About a month ago we bought our son a fidget cube as an attempt to help him focus during church. Shortly after his cube arrived, he told us he would rather have a fidget spinner. Suddenly we start hearing about fidget spinners from everyone. It was the talk of every household with elementary aged kids. I held off on buying my son one because he already had the fidget cube. But then his friend brought one over, I got curious. I wanted to see what made these things spin so well. So I bought one, and told my son we were going to figure out how these things worked. We were going to reverse engineer a fidget spinner!

Reverse Engineering a Fidget Spinner

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Since summer is coming up, along with three patriotic holidays, I decided to buy this patriotic fidget spinner. Once the fidget spinner arrived, my son was soooo excited. He immediately started playing with it, and shouted at me “It looks like Captain America’s shield when its spinning!!”.

Then my husband got home,  and  he also immediately played with the spinner, trying to do all sorts of tricks.  He eventually got bored, and we started talking about how we thought the spinner was made. We noticed the center of the fidget spinner was easier to spin than the three other circles on the outer edges, and, of course, we wanted to take it all apart!

I found a video on youtube that showed me how the fidget spinner could be disassembled, and I realized I didn’t really need to take the spinner apart to reverse engineer it. After using a flathead screwdriver to take the caps off the center rotating part, my son and I saw that the spinner was made of 5 pieces:

1. 3 slow moving bearings
2. 1 fast moving bearing
3. casing

Outer bearings:

My son learned about bearings when rebuilding his RC Car about a year ago, so he knew a bearing was made up of an outer and inner ring with small balls in between.

My son and I had also explored friction factors, and talked about how friction causes things to move slower, or not move at all. So it made sense that the 3 bearings were moving slower because the friction between the bearing’s balls and inner and outer rings was greater than the friction of the center bearing. But why?

To discover why, we needed to find out more about the three outer bearing.  I looked at the bearings and saw “608RS” etched onto the surface.

I then looked up “608RS bearing” on amazon, and found out that these were STEEL bearings.

Middle Bearing

Now I wanted to know what was different about the middle bearing on my spinner. First, I looked at the fidget spinner’s packaging, and on the back of the package was the following:

Two things stuck out at me:

1. Ceramic
2. High Speed

Because of my experience in a diaper factory making thousands of diapers a minute, I was very familiar with high speed bearings. When rotating equipment is moving at crazy high speeds, their parts have to be made to handle it. At high speeds steel bearings can start falling apart on you, but ceramic bearings do not fall apart at the same speeds for two main reason:

1. Smoother surface finish – if you looked at the surface of the steel and ceramic bearings under a microscope, you would see that the ceramic surface was smoother than the steel surface. In other words, the ceramic surface would have fewer “bumps” on it. Additionally, when steel comes in contact with water, it starts to rust, which adds to the roughness of the steel surface. Ceramic, on the other hand, does not rust when it comes in contact with water.
   
2. Lower coefficient of friction. While my son played in the snow during spring break, I taught about friction factors, also known as coefficient of friction. He learned that the lower the friction factor, the more he could slide down a hill of snow. The same applies to bearing surfaces. The lower the coefficient of friction, the less resistance there is to rotational movement of the bearing. Since the ceramic bearing is smoother, its coefficient of friction is lower than that of the steel bearing.

The middle bearing of the fidget spinner is a high speed ceramic bearing because its more durable, a trait that is especially important for a toy kids would be spinning continuously. It also makes the toy more fun because it will spin for a long time.

Casing

The casing of the fidget spinner is made of a hard plastic, and is probably formed by a process called injection molding. Injection molding is a way many plastic toys are made, and can be simplified into a three step process.

1. First a mold of the object is made. A mold is a hollow container used to shape melted liquid material when it cools and hardens.
2. Melted plastic is then injected, through a small hole, into the mold.
3. Once the melted plastic cools and hardens, the mold is broken open and the finish part is taken out.

Look for injection molding on YouTube, and you’ll find a lot of great videos explaining all the details!

So there you have it. A complete detail of reverse engineering a fidget spinner. I never thought this simple toy would be a great way to teach my son about engineering equipment. Try reverse engineering your kid’s spinner today, and see what you both learn!

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Interested in other ways to teach your kids about Engineering? Check out some of my other posts!

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