Newbie introduction

[Bill Wells]

Hello everyone, I am so glad to finally join itopspin!

I am a retired mechanical engineer living in Olympia Washington USA.
Although new here, I have been experimenting with tops for several years. I am also a woodturner, and use my lathe to create my spinning tops.
I have learned that creating tops is both an art and a science. And patience is required!
Now working with spinning tops in a vacuum.

Best regards to all
Bill Wells

[ortwin]

Welcome Bill!
Good to have you here.
Tell us more about your tops in vacuum: how good is the vacuum you are using?
Iacopo had a top spinning in vacuum for four hours, maybe you found his post about that already.
This is my latest effort in vacuum. Looking forward to discuss top stuff!

[the Earl of Whirl]

Hello Bill.  Nice to have you on board with our board.  I look forward to getting to know you.  Hope things are calmer up that way with air quality and more.

[Jeremy McCreary]

Welcome aboard, Bill! As a fellow topmaker, couldn't agree more about the interplay of art and science involved.

Several of us are very much into top engineering, myself included. So your expertise and experimentation are especially welcome. Want to hear all about any experiments you'd like to share.

Recurring engineering discussions here include...
1. Understanding and combatting spin decay — including what can be learned from comparing spin decay curves among various tops.
2. Top aerodynamics.
3. Contact resistance at the tip and the physical processes involved.
4. Diagnosing and fixing unbalance.
5. Do unbalanced tops have their own kind of whirl (in the engineering sense)?
6. All the sources of wobble, including structural vibrations excited during startup. (As you can see at https://www.youtube.com/c/JeremyMcCrearyTechnicalLEGO , many of my LEGO tops aren't effectively rigid).

I could go on, but I think you can see that serious discussions of top engineering are welcome here. One of us, Iacopo Simonelli, is both a master topmaker and a very clever experimentalist who's also done vacuum work.

[Texture]

Welcome to the forum, Bill! 

What kinds of tops do you make on the lathe?

[Joah]

Welcome Bill! 

[mailman]

Welcome, Bill!  I'm looking forward to seeing your top turning....

[Bill Wells]

Thank you all for your replies.  I hope this message is being received by all that commented on my "newbie" post.  I am still learning the site.

Ortwin, I use a two stage vacuum pump sold by Viot. However, I am seeing what appears to be the same pump being sold elsewhere, even by Harbor Freight under their name. The advantage of this pump is high vacuum,  29" Hg under optimum conditions. Disadvantage is low flow capacity, there must be no leaks anywhere. Usually I get 28.5" Hg consistent during run.

Texture, on my "medium" size lathe I started with very hard and dense wood like Jatoba. These were about 6" (150mm) diameter. I first drill the stem hole (3/8", 10 mm) and use a brass shaft. I use the shaft held in the lathe chuck to turn the top to desired shape. I have recently turned aluminum, it is soft enough to turn (carefully and slowly) on a wood lathe. Also can turn brass.

Jeremy, Yes I contemplate all six of your discussion topics. But I scratch my head on your #5.

Mailman: Yes, I will post videos and charts, will wait until I am more comfortable with the website.

Joah: Thanks for the smile!

Earl of Whirl: Yes, I also would like to know more about all of you, not just tops. About me: I will be 80 y/o in a few months but not acting my age. I am a bit obssssive, but do not have the patience of Iacopo. Here we are experiencing less smoke than last couple years. Where we live (Olympia) much hotter and drier this year.

[Jeremy McCreary]

I will be 80 y/o in a few months but not acting my age.

Just turned sweet 73. This is the birthday card from my son.

Jeremy, Yes I contemplate all six of your discussion topics. But I scratch my head on your #5.

I know just enough about rotordynamics to be dangerous, but I really think it has a lot to teach us about the way unbalanced tops behave. The modes of an overhung rotor on soft bearings would seem to be pertinent. Looking forward to hearing a mechanical engineer's take on that.

[ta0]

Welcome to the forum, Bill!
I also belong to the refusing-to-grow-up club 

Jeremy, Yes I contemplate all six of your discussion topics. But I scratch my head on your #5.

Don't worry. Only Jeremy likes to talk about whirl 

[Jeremy McCreary]

Jeremy, Yes I contemplate all six of your discussion topics. But I scratch my head on your #5.

Don't worry. Only Jeremy likes to talk about whirl 

My days of wailing in the wilderness will end one day. Hopefully before I kick the bucket.

[Bill Wells]

Ha ha - thank you Jeremy

[jim in paris]

Howdie Bill !
welcome here,you ll find plenty of information
and support for any toupie-related project
Looking forward to more info about your work
Jim

[ortwin]

...The advantage of this pump is high vacuum,  29" Hg under optimum conditions. Disadvantage is low flow capacity, there must be no leaks anywhere. Usually I get 28.5" Hg consistent during run....

Eh, I admit I fail at making sense of the values for the vacuum.
If I look up 29" Hg,  I get this:
29 Inches of Mercury = 982.05281 Millibars 

Which like no vacuum at all. So I must be misunderstanding something about those units and numbers you are using.

[Bill Wells]

Ortwin, you are so correct about measurement units for vacuum! I should have written -29" Hg (negative 29 inches mercury, where -30" is theoretical total vacuum). We are all struggling with metric, imperial, weather reporting units, and archaic jargon. Plus several more that I don't even try to remember.  I will try to attach an image of the typical vacuum gauge.