Music boxes are known for their tinkly sound. But wind-up music boxes are also finely tuned machines. Turn the key to tighten a spring, open the lid to release the catch that lets the spring unwind, and gears and flywheels start to move the mechanism at just the right speed.
The music is produced by a rotating cylinder studded with tiny pins. As the cylinder (known as the drum) slowly spins, the pins pluck the teeth of a metal comb. The teeth on each comb are different lengths and thicknesses, depending on the notes needed for the melody each box plays. Every part of a music box takes artistry and expertise to create.
Music boxes also have inspired musical inventors to get creative. Like thumb pianos, the teeth can be made out of any material that makes an interesting sound when it is plucked or tapped. Our version uses assorted wire springs, but you can try other kinds of noisemakers as well.
Musical Inventors: Koka Nikoladze
My Experimental Music Box was inspired by Koka Nikoladze of Norway (nikoladze.eu), who builds hand-cranked Beat Machines—music boxes that use objects like forks and plastic rulers instead of a metal music box comb. He also makes computerized versions using programmable Arduino microcontrollers. His other musical inventions include a MacBook Pro that you play with a bow. He has said that his goal is to make a bassoon you can read your email on.
Safety Warning: Children should get adult help cutting materials like wooden boards and rods.
Note: Because it’s experimental, this project uses quick-and-dirty construction techniques that are easy to modify but not very permanent. Can you think of ways to improve the design to make it play better and last longer? Test your ideas to see if they work!
1. The “comb” of the Experimental Music Box follows the same basic design as the Thumb Piano earlier in the chapter. You will attach coffee stirrers to a wooden board using rods and rubber bands. However, in this case, the coffee stirrers are simply used as anchors for the springs. The board then fits into the box (which also holds the drum you turn to pluck the springs). The first step is to figure out where to place the springs.
To get started, take the board and stand it on end inside the box. Then lay a pencil (or other rod) so it rests on the sides of the box next to the board. Draw a line above the pencil across the front of the board.
2. Take the board out of the box, still standing on end. Take a coffee stirrer and stand it up against the front of the board. Mark the height of the line on the coffee stirrer. Now attach a spring to the coffee stirrer, just above the line.
To do this, squeeze the stick between the coils of the spring as close to the bottom as possible. Turn the spring (like unscrewing a bolt) until just the bottom tip of the wire is below the stick. Take the pliers and pull the tip until it wraps around the far edge of the stick. This will hold it in place. Repeat with the other springs.
3. Lay the board down and line up the coffee stirrer sticks with the springs attached so the springs are sticking up. They should be evenly spaced. Leave room on either end. If any of the springs are angled toward the spring next to them, adjust the spacing as needed.
Place a pencil or other rod on top of the sticks, next to the springs. Place another pencil on the back side of the board, and attach them with rubber bands, just like you did with the Thumb Piano. Do the same with the other pair of pencils on the other side of the springs. When you’re done, trying plucking or scraping the springs to see if they are tight enough to make a good tone. If the pencils curve a bit in the middle and make the middle stick loose, wedge a shim (such as a piece of paper or a second coffee stirrer) behind it. If you want to secure the ends of the sticks, press them down with a tongue depressor held in place with pushpins.
4. Put the board back into the box. Push it all the way back against the side of the box so the springs stick out toward the middle. Take two of the clothespins and clip them over the sides of the box to hold the board in place. To make a tracing of the springs to help with positioning the pins on the rotating drum, hold a piece of paper flat under the springs and trace around them.
5. Now it’s time to make the drum. You will use screws as pins to pluck, scrape, or tap the springs to get them to make a sound. To begin, take your wooden rod or rolling pin and lay it across the top of the box, leaving a little space between the rod and the longest spring. Use more clothespins as guides to hold the rod in place. Make sure at least one end of the drum is sticking out far enough past the clothespins for you to hold onto it in order to rotate the drum. Wrap some tape around the rod.
6. To keep the rod from sliding side to side, wrap rubber bands around the ends of the rod just outside the clothespins to make a little ridge as guides. Wrap some tape around the rod to keep it from rubbing against the clothespins or the side of the box.
To prevent the rod from rubbing against the box, loop loose rubber bands around each pair of clothespins to hold them together. Slide the rubber bands down until they are just above the side of the box. Let the rod hang in them like slings. You can also stick a strip of peel-and-stick foam tape along the inside of the clothespins, in a “U” shape.
7. Now it’s time to attach the pins. For the first pin, find a screw that is a little bit longer than the distance between the rod and the first spring. Important: The head of the screw should be wider than the spring. Make a mark where the screw should go — hold a stick straight across from the spring to the rod to help you line them up. Take the drum out and use a pushpin to make a starter hole at that spot.
Then take the screw and a screwdriver and carefully turn the screw a few times into the wooden rod. Test the screw by replacing the drum and turning it. The screw should touch the spring to make a sound, but not get caught in the coils. If you need to adjust the distance, use the screwdriver to turn the screw further into or out of the drum.
8. Mark the spots for the remaining pins. If you want to play two or more notes at the same time, line up the pins for those springs in a row straight across the drum. If you want to play the notes separately, place them at different spots around the rod. Insert the screws as you did in Step 7, testing after you add each one before you go on to the next screw.