Keeping your chain properly sharpened is crucial for safe and efficient cutting. As Stihl's Sharp Advice for Chainsaw Owners Guide explains, "Trying to cut with a dull chain means a loss of power and cutting speed, higher fuel consumption, an excessive rate of wear on the guide bar and the engine and fatigue for the operator." You should sharpen your chain when the saw no longer cust straight, requires a lot of pushing, rattles against the wood or when you are getting fine sawdust instead of woodchips.
Select the size of round file that is best for your chain. Look on the box of the chain or in your operator's manual to determine the type of file for your chain. Locate the "master chain" on the chain. The master chain will have the shortest top length and might be marked with a yellow or blue dot on the inner wall of the chain.
Place the front tip of the round file into the master tooth. Many Stihl chains have an angle guide burnished into the top plate of every tooth. If this is the case for your chain, follow the grinding angle for every tooth. If no angle is present, refer to your chain's box for sharpening angles.
Hold the tip of the file at a 90-degree angle, perpendicular from the bar. Rotate the round file to the angle specified on the chain's box. If no guide angle is present, use about a 35-degree angle with the bar and engine.
Hold the file steady and parallel to the ground or workbench. Push the file across the tooth. Use the entire length of the file to grind the tooth evenly. Count the number of strokes. Make sure every stroke of the file is at the same angle as the first. Grind out any nicks or burs along the front cutter.
Move the chain forward to the next tooth angled in the same direction. Sharpen the tooth using the same angle as the first tooth and the same number of strokes. Keep the file flat and steady. Sharpen all of the teeth on one side. Turn the chainsaw bar around and sharpen all of the teeth on the other side.
Developing a keen eye and a steady sharpening hand will take practice but save a lot of time in the long run.
Always wear leather gloves when sharpening chainsaw chains.