. If you give some teeth 3 strokes and others 5, the teeth end up different lengths. The chain pulls to the side with shorter teeth. Use the same number of strokes on every tooth. Ignoring the depth gauges. After 3-4 sharpenings, the depth gauges are too high relative to the shortened teeth. The chain cuts slowly even though the teeth are sharp. File the depth gauges down using the flat file and a depth gauge tool. Sharpening a dirty chain. Sawdust, sap, and bar oil on the chain clog the file and reduce sharpening effectiveness. Wipe the chain with a rag before filing. Bottom Line
Sharpening a chainsaw chain is a 15-minute job that makes a dramatic difference in cutting performance. A $15 file kit and some practice is all you need. File at 30 degrees, use the correct file diameter for your chain pitch, maintain consistent stroke counts, and check the depth gauges every few sharpenings. If you sharpen frequently, the Oregon 520-120 bench sharpener speeds up the process significantly. And when the teeth are too short or the chain is damaged, do not hesitate to replace — a new chain costs $15-25 and cuts like new. Frequently Asked Questions
How often should I sharpen my chainsaw chain?
Sharpen after every 2-3 hours of active cutting, or sooner if you hit dirt, rock, or metal. Signs that your chain needs sharpening include fine sawdust instead of chips, the saw pulling to one side, needing to push the saw instead of it feeding itself, and smoking even with proper chain oil. What size file do I need to sharpen my chainsaw chain?
The file size must match your chain's pitch. For 1/4-inch pitch chains, use a 5/32-inch file. For 3/8-inch low-profile chains (most homeowner saws), use a 5/32-inch file. For full 3/8-inch pitch chains, use a 7/32-inch file. For .325-inch pitch, use a 3/16-inch file. Check the markings on your chain or the owner's manual. Can I sharpen a chainsaw chain too many times?
Yes. Each sharpening removes a small amount of metal from the cutter. Most chains can be sharpened 5-10 times before the cutters become too short to cut effectively. Once the cutter length reaches the wear mark stamped on the chain, it is time for a new chain. Over-filing the depth gauges can also make the chain dangerously aggressive. Is it better to sharpen a chainsaw chain by hand or with an electric sharpener?
Hand filing with a round file and guide gives more control and is sufficient for most homeowners. Electric bench grinders sharpen faster and produce very consistent angles, making them worthwhile if you sharpen chains frequently. The trade-off is that grinders remove more material per pass, reducing the total number of sharpenings per chain. What angle should I sharpen my chainsaw chain at?
Most standard chains use a 30-degree horizontal filing angle and a 10-degree downward angle. Low-kickback chains and some specialty chains use 25 degrees. Check the chain manufacturer's specifications for your exact chain type. Using a filing guide with angle markings ensures consistency across all cutters. 
