During the "stay at home", I am working in the shop. A friend asked me to build a shelf to go above his patio doors. It will be 78" long, 1 1/2" thick and 8" deep. I was going to use Oak but a friend of mine gave me two Ash boards 1" thick and 10" wide. The raw boards are shown in the first picture. One board was warped, so I ripped it into two pieces, planed, and glued back together. I planed the second board on one side so I could glue the two board together to get the final planed dimension of 1 1/2" thick. The second picture is the cut off from the shelf. I used this piece to practice routing the edge and mortising for the hidden shelf bracket sold by Rockler. See picture three. The other pictures show the progress through staining and 3 coats of Urethane. Finally the shelf was mounted.
As for the installation, you have to have 4 holes in the wall to match the holes and mortises in the shelf. Since I started with a 10" board, I had a cut off that I decided to use as a template. I clamped to the shelf and transferred the hole center from shelf to template. I used a brad point bit to drill a precision hole in the template and then drilled to size with a regular bit. I marked the template as to which side went towards the wall and which end matched the shelf. Since the requirement was to be 2" above the door molding, I made three pieces 2" long and attached to the template. Since the door frame was level, I sat the template on the frame and drilled 4 holes in the wall. The using the pre-drilled holes, the drill was level making the holes perpendicular to the wall. I removed the template and finished drilling holes to the required depth. I placed the Rockler bracket into the holes and was able to place the hole from the shelf onto the pins and the mortises covered the brackets perfectly. There is not any mechanical fasteners on the shelf pins, so I used my Kreg jig to put two holes in the top where they cannot be seen and attached shelf to wall with two 2 1/2" screws.
My friends wife was very happy and now has the shelf full.