I had enough yard-sale oak for four 12″ by 14″ shelves, but needed to make a trip to the hardwood store for enough oak for the frames. A single 4′ piece of 6/4 oak was cut up to make 32″ long sides and the 15″ horizontal rails (to include the tenons). Sawing these by hand took a long time and I had to keep flipping the piece front to back in order to keep to the lines. The subsequent planing was not an option, but a necessity!
The pieces were planed flat and to size before the mortise and tenons were cut. Because the frame will be leaning (and given the 12″ shelf depth) the rails are fitted at a 65 degree angle to the sides. The shelves will be fitted in dados at the same angle so they will be horizontal when the frame leans against the wall.
The frame glue-up was relatively straight forward. I’m wondering whether I should have cut the dados for the shelves first, but I think there is plenty of working room within the assembled frame.