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ITSA General Assembly: December 5th - 12th

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 91 
 on: January 11, 2019, 11:51:15 AM 
Started by the Earl of Whirl - Last post by ta0
This is a weird coincidence. Although I'm aware that I have dreams every night, I don't generally pay attention to them when I wake up and very seldom are they about tops. But just today I woke up in the middle of a long an elaborate dream related to tops. It was about Cyril's collection. Although he lives in a large house, in my dream it was a much larger old castle. The collection was below the ground level, instead of the second floor. There were many visitors exploring the castle, which had many surprises, although the whole thing doesn't make sense (dream logic). I guess it was prompted by Lassanske's collection video and my recent visit to El Castillo de Piria. But perhaps also it's due to guilt as a new Marines festival is coming up and I never posted a video from my visit to Cyril a year ago. Perhaps I can make one before Marines about his Toupie Hollandaise tables  . . .

 92 
 on: January 11, 2019, 11:42:50 AM 
Started by paxl13 - Last post by paxl13
It's been a long time since I've posted in my own topic! Let's go then :P

Played a log bearing tops lately. I was able to get down a couple new tricks :
 - Hop the fence ( I actually like quite a bit this one )
 - Hammer ( they are semi-regenerating at this point but I think I have the right motion )
 - Mach 5 ( never was able to do this one properly... It just clicked this morning )
 - Gyro flop ( but vertical to vertical without any correction, again. clicked in the past couple of days )

Currently working on :
 - Whips ( from merry go round and from trapeze )
   => Anyone has any tips on them, from MGR... I tend to get it.. but from trapeze I never landed one so far...
  - Barrel Rolls

Cheers y'alls!
paxl

 93 
 on: January 11, 2019, 09:14:37 AM 
Started by the Earl of Whirl - Last post by the Earl of Whirl
I looked up "dreams" in the different sections of this board but it appears that the use of dreams is always in connection with "hopes" and future "plans".  In a his thread I would like to talk about real life sleeping dreams.  When I woke up this morning I had a pretty good one!!!

I was at some out of town event and trying to explain to someone about people I know.  In the course of the conversation we got talking about air travel and space travel.  I pointed out that I know a guy who has been working on going to the moon. He has been making calculations and has been building his own rocket.  It has been something he has worked on for years and knows it will take many many more years but he doesn't seem to mind and keeps at it.  His name is Jorge Alcoz.  As we talked some more I eventually pointed out that I also knew one guy who had already been to the moon.  He is into some of that stuff and likes to travel.  His name is Jon Gates.

 94 
 on: January 11, 2019, 04:30:02 AM 
Started by Jospin - Last post by Jeremy McCreary
They are the two lower parts of the case you can see in the design below.
The rest of the case is made of wood.

Looks like good protection.

 95 
 on: January 11, 2019, 03:59:16 AM 
Started by Jospin - Last post by Iacopo
Are you sure those Delrin parts you made aren't top rotors?

They are the two lower parts of the case you can see in the design below.
The rest of the case is made of wood.



 96 
 on: January 11, 2019, 01:41:16 AM 
Started by ta0 - Last post by cecil
I think every one knows I would love to go to Colombia. At this time I think I have the best numbers for a 4 1/2 trick top. Wish I could make a bunch of them. My new trick fighters are BLACK WALNUT and MAPLE. There going to be hard to split. Thanks for the great videos.

 97 
 on: January 10, 2019, 10:26:08 PM 
Started by the Earl of Whirl - Last post by the Earl of Whirl
You gotta hand it to the Go calendar and game stores.  It is hard to find tops of any kind anywhere in our area but today I saw most of a box of Schylling Tiny Tin Tops.  It is January of 2019 and that makes several years in a row that they have come through with some tops for sale.....and now 50% off!!!  Tiny Tin Tops they call them on their display box.

 98 
 on: January 10, 2019, 08:14:40 PM 
Started by jim in paris - Last post by Jeremy McCreary
Did you see this thread from last  year?

festival Marines 2018


Thanks! Looks like a great time was had by all.

Hoping to get a better idea of the display area and the visitors.

 99 
 on: January 10, 2019, 08:09:20 PM 
Started by Diz - Last post by Jeremy McCreary
And another one...

Personally, I'd rather not mix tops and spiders. Lobsters, maybe, but not spiders.  >:D

 100 
 on: January 10, 2019, 08:02:11 PM 
Started by Jospin - Last post by Jeremy McCreary
I am receiving more requests than I can manage. I am constrained to select what commissions to accept.

No surprise that you're having this problem of success! The Delrin tops I mentioned were just fantasies out loud. Maybe I'll commission a Delrin top one day.

If you have the possibility to use a lathe or if you are willing to ask someone else to make them, I give you permission to duplicate them.

Thanks!

In the past I used aluminum for to make the same pieces that now I made with delrin;
these pieces have a thread and are for the closing of the case of the top.  But aluminum is not slippery, while closing the case the thread tends a bit to seize, nothing serious but this is a reason that I wanted to try a different material.
I am happy about the choice because with delrin now the closing is smooth, how I feel it should be.

Ugh, aluminum-on-aluminum threads are the worst! Not surprised that Delrin-on-Delrin worked much better.

Are you sure those Delrin parts you made aren't top rotors?

Your idea to compare behaviour and spin times of Nr. 26 and 29 made with delrin could be interesting; certainly they would spin for much less time, because delrin is much less dense than brass.

Your usual "dense metal flywheel on light wooden core" design puts its mass where it counts in a way that no structurally sound 1-piece Delrin top ever could. For a given overall shape and size, you can reach a much larger total AMI and a much larger specific AMI (AMI per unit mass) as well. The greater the latter, the lower the critical speed, and the longer the spin time. For a given total AMI, greater specific AMI also means less weight on the tip -- hence, longer spin time via smaller tip resistance.

I believe that a delrin Nr. 29 would spin slightly longer than a delrin Nr. 26 because of the rounded instead of squared section of the flywheel.

I believe that, too. As usual, the aerodynamics matter.

The workability advantage of delrin, compared to metals, is that the material is removed much more rapidly. So, for making large pieces, which would take many hours to be made of metal with a lathe like the mine, delrin is an interesting alternative.... I agree about your doubt to use delrin for the stem. I am not sure whether it is stiff enough to stay perfectly straight by the time. Certainly a top made from a single piece of material would take much less time to be made, delrin also doesn't need to be varnished.

Finding the best stem solution would take some testing. So what to test first? For Delrin's very nice feel in the hand, and for all the reasons above, I'd be inclined to test the "all one piece of Delrin besides the tip" approach first. Some plastics are pretty stiff, and some hold their shape quite well. The proprietary ABS plastic used to make LEGO parts is an amazing material (though not necessarily the best for some top designs).

As for the geometry of the top, I don't think that delrin would give me more freedom than the materials I use usually.
At the countrary, delrin being a plastic, softer than metals and hardwoods, would constrain me to more massive shapes for to maintain sufficient stiffness.  Particularly, I would feel constrained to make the stems shorter and larger than I would like.
But also for the other parts of the top I wouldn't use delrin.
Cores are lighter and more beautiful when made of wood.
And, for the flywheels, metals are more suitable because of higher density, (at least, if longer spins are wanted), and more beautiful.

Your tops are hard to beat WRT spin time, looks, and rigidity (which ultimately goes to wobble reduction). No Delrin top could compete on spin time, but Delrin could probably be made rigid enough with the right structural engineering.

As for looks, I can imagine some stunning spinnable objects in polished Delrin.

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