The two opposing cuts form a V-shaped groove that appears to be cut in the surface of the mat. However, most often you will have cut all the way through and have to tape on the back of the mat with acid-free masking tape or white artist’s tape. Next, rotate the mat a quarter turn, reposition the V-Groove stop so the stem is back in contact with the top edge of the mat, and repeat the cutting procedure. After you have made two cuts, you can inspect the over cut/under cut situation and diagnose the solution based on what you see. Here, the over cut is occurring at the beginning of the cut, which would require a resetting of the guide rail stop.