This video is how to sharpen your chainsaw The manufacturer recommends a 7/32 round or rat tail file. That can be found on the box that the chainsaw came in. Check your box to determine which file to use. Use WD 40 as a lubricant on the file. Use the entire length of the file as you file the teeth. Files are designed to cut in one direction. Use the same number of passes with the file on each cutter to ensure each cutter will wear evenly over the life of the chainsaw. Remember two angles: 35 degrees perpendicular to the chain treadle and 5 degrees perpendicular to the face of the bar. 5 degrees will vary depending if it's a left or right hand cutter. Use a permanent marker to mark the first cutter that was sharpened to decipher when we are at the end since the chain will be rotating. Make sure the saw is tight in the vise. Begin with all the right hand cutters. Next, file the cutters on the left side.