Hello! It's been a while. I would like to share a bunch of data I collected for my newest video:
Do check it out! I am quite proud of it, and thank you for 10k subscribers.
The raw data should be in an attached PDF and the graphs can be found in the YouTube video (otherwise too-big of a file!)
To summarise, I tested different Diameters, Knurling directions, Tapers, Concavities and Knurling Patterns to find the grippiest design. This would be a large-diameter coarse diamond-knurled design. However grippyness doesn't correspond to maximum starting speed. I tried attaching designs to Mk.23 to see how fast I could start it with each. This time, I tested Diameters, single and double tapers and some knurling patterns including concave/convex. The conclusion was that a 2-3-1mm double taper (5mm:20mm) with a smooth finish was best. I suspect the smooth finish coming on top was more to do with stiffness of the plastic grip than anything else. With this design, I reached a launch speed of 3202 rpm, my best by far and the fastest for tops my size (380g, 70mm diameter) that I could find.
I also developed a new spinning technique: I get the top up to around 1500rpm with my left hand, then use my right thumb and index up to ~2200rpm, and finally right thumb and middle up to 3000+rpm. During this final stage, when resting my right hand, I keep the top going with my left hand.
I am very happy with the results of this experiment and hope it translates to some improvement in spin time of Mk.25!
EDIT
Not sure why attachment didn't work so here is a link to the pdf in a google drive:
What's the Best Grip for a Spinning Top?
Re: What's the Best Grip for a Spinning Top?
You worked a lot doing the experiments and making the video. Congratulations on the sponsorship by Bambu.
The stem serves as a kind of a "gear box" or "impedance match" between the power that your fingers can generate and the moment of inertia of your tops. It's not about angular speed or torque alone, but the product of torque times angle, as that is the energy ("work") transmitted to the top. Or torque x angular speed x time. A thicker stem corresponds to a low gear ratio and a thinner stem to a high gear ratio. The ideal will depend on both, on how large the moment of inertia of the top is and on how strong you are.
When I spin difficult finger tops, I get the best result with the thumb and middle finger. So I think I have more power than using my index finger.
The palm start would make it a different category of top. You can start a much heavier top that way and should get longer spinning times.
The speed record is nice as a personal record, but it's dependent on the top. A light top is easier to spin fast.
I see that you used a shroud and plan to make a video about it. I hope you give credit to Iacopo for coming up with the idea and proving that they can increase the total spin time.
The stem serves as a kind of a "gear box" or "impedance match" between the power that your fingers can generate and the moment of inertia of your tops. It's not about angular speed or torque alone, but the product of torque times angle, as that is the energy ("work") transmitted to the top. Or torque x angular speed x time. A thicker stem corresponds to a low gear ratio and a thinner stem to a high gear ratio. The ideal will depend on both, on how large the moment of inertia of the top is and on how strong you are.
When I spin difficult finger tops, I get the best result with the thumb and middle finger. So I think I have more power than using my index finger.
The palm start would make it a different category of top. You can start a much heavier top that way and should get longer spinning times.
The speed record is nice as a personal record, but it's dependent on the top. A light top is easier to spin fast.
I see that you used a shroud and plan to make a video about it. I hope you give credit to Iacopo for coming up with the idea and proving that they can increase the total spin time.
Re: What's the Best Grip for a Spinning Top?
Thank you! Yes the 'best grip' is different depending on a bunch of factors. Im away for a few weeks but am excited to continue my shroud experiments and other aerodynamic tests when I get back. I already have a lot of interesting data which I will share upon the next video release. I will give Iacopo credit in the description I think - he has suggested in the past that I tried using them. However there are quite a few academic papers about the use of shrouds for kinetic energy storage systems which have been my main source of information. I may mention this in the video.