Curtain Ring tops + follow ups

[ortwin]

fidget spinner wind up top

An improved version of the wind up top without curtain-ring can be found in this other thread.

[ortwin]

Curtain-Ring-Top Nr. 9 - simple reversing top - shows its name, but then decides to change it!




Just a piece of wire from a paperclip roughly shaped into a figure 9 and stuck into a curtain ring.
https://youtu.be/YJ9rEtX1-0Y

Since this one was not planned before today, there is at least another one to come that I had planned before. Some of you following my other posts of today might guess that there is also a plan for a multiple reversing curtain ring top. The first try on that was a fail, but I have ideas what should be improved. So if that works, there are two more curtain ring tops to come for now. But every day you guys seem to inspire new ideas, so we'll see.

[Jeremy McCreary]

Curtain-Ring-Top Nr. 9 - simple reversing top - shows its name, but then decides to change it!
Just a piece of wire from a paperclip roughly shaped into a figure 9 and stuck into a curtain ring.

Since this one was not planned before today...

Excellent! You're a born modular topmaker!

One of the best things about quick prototyping is the ability to turn an impulse into a working top in short order. That often gets me farther than my best-laid plans.

[ortwin]

Curtain-Ring-Top Nr. 10 - multiple reversing top




The transparent bluish bead can freely slide along a wire fixed across the ring. The two solid blue beads ad some AMI. One part of the ring got some black marker on it so one can sometimes follow the flips.
https://youtu.be/0AVngQ67ADk

It is working somehow. Hard to see clearly, but I think in some of the spins it is visible that it really flips more then once.

[ta0]

Very nice!
I love how on the normal tippe top it looks like the eye climbs the inner wall.

There are some clear rapid flips on the flippe top around 0:35. By going frame by frame I can even see the bead falling on one of those. But it would be worth filming in slow motion.

You have achieved quite a bit using curtain rings!

[ortwin]

Curtain-Ring-Top Nr. 11 - triple tribute top

It does not look much different then some other tops in this series. But there are some details about it that point to future metal (non curtain ring ) versions I am planning to build.
But lets get to the letters in the next pic:

T : spokes and needle are a tribute to ta0 who prompted this series by a remark about his guess on the longest running tops.
I : the torus flywheel is a tribute to Iacopo and his tops of unsurpassed elegance.
J : the hub is a tribute to Jeremy - for obvious reasons if you can see it well in a close up.




The paperclip visible in the material picture ended up cut to little pieces of wire. Every piece stands for setscrew in metal tops to come later. The setscrews I am thinking of look similar to this:

The pieces of wire are marked with different letters in the following picture:

A : stands for the three setscrews that tension the spokes and center the tip
B : stands for the three setscrews that are used for static balancing of the top
C : stands for the three setscrews that are used for dynamic balancing of the top

The wire of the needle represents the 10th setscrew that enables the adjustment of tip height.


https://youtu.be/t6-UDhIYLPY

The performance is not that great, but after all it is just build from plastic and all the possibilities for adjustment are more or less symbolic.I hope to see some improvement when turning to metal flywheels next. It wil not be heavy metal for starters, more like easy listening.

[Jeremy McCreary]

Curtain-Ring-Top Nr. 11 - triple tribute top...
The performance is not that great, but after all it is just build from plastic and all the possibilities for adjustment are more or less symbolic.I hope to see some improvement when turning to metal flywheels next. It wil not be heavy metal for starters, more like easy listening.

I'd call that a success! LEGO tip holder duly noted. Amazingly well centered and balanced considering all those paperclip fragments.

Your design goals seem to be headed in the direction of Maxwell's dynamical top -- a laboratory top that ended up making significant contributions to both rigid body dynamics and the modern theory of color vision.

Maxwell never tired of toys and used them in his experiments whenever he could. The spinning top was a favorite.

[ta0]

Yes, great job using those materials!

T : spokes and needle are a tribute to ta0 who prompted this series by a remark about his guess on the longest running tops.

Well, I have somewhat changed my opinion. If tip friction was the limiting factor, this would be ideal. But if one doesn't care about tip friction (and therefore how heavy the top is) and only cares about air drag, a compact top with the mass against the axle may be ideal. It may be an inefficient use of the material to reach the desired moment of inertia but will probably provide the least air drag. Not good news to those wanting to make a top out of gold or platinum

Jeremy: great link to that picture of an original Maxwell dynamical top and the video from Aberdeen University Museum.

[ortwin]

Preview of the first "follow up" to the curtain ring tops
Not that I think anybody is waiting anxiously for the follow up, but I planned to have it ready by today and to present something.

The problem I ran into were the setscrews: I meant to drill small axial holes into three of them so I could thread my nylon spokes through those holes and secure them by knots.
But the screws I had, turned out to be too hard. I broke my 0.5 mm and my 0.6 mm drill on them. My friend with the lathe is going to make brass screws now for me, but that will take a few days until I get them.

So I just show the hub (the hex nut) and the one end of the three nylon spokes. They run through three holes I put into the nut and are secured by simple knots. The tip, a 4 mm ceramic ball from a ball bearing is glued with a drop of crazy glue to a setscrew.

See, I have the equipment to post better close ups than I usually do.

[ortwin]

Curtain-Ring-Top Nr. 12 - The Link - soon to be called "The Missing Link"
The transition in moving on from the plastic curtain ring tops to metal tops should not be tooooo hard and sudden. So this should be the link between the curtain ring tops and the follow ups. Of the "follow up" I showed a preview in the last post of this thread, it was basically the tip and the hub plus one end of the nylon spokes. Since I still don't have those three special grub screws that I need for precisely centering the tip I am doing other stuff like this curtain ring top.
The flywheel I am going to use was a very lucky find a few days ago after I had the idea for it ready in my mind.
I saw that this part of old adjustable base I had made long time ago for some diamagnetic levitation experiment. It had already all holes in the right places where I needed them and almost all threads. So that was easy, that is where the "easy" comes from in "easy listening", the name for the follow up. It is made from aluminum and it is quite big, but the larger size makes setting up also somewhat easier.
(outer diameter: 90 mm, inner diameter: 68 mm, height 12 mm, weight: about 85 g )

A curtain ring like the one used in the other tops of this series serves here as hub and as tip at the same time. Some inspiration came definitely from Jeremy's second batch of STs (suspension tops), mostly from what he calls "Top 4", "Hercules wheel in chains". There are also some strong features of "communication towers kept upright by guy lines" that Jeremy mentioned in the "Suspension Tops" thread.

The following video shows actually the first spin of which I measured the duration. It ended after about 2 minutes I think. In the meantime I had a few spins with 2:45 abouts.

As I said there is still no precise centering possible here, so I did not bather to really balance anything here. Also the PING in the nylon is not at the level I aim for. It is mostly just like what you can do with knots when doing your shoe laces.

https://youtu.be/YzGxFKhchZE

Bu what is that upper part of the curtain ring good for? Okay, I can spin by it as if it where a stem, but really .....

Lets just get rid of that half! Good bye my precious Curtain Ring!

rigging indicated in colors

At the beginning of this post I explained the "link" part of the name. Since the flywheel will soon be incorporated in the follow up that has no curtain ring, this top will not exist any longer and that's why I will soon call it "The Missing Link".

[Jeremy McCreary]

You cut off my last hope of a stem!!

Very interesting line rigging to hold the curtain ring upright. Surprised at how smoothly the top spins given that there are lines crossing between the curtain ring and tbe mirror.

[ortwin]

[size=78%]. Surprised at how smoothly the top spins given that there are lines crossing between the curtain ring and tbe mirror.[/size]

Ah, no. No crossing between curtain ring and mirror. There are four tiny holes visible in the material picture in the curtain ring. I used the two central ones of those.
I should have made the rigging clearer. I might insert a clarifying sketch.

[ortwin]

You cut off my last hope of a stem!!

But if I would have cut off a little less, you would have been left again with the two stems I designed for you before!

[Jeremy McCreary]

So the metal flywheel will ultimately be your starting torque input -- presumably with the two-hand shear method.

At my skill level, I think I'd need a good 10-15⁰ of scrape angle to get a fast, scrape-free release without a stem for fine tilt control.

If G = ground clearance with no tilt, and R = max flywheel radius at its base, then

CORRECTED: scrape angle = arctan(G / R) ~ 90° 45° G / R

to a very good approximation for G / R < 40% 90%.

Which brings us to ground clearance G. How much are you planning to get with the metal flywheel on the nut+bolt core with white tip?

[ortwin]

...
Which brings us to ground clearance G. How much are you planning to get with the metal flywheel on the nut+bolt core with white tip?

To me that sounds as if you took all the date I gave about the flywheel, put everything in the appropriate formulae and are ready to give me the ground clearance you would start with, what critical speed I can expect and what starting speed with the typical energy one can put into a twirl (Iacopo's numbers). That would be all very welcome, go ahead give me those numbers and if you dare even your estimate for spin time. I will go about it the playful way and play around with all the ten grub screws once I have it ready and try to get to the values you calculated as good as possible. If we get into the same ballpark with our values, both of us could call it a success.

Should we get that far, a recalculation for a flywheel made from brass with a square generator would be the next logical step. Either keeping AMI or mass the same. What new diameters would we get? What would the new, lower, ground clearance be and what the new lower critical speed? What would we estimate as the spin time, would we think its worth getting it build?

In my play-around approach, I plan to start with a ground clearance of about 5 mm with the option to change it either way by about 3 mm.