The most common factory-ground cutting angle on a chainsaw is 30 or 35 degrees. The majority of chainsaw file guides have options for 30- and 35-degree angles. File the cutter while maintaining the factory angle by moving the file away from your body and toward the cutting edge.
File the cutter until there is a burr on the cutting edge and new metal is exposed. After the cutter faces are ground along one side of the saw, switch to the opposing side and repeat the process. Removing metal from the cutter face may lower the height of the cutter, and the depth guide may need adjustment. File the depth guide flat so that it is slightly lower than the cutter to ensure that the cutter will contact wood.