While distinguishing between copper and zinc pennies simply involves looking at the date, sorting through large numbers of pennies can be a time-consuming and difficult task. Pennies minted after 1961 were composed of 95 percent copper and 5 percent zinc, until a rise in copper prices in 1982 changed this composition to 97.5 percent zinc and 2.5 percent copper. With copper pennies being worth around two cents more than their zinc counterparts, penny sorting has become a lucrative hobby. The process can be streamlined using a penny sorter, a device made from simple materials that will sort pennies based on their weight.
- 1/4-inch hardwood sheet
- 1/2-inch hardwood sheet
- Table saw
- Wood glue
- Long nail, 1/16-inch thick
- Electric drill
- 1/16-inch drill bit
- 1/8-inch wood dowel
- Post-1982 zinc penny
Cut a one-fourth of an inch of hardwood sheet into two 9-by-9-inch boards, one 12-by-1-inch piece, and three 4-by-1 inch pieces with a table saw. Cut the 12-by-1-inch piece into one 2-inch piece, one 4-inch piece and one 6-inch piece. Set the pieces aside, and cut out a 2-by-10-inch piece from a half-inch hardwood sheet.
Lay one of the 9-by-9-inch boards on the work surface, with a flat end facing you. Mark a point 8 inches from the bottom on the left side with a pencil, and mark another point 2 inches down and 5.5 inches to the right of the first one. Draw a line between the two points, and also mark a point 1 inch to the right of the lowest point.
Stack the two 9-by-9-inch boards on top of each other, with the one from Step 2 on top facing up. Drill a hole through the third-marked point using an electric drill with a 1/8-inch drill bit, making sure to drill through both boards. Set aside the 9-by-9-inch board without the markings.
Glue the 6-inch piece to the 9-by-9-inch board along the line between the first two points. Position it so that the piece is upright and the bottom of the piece doesn’t extend past the lowest point, with the rest of it extending past the left side. This will be the ramp that pennies travel down for sorting.
Mark a point 1 inch to the right of the hole drilled in Step 3. Draw a line extending 4 inches to the right of this point. Glue a 4-inch piece along the line so that it’s upright in the same manner as described in Step 4. This should leave a 2-inch gap between the two glued pieces.
Glue a 4-inch piece upright along the left side of the 9-by-9-inch board, so that it extends toward the 6-inch piece. Glue two more 4-inch inch pieces in the same manner to the 9-by-9-inch board, one 6.5 inches from the first board, and another on the right side. There should now be three more pieces glued to the board that divide the bottom half into two compartments.
Draw a line down the middle of the topside of the 2-inch piece so that it’s divided into two 1-by-1-inch sections. Drill a hole through the side of the piece directly under the drawn line using an electric drill with a 1/16-inch drill bit. Glue a zinc penny to the piece so that it’s one-eighth of an inch from one of the edges.
Cut off a 1-inch section from a one-eighth-inch dowel with a hacksaw. Glue it to the underside of the 4-by-1-inch piece on the edge closest to the gap so that the 1-inch sides of each piece run parallel to each other, and that half of the one-eighth-inch piece protrudes outwards into the gap. This should create a small one-sixteenth-inch-wide ledge inside the gap.
Glue the other 9-by-9-inch board directly on top of the glued pieces so that the holes on both boards align. Stand up the assembly so that the side of the 9-by-9-inch board closest to you is the bottom. Glue the bottom to the 2-by-10-inch piece.
Hold the 2-inch piece from Step 7 inside the gap between the 6-inch and 4-inch pieces, and position it so that the copper penny is facing down, and that the same side is resting on the ledge from Step 8. Make sure that the holes from the 2-inch piece and the two boards are aligned, and slide a nail through all three. When a copper coin comes in contact with this piece, it will outweigh the zinc penny underneath and be dropped into the compartment below it, while all others will continue on the path into the other compartment.
Tips & Warnings
- Drop pennies into the machine one at a time to prevent jams and incorrect sorting.
- Take caution when using power tools by wearing protecting clothing, safety goggles and gloves. Also be sure to keep your fingers away from moving parts or blades.
- Wear gloves when working with superglue, because it can easily stick fingers together.