I confess, this one has been on my mind ever since I came across an article about CNC’ing Yoyos back in 2006 on Practical Machinist. Here is the YoYo from that article:
The CNC’d YoYo that caught my eye…
And here is my quick and dirty CAD drawing that’s been kicking around ever since:
My original CNC YoYo sketch…
Since then, I have kept eyes peeled for similar projects. In this article, we’ll take a look at some of the important design principles if you want your YoYo to perform well.
Shape and Balance for Maximum Spin
Generally, you want a profile that puts as much weight as possible out on the rim. This will give you maximum spin. Here’s a good cross section of a high performance YoYo showing such a profile:
This is an ILYY E1ns YoYo I saw over on TheYo.com…
Note how the rim is thin towards the center and thickens at the edge to promote the best edge weighted balance. I imagine if you wanted to go to the trouble you could even engineer a two piece rim where the outer piece was made of a heavier material.
Most high performance YoYo’s are set up with a ball bearing on the axle. This creates very low friction with the string. Typically, there is a press fit of the bearing to one half of the YoYo, and the other half may press fit to a protruding hub or it may thread onto the hub. You will want to be able to take the YoYo apart to replace the Response Pads from time to time. Suitable bearings are easy to come by from sources like VXB.
Nice shot of the axle bearing and a threaded stud to hold the halves together from HighspeedYoYo.com. You can also see the groove where the Response Pad (see below) will go…
High Performance Response Pads
The friction is so low with a bearing hub that there’s nothing for the string to grab to make the YoYo come back up unless you install a response pad:
Response Pad: Silicone rubber pad is glued down in a groove around the bearing…
A YoYo that’s had this much care lavished on its design and construction deserves to have a premium presentation case made for it as well. A site called GordsGarage.com has a great article on making a YoYo for his daughter’s school fund raising auction and I thought his presentation case was particularly neat:
The YoYo just drops onto the pedestal…
The glass top was purchased separately and the base was machined to fit. Now that’s Genius!
It’s been years since I played with a YoYo, but I may just have to give this project a go some day soon!
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Bob is responsible for the development and implementation of the popular G-Wizard CNC Software. Bob is also the founder of CNCCookbook, the largest CNC-related blog on the Internet.
I actually have a prototype of something very similar, just a different size and material. Interesting!
Thanks for your post. I’ve always loved YoYo’s since I was a kid. Here are some links to one I made a few years ago. It features a bronze ring to help the flywheel effect.
Frankie, very neat yoyo!
We love doing these sorts of projects around our shop when we have the time.
We made these yo-yos as gifts for our customers and some leaders in the community.
They were turned as one complete piece from aluminum bar stock.
(therefore they have a solid axle and no bearing, they were meant for aesthetics)
We then anodized them and lastly engraved through the anodization.
The gray gear was also aluminum and anodized gray and press-fit.
The gear was because our shop backbone is gearing.
Love the gear detail!
Anyone look at high-quality very balanced, Tops, might be worth a novelty project.