Cutting angle molding for ceilings can be accomplished with a miter saw and the proper setting. This cut will provide a nice box fit for the mitered joints when joining 2 pieces of molding together. This is helpful when joining 2 pieces of crown molding to a ceiling or baseboard to a wall.
The way to make a 90-degree angle molding cut is by either cutting the molding 90 degrees on a miter saw or cutting a molding joint for a 90-degree corner. Here is a tip on how to accomplish this.
Making a 90 Degree Miter Cut
To form a 90-degree corner angle, you want to set the miter saw to 45 degrees. Using a compound miter saw, which is made specifically to cut molding, will aid in making the cut perfect. Set the molding into the miter saw upside down and backwards in order for the cut to work. Remember that the corners must be cut opposite each other. This way, the pieces will fit together and form a 90-degree angle.
You can also simply cut the molding on the miter saw at a 90-degree angle setting. This will provide you with a straight cut or box cut which will butt against the adjacent piece of molding.