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YouTube video about sphere with holes drilled through it

J

Jesse Tutterrow

Joined
May 5, 2017
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Saint Louis, Missouri, USA
A while back I was researching how to turn a sphere and if I needed a jig. I came across a video where a compass was used to draw a bunch of circles and where ever two circles intersected a hole was drilled. Does anyone recall this video? Please send me a link.
 
Bill, Thank you for your reply.

The video I was thinking of was taking a preturned sphere and drawing circles and drilling holes where the lines intersect. This resulted in a single sphere where most of the surface was removed via the holes.

The connection to a sphere turning jig was simply in the search criteria.
 
The layout geometry is about finding isohedron inside the sphere.
An isohedron has 12 vertices and 20 faces

The true compass setting is a tiny bit bigger than the radius - about 1.05 x radius.
The radius works well on small spheres because it is within a 1/16” for a 2.5”sphere
1.25 is easy to find on the ruler 1.31 isn’t. Lets go to metric!! :)

The tapered holes are drilled at the 12 vertices of a regular isohedron
The small decorative holes are drilled in the centers of the 20 faces of the isohedron.

The reference below we need to find “a” the edge length 1.05=1/.951
51AC378C-78E6-4904-9993-0269213E458A.jpeg
 
Last edited:
hockenbery said:
The layout geometry is about finding isohedron inside the sphere.
An isohedron has 12 vertices and 20 faces

The true compass setting is a tiny bit bigger than the radius - about 1.05 x radius.
The radius works well on small spheres because it is within a 1/16” for a 2.5”sphere
1.25 is easy to find on the ruler 1.31 isn’t. Lets go to metric!! :)

The tapered holes are drilled at the 12 vertices of a regular isohedron
The small decorative holes are drilled in the centers of the 20 faces of the isohedron.

The reference below we need to find “a” the edge length 1.05=1/.951
View attachment 24947
Click to expand...

This illustrates the subtle difference between a mathematician ( exact answer) and an engineer (practical answer). Or when the exact analytical answer is unavailable the difference would be the best wrong answer (mathematician) versus an acceptable wrong answer (engineer).
 
In April 13, one member of our Bay Area Woodturners Association asked me about a Youtube that he saw about the making of a sphere with a star inside from one piece of wood, but it was in french and asked me if I could check it. I didn't get the URL yet but I started to do some search and to my big surprise found a book titled "Manuel du Tourneur" (Manual of the woodturner) published in 1816, 560 pages of instructions and step-by-step how to do anything you can think of. I found also the 296 pages of figures and drawings of the related book.
I dig a bit more and found out that the first 4 spheres inside a sphere was done in 1581 by Georg Wecker. When you think about it .... and they didn't have computers or $4,000 lathe.
Obviously some woodturners knew the existence of these manuals and could reproduced some pieces.

History
The earliest known reference to these items dates from 1581 by Georg Wecker, court turner to Duke Augustus, Elector of Saxony. Many of the modern tools and processes for these creations were outlined in 1816 by L. E. Bergeron in his 'Manuel du Tourneur' which included detailed drawings and explanations. These were further covered in 1881 by John Jacob Holtzapffel in volume IV of 'Turning and Mechanical Manipulation'. Chinese craftsmen started making them in the 18th century. Often made of ivory, these 'Chinese balls' were usually intricately carved and ornately decorated.

I attached and extract of both manuals.
 

Attachments

I went through several pages of the first pdf looking for a picture of what was being designed. They had angles measured at 20*30" 54' ! OK. I can measure that(not). At least the second pdf had pictures. I would think that any wood in my shop would absorb enough water over night or loose enough moisture while I'm working on it to move a degree or 2 let alone minutes or seconds. How in the world did they make those pieces? And I thought the pyramids were a mystery!
 
I enjoyed the labors of your research.
The work from 1500s in museums particularly the ornate ivory turnings was much of David Springette’s inspiration.

In Wood turning wizardry and other books David describes how to do many of the ball turnings.

I saw in the diagrams the ball chucks with screws to hold the balls and the inside parts in place for turning.
David usually uses wooden plugs with hot melt glue to hold the inside parts in place.
 
Yes, I noticed. I am so glad David was able to bring back to life in his books all these 18th century processes, tool designs and techniques with his own improvement. Without outstanding woodturners like Robert Bosco, Paul Texier, Clause Lethiecq, David Springett and others these remarkable processes, tool designs and techniques will be lost forever. It is always fascinating to go back some time to history.
 
I have a rock climbing friend, André, who enjoys making these Chinese balls on a tiny lathe in his basement. This is quite far away from a $4000 lathe. He loaned me his copy of David Springett's Woodturning Wizardry. Its quite another dimension. André does all his work with tiny scrapers. He was shocked to see my wife aiming a bowl gouge at a moving piece of wood on our lathe. The photos below give an idea of his equipment and pieces.

081129_Schwartz_002.jpg 080214_DD-Schwartz_003.jpg 080214_DD-Schwartz_007.jpg
 
hockenbery said:
The layout geometry is about finding isohedron inside the sphere.
An isohedron has 12 vertices and 20 faces

The true compass setting is a tiny bit bigger than the radius - about 1.05 x radius.
The radius works well on small spheres because it is within a 1/16” for a 2.5”sphere
1.25 is easy to find on the ruler 1.31 isn’t. Lets go to metric!! :)

The tapered holes are drilled at the 12 vertices of a regular isohedron
The small decorative holes are drilled in the centers of the 20 faces of the isohedron.

The reference below we need to find “a” the edge length 1.05=1/.951
View attachment 24947
Click to expand...
I will apply this to my next sphere, lol
 
Paul Lajoie said:
Thanks for the link Don, lots of fantastic information there but I’m not seeing a translation button. And I stopped speaking/ learning French many many years ago.
Click to expand...

There are add-ons for your browser that can do this. For Firefox there is Translate Man and Google Translator.
 
Paul Lajoie said:
Thanks for the link Don, lots of fantastic information there but I’m not seeing a translation button. And I stopped speaking/ learning French many many years ago.
Click to expand...
It is not always easy to OCR or translate text with pictures. On way will be to type in Word Doc the sentences that you want to translate and save your doc file. Open Google translate, select Documents, browse your computer, open your Word Doc, translate your Word Doc and cut and paste the translation. See attached. The translation is not always perfect.
 

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