Floating Shelf with Hidden Closet Rod

Attach the 1x4 pieces into a rectangle. Use 2" screws at the joints (pocket holes placed on the outside also work if the ends will be hidden), or 1-1/4" brad nails and wood glue.

Attach the 1x8 top to the 1x4 frame with 1-1/4" brad nails and glue.

Cut the closet rod dowel into five pegs and space them evenly along the bottom of the shelf. Attach with 2" screws or 1-1/4" brad nails and glue.

Finish as desired, then hang to wall studs with screws — adjust screw length to your wall thickness and construction; 3" self-tapping screws suit standard stud-framed walls with 1/2" drywall. Check level before final tightening, since a loaded hanging peg amplifies any lean.