To cut crown molding, the miter saw size that must be used varies according to the width of the molding that is to be cut. The saw size must be double that of the size of the crown molding. For a crown molding that is 5 inches in breadth, the saw blade must be 10 inches wide. For a molding width of 6 inches, use a miter saw that is 12 inches in breadth. However, if the molding width is more than 10 inches, use a compound miter saw that has a 12 inch sliding blade.