The Magic Propeller

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Introduction: The Magic Propeller

45 years as a professional documentary film producer. Now using state of the art HD digital stud...


Introduction:

OK, this is a silly one, and I even have to admit you can find a few toys like this on the internet. A site for teachers describes how to make one using a pencil. But I feel entitled posting this Instructable because I can remember when my dad made one for us kids roughly 60 years ago. My brother and I were completely baffled how he would rub a little dowel on a notched stick and the little wooden propeller at the end would start spinning, and then he would say, "stop and go the other way," and without the slightest perceptible change in anything he was doing, the propeller would obey. And of course we would try and try and fail.

Naturally there was a trick, and for those who have not seen this toy, I will reveal the trick at the end of this Instructable.

You need a few little pieces of scrap wood -- almost any kind will do, and a small brad.


Step 1: Step One


I used my table saw to rip a piece of pine to about 5/16th inch square, and cut it to about 12 inches in length.

Starting about three inches from one end, and continuing to about one inch from the other end, I marked one edge, using pencil, with 1/4 inch intervals.

Then, using a small, fairly coarse, square file, I filed notches in one edge.

Since folks are going to be rubbing this stick like crazy, it needs a very good sanding including rounding the edges slightly.

Step 2: Step Two


The propeller is another little piece of wood -- I used a little scrap of maple since it is nice and hard and the hole will likely remain true and clean after drilling. But I bet a little piece of Masonite or Plexiglas would also work fine. Even a soft wood like pine should be OK if you make a nice clean hole and get rid of any little fibers.

The one I cut out is a full 1/8 inch thick, and is 2 3/4 inches long X 5/8 inch wide. These dimensions are not critical.

It is important to drill the hole in the exact center to prevent the propeller from being out-of-balance. I used a #48 drill from my numbered drill set. I did not measure the drill with a caliper, but it is probably about 1/16th inch in diameter. You should use a larger drill or countersink plus a bit of sandpaper to clean-up the edges of the hole -- it must be nice and clean to allow easy rotation. It is a very loose fit on the brad that attaches the propeller to the notched stick.

Step 3: Step Three


I bet the hardest part of this project is finding the perfect little nail to attach the propeller to the notched stick. In spite of a huge collection of nails and screws in my shop, this little baby was elusive. It is about 3/4 inch long, and very thin.

You just drive the nail straight through the hole in the propeller into the end of the notched shaft. Sure, go ahead and try to center the nail on that tiny end, and while you're at it try to get the little devil to go in straight. Good luck! I had to bend mine straight after nailing, but don't tell anyone.

For the rubbing stick, I was looking around for a piece of 1/4 inch dowel, but I only found a few scraps of 3/8 inch material. I cut a piece to about six inches long, smoothed-up the ends, and that seems to work fine.

Step 4: Step Four (secret)


OK, here is the big secret. Please do not not ask me to explain why this works. For all I know, it really IS magic. In the photo, please note carefully the positions of the fingers when holding the dowel. When rubbing the stick, the index finger (if you are right handed) will be riding up and down on the left side of the notched shaft. Your middle finger will be riding up and down on the right side of the shaft. When you rub the notched stick, if you continuously hold your middle finger against the edge of the shaft (with no pressure from the index finger), the propeller will rotate to the right. If you hold your index finger against the shaft while rubbing, the propeller rotates to the left. No one sees your tiny shift in position to reverse rotation because it continues to sound the same and they are all watching that ridiculous obedient propeller! Have Fun!!

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    82 Discussions

    My dad does this often and it always puzzled me, now i can finally do it myself!
    THANK YOU!!!

    I made one! I used some wood I originally cut to make a bow but never got around to making it. I didn't put as many notches on the handle, but it still works alright.

    Great instructable.

    Photo0209.jpg
    1 reply

    it works with heat if you balans a piece of wood pefectly rub you hands together
    and put youre hands next to the piece of wood it will spin

    I got one of these from a Navy pilot in the late '60s. He called it a "hooey stick" and when you said "hooey" the propeller would reverse. He also had a "twin engine" hooey that he could reverse the right or left prop on command. I guess carrier duty had long hours of waiting around between missions.

    5 replies

    As best I can recall,(40 plus years ago) it was "T" shaped with two short dowel "engines" the same diam. as the main riffled dowel. I don't recall how the parts were attached. I was about nine or ten at the time, but I think the top of the "T" was also a dowel, coped into the top of the main shaft and the sides of the two "engines".

    I've only made singles. 7/16" dowel, popcicle sticks, round (chain-saw) file, ruler, saw. You get to use all the tools! Quick and easy. I showed a troop of girl-scouts how to make them and we had a lot of success. Even spacing of the grooves is pretty critical.

    Here is a website that shows an example of what the twin engine may have been. This site calls it a Double-Whimmy-Doodle:
    http://www.mugwumps.com/whamdbl.html

    Sorry I missed this comment a while back. I wish I could be more specific on how these work. As I said below, some of my attempts didn't work at all and others would spin like crazy. The amount of pressure of your fingers on the shaft and how smoothly they slide -- sweaty or sticky being worse -- seems to make a difference.

    I have made a few that didn't work and I am really not sure why. I think the size of the hole in the propeller with respect to the diameter of the nail, and just how tight -- or far in -- the nail is driven seem to be very important. It needs to be rather loose but not too loose.

    hi i like this and i want to bring this to school to show off but i dont know if i can make this because i dont have any tools and i dont know if i can get the right wood i can deal without the tools i just need to know if the dowel and the stick need to be exect or can i just use some chopsticks i got from a restraunt

    2 replies

    I have a good feeling about using chopsticks, but you need to make the little notches and drill a hole in the propeller, etc

    What fun! Haven' t seen one of these but I love the idea.
    Great explanation:)

    1 reply