Inset Bookshelf Doorway

Measure the overall doorway opening, then subtract 1/2" from height and width so the finished door has a 1/4" clearance all around. From those numbers set the frame stile and rail lengths; remember 2x4s are 3-1/2" wide, so the 2x6 cross-pieces are the door width minus 7".

Assemble the door frame from 2x4s and 2x6s with 1-1/2" pocket holes and 2-1/2" screws — but do not glue yet. Fit the frame into the opening and confirm it swings and closes easily with an even gap. Adjust until it's right; gluing a frame that doesn't fit is a mistake you can't take back.

Take the frame apart and drill 3/4"-stock pocket holes around all the inside edges where the bookshelf will attach — far easier now than reaching inside an assembled frame. Then reassemble the frame, this time with glue for a permanent joint.

Build the shallow bookshelf from 1x6 sides and shelves to fit inside the frame, then glue-and-nail the 1/4" back on with finish nails — the back squares and stiffens it, which matters double on a door.

Attach the bookshelf to the frame through the predrilled 3/4" pocket holes with 1-1/4" screws and glue. Hang the door on heavy-duty hinges, adding a caster at the swinging bottom corner if it's wide or heavily loaded. Add door-stop molding behind the frame for a clean close, plus a lock or clasp. Load the shelves gradually and confirm it still swings true.