Mark a Starting Tooth

What happens here

Before you begin filing, select any tooth on the chainsaw chain and mark it clearly. This can be done with a black Sharpie marker, but a lumber crayon (red is used in the video) is often preferred because it's highly visible against the metal and can be easily wiped off once sharpening is complete. Marking a starting tooth ensures that you sharpen every tooth on the chain and know exactly when you've completed a full circuit, preventing over-filing or missing teeth.

Goal: Establish a clear starting and stopping point for sharpening the chain.