This is the only bit you need to make a complete window sash. The bearing guide controls the pattern depth and also allows you to make arched or curved windows and glass doors. This assembly with the straight end cutter cuts the inside edges on both the stiles and rails. Convert the assembly to make the mating end cut by exchanging the straight cutter for the spacer. The spacer can be installed between the profile cutter and the shank if additional reach across the workpiece is needed. Now make the mating end cuts on the rails. This bit can also be used to cut both the decorative edges and the mating end cuts required to make your own window mullions crosspieces.