What you need to make the table top version:

Step 1

Punch two holes and cut out two rectangles out of a milk carton.

Print this page and this page.Some browsers--especially Netscape--change the scale and the size of the printed pattern. If the printout says something like, "Scaled-60%" try another browser. Also, the printout has a scale check. It says 2" line to line or 5 cm line to line. Make sure it's accurate. On the two pages, cut out the two identical rectangular patterns on the solid lines save the circle and fan patterns. Carefully fold on the dashed lines.

Tape the patterns on opposite sides of the bottom of the milk carton, and with the spout side of the carton facing one of the patterns, as shown. The bottom edge of the patterns should line up with the bottom of the milk carton.

With a ball-point pen, punch the 4 holes indicated by the circles with a "+" in the middle. Push the pen in to its full diameter. Usually the carton will not buckle if you punch the holes before you start cutting the carton.

With a utility knife, other sharp knife or sharp scissors, cut out the rounded rectangles from each pattern. Be careful not to cut yourself.


Step 2

Insert and retain the pen and pencil.

Lay the milk carton down so that the spout side is the bottom. In the top pair of holes insert the pen. I should be a fairly tight fit and not move around. Tape it fast if you have to.

Insert the flat-ended (unsharpened pencil) into the bottom pair of holes. Unlike the pen, it should be loose in the hole and spin around freely. If it does not, make the holes bigger.

While we want the pencil to rotate freely, we don't want it to move sideway very much because it would come out. We can do this the same way they do it in Bangladesh: by making two big bumps of wrapped string. We will wrap two lumps of string (shown in green in the left illustration) just outside of the milk carton. The dashed lines here indicate a "hidden object--as if you had x-ray vision.

To wrap the bump, first center the pencil so the ends stick out about the same amount on each side. Tape (shown as a red square in illustration at right) the end of a 2 foot piece of string to the pencil close to the milk carton. Start turning the pencil so as to wrap up the string. Then wrap tape around it to keep it from unraveling. Repeat on the other side of the milk carton, being careful not to wrap the string up tight against the carton. The pencil must rotate freely, so make the string wraps close to--but not touching--the milk carton.

Step 3

Rig the remaining string around the pen and pencil

Rigging the string is a bit tricky because space is cramped inside the milk carton. To have access to the pen and pencil from the top and bottom, tape the milk carton down on the corner of a table. Place it so the half of the carton with the rectangular holes is cantilevered (hanging out) over the edge of the table.

Two views of the rigging. The view on the left shows the two halves of the string in different shades of green for clarity.

Needle nose pliers or a wire hook can help extend your reach into the carton to work with the string. Drape the string over the pen and make sure that both halves of the string go to the same side of the pencil (it doesn't matter which side at this point, just both on the same side). Then wrap them once around the pencil, both in the same direction.

Step 4

Add a flywheel and learn how to work the spinner.

Although the spinner will work now, it will work better and you will be able to see how fast it's going if you add a simple flywheel cut out from the second milk carton. With a sharp knife or scissors, cut off the bottom of the other milk carton. Cut on a corner to open it up. Tape on the circle pattern. One of the sides of the carton will have an overlapped seam. Avoid using that side to cut a circle from because the double layer of cardboard will be unbalanced and shake as it rotates.

To punch the holes in the center of each circle, I put the circles on 4 layers of a towel or wash cloth. I use a ball-point pen to start the hole, but pick up the circle and finish it with a pencil because the circles should fit tightly onto the pencil. To finish the hole with the pencil, I hold the circle as shown and twist the sharpened pencil further and further in (then through your fingers) until it goes all the way on. Because you have already started the hole, you know exactly where the pencil is coming through, so there is no chance of poking your fingers. Try not to bend the circles as you make the holes.

Make at least one circle for the flywheel. More circles will add more momentum to the flywheel. You can reuse the pattern. Push the circles on one end of the pencil. You might have to tape them to the pencil. If using more than one circle, tape them together.

Operating the spinner is easy, but the motion will be choppy at first. With practice, you will learn to make it rotate smoothly without breaks. Holding an end of string in each hand, alternately pull them down. Whichever string you pull down, the flywheel should rotate the same way. You might have to fasten the spinner down with more tape or have someone hold it down.

To make it rotate continuously, actually lift up on the one string while snapping the other string down. It should not stop in between pulls.

The spinner can be used for its original purpose by taping on a hook made from a paper clip to spin fibers. If you know of someone who spins wool, there is a good chance they would like to see your variation of a spinning wheel. There is also a good chance they would show you how to spin a few feet of yarn.

To operate the spinner as a fan, use the fan pattern to cut the shape out of a section of milk carton. Fold on the dashed lines. Fold so that both sides of the propeller curve up (say, if you are using a straight edge to bend it) or both sides curve down (if you are using the corner of a table to bend it). Remove the flywheel and replace it with the fan. The fan blade should curve away from the spinner or you'll blow the air the wrong way. You will probably have to tape on the fan. It moves a lot of air, so it is under a lot of stress.

Although the illustration at left shows the fan spinning clockwise, the correct rotation direction depends on how you bent the fan. If the leading edge in not leading, you will have to wrap the strings around the pencil the opposite way you have them now. That will reverse the direction of the fan.


For more about spinning fibers and about Bangladesh click here or on the picture.

Back to the Bangladesh twine spinner introduction page.

Back to the science toymaker home page.

I'd like to know how this project goes for you. I'm happy to answer questions about it. Feedback from you is an important way for me to know what works and what needs clarification.
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