Wind pumps vary greatly in their design complexity. The American farm style water pumping mill, for example, is a sophisticated piece of engineering. The Dutch tjasker is the simplest type of wind pumps. They are found all over the Netherlands, and are still used for land drainage and drawing fresh water from wells.
The basic components of a tjasker are an Archimedes screw and a rotor.
Preparing the Parts
Draw eight circles with a 1 1/2 inch diameter on your poster board using the drawing compass. Six of these circles are the Archimedes screw's threading. The remaining circles will cover the tube's top and bottom covers, holding the rotor and axle in place.
Cut out all circles. Punch the pencil through the center of each circle. Twist the pencil until it can move freely. Place the circles that will make the threading to the side. Draw a line from the tube covers' perimeter through its center and all the way to the other side. Place a mark at 1 inch in for each side. Cut out the 1/2 inch circle in the center.
Make a straight cut from each of the threading circle's perimeter to the center. Pull each circle slightly apart.
Cut the craft stick in half. Cut four strips of poster board to a size of 2 inches by 1 inch.
Assembling the Tjasker
- Center of a toilet paper roll
- Craft stick, 4 inches long
- Poster board
- Drawing compass
- Masking tape
- Cereal bowl
- Styrofoam pellets
- Hot glue gun
Place seven marks at equal intervals along the pencil's bottom 4 inches. Tape one end of the first threading piece to the first mark. Pull the other end to the second mark and tape it in place. Tape the next threading piece to the first threading piece. Pull its other end to the next mark. Tape it in place. Repeat this process with the other threading pieces. It should resemble a threaded screw.
Tape the bottom cover to one end of the toilet paper roll. Insert the threaded pencil. Make sure the pencil's 1/8 inch free end slides into the bottom cover's hole. Slide the top cover onto the pencil's other end. Tape it to the toilet paper roll. This is the axle.
Hot glue the craft stick pieces together so that they form an equal-armed cross. Tape the poster board strips to each of the cross' arms so that the left side of each strip is flush with the left side of each arm. Bend the poster board strip's overhanging pieces slightly back. This is the tjasker's rotor. Hot glue the rotor to the axle.
Pour Styrofoam pellets into the bowl. Place the tjasker into the bowl at a slight angle.
Things You'll Need
- "The Dutch Windmill;" Frederick Stokhuyzen; 1965