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Author Topic: My new top inspired to the Maxwell dynamical top  (Read 10185 times)

Iacopo

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My new top inspired to the Maxwell dynamical top
« on: December 19, 2016, 09:09:01 AM »

This top (Nr. 23) has a system of screws in the flywheel whose aim is to allow the tuning of the balance of the top.
I designed this system after having seen the dynamical top of Maxwell, which uses screws for adjusting the balance, and I used it in my top Nr. 17 for the first time.  This system is easy to use compared to my usual method of balancing a top by centering the tip, filing one side of it.  I was worried about worse aerodynamics, because of the holes and the screws, but spin times, (up to nearly one hour), demonstrate that the loss is negligible.   

This top uses replaceable spiked tips, which can be resharpened.
I have designed and made a honing guide for to ease the resharpening of the tip when it is too weared, after many hours of spinning.   

My goal designing this top was to make a top easy to maintain but still able to spin for very long.
I am satisfied with the result.  I have run two wear tests and the contact points resulted to last for at least 25-30 hours of spinning, using the HSS tips. 
Restoring the contact points then is not difficult with this top, also if it still takes time, (15 minutes to resharpen the tip, one hour to restore the base, and half an hour to balance the top).

Overall this is my actual best top.

https://www.youtube.com/watch?v=83dlHf7ZyuY
 
« Last Edit: December 19, 2016, 09:13:28 AM by Iacopo »
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Russpin

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Re: My new top inspired to the Maxwell dynamical top
« Reply #1 on: December 19, 2016, 10:12:24 AM »

Beautiful work and video. How did you make the HSS and carbide tips? It looks like the threads are a different metal than the contact point.
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lincolnrick

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Re: My new top inspired to the Maxwell dynamical top
« Reply #2 on: December 19, 2016, 10:56:30 AM »

Beautiful top and video. The precision you put into each of your tops is incredible. Congratulations on another masterpiece.
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Jack

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Re: My new top inspired to the Maxwell dynamical top
« Reply #3 on: December 19, 2016, 11:02:23 AM »

stunning. thats really nice eh
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Iacopo

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Re: My new top inspired to the Maxwell dynamical top
« Reply #4 on: December 19, 2016, 12:46:21 PM »

Beautiful work and video. How did you make the HSS and carbide tips? It looks like the threads are a different metal than the contact point.

Thank you, Russpin.   HSS and carbide are too hard to be threaded, at least for my means, so I used brass for the threads.  I holed the threaded brass pieces, then I inserted the cylinders of hard metal in them, fixing them with epoxy resin.  After the resin was hardened, I shaped the tip conical, initially roughly by a grinder, then accurately, by the honing guide and the diamond sharpening stone.   
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Jeremy McCreary

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Re: My new top inspired to the Maxwell dynamical top
« Reply #5 on: December 19, 2016, 01:42:36 PM »

Beautiful in both appearance and design, Iacopo! I take it that the paint points to the light side, the usual case.
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ta0

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Re: My new top inspired to the Maxwell dynamical top
« Reply #6 on: December 19, 2016, 01:59:56 PM »

 :o 8) 8) 8)

Beautiful top and video. The precision you put into each of your tops is incredible. Congratulations on another masterpiece.
A Masterpiece is the right word.
Congratulations!

Beautiful in both appearance and design, Iacopo! I take it that the paint points to the light side, the usual case.
I believe the heavy side, which is the case for his low center of mass tops.

ps: Somehow I need to start saving for number . . .  27 (?)
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Iacopo

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Re: My new top inspired to the Maxwell dynamical top
« Reply #7 on: December 19, 2016, 03:16:47 PM »

Thank you everybody for the kind words.

Beautiful in both appearance and design, Iacopo! I take it that the paint points to the light side, the usual case.

Thank you Jeremy.  Ta0 is right.  The paint in my tops point towards the heavy side, because of their low barycenter.

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Jeremy McCreary

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Re: My new top inspired to the Maxwell dynamical top
« Reply #8 on: January 01, 2017, 02:53:44 PM »

Ta0 is right.  The paint in my tops point towards the heavy side, because of their low barycenter.

All of your tops mark on the heavy side? At all speeds?
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Iacopo

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Re: My new top inspired to the Maxwell dynamical top
« Reply #9 on: January 02, 2017, 03:57:05 AM »

All of your tops mark on the heavy side? At all speeds?

Generally my tops have the recessed tip and very low center of mass: all these tops always mark on the heavy side, at whatever speed.
Some of my older tops have a higher center of mass and behave differently.
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Jochen

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Re: My new top inspired to the Maxwell dynamical top
« Reply #10 on: January 23, 2017, 02:52:37 AM »

Hello there,

and wow... I'm speechless!

You are building awesome tops!

As for the tips I would use a so called "silver steel" at least we call that like that here in Germany. Its a 1.2210  steel which can be machined pretty good. It can be hardened up to 64HRC. You could turn the tip out of it, add a threat and harden it just using a torch. Works pretty good! a lot of hobby machinists are building even turning steels out of this material.
If you are intersted I can provide you a datasheet and some more infos how to heat treat it to the desired hardness. Its pretty easy and you get the material everywhere.

Jochen
« Last Edit: January 23, 2017, 03:23:21 AM by Jochen »
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Iacopo

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Re: My new top inspired to the Maxwell dynamical top
« Reply #11 on: January 23, 2017, 12:08:03 PM »

Jochen,

thank you.  I have seen your tops, they are very very nice, so the esteem is reciprocal.  :)

I don't know silver steel, never used it.  I see that rods of silver steel are easily found on E-bay, I would be curious to try it.
If you can post infos how to heat treat it, I will read them with interest.

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Jochen

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Re: My new top inspired to the Maxwell dynamical top
« Reply #12 on: January 23, 2017, 05:21:06 PM »

Thanks Iacopo,

I have the Datasheet here and a long description how to do it.
But there are more practical ways...

If you turn your tip I think its enough to harden just the tip and not the whole part. So heat it up with a propane flame or whatever you have till its a bright cherry-red (thats around 800 grad). Then quench it fast in water. Use a file to check it if worked. Shouldnt be possible to easily file metal off the part at 64HRC. Just as to compare if you build knives you normally heat treat to 58-62 HRC. Thats pretty good!
If you are not sure about the colour and if you hit the right heat, Just heat it till its not longer magnetic. then  quench it fast.
Now its at max. hardness and brittle. Maybe ok like that because your tops dont get hits on the tip?
If you want it to be less brittle and more elastic you have to anneal it. Here is a diagram at which temperature you get the according hardness. You can use the kitchen oven for that. Leave it in there for two hours at the desired temperature. But be careful its very dangerous!!! Be sure you sent you wife shopping before you bake your oily parts ;-)
Thats a short description and normally it should work pretty good. If you have any questions feel free to ask!

But something else... how do you center your tip when its just screwed in? Threads are not exact enough to center something...

Jochen
« Last Edit: January 23, 2017, 05:30:19 PM by Jochen »
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ta0

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Re: My new top inspired to the Maxwell dynamical top
« Reply #13 on: January 23, 2017, 07:43:14 PM »

Great info!

Quote
You can use the kitchen oven for that. Leave it in there for two hours at the desired temperature. But be careful its very dangerous!!! Be sure you sent you wife shopping before you bake your oily parts ;-)
;D ;D ;D
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Iacopo

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Re: My new top inspired to the Maxwell dynamical top
« Reply #14 on: January 24, 2017, 05:33:41 AM »

If you are not sure about the colour and if you hit the right heat, Just heat it till its not longer magnetic.

How do you check whether the steel is still magnetic ? You check it when it is red hot ?

And, what if the steel is cooled down in the water at a temperature higher than 800 degrees ? It becomes too brittle ?

But something else... how do you center your tip when its just screwed in? Threads are not exact enough to center something...

With some precautions, threads can be accurate enough.  For the best concentricity, I first fix a full brass cylinder inside the core of the top, with epoxy resin. When the resin is hardened, I put the whole top on the lathe, precisely center it, and only at this moment I drill the hole to be threaded.
I finish the hole with a boring tool for better centering the hole. Then for threading I use a screw cutting tool, which is more accurate, as for centering, than a tap threader.
Two grub screws are screwed in this hole; the first is a short one, the second, holding the tip, is screwed in tightly against the first one, not only for steadiness, but this set up also helps improving the concentricity of the tip.
Still there can be a few hundredths of millimeter of error in concentricity of the tip, which are enough to make the top to wobble a bit:
I don't correct this by shifting the tip, but by moving the grub screws in the flywheel.
Doing so, I shift the center of mass of the top exactly above the tip, and the top doesn't wobble anymore.
In my older tops I didn't use the grub screws in the flywheel and I corrected the unbalance in them by shifting the contact point of the tip, filing on side of the tip, which is an effective but a somewhat rough technique; the grub screws in the flywheel are easier to use and permit a more accurate balance.
Someone in this forum (Aerobie) made a top with three screws for fine tuning the position of the tip, which is another way to solve the problem.
I think that a balancing system integrated in the top is useful in heavy tops, which suffer wear of the tip, because each time a tip is replaced or resharpened, the top needs to be balanced again. 

Some time ago I made this video, about how to balance a spinning top, (by simple methods, not high tech):

https://www.youtube.com/watch?v=fpRlsWLgeQ0

 

« Last Edit: January 24, 2017, 05:43:19 AM by Iacopo »
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