Chainsaw file Round shape Knurl cut for more aggressive sharpening Tighten tension on chain to firmly support cutters when filing File from inside to outside of cutter Place file against beveled cutting surface of teeth 20 to 45 with saw Follow saw manufacturers specifications Sharpen all left hand cutter on one side of chain Then move to the other side and file all the right hand cutters Check depth gauge height every 2 or 3 sharpenings