how do i use an edge finder
Place the edge finder in a collet so that you can secure it into the spindle of a milling machine. Slide it into the loose collet and tighten the draw bar, located at the top of the spindle head with the appropriate wrench.
Move the spindle to the outside of the edge you will be measuring. Raise the table or lower the edge finder using the quill feed below the surface of the edge you are looking to find and slowly move it towards that edge. Tap the bottom of the edge finder so that it is no longer concentric with its body. Wait for the edge to push the bottom part back into concentricity.