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Author Topic: Little top spinning for over 50 minutes  (Read 4863 times)

Iacopo

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Little top spinning for over 50 minutes
« on: January 06, 2016, 06:18:11 AM »

This is my experimental top Nr. 15:

https://www.youtube.com/watch?v=NUxemAvWSSA

It is an evolution and an extreme version of my top Nr. 10:

https://www.youtube.com/watch?v=0rKrnUv6g8w

In this video I explain what I have devised to make the Nr. 10 spin for a long time, and those considerations are still valid for the Nr. 15.

But then there are some more refinements and improvements:
the stem has better shape and proportions, and it is knurled, for a better grip;  the long stem permits a better control; thanks to this stem I can start this top at 1200 rpms, practically the same as the Nr. 10, in spite of the fact that the Nr. 15 weighs 186 grams and the Nr. 10 only 160 grams.

But the most important improvement regards the tip of the top:
I have bought better diamond tools, by which, with the help of lenses, I can now shape the tip to make it very sharp, so that the diameter of the contact point of the tip is about 0.01 mm.
This helps to obtain a very low attrition of the tip.
I use high quality carbide for the contact points, (it is the best material I have found for the aim); anyway, the sharp tip wears out a bit while spinning, so the tip needs to be reshaped and centered again after each single spin.

Also the base has to be polished often, or the tip will start digging a microscopic hole in it.
This fact involves much maintenance work, patience and time.  The Nr. 15 is not a recreational top, nor an easy top.
It is an extreme top, designed to spin for an extremely long time.
It is delicate, the lead flywheel can be easily scratched or dented, the obeche wood used for its central part is very light but also delicate, the thin mahogany stem too is not strong.
Also the tip, being very sharp, is fragile. 
Spinning this top with strenght, wich is needed for a good initial speed of the top, made me nervous;  for two times I chipped the sharp part of the tip, because of my impetus spinning it, and I had to reshape it.
After various attempts, I have been able to obtain this very long spin.

Commercial finger tops never spin for so long, generally they are too light, (for commercial reasons, I guess), and they are built relatively robust, easy to use, and maintenance free, and generally these qualities are not suitable for longer spin times.


Here the complete 51 minutes video of this spin:
https://recordsetter.com/submit/review?pend=478f3ed9-60f1-411d-a6e4-70777f497bf3
« Last Edit: January 06, 2016, 06:44:52 AM by Iacopo »
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jim in paris

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Re: Little top spinning for over 50 minutes
« Reply #1 on: January 06, 2016, 11:38:45 AM »

hello hello  !

what an incredible spintime for a small top !!

your craftsmanship and skills are simply stunning !
have you ever exhibited your works ? i mean not on the internet..

you should get in touch with a physics lab for some measures (decay time, friction etc..)

thanx for sharing

ciao
jim
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ta0

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Re: Little top spinning for over 50 minutes
« Reply #2 on: January 06, 2016, 01:15:26 PM »

Your craftsmanship and dedication are extraordinary!  8)

Now, I have a doubt about the end, when it spins at about 30RPM: is it behaving as a top or just balancing?
What is the height of the tip with respect to the center of mass of the top? Is it below?
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Iacopo

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Re: Little top spinning for over 50 minutes
« Reply #3 on: January 06, 2016, 03:21:13 PM »

hello hello  !

what an incredible spintime for a small top !!

Hello, Jim !

What is incredible to me, is that nobody else seems to have made this before.
The concepts behind this top are relatively simple and intuitive, (I have exposed them), and, apart from a decent metal lathe, not much more is required.
But maybe the reason is that there are no rewards for developing such a thing, it is just a curiosity, nothing more...

I never thought to exhibit my tops, still less to ask for lab data, because I am not very attracted by the idea to be involved in a serious commerce and sell many of them.  Too much work is needed to produce these tops and the price would be too high, it would be a failure I think. 

 
« Last Edit: January 07, 2016, 12:11:38 PM by Iacopo »
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Iacopo

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Re: Little top spinning for over 50 minutes
« Reply #4 on: January 06, 2016, 04:07:05 PM »

Your craftsmanship and dedication are extraordinary!  8)

Now, I have a doubt about the end, when it spins at about 30RPM: is it behaving as a top or just balancing?
What is the height of the tip with respect to the center of mass of the top? Is it below?

Thank you, Ta0, you are always kind.
It behaves as a top, the contact point is under the center of mass, but very near to it, (less than 1 mm).
The tip is mounted on a screw, I could shift the tip so that the contact point stays slightly above the center of mass, and in that case the top would stay vertical until the end of the spin, never leaning nor toppling down, (apart from maybe a bit of wobbling at low speed).
The purpose of the screw is to adjust the height of the tip to a level where the top still topples down, but only at the lowest possible speed, to elongate the spin time.   

Another clue that, in this top, the contact point is below the center of mass, is given from the fact that, in the first one or two minutes of spinning, it can be seen (in the complete video I linked) that precession movement occurs in clockwise direction, (very slowly, because the center of mass is so low), while the top is spinning clockwise along its axis.  If the contact point was above the center of mass, the precession movement would have occurred in counterclockwise direction.
 
« Last Edit: January 07, 2016, 11:47:42 AM by Iacopo »
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Jack

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Re: Little top spinning for over 50 minutes
« Reply #5 on: January 07, 2016, 10:34:08 AM »

you air are a god of spin @-@
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Iacopo

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Re: Little top spinning for over 50 minutes
« Reply #6 on: January 07, 2016, 11:22:19 AM »

you air are a god of spin @-@

"you air are.."
If there is a play on words, I haven't undertood it, my english is a bit poor...

Jack, you surprised me with your last video, it is the first time that I see someone to play with a lamp part,  :) and also you do it with mastery. Bravo !
« Last Edit: January 07, 2016, 12:02:23 PM by Iacopo »
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jim in paris

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Re: Little top spinning for over 50 minutes
« Reply #7 on: January 07, 2016, 12:55:21 PM »

ah ah!!
maybe jack has big fingers (like homer) :D :D
when he types "s" it becomes "a" :o
no pun here,"you sir are a god of spin"

jim

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Jack

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Re: Little top spinning for over 50 minutes
« Reply #8 on: January 07, 2016, 01:52:44 PM »

ah ah!!
maybe jack has big fingers (like homer) :D :D
when he types "s" it becomes "a" :o
no pun here,"you sir are a god of spin"

jim

oh my god im laughing my head off, even i couldnt figure out what i was trying to spell!!! lol
bravo jim that was what i tried to type lol
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Jack

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Re: Little top spinning for over 50 minutes
« Reply #9 on: January 07, 2016, 01:53:40 PM »

you air are a god of spin @-@

"you air are.."
If there is a play on words, I haven't undertood it, my english is a bit poor...

Jack, you surprised me with your last video, it is the first time that I see someone to play with a lamp part,  :) and also you do it with mastery. Bravo !

lol no pun except im an idiot that cant type properly lol!!!
thanks for the compliment, lamp parts are very fun  ;)
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DerrikH

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Re: Little top spinning for over 50 minutes
« Reply #10 on: February 07, 2016, 03:30:33 AM »

i just found your videos tonight and then you on this forum, very well done sir, really nice job crafting your spinners :)

have you looked into using tungsten copper instead of lead? its supposed to be easier to machine but still fairly heavy.
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Iacopo

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Re: Little top spinning for over 50 minutes
« Reply #11 on: February 10, 2016, 04:38:46 PM »

Thank you, DerrikH, for the compliments, and for the suggestion too; I didn't know about tungsten copper, I will keep it in mind.
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