Measure the angle between the adjacent walls in the corner with your Take a close look at the above picture of a typical cathedral ceiling. Details are on page 42 in our new 2nd edition book.

Joint "A" is a standard inside corner. The horizontal turn crown slope angle for joint "A" is 52 deg. (Joint "A" is a horizontal turn of the crown molding)

True Angle® Tool and, using the Crown Molding & Trim book,  Compound Miter Chart, Crown Molding Table or the Excel Program, look up the miter and blade tilt to cut the crown molding. Use your crown molding templates to make sure you have set up you saw correctly.

This is the left-hand piece, inside corner, horizontal turn that will go in the corner at joint "A".

For and inside corner horizontal turn you will always be able to see the saw cut and the pointed end will always be at the bottom of the crown molding.

Cut the mating right-hand piece using the same saw settings. This is the crown moulding that goes from joint "A" to "B".

Now this is where it gets a little tricky.

Joint "B" is an outside corner, vertical turn. (The crown turns up and continues on to joint "C".)

note, in this photo: The right end of the crown is the good piece. This is the short piece that goes from joint "A" to joint "B". (I am now cutting the left-hand side of joint "B")

Use your True Angle® Tool and measure the angle between the wall and the ceiling, then add 90 degrees to it to get the actual corner angle for joint "B". (i.e. Our example is a 20-degree sloped ceiling; therefore, the angle between the wall and the ceiling is 110 degrees. The corner angle for joint "B" is 110+90=200 deg.)

The bottom of the crown is next to the fence and the top will be cut so it is 0 inches long (makes a point). Again, it is very important to use your crown molding templates to make sure you are cutting the correct type of cut.

Using 200 deg. as the corner angle and a vertical turn crown slope angle of 38 deg. you can obtain the miter and blade tilt from the Compound Miter Chart, Crown Molding Table or the Compound Miter Excel Program. (When you are turning the crown molding up or down, the crown slope angle is always equal to the crown spring angle. 

We am now cutting the right-hand piece of joint "B".

Cut joint "B" as shown using the above corner angle of 200 deg and crown slope angle of 38 deg.

Joint "C" is an inside corner vertical turn down. Use your True Angle® Tool and measure the angle that both ceilings make with each other. In our example, that corner angle is 140 deg. and the vertical turn crown slope angle is, of course, 38 deg. From the Compound Miter Chart, Crown Molding Table or the Excel Program, you can obtain the correct miter and blade tilt for this joint. Continue around the room until completed.