Sharpen your chainsaw’s cutters after every hour of use or when it is accidentally run into rocks or sand. Each saw’s cutters are unique in profile and size, so consult your manual or a good shop to get the right sized file for your make and model. Maintaining the cutter profile is of the utmost importance: armed with the correct file, technique is next.
Refer to figure 1 above. It is a top down view of the saw chain; notice that each cutter (represented in red) alternates direction. The white arrows represent the direction and the angle in which to file each cutter. It makes more sense to do all the cutters that face the same direction first, then switch sides and file the other half.
Set up the saw on a comfortable working surface. Select a cutter to begin; notice the rounded face (fig. 2); with the file parallel to the work surface, nestle the tip of the file into this face and push the file all the way through until the handle reaches the chain bar (fig. 3). The bevelled edge of the handle should be parallel to the chain.
Lift the file out and make two more strokes just like the first. The file only sharpens on the push stroke. Do not pull the file back across the cutter. For basic maintenance file each cutter 2-3 times. Don’t over-file. When operating a chainsaw, safety cannot be understated. As Don Bowman says in The Power Tool Song, having a chainsaw is like owning a man-eating shark. Refer to your manual for safe working habits and personal safety gear.