Appropriate for diameter of project ( 6-8-in diameter, 400 rpm. )
Note:
There are three axes involved in turning a sphere
Place prepared blank between centers and turn to a cylinder using a roughing gouge.
Make cylinder length equal to the diameter by performing the following
Mark the center of the cylinder all the way around the circumference
Measure and mark out 1/2 the diameter from the center line on each end
Using a parting tool, part down each end to approximately 1 1/4-in diameter
Remove waste wood on outer edges down to parting tool diameter and mark cylinder 1/2-in on each of center line all the way around circumference ( these are used as reference marks )
With a gouge, round over corners toward outer edges to form first arc of the sphere and with a parting tool part each tenon down to 1/2-in diameter, continuing from the original 1 1/4-in diameter. Do remove reference marks. If so, put them back on and continue. This is axis number one.
Remove project from the lathe and saw off large part of both tenons
Install chucking fixture and position sphere on second axis by rotating 90 degrees from original position
Using a gouge, turn away small tenons and excess material, observing reference lines, stopping as soon as tool approaches reference lines. This process forms the uniform, even arc of the second axis
Draw a center line and a line 1/2-in each side of center line all the way around the circumference and reposition the sphere 90 degrees by rotating it horizontally so the intersecting marks you see are in the chucking fixture
Turn away excess material, observing both sets of reference lines. This completes the third axis. Repeat the process until desired results have been obtained
Sand sphere on the lathe at different axes until smooth
