The Crescent Nicholson round knurl-cut chainsaw file with a set of 3 round chainsaw files is perfect for more aggressive sharpening. Proper chainsaw sharpening procedure is important; first, secure the chain with adequate tension to hold the cutters in place during filing. Then, file from the inside of the cutter to the outside, doing first the left-hand cutters and then the right-hand. Sharpen the teeth of your chainsaw's chain at an angle between 20 and 45 degrees.