Canjo
What Will You Make?
A single string guitar that uses a tin can to amplify the sound.
What Will You Learn?
You will learn basic woodworking techniques and how to build a simple musical instrument.
Building a Canjo
Cut and measure
Cut a piece of your board to about 36″ long. Measure 3/4″ from the bottom and then 2-1/4″ from the bottom, making points in the middle of the board.
Measure and drill
Measure another point 1″ from the top and mark it in the center of the board. Now drill the 3 points you marked. Make sure to use a backer board to avoid drilling into your table.
Drill your can
After cleaning out your can, measure a point 3/4″ from the bottom and another point 2-1/4″ from the bottom, and then drill them. Drill a small hole in the center of the bottom of the can.
Add the bolts
Place your two 1/4″ bolts through the board and into the can. Secure them using 2 washers and 2 nuts.
Screw the eye bolt into the top of the stock. If it’s hard to turn the screw, thread a screw driver through the eye for extra leverage.
Secure the bolts
Secure the eye bolt with a nut on the bottom and then hot glue the 3/8″ bolt across the board about 1″ from the eye bolt.
Make the string
Using your guitar string or wire, thread a knot onto the string. Twist the wire tightly together to keep the nut on.
String the canjo
Cut enough wire to reach the length of the guitar plus an extra foot. Thread a washer onto the wire and then thread the wire through the hole in the bottom of the can. When you reach the top, thread the wire through the eye bolt.
Tie the wire
Make a few loops of wire around the side of the eye bolt, then thread the wire through the loops and pull it tight to tie it on.
Tune the canjo
***Wear Safety Glasses***
This is the dangerous part! We are going to tighten the string so it will make a tone, but overtightening can break the string and make it whip around. Wear safety glasses.
Tighten the wire while plucking periodically. When it begins to sound the way you like, you’ve got it. Cut off the extra wire and your canjo is complete!
What Is Happening Here?
The history of the canjo
The canjo is based on an older instrument, the diddley bow, which ran the string over a glass bottle and used two nails to secure it. It was played in a similar way as a slide guitar. It first became popular in America in the 1930s, though its roots can be traced back to West Africa. The diddley bow is significant to blues music in that many blues guitarists got their start playing it as children.
As cans became more popular musician makers replaced the glass with metal, giving us a new easy-to-play instrument with a great “twang.” The canjo is attributed to an old-time instrument maker, Herschal R. Brown of Jacksonville, NC, who added a fret so the canjo can be fingered more like a banjo or string fiddle.
Brown freely shared his design with anyone who was interested in building canjos, and is said to have made thousands of them for children everywhere. Mr. Brown loved the idea of making an instrument that anyone could learn to play, and refused to copyright his canjo design. His son has continued the tradition, and has sent canjo’s to the soldiers serving in Iraq.
Acoustics
When the string is plucked its vibration is transmitted from the bridge, resonating through the can, resonating through the air of the body, and finally producing sound from the hole. Different metals and can dimensions will affect how the sound vibrates in the can, making each canjo’s sound unique.
Larger stringed instruments like the guitar work the same way, but over have a larger wooden body and multiple strings of different thicknesses that produce different vibrations, and therefore different pitches of sound.
What Is Next?
Make it electric
Try tuning your canjo using a free guitar tuning app for a smartphone. Adding a piezo pickup can turn your acoustic canjo into an electric guitar.
Materials:
- 2"×1" hardwood board
- Can of Spam
- 1/4"×2" bolts (2)
- 1/4" washers (3)
- 1/4" nuts (3)
- Eye bolt with nut3/8"×2" bolt
- 22 gauge picture wire or guitar string
- Saw
- Drill
- Yard stick
- Hot glue
Maker Camp Project Standards
Based on NGSS (Next Generation Science Standards)
CCSS (Common Core State Standards)
The Common Core is a set of high-quality academic standards in mathematics and English language arts/literacy (ELA).Geometry
- Grades K-2
- CCSS.MATH.CONTENT.K.G.A.1 Describe objects in the environment using names of shapes, and describe the relative positions of these objects using terms such as above, below, beside, in front of, behind, and next to.
- CCSS.MATH.CONTENT.K.G.A.2 Correctly name shapes regardless of their orientations or overall size.
- CCSS.MATH.CONTENT.K.G.A.3 Identify shapes as two-dimensional (lying in a plane, "flat") or three-dimensional ("solid").
- CCSS.MATH.CONTENT.K.G.B.5 Model shapes in the world by building shapes from components (e.g., sticks and clay balls) and drawing shapes.
- CCSS.MATH.CONTENT.K.G.B.6 Compose simple shapes to form larger shapes.
- CCSS.MATH.CONTENT.1.G.A.1 Distinguish between defining attributes (e.g., triangles are closed and three-sided) versus non-defining attributes (e.g., color, orientation, overall size); build and draw shapes to possess defining attributes.
- CCSS.MATH.CONTENT.1.G.A.2 Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, half-circles, and quarter-circles) or three-dimensional shapes (cubes, right rectangular prisms, right circular cones, and right circular cylinders) to create a composite shape, and compose new shapes from the composite shape.
- Grades 3-5
- CCSS.MATH.CONTENT.4.G.A.3 Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.
- Middle School
- CCSS.MATH.CONTENT.6.G.A.4 Represent three-dimensional figures using nets made up of rectangles and triangles, and use the nets to find the surface area of these figures. Apply these techniques in the context of solving real-world and mathematical problems.
- CCSS.MATH.CONTENT.7.G.A.1 Solve problems involving scale drawings of geometric figures, including computing actual lengths and areas from a scale drawing and reproducing a scale drawing at a different scale.
- CCSS.MATH.CONTENT.7.G.A.2 Draw (freehand, with ruler and protractor, and with technology) geometric shapes with given conditions. Focus on constructing triangles from three measures of angles or sides, noticing when the conditions determine a unique triangle, more than one triangle, or no triangle.
- CCSS.MATH.CONTENT.7.G.A.3 Describe the two-dimensional figures that result from slicing three-dimensional figures, as in plane sections of right rectangular prisms and right rectangular pyramids.
- CCSS.MATH.CONTENT.8.G.A.1 Verify experimentally the properties of rotations, reflections, and translations.
- CCSS.MATH.CONTENT.8.G.A.3 Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.
- CCSS.MATH.CONTENT.8.G.A.4 Understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations; given two similar two-dimensional figures, describe a sequence that exhibits the similarity between them.
National Core Arts Standards
The National Core Arts Standards are a process that guides educators in providing a unified quality arts education for students in Pre-K through high school. Also see Standards with cross-cutting anchors in Creating, Performing, Responding, and Connecting through art for Music.NGSS MS.Engineering Design
The Next Generation Science Standards (NGSS) are K–12 science content standards.- MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
- MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
- MS-ETS1-3. Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
- MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
NGSS HS.Engineering Design
The Next Generation Science Standards (NGSS) are K–12 science content standards.- HS-ETS1-1. Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.
- HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
- HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.
- HS-ETS1-4. Use a computer simulation to model the impact of proposed solutions to a complex real-world problem with numerous criteria and constraints on interactions within and between systems relevant to the problem.
