Create a floating shelf that doubles as a hidden storage box using scrap materials.
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Time One to two days
ComplexityIntermediate
CostAround $200
Introduction
Build this wall-mounted floating shelf that appears ordinary but contains a hidden storage box complete with a secret locking system.
In my experience as a builder, as well as someone who has worked in the film industry for many years, I have always been intrigued by the neat little secret contraptions found in films such as James Bond, Batman, and Indiana Jones.
When I decided to build a custom floating shelf using wood scraps from an earlier project, I decided it would be fun to give it a James Bond feel by adding a hidden compartment with a secret locking device.
Time to channel your inner spy gadget maker. Here’s how I built this hidden compartment shelf, which is equal parts functional and fun.
Figure A: Shelf Overview
Figure B: Hidden Box Overview
Cut List
| KEY | QTY. | PART | DIMENSIONS |
| A | 1 |  Live edge top | 7/8″ x 10-3/4″ x 20″ |
| B | 1 | Floating shelf face | 3/4″ x 6″ x 18″ |
| C | 2 |  Floating shelf side | 3/4″ x 6″ x 9″ |
| D | 1 | Floating shelf back | 3/4″ x 6″ x 16-1/2″ |
| E | 1 | Floating shelf bottom | 3/4″ x 6-5/8″ x 16-1/2″ |
| F | 1 | Floating shelf slat | 3/4″ x 6″ x 16-1/2″ |
| G | 2 | Floating shelf slide | 1/2″ x 1-3/8″ x 5-1/4″ |
| H | 2 | Inner box front/back | 1/2″ x 3-3/8″ x 15-3/4″ |
| J | 2 | Inner box side | 1/2″ x 3-3/8″ x 5-3/8″ |
| K | 1 | Inner box bottom | 1/2″ x 5-3/8″ x 14-3/4″ |
| L | 4 | Inner box trim | 1/4″ x 1/2″ x 3-3/8″ |
| M | 1 | Ledger | 1-1/2″ x 5-1/2″ x 16″ |
Overall Dimensions: 20″w x 6-7/8″h x 10″d
Tools Required
- 18-gauge brad nailer
- 23-gauge pin nailer
- Clamps
- Dowel centers
- Doweling jig
- Drill press
- Drill/driver
- Forstner bit set
- Mallet
- Miter saw
- Pull saw
- Speed square
- Table saw
- Track saw
Materials Required
- 1-1/2" brad nails
- 1" 23ga. pins
- 1/2"x2'x2' walnut plywood scrap
- 1/4" dowel pins
- 1x8x8' walnut
- 2 - 3/4" overlay hinges
- 2" Screws
- 2x6x2' scrap
- 5/16" x 3" bolt w/ nut
- 5/8" round magnets
- Assorted sandpaper
- Beeswax wood finish
- CA glue
- Chip brush
- Contact cement
- Live edge board
- Painter's tape
- Shop rags
- Walnut veneer
- Wood filler
- Wood glue
Project step-by-step (14)
Cut the parts
Using the miter saw and table saw, cut the components listed in the cut list above.
Assemble the outer frame of the floating shelf
Use wood glue, clamps, and 1-1/2-in. 18-gauge brad nails to assemble the outer frame of the floating shelf out of the floating shelf sides (C), back (D), and bottom (E). Be sure to leave a 1-5/8-in. gap between the back of the shelf (D) and the back edge of the shelf sides (C) to accommodate the 2×6 wall ledger. Use a Speed Square to ensure everything is square as you nail.
Attach the face
Use soft-close 3/4-in. overlay European-style hinges to attach the face (B) to the floating shelf bottom (E). Install the cup side of the hinges along the bottom edge of the face (B). Follow the instructions regarding the tab size so that the face (B) aligns flush with the bottom edge of the floating shelf’s bottom (E) and sides (C) when closed. Use a 1-3/8-in. Forstner bit to drill the cup holes. Install the other side of the hinge using the included screws, making sure to drill a pilot hole in order to avoid splitting the bottom (E) of the floating shelf.
Install plywood strips for inner box to slide on
To allow the inner hidden box to slide in and out of the floating shelf compartment without catching on the hinges, install 1/2-in. plywood slide strips (G) with CA glue to the bottom (E) of the floating shelf, aligned with the screw side of the hinges.
With the plywood guide strips installed, use wood glue and 18-gauge brad nails to secure the cross slat (F) from side (C) to side (C) across the top of the floating shelf compartment, keeping it square and solid until the live edge top (A) is installed. Center it on the floating shelf opening, leaving 5/16-in. at the front and back.
Make the locking mechanism
The locking mechanism for the hidden drawer it’s simple. It’s just a 5/16 x 3-in. bolt, with the head cut off, and a nut threaded onto the end threads, and two magnets CA-glued on top of the nut. After doing a little prototyping, I learned that the magnets adhered better to the non-flat surface of the nut and end of the bolt because they could seep into the threads, than they did if I just CA-glued them directly to the head of the bolt.
Drill a hole for the locking mechanism
On the edge of the face (B) opposite the hinges. Drill a hole for the locking mechanism. As the hole needs to be deep, drill it on the drill press using a square to ensure the hole stays plumb vertically.
Drill down 1/2-in. with a 5/8-in. Forstner bit, then switch to a regular 11/32-in. twist drill bit and finish the hole drilling at least 3-1/2-in. into the board.
Build the hidden box
Build the hidden box as shown in Fig. B. Assemble it using wood glue and 1-in., 23-gauge pin nails. Pin nails will prevent the MDF core of 1/2-in. walnut plywood from blowing out and splitting.
Trim out the inner box
Use spray contact cement to secure the veneer along the top of the inner boxes front/back (H) and sides (J). Tape off the inner portion of the box, or be very careful when spraying, to not get contact cement all over the sides of the box. Secure the walnut trim pieces (L) to cover up the MDF core at the ends of the plywood with pin nails and glue. When the glue has cured, cut the trim (L) pieces flush with a pull saw and sand them smooth.
Cut the live edge
Cut the live-edge top (A) out of a wood slab that has been planed on two sides. First, use a track saw to cut the back edge so that it’s roughly one inch deeper than the floating shelf. Then, use that straight edge to cut it to width on the miter saw so that it is two inches wider than the floating shelf box. That will give you an inch overhang on either side and the front, though not exactly because of the natural edge.
Drill holes for dowels and the locking mechanism
Using dowel centers and a dowel jig or drill press with a 1/4-in. bit, drill corresponding holes for 1/4-in. dowels into the top edge of the floating shelf sides (C) and the bottom of the live-edge top (A). Be sure to leave the a one-inch overhang on each side of the top and keep it flush across the back.
While drilling into the bottom side of the live edge top (A), use a 5/8-in. Forstner bit to drill a corresponding hole for the locking mechanism, ensuring it aligns with the 5/8-in. hole on the top edge of the floating shelf face (B). Drill this hole 5/8-in. deep to allow a magnet placed on top of it to magnetize through the live edge top (A).
Fill nail holes, sand and finish
With everything built and ready to assemble, fill in any visible nail holes using wood filler.
Sand all surfaces to 220-grit for a soft, smooth feel. When sanding, make sure to break any sharp edges, particularly those along the inside of the floating shelf compartment or along the veneer at the top edge of the hidden box.
Apply a couple of coats of a beeswax and oil finish such as Rowdy Rooster to all surfaces except the top of the floating shelf slat (F) and bottom of the live edge top (A) where you’ll apply glue at assembly. Use a chip brush to get the finish deep into the bark crevices along the front edge of the live edge top (A).
Assemble the shelf
With the beeswax finish dry, use wood glue, 1/4-in. dowels, a mallet, and clamps to attach the live edge top (A) to the top of the floating shelf. Wipe up any glue squeeze-out with a damp shop rag.
Drop the locking mechanism into the hole on the top of the floating shelf face (B).
Drill a one-inch hole in the center of the inner box front (H) using a Forstner bit to create a pull.
Hang the shelf
The floating shelf is now ready for installation. Mount the 2×6 ledger (M) 7/8-in. lower than the desired height of the floating shelf, level, and centered where the shelf should be positioned.
Attach the ledger (M) to at least one wall stud. Use a flip toggle drywall anchor with the bolt head countersunk into the ledger on any side if a wall stud isn’t present.
Simply place the floating shelf over the ledger (M) so that the bottom of the live edge top (A) along the back edge is sitting on top of it. Screw the floating shelf to the 2×6 ledger (M) through the back (D) using two-inch screws.
Make a locking device
Now here’s where it gets interesting. Embed some of those 5/8-in. magnets into anything you have – a book, notebook, or, in true Bond fashion, a chess piece -to make a locking device.
Now simply place the object with the magnet embedded inside it over the locking mechanism on the floating shelf top (A), and the compartment will be locked. Move it and you’ll be able to open it to all the goodies!
FAQ
Do floating shelves have to be installed into studs?
In my opinion, a floating shelf should be secured to at least one stud, but the more the better. There are some excellent heavy-duty drywall anchors available, but nothing adds as much strength to a shelf as attaching it to a stud.
What are the common mistakes with floating shelves?
The most common mistakes with floating shelves stem from improper installation or overloading them beyond their weight capacity, especially near their front edges.
