This video, from Superior Building Supplies, demonstrates the proper technique for cutting the inside corners of crown molding. The presenter suggests downloading several diagrams from the Superior Building Supplies website. These diagrams show the correct position of the miter for several different cuts. When using a miter saw think of the fence as the ceiling and the table as the wall. Cuts for inside corners will always be made using 45 degree angles on your miter saw. Using these techniques the inside corner is virtually seamless. You will always want to use a blade with at least 96 teeth or more. This will ensure a sharp cut and a seamless corner.