Adjust the Fences and Position the Board
A rabbet is a two-sided groove cut along the length of a board. The cut in the edge of this board is called a stopped rabbet. The rabbet cut starts on one end of the board but stops before reaching the other end. This kind of rabbet is used in cabinetry. The back of the cabinet is inserted into the rabbet, which stops before reaching the top so that you can’t see the cut in the top of the cabinet.
Put a fluted bit into the router table, then push both fences toward each other -- to the point where they almost touch. With the fences this close together, you won’t have to make a mark on the fence to tell you where to start and stop the cuts – the fences themselves will serve as the marks. (You will, however, have to make marks on the board.)
Place the end of the board against the fence and pivot the board off the back of the fence.