An mbira -- also known as a kalimba -- is an African thumb piano. It is played by plucking metal tines of various lengths with your thumbs. African craftsman make mbiras out of almost anything, including gourds, coconuts and wooden boxes -- anything that will resonate. The tines themselves must be made of springy metal that won't bend under the constant pressure from your thumbs, and spring steel is an excellent choice. An electrician's fish tape provides yards and yards of spring steel that's just the right width; you just need to flatten the ends out a little.
Making the Mbira
Cut the gourd in half with the hand saw. Choose one of the halves, and scrape any seeds or pulp out of it with a spoon. Remove any remaining pulp with sandpaper. This will be the resonator for the mbira.
Place a sheet of medium-grit sandpaper on a flat surface and rub the gourd over it, cut-side down. Sand the cut edge of the gourd until it is perfectly flat.
Place the gourd cut-side down on the unfinished side of the plywood and trace a circle around it with the pencil. Use a jig saw or band saw to cut out the round shape.
Turn the plywood finished side up and draw a straight pencil line through the center of the circle.
Drill a 1 inch hole along the center line, 1 inch up from the end nearest you, using the spade bit. This will be the sound hole.
Draw a straight line 3 inches long at a 90 degree angle to the center line. This line should be about 1 1/2 inches down from the end of the center line farthest from you, and should extend 1 1/2 inches from either side of the center line.
Drill a 3/8 inch hole on each end of this 3-inch line. Turn the wood over and position the two tee nuts, blade-side down, over these holes, and tap them in with a hammer. Turn the circle back over.
File a groove about 1/16 inch deep down the center of one of the sides of a 1/4 by 1/4 by 3 inch piece of hardwood. Place of bead of glue into this groove and place the length of coat hanger wire into it. Allow the glue to dry for about an hour.
Glue the piece of wood with the attached wire to the top of the mbira, centered on and at a 90 degree angle to the center line, about 1/4 inch from the line with the holes in it and toward the sound hole. Clamp it and allow the glue to dry for 1 hour.
Glue the other 1/4 by 1/4 by 3 inch piece of wood, parallel to the first piece, but 1/2 inch away in the opposite direction from the sound hole.
Drill two 3/8 inch holes in the 1/4 by 1/4 by 3 1/2 inch piece of wood, 1/4 inch in from both ends. Place the machine screws through these holes and screw them through the mbira top, into the two tee nuts. Screw them just far enough so that the threads are fully engaged, but the bottom of the wood is just higher than the tops of the two pieces of wood glued to the top.
Place a bead of glue around the cut edge of the gourd, and place the top on it. Clamp it and allow the glue to dry for at least an hour.
Making the Tines
Use the wire cutter to cut seven lengths of steel fish tape, each about 3 1/2 inch long. These will be the tines for the mbira.
Put on the safety glasses. Grasping the end of one of the tines with pliers, heat the other end with the butane torch so that the last 1/4 inch is cherry red.
Place the red hot end of the tine on the anvil and pound it with the hammer until it is flat. Allow the tine to cool. Repeat this process with the other six tines.
Smooth and round the rough edges of the flattened tines with a grinding wheel.
Insert the tines over the two pieces of wood glued to the top and under the piece of wood with the screws. The flattened ends of the tines should point toward the sound hole. Tighten the screws until the wood piece they're attached to holds the tines firmly in place.
Arrange the tines in a fan shape, with the wide side of the fan facing the sound hole. Tune each tine by pushing it in toward or pulling it away from the wooden holder. The longer the overhanging portion of the time, the lower the note; the shorter the overhanging tine, the higher the note. Mbira tines are traditionally arranged with the longest tine in the center, the shortest tines on the outside, and the four other tines at intermediate lengths.
You play the mbira by holding the gourd with both hands, with the sound hole facing you. Pluck the tines alternately with your thumbs. You might want to use the wire cutters to trim the other ends of the tines once you've got them tuned, but it's very traditional to leave them at uneven lengths. That way you can change the tuning any time you want.
The heated tines will grow very hot; always handle them with pliers until they have completely cooled. The red-hot ends of the tines may throw sparks as you beat them flat. They will also throw sparks as you smooth them on the grinding wheel. Always wear eye protection for these steps. Operation of a butane torch is a fire hazard. Use extreme care while heating the tines and extinguish the torch as soon as you are finished.