Banjos are stringed instruments usually associated with American country, folk and bluegrass music. They first began to gain popularity in the early 19th century, and early banjos were usually made with a gourd body and stick neck. Modern banjos typically are four or five strings with a wooden or metal body. These banjos have a plastic or animal skin membrane over the frame of the body. A simple three-stringed banjo can be made out of a tin can and a piece of wood.
Cut a piece of straight wood about 30 inches long and ¾ inch on each side using a saw. Cut the last 4.5 inches of one end of the wood off at an angle to form a slant. Drill three ¼-inch holes into the angled end spaced diagonally.
Carve three small wooden tuning pegs out of a piece of scrap wood using a knife. The pegs should fit snugly into the drilled holes. Sand the pegs until the shafts are round and smooth.
Cut a hole into the side of an empty tuna can and insert the non-drilled end of the wood. It should be flush with the top of the can and fit snugly inside the hole. Push the end of the wood against the inside of the can, and hammer a nail through the can to hold the wood in place. Leave part of the nail exposed to which to hook the strings.
Insert one of the tuning pegs into the underside of the holes on the neck of the banjo, and drill a 1/16-inch hole through it near the end of the peg. Hook the loop on one end of a banjo string to the nail, and feed the other end through the tuning peg hole. Tie a loop in that end of the string to secure it to the tuning peg. Repeat this step for the other two strings. Alternatively, you can use a fishing line or other type of wire for a banjo string.
Cut a piece of wood into a 2-inch-long triangle measuring 3/8 inch on all sides. Cut three small notches on one edge of the triangle, which will be used to hold the strings onto the bridge. Measure 60 inches from where the angled end of the neck begins to slope, which should be near the middle of the tuna can, and glue the bridge in that spot with epoxy glue. Make sure the notched edge is facing up when you glue it. Allow the glue to dry for about 20 minutes.
Set each string into one of the notches on the bridge, and then turn the tuning pegs to tighten them. Use a piano or online pitch pipe to tune each string to the desired key.
Frets can be added to the neck of the banjo by cutting paper clips into the appropriate width pieces and gluing them at the proper intervals. Having frets can help you play exact notes.