Top That Spins Forever!

Intro:

As an avid Instructables reader and a part time inventor, I have always wanted to make some of my own Instructables to share some of my ideas, but never got around to it. Finally, with a little incentive from the First Time Author contest, I bring to you: a top that can spin FOREVER!

If you are just interested in reading through how to make it, skip to step 2: The Base!!!

Theory of Operation:

The Top that Spins Forever consists of two parts, a spinning top and a base. The top contains a magnet hidden under the surface of the plastic, and the base contains a motor holding a magnet. The top continues to spin because the magnet inside the top wants to align with the spinning magnet inside the base.

Why do the magnets "want" to align? A full explanation of how magnets work would be beyond the scope of this Instructable, but an excellent resource is How Stuff Works. If you imagine the magnetic field of each magnet leaving the north pole and curling around through the air to the south pole, anything in this field that makes it easier for the field to travel from North to South feels "attracted." If the magnets face opposite directions, they assist each other's fields and are in a stable position. If they face the same direction, the north pole of one pushes the field from the north pole of the other away. In this situation, if one magnet is free to spin, it will. The magnets will naturally align north to south. See image of magnets.

Because the magnets align, if they start aligned in opposite but parallel directions and you turn one slightly clockwise, the other will be pushed to turn clockwise as well. As naturally follows, if you have a top which a user spins, as long as you have a magnet underneath spinning in the same direction at the same speed, the top will keep its speed.

Goal of Instructable:

In the coming steps, my goal is to deliver clear, well documented, and decently photographed steps of how to build the simplest version of the Top that Spins Forever that I could devise given the time constraint of the contest. If you find the design interesting, whether or not you end up constructing it, I recommend you vote for me in the First Time Author and Plastics contests. If I see community interest from you brilliant friends I have never met, I would love to post two follow up Instructables:

• How to design your own top in FreeCad that spins forever
• How to make an intelligent speed controller for your top that spins forever

But I will judge interest on favorites, votes, and comments. If I win a camera out of it, that means better pictures for my next post!

Notes:

For young inventors:

When I was younger, I would read warning labels as opportunities for fun. I never cared much about the little warning statements people posted, figuring that was for people even newer than I was to the topic. Looking back, I had a number of close calls and accidents that would have been easily preventable if I had listened. For this, anything with a blade or heater of any kind is inherently dangerous. Bring your parents into your creating process. Not only should they be happy to help to make sure you stay safe, showing them how excited you are to begin your pre-engineering work might make them want to put a little more money into it, which means more projects for you!

For all inventors:

If you are not sure if you can do a step safely, ask. Instructables has an incredible community that is more valuable than any individual Instructable or contest. Take advantage of it. I will not be responsible for any injury, death, or property damage from your proper or improper execution of my instructions, so take care of yourself.

Required:

• 3D printer
  • your own
  • your local library
  • purchase parts from 3D printing service like Shapeways
• Small motor
  • like these from Amazon. Choose whichever you would like, but if you want to use my models for the plastics you will need one of the same form factor, and if you would like to use my simple circuit you will need one that runs on up to 3v DC.
    
    • $14.99 for 15, or like half that for one. I went with the option of getting extras.
• 25 - 100 ohm rheostat
  • from your scrap pile or like this one from Amazon
    • $10.41 for 1
• Knob
  • For rheostat, for looks and easier control. Guess where I recommend buying it
    • $6.50 for 10 of them
• A switch
  • Like this one from Amazon. If you want to use my plastics you will want one remotely similar to the switch linked, if you know how to modify the model use what you have on hand!
    • $10.59 for 20, you need one.
• STRANDED wire
  • 22 gauge should be fine. Once again, here it is on Amazon.
    • Why stranded? With a motor involved, you naturally will have a decent amount of vibration. Over time, the single wire in the solid core will break and your performance will be intermittent at best. Stranded core wire can have every single conductor broken over the length of the wire, but still function because others cover the slack in those broken areas.
    • $10.35 for 100', you will likely need less than one foot
• Magnets
  • Amazon can deliver them right to your door! 8mm diameter, 3mm thick.
    • $7.61 for 35 of them. You need two, buy plenty of extras if you plan to design your own top. They are fun to have on hand!
• Epoxy
  • Like this from Amazon
    • $5.41 for a tube
• AA batteries
• AA battery holder
  • like this from Amazon
    • $9.99 for 5 - there are cheaper options but those had only a few left or did not have prime as an option. Feel free to find a different one that is the same approximate size. Together we can make it work <3.

Optional:

• Metal tip for top
  • All you need is a hanger, a drill, a hack saw, and sand paper! Instructions in a later step.

Pricing:

See the image for pricing information, but excluding the printing supplies this project will cost you $16 per top. If you do not have anything on hand and choose my recommendations on what to purchase (in bulk), it will cost a hefty $76.

To Print:

• No metal tip:
  
  • Base
  • Magnet Holder
  • Spin Surface
  • Top Base No Tip
  • Top Top No Tip
• Metal tip (better performing)
  • Base
  • Magnet Holder
  • Spin Surface
  • Top Base Metal Tip
  • Top Top Metal Tip

Get your prints going early so you can get on to the building!

The base is the magic behind the machine. Without the base, nothing would add back the energy lost to friction and the top would topple. Let's test that the parts fit together and then proceed with final assembly!

Test Fit Time

Let's check the fit of your freshly printed base, top of base, and magnet mount. Gather the following:

• Motor
• Switch
• Rheostat
• Knob
• One Magnet

The dimensions were designed to be printed on the not-so-great Dremel 3D20 printer so your prints may be loose. A little loose is okay, we will be putting some epoxy in there to seal things up. If your printer prints holes too big instead of too small like mine, some parts may not fit, and if you do not know how to modify the 3D model I would be glad to help if you request in the comments (and vote!!). One of the toughest parts to get to fit is the motor into the base, so let's test that first. Take your motor and place it into the holder in the middle of the base. For me, I ran into issues in early iterations of my printer messing with the interior hole dimensions, so I had to use a heat gun or hair drier to soften the plastic to get the motor to slide in. The key is to not hold the heat on too long. Keep checking the malleability of the plastic to avoid it just sagging completely out of shape. I changed the dimensions to prevent this, but I figured better to know the solution just in case. Once it fits, smile. You are one step closer to the coolest toy ever.

Remove your motor and have the magnet mount in hand. Slide the small hole end of the magnet mount onto the motor, and slide the magnet into the magnet mount. Everything should fit in and not wobble too much, but a little is okay. Disassemble this and place the parts aside.

Take the base and test fit the switch and the rheostat. They should seat nicely and the rheostat's tab should fit through the square hole with a little wiggling. While you are at it, screw the ring bolt onto the rheostat to hold it in place and put the spin surface on top. Seeing things look closer to finished is always something that excites and inspires me.

Disassemble everything, using a paperclip or pointy thing to pull the spin surface off of the base. I left a little hole in the side of the box to pry it out from underneath. If it takes a lot of work to get out, use some sand paper to trim down the size of the spin surface.

Epoxy Time

Before we glue, let's prepare the spin surface. Get some sand paper (~200 grit) and smooth off the bumps from ascending layers on the spin surface. We will coat it with a little epoxy to make a smooth spinning surface. Read that out loud ten times fast.

Once you know everything will fit and have the spin surface prepared, mix up some epoxy. I highly recommend mixing right on a paper pad so that you can tear off the layers soaked with epoxy for easy cleanup. Mix enough to glue the magnet holder and to cover the spin surface with a thin layer. Add a tiny dab of glue in the motor shaft hole and push it onto the motor until just before the tip of the shaft invades the magnet's housing area. Add a little more glue to the magnet side and slide the magnet on in. Be careful putting this near anything metal! The magnet could pull out of the glue. Set it aside in a way that will allow the glue to set with everything aligned. I used a woodworking clamp to gently hold the motor, but pinching it between two things on your desk should be sufficient. Using either an acid brush with trimmed hairs (which I keep on hand, I trim the horse hair with scissors) or a small corner of cardboard, smooth a bit of epoxy onto the spin surface. No need to go super thick, that will make it bumpy. I recommend two coats with a gentle sanding in between (200 grit is still fine). I waited about 20 hours for the glue to be nice and hard before sanding, but that depends on how fast the epoxy you choose dries in your environment. With two coats, the surface should be glassy and smooth.

Feel free to work on the top while you wait for the glue to dry!

Circuit Time

Get stuff out:

• Switch
• Rheostat
• Motor with dried epoxy
• Base
• AA batteries
• Battery holder
• Knob
• Stranded wire
• Solder
• Soldering iron
• Hot glue gun

I attached an image of the circuit. Give it a look. A note to the professionals: If you know circuitry well enough to do it without my guidance, be sure not to solder the switch on without running the wires through the hole that holds the switch (see steps 6-7). If you were to, you would have to desolder it to put it in place correctly.

Back to the instructions:

1. Plug in your soldering iron and hot glue gun.
2. Loop the tip of the black wire from the battery holder through the right terminal of the motor. Add a dab of solder. NOTE: FOR LEFT HANDED OPERATION, SWITCH THE LEFT AND RIGHT MOTOR WIRES.
3. Cut a segment of stranded wire from your spool that is about 4 in (10 cm), stripping a little under a half an inch (1 cm) off either end.
4. Loop one end into the left terminal of the motor and the other into the right terminal of the rheostat. Solder both. This orientation will make a clockwise turn increase the speed.
5. Cut another segment of wire around the same length (or slightly longer if you are new to soldering)
6. Trim both ends again, feeding only one end through the middle terminal of the rheostat. Solder it on. Leave the other end of wire unsoldered for now.
7. You now should have everything but the two wires for the switch soldered together. Put everything into the base except for the switch.
8. Take the two loose wires and feed them through the hole that will hold the switch. Solder one to the switch's top terminal, and the other to the switch's middle terminal.
9. You should now have everything soldered together and the switch hanging out of the box by its wires. Slide the switch into its hole with both wires closer to the up position. This will make the "up" position "on" for the circuit.
10. Screw the rheostat into place and attach the knob to the tip.
11. Install batteries into the battery holder.
12. Flip the switch and turn the knob clockwise. The motor should spin! If so, turn off the switch. If not, check your wiring and then post an angry comment below.
13. Add a dab of hot glue to the switch to hold it, taking care not to get any on the sliding parts inside. Add another dab to hold the motor in place.
14. I used hot glue to hold the battery holder in place, which you can do too. Just be sure to not use too much, you will need to pop it out and re-glue to change the batteries if you used a holder like the one I used.

Excitement and Testing

You did it!!! You should have a working system. Here is how to test that it will work once the top is ready:

1. Place the spin surface on the completed base.
2. Take the remaining magnet that we will use for the top and place it on its thin curved side right in the middle of the spin surface.
3. Flip the switch and turn the knob up until the motor begins to spin. The magnet should spin with it!

See the video for an example.

The beauty of an Instructable is that you can make any modifications you want when building your copy because it is simply a guide to success as opposed to the only way to succeed. That is as true as ever in this Instructable. I will provide two options for the top, one as simple as I could design it, and one designed to last a little longer. I will provide .stl files (stereo lithography files, commonly used for 3d printing) for if you would like to print off a copy of what I made, but I will also leave enough information on the design process for someone of a moderate 3D modeling skill level to design and construct their own.

If you would like more detailed instructions for designing your own top, aimed at someone who has never 3D modeled, vote for me in the contests and comment that you would like that. With community interest I gladly will create an Instructable.

Simple Top Design:

If you are looking for the simplest mechanical construction, or just want a simple build to test out the function, this option is for you. Remember that you can always make more tops!

Supplies:

1. One magnet
2. Epoxy
3. 3D printed parts

First, clean up your printed parts as necessary, and slide the magnet in to make sure it fits. Test fit the spin rod, sliding into the hole on top of the magnet. With my printer, it does not quite fit. I use a blade or sand paper to cut it down a tiny bit; it is better to have a fit you have to push a little than to have it too loose. Once you know you can get it to go in, remove it.

Use any metal object to get the magnet back out. Mix your epoxy (I recommend doing so on a pad, preferably not an iPad. This way you can peel off a layer when done!) and put some into the magnet holder area.

Long Lasting Top Design:

The issue with making a top completely from 3D printed plastic is that the tip can wear away pretty quickly. Luckily, I have a solution for this. If you make a metal tip that you can insert into the bottom of the 3D printed part, it will last significantly longer.

Supplies

1. One magnet
2. Epoxy
3. 3D printed parts (with hole in tip)
4. Wire hanger
5. Drill
6. File (or sand paper)
7. Hack saw

First, cut a 0.15 in (4 mm) section of metal hanger. To do this, I recommend cutting off the entire straight section of the hanger and putting the rest aside. When using the hack saw on the hanger, be careful not to bang your finger with the falling saw, mine is pretty heavy and would surprise me when it broke through the first few times I made it. Also, I do not recommend using wire cutters you care about to cut the top. They are usually designed for copper and will dent if used to cut steel.

Next, take that small section and close the teeth of a drill around one end, leaving half sticking out of the teeth. With your file or sand paper, spin the hanger tip against the rough surface to form it into a dull point. Too pointy and it can scratch surfaces you use it on, too dull and it will slow down faster. Take your time and rock the drill slowly to get a bit of a curve on the tip.

Once to an acceptable point, remove the tip from the drill. Test fit it in the bottom section of the top; if it slides in you can skip the next step.

Assuming it does not slide in easily, you will need to heat it a little to get it to melt it's way in. This will allow it to

Follow the simple path instructions for assembly of all but the tip of the long lasting top.

So you made the next coolest toy... Now what? If you ask me, it is pretty useless if you do not know how to use it!

How to Use:

1. Spin the top clockwise between your thumb and pointer finger. Lefties have to spin it backwards, which can feel awkward. If the motor is hooked up in reverse polarity it switches this around and makes it easier for lefties.
2. Once you get a good spin, you may need to tilt the base to get the top to slide to the center, right over the magnet.
3. Flip the switch and turn the knob clockwise until you hear the motor turn on.
4. Turn the knob counter-clockwise to slow the motor down until it has almost stopped. You should hear it change tone when it syncs up with the top spinning above it. This may take a few tries.
5. Slowly increase the speed by turning clockwise until the top is spinning stably at decently fast pace, likely a little faster than you would spin it by hand.

You have done it! Congratulations. Show all of your friends and your cool neighbor who likes to build stuff.

You can increase the speed beyond this, but the top will eventually become out of sync with the motor and you will hear the motor jump way up in speed. I enjoy getting it going super fast and then dumping it off the platform onto a surface I do not mind scratching and watching it spin.

Tricks I Have Learned:

I have found a few fun tricks to do with the top over the weeks-long iteration process. Be careful, some of these are not too safe.

1. When spinning, try to get one of the holes of a fidget spinner over the spin post. I have been able to get it to keep spinning! It looks cool.
2. DANGEROUS, BE CAREFUL: Take two more magnets and latch them onto the sides (see the picture and video). Slowly increase the speed, keeping your face far from the spinning top. The magnets will fly off. WEAR GOGGLES TO KEEP FROM LOSING AN EYE.
3. Customize your top! Paint patterns or stripes on it to make it look cool especially in slow motion videos.

Do you have an idea for your own trick? Post it below! I will add the best ones to this Instructable!

Potential Upgrades:

• Big, powerful motor
  
  • Get that top spinning as fast as you want, even SCARILY fast
• Wooden spinning top
  • You will need to be good at woodworking and VERY patient for this. Getting the shape of the top right to spin stably and easily took a while with printing, I cannot imagine the iteration process with woodworking
• Motor control circuit
  • A rheostat/variable potentiometer/volume knob thing (everyone uses a different term for it) is not the "proper" or efficient way to control the speed of a motor, but the beauty is in the simplicity. I designed a speed controller that used buttons connected to an ATTINY85 microcontroller for this project, but decided it would limit the audience of who could build this fun little project. If you want an Instructable to show how to make a speed controller with an ATTINY85, vote for me in the contests and let me know down in the comments!!!
• Fly away top
  • Make some fins on the bottom of your top. If properly designed, it should lift off when you turn up the speed. Want some files? Let me know by voting and commenting! I have not designed one yet but I want to leave you with lots of options of where to take this.

Thank You:

Thank you for reading my Instructable! Vote for me in the Plastics and First Time Author contests if you like what I made!

9/18/17

Greg