Measure and mark four 12″ lengths and two 5 3/4″ lengths on your board. These will be the four sides and two ends of your box, respectively. Cut the board, then sand the raw edges. Use a pencil to mark the four long pieces “bottom,” “top,” “front,” and “back.”

Quickly mock up the box as in Figure 1-3, just to be sure you have a sense of how this is all going to come together. Note that the end pieces are oriented so that their cut edges are at the top and bottom, not left and right.

Figure 1-3. The mocked-up box

Take apart your mock-up. Measure 6″ along the edge of the “top” board. Use this as a guide to draw a line across the middle of the board, then saw it in half. These are your double doors.

On your “front” board, measure 4″ from one end, mark it, and saw it; this is the barn door.

Now for the mouse door (shown on the far right of Figure 1-4). Take the “back” board and measure 3 1/2″ in from each end and 4″ up from the bottom. Use these as guides to draw your back door, and then cut it out using either a manual keyhole saw or an electric jigsaw. If you’re using a keyhole saw, you will probably have to drill a hole in one of the upper corners of your door in order to make the last cut across the top. Sand down the rough edges.

Figure 1-4. From left to right: the top, front, and back, sawed and ready to go

If you’re going to stain or paint your box, do so now.

Now it’s time to start building the box. Stand the two end pieces up on your worktable, about a foot apart, with a cut edge down. Place the bottom (the piece that has no extra cuts) on top of the two ends, as shown in Figure 1-5 (you can also place the front and back in place, in order to help you center the end pieces). Pre-drilling guide holes, rather than driving the screw directly into the wood, will help prevent cracking. Guide holes should be a tad smaller than the actual screws: Find the bit that’s the same thickness as your 1 1/2″ screws, and then use the next smaller bit. Drill a set of guide holes through the bottom of the box and into one end, and then drive 1 1/2″ wood screws through the bottom and into the end piece. Repeat with the other end piece.

Install the back board and the anchored side of the front board (see Figure 1-6 for the final result). For the back, drill two guide holes along each side edge and two along the bottom edge, then drive in the screws. For the anchored side of the front, screw the shorter length of the board to either the left or right end piece. Don’t forget to drill those guide holes first!

Figure 1-5. Installing the bottom; note the pre-drilled guide hole in the front right corner

Figure 1-6. The back installed (the anchored side of the barn door, attached to the left end piece, is also visible)

Now for the hinges and doors. The lid hinges are attached to the exposed outer edge of each of the double doors, then anchored to the face of each end piece; note that the pins of the lid hinges are on the outside of the box. The hinge for the front barn door is mounted on the door’s edge, then anchored to the outer face of the box’s end piece (this sounds confusing, but looks simple; let Figure 1-7 guide you). The mouse door hinge is mounted on the outside face of the box. (You may need to sand down or trim the mouse door a bit so it can swing freely.)

Figure 1-7. Hinge orientation for lid (top) and barn door (right)

Install your locks, latches, and knobs. Use the 3/4″ wood screws to secure your latches; the knobs should come with whatever mounting hardware they need.

(optional) Fill the Lock-n-Latch Treasure Chest with some toddler treasures, like orange juice can lids.