Things You'll Need
1/8-inch sheet metal
2 large hinges
Drill and drill bits
Rubber washers (optional)
Metal lock boxes can serve a variety of purposes, including storing ammunition, hauling cargo over rugged terrain and keeping tools safe in your truck. Commercially-produced metal boxes are costly, however, and a a skilled welder with a bit of construction experience can easily make one. Although it takes some expertise, the materials aren't costly and the procedure isn't complicated.
Plan the dimensions of your box according to its job. A typical box will have six panels total, with opposite sides matching one another in length and width. Lay out the panels for your box on the sheet metal using the measuring tape and the permanent marker.
Use the cutting torch to cut out each panel, and then grind the edges smooth with the hand-held grinder. Lay the bottom on the ground and weld the two ends on first. Shielded metal arc welding with a borax flux-covered rod normally yields the best results; however, if you are working with tin-based sheet metal, use a rosin rod.
Weld the front and back onto the bottom panel, and tie them into the side panels. Tac-weld the side panels first and use a square to make sure your angles at each of the four corners are perpendicular. Finish by welding a solid bead along the edges of the panels and allowing to cool before moving the box.
Attach the final panel (the top or lid) with the two large hinges. Drill holes in the top panel to match the pattern on the hinges and then attach the hinges using the supplied hardware. If you are making a waterproof box, insert rubber washers on the bolts before installing the hinges. This should keep water from entering through the hinge holes you drilled.
Drill two more holes in the top of the lid opposite the hinges in a pattern matching that of the latch. Attach the latch to the top of the lid with the supplied hardware and line it up with the front panel where you are going to mount the receiver. Mark the area for the receiver and drill the appropriate holes (according to the bolt pattern on the receiver itself). Mount the receiver in place with the appropriate hardware and close the lid to check for proper alignment. Start loading your newly built box with cargo!
Follow the link provided below to research a technique known as metal-braking, which allows you to use a single piece of metal to construct a box. This technique eliminates a large amount of welding and conserves metal.
Wear safety equipment when welding the box together, and wear gloves and eye protection when grinding the edges down.