You can use the crusher for “tin” as well as aluminum cans. “Tin” cans, as you probably know, are actually made of steel. But make sure you don’t mix the steel and aluminum. You’ll need a magnet for that job. Don’t be fooled, though. Some cans with pull-off tabs have aluminum tops and steel bodies. So test the can all over with the magnet before you start crushing.

     One more thing: Most frozen food trays are aluminum. These items, too, are worth money and can likewise be flattened in the crusher you are about to build.

      Your crusher will only be as strong as the hinge you use. So the huskier the hinge, the better. Position each hinge plate on the boards as shown in the drawings (you don’t have to take the hinge apart to do this). Note that the hinge-pin loops extend beyond the board edges. Also be sure the countersunk screw holes are facing upward.

      Mark the hole locations. After drilling the holes, screw the plates in place. That just about does it, except for drilling five holes down the center of the base board for the lag bolt. Start the hole 7 inches from the hinge end of the board, and space

them 1 inch apart. The purpose of the lag bolt is to prevent the cans from sliding when you apply pressure on the arm. Put the lag bolt in whatever hole is necessary for the length of the can you’re going to crush.

     The amount of force transmitted through the hinge during crushing will be very high. The wood screws may eventually pull out. If that happens, re-mount the hinge using 2-inch flat- head machine screws, washers, and nuts. You might also have to drill two more holes in each hinge plate as shown, to keep the ends of the plates from bending upward. Wait and see on this point.

     Good luck in the materials conservation and metal-selling business.