Just found some detail shots of a few pressure fit shelves i made circa July 2013 using CNC joinery – no glue or screws, just gravity holding them in place.
The white of the face made for a nice crenelation pattern down the seams.
You can also see i ‘dogboned’ the mortise corners, although my general preference on dogbones is to do a symmetrical split such that no one direction gets its material cut out more so. It also technically requires less material to be removed; using a circular bit to describe an interior corner necessarily requires that corner to work, which means mating it with a 90 degree object will only allow it to sit so far. The solution is “dogboning” such that you move your bit at least 50% of the bits width into your material at the corner (meaning beyond your cut path) which allows for complete nesting of the tenon. If you choose for these semi-circle shapes to oppose each other (instead of pin-wheeling them, or symmetrically centering them off the corner), the result resembles a doggy treat. If you center it on the corner, you only end up losing about 25% of the bit volume, and you get a cleaner look – not perfect, but cleaner.
This one was almost about done, and you can see a file was needed to relieve hopelessly tight joints, while the hammer sorted out the rest.
So you can see the shapes are very Willy Wonka. This is because they were intended to hoist speakers off the ground, but canted in towards the middle of the room. This meant the exterior side furthest from the rooms center had to be deeper than the interior face.
Right speaker, installed.
Left speaker, installed. This one was a bit different as the exterior edge just rested on the door frame, and then the interior support had to be notched a bit to clear the door when propped open. Worked like a charm.
I also made a set of similar design for my man cave, which are also now in my current shop – and holding the same set of MB Quartz speakers that i had to entirely rebuilt. They had been dropped which broke all the glue seals, so they were entirely disassembled & reglued, the cones had some “room temperature vulcanization” patching done to them, and one of the speakers terminals was replaced.