Spheres - how do we make them?
  
   

The choice of good material is important.

This is serpentine marble.

 
   
   

We start by making a cube.

 
   
   
The sides of the cube must be cut to exactly the same length.
   
   
Here we are cutting off the edges, and cutting off the edges, and cutting off the edges...
   
   
This is as round as it gets - in the saw.
   
   
Cutting by hand against a diamond wheel, for as long as you can, until all sharp edges are gone.
   
   
Almost round?
   

Silicon carbide with three different degrees of coarseness.
80
220
600
  
   

Here the stone is rotating between two motors of opposite directions.

Silicon carbide and water drips down so the stone is cut on its highest point.

This step needs constant supervising.
   
   

After many hours of rotation our stone has got a proper shape of a sphere.
   
   
After rotation with silicon carbide of a finer grain, all rough scratches disappear.
   
   
One more step
   
   

All polished and done!

It takes 3-5 days to make a sphere.

More spheres