Once the plans were drawn up, I took the top off. It was attached using somewhat of a tongue and groove. I took some measurements and made two new sides pieces using our router to round over one side on the front of each piece. Once I was sure the size was right, I cut a groove into the bottom of each piece using a dado blade on our table saw making sure not to over cut. I also made a tongue in the top so the original top could easily fit.