Mk1 Mechanics - Yoyo design - Part 10, why not fingerspin?

I’ve been working on a video series about the design of a bimetal yoyo from scratch. I intend to take this yoyo through prototyping and production (if it’s good) and release it as a main line Mk1 yoyo.

This yoyo (as a digital object) is currently called the Spyglass, a cool name that @EOS44 came up with in the team chat.

I already talked about this yoyo a bit in the CAD & Prototyping Adventures thread, but making a new thread just for this yoyo seemed like a good idea since it’s a bigger project now, and I love hearing community feedback about my work.

There were a couple big driving factors behind this design. The biggest is that I wanted to revisit the cup that was in the first Mk1 design, the Diffraction 1/2. It’s special to me specifically because it was my first, and I’ve somehow managed to make 4 yoyos afterwards where none of them had that cup. So, this yoyo rectifies that.

Second, this yoyo has profile-fit steel rings. It’s an interesting feature to work with and allows a nice broad-looking and comfortable ring on this shape of yoyo.

Third, this yoyo is smaller than usual, especially for an Mk1. The current file has the dimensions 53x44mm. I hope the design I made for it still retains some of the good playfeel that larger yoyos have.

So far I’m really happy with how it looks, aesthetically.

I’m currently fretting over the “final” CAD file and getting ready to send it off for prototyping. Little tweaks here and there.

Videos so far:


Grateful for this series and your open source attitude to yoyo design!


I love seeing the process like this, thank you!

I’m also really interested in the yoyo, especially after seeing the specs.

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Why did you choose to go with this ring design? With a smaller profile, I would have thought to push the weight further out on the rims in order to retain the feel of a larger yoyo.

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I like the chamfer you added in part 5. Gonna try and implement that

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I think that the large feeling mostly comes from the shape of the profile, rather than the distribution across that profile - in addition, there are manufacturing and playfeel benefits to having the weight closer to the string plane. That’s one of the reasons why I think the Edge 1.0/1.5 is such a clever and successful design.

I’ll be putting it to the test, either way!


That’s interesting, with a smaller diameter but more surface area to the catch I think I see what you’re getting at. I’m no yoyo designer, but it’s fascinating how there’s so much more to how a yoyo plays/feels.

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That design is so nice, I already want it.


Yeah, it’s also especially tricky to guess how the brain will interpret the yoyo’s physical properties. I have some heuristics I’ve been leaning on (as mentioned above) but I haven’t designed enough yoyos to be quite sure of them yet.

Generally though I’ve found the following makes a yoyo feel larger:

  • Larger diameter (of course lol)
  • Broader rims
  • Shallower angle on the rims
  • Wider overall

And these make it feel smaller:

  • Smaller diameter (!)
  • Narrower rims
  • Steeper rims
  • Less wide overall

At some point yoyos start to feel Very Large Indeed, if they are getting bigger, and in the other direction they feel Compact, and then Teeny Tiny. I think this yoyo (the spyglass) will feel Compact-ish but also capable and forgiving for general yoyo tricks.


Nice job on this series - really well done!


Im going to binge these!!! Looks great!

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First photo from the machine shop! Anodized, rings installed, awaiting assembly, testing, and shipment.


Mk1 Spyglass

A 6th video is due, though I’m waiting on my team mates for feedback and video clips of this prototype.


This looks goooood!


So this is sort of like a reduced-size, organic Edge? Does it play with any of the competition-performance characteristics of the Edge?

The ring fit looks similar to the edge, but I’d say that’s the only similarity you could make. Excited to see how these play Mark.


It’s pretty stable but can’t really compare to the edge due to the shape and relative compact-ness. I can do horizontal on it, which wasn’t really possible on the similar-shaped Contact. On these spyglass the response bump and schmoove are more exaggerated, giving the string more clearance.

It’s also a gram or two lighter than the Edge. The edge is really optimized and a brilliant design. I guess overall the similarity begins and ends with the ring placement.


Part 6: Prototype Analysis

A close look at the prototypes, some play examples, fingerspins, then back into FreeCAD for some possible changes.


Pictured below is another 3d render!

Ordered a second prototype to try out a couple things.

  • Blasted rings
  • The color orange
  • Subtle undercut for thumb grinds
  • Slightly improved fingerspins, hopefully, with a deeper center area
  • Gap just a bit larger, from 4.44 to 4.50mm

4.5 gap :+1:
Please send to me so I can confirm