How A Cutter Tooth Works
If you are going to sharpen saw chain, it is important to have a good understanding of how a cutter tooth works.
Step #1. The depth gauge rides against the wood or bark and controls the thickness of the chip the tooth tries to cut. On a hand held chain saw, the depth of this bite is usually .025" or about half the thickness of a dime.
Step #2. The corner digs into the wood at the level set by the depth gauge and begins severing the cross grain. Most people don't realize the corner and side plate do the hardest work.
Step #3. The top plate angle lifts the severed cross grain out of the kerf. Under normal cutting conditions, this is easier work than severing cross grain.
The movement of the chain causes the chips to flow under the tooth. The space under and behind the cutter tooth carries the chips to a point where they can be expelled..