So you begin cutting away down to the line in the center to create a half sphere. You have 3 different means to help you. First, there is the usual ‘ghost’ image. Turn away all that is not solid. Second, as your cuts approaches that center line, keep the ‘flat’ part parallel to each other.

07 Parallel Flat thumb

 

Thirdly, you have the middle line to carefully approach. When you are almost there, switch to a scraping cut. When you have cut/scraped away everything except just barely that line you have a perfect half sphere on a half cylinder.

08 Half Sphere Cylinder thumb

 

Then you need a second chuck with a tapered 64 mm hole, in which you jam the just turned spherical half of your ball, notice that it is not important to have it parallel or seated against the chuck, in fact having that space allows you blend the two halves together seamlessly and turn away the second half, again cutting down just to leave the line on the sphere. When you have reached that line your sphere is done. Sand to exact size.

09 Sphere in Chuck thumb

 

Of course, an alternative method is to use a sphere jig, and when great accuracy is needed, this is probably the way to go. We practiced with sycamore, and even turned our first Chinese ball with our hand turned sycamore spheres, but he then had some perfectly turned boxwood spheres for us to use also.

 

 

Part II: Turning the Chinese Ball

 

Now you want to mark the 12 points of a dodecahedron on your sphere.

10 Marking Sphere thumb

 

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Monday the 19th. Thanks for visiting Woodturners Unlimited.