I must be doing something wrong with my referencing the Domino. Connecting two boards at right angles I end up with a slight (1/8") lip on one of the boards. I've tried referencing the way I'd think it should be with the first board flat on the workpiece, there's only one way it can be mortised. The next board that would go on "top" to make the right angle is where I must be off. To me, it should be referenced on the "outside" edge to create the mortise on the end of the board. I do it that way and end up off by 1/8". ???