I really like the utility and look of these lunchboxes, so I wanted to try making my own. Tuna cans seemed like the perfect compartment -- the only problem was getting them to nest nicely. I was really impressed with how well the can-shaping jig worked. It pulled in the bottom of the can and made a uniform ring just above it. After that, the cans fit together really well, and all I had to do was add draw catches and sand everything...and eat the tuna.
Step 1: Make the Can-Rolling Jig
Building the jig is very easy. In a piece of scrap 1x1 wood, drill two holes to accomodate the hinge pin shafts. Space these holes so the pins are roughly parallel when the heads are nested. Slip the hose clamp over the pins and stick them in their holes.
The top pin will stick out further than the bottom on account of the heads being nested. If everything works out, this should be enough so you can clamp the vise grips to the top pin and turn it through a complete revolution. You may want to trim a bit off the bottom shaft to give yourself more room to work.
Use a vise to clamp the wood and hold the whole thing steady. You're ready to roll.