Using the white oak that I bought from a sawmill in Iowa, I laid out the sides for two of the shelves. Using my router and a 1/2 inch bit, I cut blind dado grooves into the sides. I want the strength of short tenons and dado joints, but I don’t plan to expose the tenons at these locations in the sides.
I used the router table to cut the tenons on the ends of the shelves, leaving the length of the tenons long at the moment. Truthfully, I have not yet decided whether to use a partial through tenon on the main shelf, and the length gives me a bit of time to think about it.
The astute observer will notice that the side pieces are not quarter-sawn — nor is the lower shelf. Because the sawmill in Iowa did not have wide widths in quarter-sawn, I opted for plain white oak. I reasoned that the positioning of the medicine cabinet does not provide much of a view of the sides — especially the outsides. The bottom shelf is going to be ebonized and the quarter-sawn features would be completely lost on it. So, the cheaper and available white oak is used. I must admit, it planed much, much nicer than the quarter-sawn pieces.
Each dado is about 5 inches long, and about 3/8 inches deep. This will provide a lot of strength, and the blind dado will allow me to put a nice joint at the front of the cabinet.
In order to be consistent, I needed a jig. Putting some scrap pieces of white oak in to play, I built a simple jig that is a strong 4 inches wide between boards. This is the width of my Dewalt DWP611PK router. I bought this router shortly before moving, and I used it very little until this project. I like it. The tool feels good, has nice power and I like the features. I am pleased with the purchase. My only complaint is the quarter inch collet. Most of my bits are now 1/2 inch.
This simple jig clamps over the top of the side and butts up to the edge to provide a nice square dado. I used a scrap of walnut as a stop block for the base of the router so that I can push until I hit the block. I made two passes on the depth to alleviate the router pulling into the wood.
Because the jig allows the base to pass underneath the brace on the far end, I can actually cut a nice wide board, but I’ll bet that someday I will make a longer one for those bookcases that I want to build later.