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[Jeremy McCreary]

In my book, ruining play value by reducing ground clearance to the point of a 2° scrape angle or less just to get a 6% ground effect in spin time is a bad deal.

In the top I am making the scrape angle is about 10°, which is comfortable to spin.
The spin time gain will be not a lot but consider that at present my longest spin is 58 minutes, and if I can improve just a bit, I can break the one hour wall for a finger top, which in my case is a value.

Yes, 10° is quite comfortable -- though it may take some practice with single twirls of high-AMI tops.

Eager to see this new top! If I were that close to the 1 hour wall,  I'd do whatever it took, play value be damned! (Not that I'll ever be in that enviable position.)

[ortwin]

...Coins are problematic in an international forum, though. A universally recognizable marker like the first 50 mm of a ruler would be best. ...

Here you contradict yourself quite severely in a single line! Quarter + Euro less universal recognizable then mm? Ha! I don't think so. Take US Americans:
Wasn't the wrongly done conversion from inch to mm the cause for a lost satellite some years ago?
As far as I know the British love their strange units also a lot. Oh, and the finger: Did you ever compare the average Uruguayan finger length to a German one? On the net I find that there is a difference of 6 cm (Well that is for the complete height of men) !
No, ta0 should supply copies of figaro to us for these pictures. 

If I were that close to the 1 hour wall,  I'd do whatever it took, ....

Jeremy, please don't push Iacopo into the black market for osmium, at least not not in the open like this so everybody can read it!

[ta0]

Oh, and the finger: Did you ever compare the average Uruguayan finger length to a German one? On the net I find that there is a difference of 6 cm (Well that is for the complete height of men) !

What finger are we talking about? 

[Iacopo]

This is the drawing of the new top.
There is a plexiglass shroud around the flywheel; the shroud can be removed partially, (with only the lower part there shoud be a bit of ground effect but the longest spins will be with the shroud), or completely, for to see a precession or a nutation with a larger angle of tilting.

I will make also another top slightly different from this one, and I will show them together, in May, when they will be ready.

Jeremy, please don't push Iacopo into the black market for osmium, at least not not in the open like this so everybody can read it!

Too easy to spin one hour with heavy metals.  I have at least 1 kg tungsten and I am not using it.  Let's figure out more esoteric metals, I am not interested.  I use plain brass for these tops, it is possible to spin for long even with the humble brass.

[ortwin]

...
What finger are we talking about? 

I know only about five different fingers plus mirror symmetry. Just chose one, I give you a thumbs up for whichever one you take.

....and now I just learned:  "ladyfingers"; In Uruguay and Venezuela: plantillas...  which again insinuates something small.

[ta0]

...
What finger are we talking about? 

I know only about five different fingers plus mirror symmetry. Just chose one, I give you a thumbs up for whichever one you take.

....and now I just learned:  "ladyfingers"; In Uruguay and Venezuela: plantillas...  which again insinuates something small.

It's true that the Frau I once dated looked me straight in the eyes (she was clearly above the average German women height), but she never complained about any of my fingers. 

PS: I wonder how I will title this thread if I have to split it and move it to the NSTR section 

[Jeremy McCreary]

Oh, and the finger: Did you ever compare the average Uruguayan finger length to a German one? On the net I find that there is a difference of 6 cm (Well that is for the complete height of men) !

What finger are we talking about? 

Thumb would be my 2nd choice.

[Jeremy McCreary]

...Coins are problematic in an international forum, though. A universally recognizable marker like the first 50 mm of a ruler would be best. ...

Here you contradict yourself quite severely in a single line! Quarter + Euro less universal recognizable then mm? Ha! I don't think so. Take US Americans:
Wasn't the wrongly done conversion from inch to mm the cause for a lost satellite some years ago?

Not just a satellite — a billion $125M-dollar Mars Climate Orbiter! Don't get me started about Imperial Units. 

[ta0]

Those tops are going to be superb, Iacopo. I hope you can break the 1 hour barrier using them. The brass 1 hour barrier!

[Jeremy McCreary]

This is the drawing of the new top.
There is a plexiglass shroud around the flywheel; the shroud can be removed partially, (with only the lower part there shoud be a bit of ground effect but the longest spins will be with the shroud), or completely, for to see a precession or a nutation with a larger angle of tilting.

Gorgeous! Love the shroud design. Can't wait to see it in action!

We burned up a lot of brain cells and testing time on shrouds in this thread. But it clearly wasn't in vain. Your new design is the payoff! Your competitors and mimickers won't know what hit them.

[Iacopo]

I hope you can break the 1 hour barrier using them. The brass 1 hour barrier!

Fingers crossed !

We burned up a lot of brain cells and testing time on shrouds in this thread. But it clearly wasn't in vain. Your new design is the payoff!

Jeremy, you are a father of this top.
I wouldn't have discovered these new things if you didn't start this thread.
Your knowledge, tests and observations, have been an important stimulus for the mine.

[ortwin]

...
Fingers crossed !
...

I am also wishing you good luck with this beauty, but at the same time I fear you might get bored by spinning tops and turn to another hobby, once you crossed the one hour barrier. I would not want that to happen.

And while you are going for the one hour barrier, I will try to convince Brass Band to cross the half hour line (in recessed mode).

[Iacopo]

I am also wishing you good luck with this beauty, but at the same time I fear you might get bored by spinning tops and turn to another hobby, once you crossed the one hour barrier. I would not want that to happen.

Thank you, Ortwin.  My will at present is to continue making tops for a long time.  I like to make them.  Now, also, I have an economic incentive which I didn't have in the first years, because I have many requests, and prices are not low.  I like that I can make each top a bit different from the others, I can always experiment new details of the design, new materials, then the physics of the spinning top by itself, I find it interesting, so in the whole it is difficult that I become bored, at the countrary, I feel lucky that I can do something I like and that I can even gain some money for it. 

[Jeremy McCreary]

Jeremy, you are a father of this top.
I wouldn't have discovered these new things if you didn't start this thread.
Your knowledge, tests and observations, have been an important stimulus for the mine.

That goes both ways, my friend!

One of the best things about this forum is that it provides a productive place to discuss top engineering and share our R&D efforts to the benefit of all the topmakers here, regardless of medium and genre.

And where else do you get to wallow in the unexpected complexities of these "simple" little toys?

ta0 deserves a lot of credit here -- not only for his own valuable contributions along these lines, but also for fostering such things in general.

[ta0]

ta0 deserves a lot of credit here -- not only for his own valuable contributions along these lines, but also for fostering such things in general.

If it wasn't because of the people that post on a regular basis we wouldn't have a forum. So, thank you guys!
I believe that the advantage we have with respect to social media is that we can discuss topics in depth and that top information is documented for the future.