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Author Topic: Spinning Top Nr.17 (41 minute spin!!!)  (Read 1943 times)

James

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Spinning Top Nr.17 (41 minute spin!!!)
« on: September 02, 2019, 01:15:58 AM »

Hey :)!

I recently finished making my 17th top. It weighs 312g, 60mm diameter and spun (with multiple twirls) for 41:01. That makes it my best spinning top. It has an internal, conical and sharp, HSS tip (not replaceable). It took about 30 hours to make spread over about 2 months using ONLY manual lathes (no CNC etc).

I also made a new base using *real* tungsten carbide (It turns out the metal advertised as carbide I was making bases out of previously is actually HSS). The carbide is permanently fixed in an aluminium ~cone - in turn held in a brass ~doughnut. The brass is for added stability and good looks (it matches the top nicely). I made an aluminium tool for retouching the base (although I think I should have made it from a harder material. Thoughts?).

A picture of the top bellow:





Below shows the underside (this was before it was finished):





Below shows part of manufacturing. I did an interference fit:

https://www.youtube.com/watch?v=iSDHr_FJ-F4&feature=youtu.be

Below shows footage of precession:

https://www.youtube.com/watch?v=fIifHO5vspg

Below shows the base in some detail:

https://www.youtube.com/watch?v=xAL_qOfnOx8

^^^*PLEASE IGNORE THE GUY TALKING IN THE BACKGROUND* I was learning about some electronics stuff.

I have not made efficiency tests yet as my tachometer is in the UK and Im in HK. I'll post the results when I get them. Thanks for reading and watching. Please feel free to give feedback, advice or tips, suggestions or anything.

PS
The videos of the top etc were posted on a friend's youtube channel so I could put them in here to show you guys. You can ignore the titles, descriptions etc.
« Last Edit: August 14, 2020, 10:00:13 AM by James »
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Once a spinner, always a spinner :)

Iacopo

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #1 on: September 02, 2019, 04:20:23 PM »

41 minutes..  !   WOOOW ! Excellent !

You are doing very well.  Again, perfect balance.  Bravo !
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the Earl of Whirl

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #2 on: September 02, 2019, 05:19:31 PM »

Perfect balance and perfectly beautiful!!!
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Happiness runs in a circular motion!!!

James

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #3 on: September 03, 2019, 01:43:11 AM »

Thank you very much!!!
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Iacopo

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #4 on: September 03, 2019, 02:37:44 AM »

I made an aluminium tool for retouching the base (although I think I should have made it from a harder material. Thoughts?).

I use inox steel for the ones I make.  Does aluminum work well for polishing the carbide spinning surface with the diamond pastes ?
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Iacopo

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #5 on: September 03, 2019, 03:07:59 AM »

One thing you can improve a bit, maybe, could be the finish of the metal surface. 
The kind of lighting you used, (direct, not diffuse), is very severe and highlights even the littler scratches, around the reflections;
so I believe that these scratches are lighter than they appear in the photo; anyway, you might want to improve a bit the surface and make it smoother.  Do you finish the metal surface by sandpaper or do you use the diamond pastes too ?  Usually I sand up to 5000 or 7000 grit, then I polish with the diamond pastes; I start with 1.5 micron, then I use the 0.5 micron, and I finish with the 0.1 micron.  With the 0.1 micron one, the scratches disappear completely, and the metal surface becomes like a mirror.
It takes time, but it can be worth.     
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James

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #6 on: September 03, 2019, 11:27:02 AM »

Hi,

I have had some difficulties using the aluminium tool. I will try a different material soon.
The top currently has a brushed finish using steel wool. I may polish it to a mirror finish in the future, however I left my lapping pastes in the UK. I will update this with photos when I do it.
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James

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #7 on: August 14, 2020, 10:01:43 AM »

New video on my channel about this top:

https://youtu.be/4s540si0jLU
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Jeremy McCreary

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #8 on: August 14, 2020, 11:36:36 AM »

Beautiful top, as usual. Enjoyed the lathe shots.

I'm doing a study of measured spin-decay curves (SDCs) in real tops of all kinds. Only a dozen or so of sufficient quality have been posted-- including one of yours (Nr. 15, I think) -- so every good data set is precious.

Q: Would you be willing to post your raw (time,RPM) data and any or all of the following stats for Nr. 17?

1. Alloys used and their densities, if known
2. Total mass
3. Brass and aluminum max diameters
4. Total length along axis, including stem
5. Max brass length along axis
6. Depth of aluminum recess below
7. Distance from brass geometric center to contact
8. Distance from overall center of mass to contact, if known
9. Typical toppling speed -- e.g., at transition from quiet sleep to rapid "death spiral"

You can learn a lot about a top from its SDC and some simple spreadsheet calculations. I'll post my analyses.
« Last Edit: August 14, 2020, 11:42:11 AM by Jeremy McCreary »
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roypwee

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #9 on: August 25, 2020, 10:36:37 PM »

Nice James!!!
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James

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #10 on: September 20, 2020, 09:27:03 AM »

Jeremy, here is some data:

Min   RPM   Efficiency   RPM drop
0   2180   94.08   129
1   2051   94.10   121
2   1930   94.15   113
3   1817   94.33   103
4   1714   94.40   96
5   1618   94.50   89
6   1529   94.51   84
7   1445   94.60   78
8   1367   94.59   74
9   1293   94.74   68
10   1225   94.69   65
11   1160   94.74   61
12   1099   94.81   57
13   1042   94.72   55
14   987   94.63   53
15   934   94.65   50
16   884   94.80   46
17   838   94.99   42
18   796   94.85   41
19   755   94.70   40
20   715   94.83   37
21   678   94.84   35
22   643   94.71   34
23   609   94.58   33
24   576   94.62   31
25   545   94.68   29
26   516   94.38   29
27   487   94.25   28
28   459   94.12   27
29   432   94.21   25
30   407   93.86   25
31   382   93.72   24
32   358   93.85   22
33   336   93.45   22
34   314   93.31   21
35   293   92.83   21
36   272   92.65   20
37   252   92.06   20
38   232   91.81   19
39   213   92.02   17
40   196   91.33   17
41   179   89.39   19
42   160   0.00   160

1. Brass flywheel, Aluminium core (Regular respective densities as far as I know)
2. 312 g
3. Brass max: 60mm, Aluminium max: 30mm
4. 70mm
5. 20mm
6. 10mm
7. I am not sure about this question, but the tip is 5mm off the ground if placed flat on a surface.
8. I am not sure about this distance unfortunately
9. around 170 rpm I believe

Hopefully some of this helps!
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Jeremy McCreary

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Re: Spinning Top Nr.17 (41 minute spin!!!)
« Reply #11 on: September 20, 2020, 10:50:10 AM »

Jeremy, here is some data:

Min   RPM   Efficiency   RPM drop
0   2180   94.08   129
1   2051   94.10   121
2   1930   94.15   113
3   1817   94.33   103
4   1714   94.40   96
5   1618   94.50   89
6   1529   94.51   84
7   1445   94.60   78
8   1367   94.59   74
9   1293   94.74   68
10   1225   94.69   65
11   1160   94.74   61
12   1099   94.81   57
13   1042   94.72   55
14   987   94.63   53
15   934   94.65   50
16   884   94.80   46
17   838   94.99   42
18   796   94.85   41
19   755   94.70   40
20   715   94.83   37
21   678   94.84   35
22   643   94.71   34
23   609   94.58   33
24   576   94.62   31
25   545   94.68   29
26   516   94.38   29
27   487   94.25   28
28   459   94.12   27
29   432   94.21   25
30   407   93.86   25
31   382   93.72   24
32   358   93.85   22
33   336   93.45   22
34   314   93.31   21
35   293   92.83   21
36   272   92.65   20
37   252   92.06   20
38   232   91.81   19
39   213   92.02   17
40   196   91.33   17
41   179   89.39   19
42   160   0.00   160

1. Brass flywheel, Aluminium core (Regular respective densities as far as I know)
2. 312 g
3. Brass max: 60mm, Aluminium max: 30mm
4. 70mm
5. 20mm
6. 10mm
7. I am not sure about this question, but the tip is 5mm off the ground if placed flat on a surface.
8. I am not sure about this distance unfortunately
9. around 170 rpm I believe

Hopefully some of this helps!

Thanks! As soon as I revive my laptop, I'll  get to work on it.
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