Hi!
Great job on breaking the hour barrier! I never had any doubts, it was just a matter of time
I am interested in your thoughts on the optimal weight for spinning tops. If a top is too light, say 100g, its moment of inertia is too small and the amount of starting energy we can give it is too limited. So, in an ideal world, we would make massive 100 kg spinning tops. However, when we try making heavier tops around 1kg like your Nr. 9, they don't spin as long as we expect. Is this due to the limitations of tip hardness and durability? The best weight seems to be around 300g based on your past tops. What are your thoughts?
Thank you, James !
I have no experience nor any data about a 100 kg top, but, at least until 847 grams, I can say that, the heavier, the better.
Generally heavier/bigger tops are more efficient and lose RPM more slowly than littler/lighter tops.
So, at parity of starting speed and toppling down speed, larger/heavier tops spin longer.
The problem is how you start the top.
If you make finger tops, the limited strenght of the fingers is not suitable for too heavy tops, so a compromise is needed.
For example, my fingers couldn't start the heavy Nr. 9 at more than 1000 RPM, so that top can't spin for much more than 40 minutes, in spite of its excellent efficiency in losing RPM more slowly than any other top I have made.
60 mm/300 grams tops, (in the case of tops with recessed tip to be started by multiple twirls of the fingers), are much better because with the fingers I can start them at about 3000 RPM, so, even if they are a bit less efficient, they can spin for almost one hour.
I made many tops with this size/weight.
But my new top Nr. 54 is even better ! This is a new size I never tried before, 70 mm/360 grams. Finger tops with this size can spin for more than one hour ! This new size is perfect for brass tops with recessed tip to be spun by multiple twirls. Now I will have to buy a 70 mm brass rod for my next tops in this category.
Then I discovered that adding a shroud around the top makes the top to spin some minutes longer.
The littler the shroud, the most close, (no openings), the better.
If you try you will see the same. I used paper to make this simple experiment.
So, thanks to the improved size and to the added shroud, I could reach 70 m 31 s.
As for heavier tops, I am considering to find a way to start them with more energy. Maybe with the palms of the hands, or a ribbon, as Jeremy suggests. Being so efficient, if I can start them at a decent speed, they certainly can spin for very long.