Full-featured custom-sized wooden boxes for the FIFO (first in, first out) storage of my preferred sizes of canned food on a 48"x18" wire rack.

The way I built them, you'll need about 40" of 6x1 (or 24" of 10x1), 90" of 2x6, wood glue, as well as a band saw and a table saw to cut the wood to size, and a pneumatic staple/brad gun for assembly.

Step 1: Design

Most of the canned food comes in two sizes of cans:

2.95" OD x 4.42" H
4.00" OD x 4.67" H

, so I made the boxes 6" wide, to hold two of the smaller cans side-by-side, and 4.25" wide, to hold a single row of the larger sized cans.

The height of the wider boxes is larger mostly for aesthetics, though when fully loaded, they do weigh more, so the increased moment of inertial (and thus strength) is a plus too.

Step 2: Cut

The best method for making the slats is probably to cross-cut the 2x6 into 18" lengths, then rip them into slats using the fence on the band saw. This generates the least waste and gives them a nice rough-hewn finish.

I needed 40 thin slats, 3/16"x1.5"x18", and 20 thick slats, 1/2"x1.5"x18". If some of your slats are slightly thicker than others, sort them by thickness and use ones with similar thickness on the same box.

I also needed 8 small ends, 4.25"x3.75", and 8 large ends, 6"x5.75", which I cut from the 1x10.

Step 3: Glue Up the Boxes

It's very helpful to have some sort of jig to assist in the gluing. Mine's pictured below.

Once you have a jig, proceed as follows:

Put the endplates in the jig, against the ends. Make sure that the edge which will be glued to the bottom rails is facing up.
Apply some glue to the places on the endplates where the bottom rails will be glued.
Place the bottom rails in place on the glue. To start, make the left end of the rail flush with the left side of the endplate and the edge of the rail flush with the edge of the end, and secure with the rail in place with a staple or brad.
Repeat step 3 for the other rail on the left hand side, then the right hand side of the rails.
Rotate the assembly 90 degrees, and attach the top rail in the same fashion, lining up the edges of the rail and the endplates.
Attach the other rails.

Step 4: Finishing

Once the glue dries, some touches which make the boxes much more useable:

File a bevel on the end of the rails, about 20 degrees from parallel and perhaps 3/8" long. This makes the boxes slide much better on the wire rack.
Break all edges and corners on the boxes, to make them smoother in the hand.
File (or cut on a table saw) a shallow groove across the back of the box, to give the box an end-of-movement detent. This groove should be about 1.25" from the end of the bevel.

Step 5: Use

Place the boxes on the wire rack with the groove at the back. You can slide them out, to the "click", to remove contents, and can reorder the boxes in any order left-to-right that you'd like.

I run FIFO in the following fashion:

The can closest to the front AND containing what I'd like to use, is removed first.
When I restock the boxes, everything is slid forwards, and the new cans are placed behind the old ones. In the case of a box with multiple types of inventory (IE, my box of fish, below), I slide the type of inventory closer to the front forwards first, fill behind it, then slide everything forwards and fill behind the second type of inventory.