Designing and Building a Square Yo-Yo Using Tinkercad

Here is how I designed and built square yo-yo using Tinkercad and how you can design a yo-yo too! This was a very fun project of mine and it is a very simple design that can be modified. I chose too make a square yo-yo because I have seen square yo-yos made before, but they were all discontinued. Because of this, I decided to design my own and 3d print it. This design for a square yo-yo can be applied to creating yo-yo's of any shape or size. This yoyo is an unresponsive yo-yo- meaning a bind must be performed on it to bring it back up. However, this design can be modified to work as a responsive yo-yo.

Supplies

Tools

3d Printing Filament (I used Hatchbox PLA, but any filament should work)
A 3d Printer (I used an Elegoo Neptune 3 Pro) (link)
Scissors (link)
A Plastic Card (Credit card, gift card, etc.)

Parts

1 4mm x 20mm Hex Bolt (link)
1 4mm Hex Nut (link)
1 C size concave unresponsive yo-yo bearing or a Half-SPEC C responsive yo-yo bearing (These can be bought on Amazon or any yo-yo retail store)
A pair of 19mm MagicYoYo response pads (These can be bought on Amazon)
Yo-yo String (These can be bought on Amazon or any yo-yo retail store)
Yo-Yo Parts- This link contains all the yo-yo parts needed, including extra bearings, extra string, and extra response pads. It also includes extra things you won't need such as a bearing tool and axles.

Step 1: Designing the Yo-yo Shape

Open up Tinkercad and create the shape you want one half of the yo-yo to be. Then, add a cylinder on the top measuring at least 21mm in diameter and if needed, 1.5mm in height (unless a 21mm area is already created). Center the circle on the shape you created the yo-yo to be (I chose a cone on top of a cube, which provided the 21mm circle on top. This is the base for the bearing and response pads. The pictures above show some options for shapes.

I would recommend a diameter/width of around 56mm and a height of around 20mm, as these dimensions will give you the size of an average yo-yo. However, you can change these if you want a bigger or a smaller yoyo.

Step 2: Designing the Response Pad Hole

Then, create a tube with a 9.75mm radius, a 3mm wall thickness, and a height of 1mm. Set it to be a hole. Next, place it 1mm below the top of the yo-yo half, creating a 1mm deep hole in the top of the yo-yo. Then, center it in the middle of the yo-yo half and group the yo-yo half to it.

Step 3: Designing the Bearing Seat

Create a cylinder with a diameter of 6.35mm and a height of 2.5mm. However, if you want a responsive yo-yo, set the height to 1.75mm. The bearing is going to go around this. Then, place it on the top of the yo-yo. If the yo-yo half has a height of 22mm, place the cylinder 22mm above the floor of Tinkercad. Next, center it with the yo-yo. With this design, you may have noticed that the bearing would be creating friction with the top of the yo-yo half.

To solve this, create another cylinder, this time with a 7.5mm diameter and a 0.5mm height. Then, repeat what you did earlier with the other cylinder, placing it on top of the yo-yo half and centering it. The two cylinders should overlap.

Step 4: Designing the Hexagon Hole

Next, we will be designing the bolt hole and bottom hole. First, put a polygon and give it 6 sides and a height of 3mm. Then, when you select one of the corners, you will see that there is a long side and a shorter side. Change the long side to a width of 8.5mm and the short side to a width of 7.5mm. Then, set the hexagon to be a hole. Finally, set the height of the hexagon using one of these formulas:

h: The height of yo-yo half from you designed in Tinkercad

Unresponsive Yo-yo: (2(h-2)+4.75)/2-11 or h-10.625

Explanation: 2(h-2)+4.75)- This calculates the width of the yo-yo overall. It subtracts 2 because of the difference of the parts of the bearing seat. 4.75mm is the width of the bearing. It then divides by 2 to get the size of one half of the yo-yo. Then, it subtracts 11 because 1/2 of the length of the bolt is 11.5mm, and we subtract 0.5 from the 11.5 to give the bolt extra room when it threads through the nut. Additionally, it helps to balance out the weight.

The second equation is just a simplified version of the first.

Responsive Yo-yo (2(h-1.25)+3.175)/2-11 or h-10.6625

Explanation: 2(h-1.25)+3.175)- This calculates the width of the yo-yo overall. It subtracts 1.25 because of the difference of the parts of the bearing seat. 3.175mm is the width of the bearing. It then divides by 2 to get the size of one half of the yo-yo. Then, it subtracts 11 because 1/2 of the length of the bolt is 11.5mm, and we subtract 0.5 from the 11.5 to give the bolt extra room when it threads through the nut. Additionally, it helps to balance out the weight.

Yes, it will round up to the nearest hundredth, but this is fine.

The second equation is just a simplified version of the first.

With a height of 24.5mm, my hexagon was placed 13.875mm (which rounded up to 13.88mm) above Tinkercad's design surface.

Step 5: Finishing the Design of the Bolt Hole and Bottom Hole

After setting the height of the hexagon, you then want to create a rod taller than the height of the yo-yo. Make it have a diameter of 4.5mm. This will fit the bolt well, which has a diameter of 4mm. Center it in the middle of the hexagon. Then, set the cylinder to a hole.

The final part of this step is to create an opening on the bottom. The only requirements for this step is that is has to overlap the very bottom of the hexagon (including the corners) when centering it on the hexagon and it has to be a hole. I chose to make it a paraboloid, but you could extend the hexagon to the bottom, you could use a cone, or even a cylinder. The picture shows multiple ways you could make the bottom hole.

Step 6: Grouping Everything

Finally, use Ctrl+A to select everything, then, center everything in the width and length dimensions. Finally, group all of them. This creates your final yo-yo design.

Step 7: Slicing and Printing the Yo-yo

First, export the file from Tinkercad by first clicking "export" and the clicking "STL". This will export the yo-yo half as a STL file.

Then, import it into Cura. Then, remove all bed adhesion, remove supports, and set the infill percentage until the weight is around 27-32g. With this range, the total weight of the yo-yo will be around 59-69 g.

Next, add support blockers to the perimeter and wherever they are needed. I chose to put them around the edge, as my yo-yo half design has beveled edges, and I do not want supports on them.

Then, slice the yo-yo and export it as a GCODE file. Then, send it to the printer using WIFI or an SD/USB card.

Then, start the print. Once it is finished, remove it from the printer, and start another because you need to halves. Once the second one is done, you can start assembling it.

Step 8: Assembling the Yo-yo (1 Half)

Remove the response pad from the plastic it is on. If there is an inner circle in the middle of the ring, make sure to remove it so it looks like the picture above. Then, stick it inside the circular divot in the yo-yo half. Finally, use the plastic card to press it and scrape it down to make it flush with the top of the yo-yo half.

Then, flip the yo-yo over and stick the bolt through it. Then, place the yo-yo half opening side down.

Next, go to the end of the string (the part without the knot) and untwist it. If you untwist it enough, a hole will form in the string. Then, place it around the bearing.

Once the string is on the bearing, place the bearing with the string on the bearing seat. Make sure that the string is completely straight and not twisted around the bearing.

Step 9: Assembling the Yo-yo (other Half and Final Assembly)

First, place the response pad in the divot of the other half. Once again, make sure the inner circle is removed (if there is one) and remove it from the plastic.

Then, place the yo-yo half on top of the other. Drop the nut in and make sure that it is in the hexagonal hole, flat against the back of it.

Finally, hold on to all the yo-yo halves. Push the bolt through the yo-yo halves. Once the bolt touches the hex nut on the other yo-yo half, screw the yo-yo halves together until they are somewhat tight. Make sure that they aren't too tight, or else the yo-yo will not spin well.

The yo-yo is now assembled, and all that remains is to cut and tie the yo-yo string.

Step 10: Cutting, Tying, and Winding the Yo-yo String

Cutting the string: Place the yoyo on the ground and hold the yo-yo string in your hand. Make sure that it is taut and vertical. Then, cut the string around 4 inches above your belly button.

Tying the knot in the string: Create a bight at the end of the string measuring around 2 inches. This can be done by folding a part of the string measuring 2 inches back towards the bottom of the string. Then, tie a overhand (normal) knot with the bight by wrapping forming a loop with it, wrapping it around the double string and passing it back through the loop. Then, pull it tight and cut the extra string off.. This should create a loop in the yo-yo string that you can put around using a slipknot. The slipknot is made by pushing a part of the yo-yo string through the loop, creating a new loop. Then, stick your finger in the new loop and pull it tight. This yo-yo knot will not come undone and it will stay on your finger until you want to remove it, which is very easy to do.

Winding the string: First, put your finger on top of the yo-yo. Then, wind the string around the yo-yo and your finger once. After this, don't wind the yo-yo string around your finger, but only wind it around the yo-yo. Because the yo-yo string is already wrapped around your finger and is unmovable, the yo-yo string is able to be wound around the yo-yo, which it wouldn't be if you did not wrap it around your finger first.