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[ta0]

Could the standing stop be some esoteric molecular contact force?

I guess there could be static rolling resistance due molecular attraction, so the ball becomes sticky and does not rotate.
For example, glass and ruby are insulators and it's posible that a static charge is generated that attracts the ruby to the glass.

I guess it's also posible that the glass base has micro pits and the top landed on one of them.

[ortwin]

All these tops that do not fall seem to make simple rules hard to find.
What if we cut the Gordian Knot by setting the lower cut off speed to 60 RPM corresponding to one turn per second?
But the top in question should have the possibility to fall, it should fall if tilted more than one degree.


Would this rule favor smaller tops too much ? Would it still give an advantage to tops with a flat? What would the current record be with this rule in the no pedestal class?  And in the pedestal , multiple twirl class?

[Iacopo]

But it is also a sub 1 gram top with a tiny ruby ball tip, so I imagine any flat spot would be too tiny to be worth noting. Could the standing stop be some esoteric molecular contact force? Or is it more likely to simply be a particularly lucky deviation within manufacturing tolerance of the sphericity of the ball?

I believe that the reason is a flat spot. Even in larger tops the flat spot is difficult to detect, let's figure out in this tiny one.
With the CM being nearer to the tip, a smaller flat spot should be sufficient for not falling. 

[ortwin]

...
I believe that the reason is a flat spot. ...

Actually it does not even need to be a completely flat spot.


Here we discussed this:
"- Ah, it is not enough for a thing to be a top to ask that CM is always above contact point! The radius of the curvature of the contact point tip needs to be smaller than the distance from contact point to CM !! Otherwise is can't fall. "

In the case of the small top the curvature at the very tip could  have the radius of only a few mm and still the top would not fall.


But what is the opinion of you people regarding an artificial cutoff at 60 RPM I suggested above?

[spincakes]

You severely overestimate my experience in the hobby; I am merely a computer science undergrad who did some physics and got irrationally interested in spinning tops of all things after watching a few youtube videos on long spinning tops. In fact, I do not even own a machined top on which to test out my half-thought out balancing ideas (which will probably involve polishing the top and reflecting a laser off of it onto a wall some distance away to magnify the motion, combined with the 480fps slow-mo camera on my smartphone).

More nerds flying into this hobby like I did! Welcome to the rabbit hole.

I'm still working on an accelerometer based top balancing setup for a similar purpose (but running into some issues still): https://www.ta0.com/forum/index.php?topic=7182.0

In my own experiments quickly 3D printing some tops I noticed the balance matters way more than I initially expected - though when thinking about it more it makes sense, the difference in friction between a top freely spinning and basically rubbing donuts is quite big.

Our interests are quite similar, I'll try to follow your posts here!

(Lots of flat spotted tip tops in this thread - I don't like them, I want the suspense of seeing them alllllmost fall before they go)

[zaggernut]

For example, glass and ruby are insulators and it's posible that a static charge is generated that attracts the ruby to the glass.

And pretty easy to test for too by grounding the base. Too bad the uploader has disabled comments.

Although, reading your and other replies I'm now more inclined to think it is indeed a flat spot too small to be seen, or just some pit in the glass.

I'm still working on an accelerometer based top balancing setup for a similar purpose (but running into some issues still): https://www.ta0.com/forum/index.php?topic=7182.0

In my own experiments quickly 3D printing some tops I noticed the balance matters way more than I initially expected - though when thinking about it more it makes sense, the difference in friction between a top freely spinning and basically rubbing donuts is quite big.

Our interests are quite similar, I'll try to follow your posts here!

(Lots of flat spotted tip tops in this thread - I don't like them, I want the suspense of seeing them alllllmost fall before they go)

I was directed to your experimentation thread early on, some very cool stuff! I might have to try out your method in case mine doesn't work (which is likely since I don't see anyone else doing it). I suppose once you intend to make tops from scratch, instead of modifying existing ones? I was looking into buying an existing tungsten top, but man are the good ones in demand like toilet paper in the heyday. They sell out within minutes on FB, and new drops are like once every couple months. Add in all these flat spot issues all but guaranteed with large bearing balls and I might just buy some magnesium cylinder and some tungsten rings and a drill and make something myself (i'm not dealing with spokes).

[Iacopo]

Actually it does not even need to be a completely flat spot.

Yes, of course...

But what is the opinion of you people regarding an artificial cutoff at 60 RPM I suggested above?

The problem is that, if we want to establish a set of rules to submit to Guinness or RecordSetter, the rules must be simple, otherwise I believe that they could be not accepted.

 

[ortwin]

...

But what is the opinion of you people regarding an artificial cutoff at 60 RPM I suggested above?

The problem is that, if we want to establish a set of rules to submit to Guinness or RecordSetter, the rules must be simple, otherwise I believe that they could be not accepted.

I was not thinking of submitting to Guiness or RecordSetter. More like establish a set of rules in our community, get some good entries in the lists and some attention from outside people (maybe there is an EDC community) and then Guinness or whoever will ask us for cooperation or advice.
That still means the rules must be as simple as possible and I think we should not start with more than two categories. I regard the 60 RPM cutoff as being simple enough.

[zaggernut]

I do not have high hopes for Guiness/RecordSetter, they are businesses first and foremost. They have their own views on things and record attempts there will be moderated by people with exactly zero interest in spinning tops. It would also be hard to change rules as new issues prop up. I also don't like how they charge money to fast-track verification of record attempts. Imo the community should maintain the leaderboards, say right here on this forum.

[ta0]

Yes, it would be natural for ITSA to manage these records. The yo-yo association oversaw various yo-yo world records for many years (I don't know if they still do).

Who wants to be in the committee for long spin records?

[ortwin]

....
Who wants to be in the committee for long spin records?

Everybody who posted in this topic so far should be in that committee I would say.

[Jeremy McCreary]

....
Who wants to be in the committee for long spin records?

Everybody who posted in this topic so far should be in that committee I would say.

I respectfully bow out. It's been an interesting discussion from a STEM standpoint, but I have no skin in this spin time record game.

[Iacopo]

I regard the 60 RPM cutoff as being simple enough.

I find it not very elegant but if the others like it, I will not oppose it.
Maybe we could simply consider the topple as the end of the spin. Not perfect, the diameter of the flat spot, (always less or more present, I believe), influences the critical speed.  But simple and universal. On the other side, putting a cutoff at 60 RPM is not much more correct anyway, because this limit is arbitrary, since the various tops have different critical speeds.

Maybe, the tops that do not topple, if someone is interested, could be considered as a subcategory apart; after all, they still behave like real tops, when they precess or nutate or wobble for unbalance.

I agree to start with very few categories, just the ones we are interested in. New categories, in any case, could be opened by the time, on request. 

[ortwin]

I regard the 60 RPM cutoff as being simple enough.

I find it not very elegant but if the others like it, I will not oppose it.
Maybe we could simply consider the topple as the end of the spin. ...

No it is not elegant at all and I do not really like it. That is why I compared it to the cutting of the Gordian Knot.
The rule would of course only come into effect if the top does not topple at a speed above 60 RPM.

[Jeremy McCreary]

Maybe the simplest rule: Tops that don't fall compete only among themselves.