Center the door on the door jamb and draw around it with a pencil to locate where to make the hinge slot. Do this for both doors.

Next using the Dremel and Diamond wheel again I marked and cut a notch on the top of each door to clear the piano hinge I will be using. I use metal hinges to eliminate any flexing of the hinge as the doors are opened and closed.

Sand the hinges so the the glue will stick better, and put a drop of lube in the hinge joint.

Cut some 1/2" x 1/4" balsa as shown to make the door frames. Carve and sand them to fit the back side of the doors. cut a notch in the top of each frame to clear the thickness of the hinges.

I glued the hinge to the door and then the frame to the inside of the door on one, and slotted the door jamb and glued the hinge in on the other. Both methods worked equally well.