A sensor (26) for indexing two components (14, 24) uses a light source (28) and a reflected light sensor (30) that provides an output as a function of light intensity on the reflected light sensor (30). The first of the components (14) is moved in a path that is spaced from the sensor (26) a greater distance than the path of the second component (24). The first component (14) is moved into the alignment position first, and is stopped when the output from the sensor (26) reaches a pre-selected threshold. The second component (24) is then moved to overlies the sensor (26) and is stopped when the output from the sensor (26) reaches a second level that indicates greater reflection of light than the first level. The electrical signals provide identification of the position of edges of the components.