Autumnal Maker School: Pulley Spinner

This fall, I’m running the Autumnal Maker School (AMS). What’s required to be in the school, and to graduate? Make ten things between September 21 and December 21. Preferably useful things, but artistic things work too. I have made a 1) Volvelle, a 2) computer program that calculates the area of a hexagon, a 3) graphic design sample that shows how to make an Egyptian god, a 4) braiding disk, and 5) picture IDs for my school; there was also an 6) art exhibit in there, and guiding a group of students into 7) designing a manufacturing process.  And shortly there’s likely to be a 9) game to teach Latin translation skills, and 10) a wind-powered toy car. But today is for 8) the Pulley Spinner.

 Pulley Spinner

Pulley spinner I admit. It’s hard to tell what you’re looking at. What it is, from a parts point of view, is the following:

  1. a block of wood from one of the Mayflower models;
  2. a paper disk
  3. a length of wooden dowel
  4. a cardboard tube (chopped in half, or maybe it’s a toilet paper tube, I’m not sure).
  5. A pair of wooden spools
  6. An extra wooden disk I had lying around
  7. two beads
  8. some glue from a hot glue gun
  9. A piece of string

And from these things I’ve assembled a pulley-powered spinner.  It’s not about to hypnotize you, I assure you.  At least, I don’t think it will. In essence, though, it’s the first of about twelve toys designed to teach the basics of mechanics that I’m building as demonstration models for a class I’m teaching called Automata.  The parents were pleased with the first two models that they saw at the first class today: a flying pig (which I promptly gave to my boss — because lots of people tell her things are impossible, and she now has a flying pig to prove it’s not.

[I have to get a photograph of it, because it’s cute, but I forgot; Anyway, the pig works like this thing— it’s just a picture of a pig with wings on cardstock, and some straws and string mounted on the back.  Cute, as I said.]

How It Works

Pulley spinner// string (with beads on the ends) goes up inside the paper towel tube, which is glued to the block of wood.  The dowel passes through two holes in the paper tube, and into a hole drilled in the wood.  The string’s middle is passed several times around the spool mounted in a fixed position to the dowel inside the paper towel tube.  As the string is pulled back and forth, the spool spins from the friction, and spins the dowel length, which spins the paper disk.  Simple.

As the disk spins, of course, the circular-checkerboard pattern rotates, creating an interesting geometric/color design visible to onlookers.  It could just as easily be a dancing rat with a tophat and cane, or a French lieutenant, or a rabbit picture.  The nature of the circle is immaterial to the key experience, which is that the disk or picture spins.

As the cords are pulled, the dowel, the axel, turns.  The slightly wider spool helps it turn more easily — more surface area to grip, more coils of string can go around the spool than around the dowel easily.  The paper towel roll was probably overkill, but it helped to hold the mechanism in place and prevented me from having to build an elaborate cage or frame as the housing for the spool and axel.  Saved my students a lot of work this afternoon, trying to get started and build the first project so they could get started on this second one.

What I Learned

I’ve already started building my second one of this design.  I try to build one such thing before I show students how to build it; and then I try to build another while they’re building their first, so I can learn from my mistakes immediately instead of waiting a year.  In this case, I have to build higher ‘walls’ on either side of the axel spool, so that the string doesn’t bumble off the spool and onto the axel.  Adding a frame or a bushing to the bottom of the paper-towel roll is a good idea; this one has holes in it to keep the strings from getting tangled inside the paper towel roll.  Creating a continuous cord rather than using beads allows the axel to spin continuously in one direction.

What the Students Learned/What they Want

Students today learned about the need to cage or stabilize a drive train.  They learned what an axle was.  They learned what bushings were (for us, small pieces of straw to help stabilize the axle), and how a pulley worked (sort of).  The next model design shows them what a vertical cam and a horizontal cam do.  The next model shows them how to integrate a crankshaft into their designs. We’re also going to build a mechanical hand with pull cords and hinges.

One of the students, a second grader, got right up in my face and said, “I want to learn how to make a machine. A machine that runs on batteries.”  I said, calmly, “Batteries are third quarter. This is second quarter.  Build a machine with batteries is hard.  First we learn to build a machine that runs properly when we work it, and then we can make it run on batteries and motors so it runs when we’re not around.”  He was satisfied with that.

This means I have to make sure that the third quarter class includes batteries. With motors.  I’ve got some learning to do.  Uh-oh.  On the other hand, I do have a sense of how to make this machine run on batteries and a motor.  Put an LED on the spinning wheel, run some wire along the axis to a strip of copper so there’s a connection, and attach the batteries to a motor to turn the axle.  Time to figure that out later, I think.

One of the students came to this class to learn more about tools.  Most of the things that we’re building are cardboard and string and duct tape and glue.  Building wooden machines, even out of balsa wood, is a substantial investment of time and money and energy.  I think that I have to make a way of developing this course so that kids who take it a second time can build their designs in better materials, invest more energy in combining multiple mechanical systems rather than building single-mechanism systems.  That’s thinking long-term, though.

Long-Term Implications

There’s a long-term structure building in my mind here, the value of which to my school’s Design Thinking program cannot be  explained adequately in words.  I’m going to try. I hesitate to call it “curriculum” because that implies a sort of circular hamster-wheel of learning which remains fixed and never improves.  But there’s a definite direction to the tinkering at this point, which is the growth of what I might call a mechanical education within our lower and middle school — a growing number of students for whom pulleys and counterweights and spinners are part and parcel of their education.

[And there’s another group for whom games, and game design, are a growing concern.  I remember the importance of the Gusenberg Chess Set, and the Mancala board, and Tablut, and others.  When I teach game design, and game play, I’m teaching students life strategies.  When I teach mechanical design, I’m teaching them problem-solving methodologies.]

So.  There’s this important mindset and program to be growing here — use paper engineering to teach 2D to 3D design — make cubes and other Platonic Solids to teach students how to create shapes and structures, and how to reinforce them, and build paper Roller Coasters to teach flow.  Teach graphic design to teach the visual processing of information.  Teach practical geometry to improve student awareness of good graphic design and 3D design (improves their 3D printing capabilities).  Teach mechanical structures like this pulley-spinner toy to help students understand machines; teach batteries-and-motors to begin to explore robotics from the ground up.

And the Hidden Stuff…?

From time to time, while reading a book about the occult philosophy, I encounter a spirit who is reportedly “good at teaching the mechanical arts.” From this, I’ve assumed the original grimoiric author meant something like what we would call Mechanical Engineering. I’ve tried to build simple machine-toys like this before, and not generally succeeded.   Today I built three such machines.  All three worked on the first try.  This one, the one I built first, not only worked on the first try — I saw how to assemble it in my mind’s eye yesterday evening, from parts I already had available.  Some of this success is due to the fact that I spend hours in the lab each week — sorting parts, sweeping up, building little things here and there.  The value of the self-education of managing a Design Lab’s parts library cannot be over-estimated.  But nonetheless, I point out that there is some value in the hidden philosophy’s guidance: calling on the right spirit, to tutor you in the right ways and in the right subjects at the right times, can be tremendously valuable.

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