The forum machinists are showing their rank...
Take the allen head bolts out of the front and the back vice jaws on either the left or the right side.
Place ball into jaw, locating it in the holes. Clamp. Enjoy... If the diameter is too large, then make some aluminum soft jaws with holes in them to hold your sphere.
Don't ever use wood, rubber, or any other stupid soft drek to clamp a part under machining forces.