It's simple to roll paper into a cone but what if you want to make a cone that's a specific radius and height? What if you want the base to sit evenly on a flat surface?
This will teach you how to make custom-sized cones for craft and home projects. I like using math in crafts BUT I know some people's eyes glaze over when confronted with it so you only have to do one simple calculation. You can also find these instructions and some uses for paper cones on my blog: Craftastic World.
Paper cones are versatile for crafting.
- tip down, they serve as hanging vases
- holiday paper cones can represent trees
- they make great party hats
paper or cardstock (either for a paper cone itself or to be used as a template)
protractor (there are printable ones on the web)
compass (helpful to have but I give directions for a substitute)
Step 1: Calculations
- Decide on the radius of your base (r) and the height you want. You'll use this to find the "slant height" which will be necessary for the rest of the cone's dimensions. This online calculator will do it for you: http://www.analyzemath.com/Geometry_calculators/pythagorean.html. Just enter the radius of the base and the height as the sides. The result (hypotenuse) is your slant height: S.
- Determine the angle of the wedge shape you'll need to cut from paper. This another simple calculation: Angle=360r/s
Step 2: Draw the Angle
Now you will be drawing the angle of the wedge on your paper. To do this, select a point for the vertex of the angle. Draw one line that starts at the point and is length S.
Using a protractor, mark a point that makes the angle you determined from this point. Draw a line that connects the point to this line and extends beyond it for length S.
At this point, you should have an angle with two legs of equal length on your paper.
Step 3: Draw the Arc
To draw the arc which will be the edge of your cone's base, you will need a compass*. Adjust your compass so the distance it spans is the same as the slant height, s. Place the point of your compass on the vertex of your angle and sketch the arc.
Substitute Compass: Cut a narrow strip of scrap paper a little longer than S. Place the paper to be cut onto cork board or some other surface you can pin into. Mark a line on the strip that is the same length as S. Make a small hole in one end of the line. Then pin the other end of the line through the vertex of your angle. Place a pencil into the hole and make your arc line.)
Step 4: Assembly
Make a tab along one side of the wedge, as shown. This will be the gluing tab. I added the red lines to this picture to show the details. Notice, I cut the tab short on the point side.
Cut out the wedge, roll and glue together.