I made my string ball with a medium density foam ball. The letter with my book mentioned the idea of using a whiffle ball.
Centrifugal Force - Forget JK and lets talk about the experience eveyone has had of twirling something on a strig and feeling it pull out against you. Between this excercise and the
first move down description it seems to me that the Bertholy swing is one that maintains a tension until release between the centrifugal force generated by the lead arm ('Rod') and the 'retaining' force of the trail arm ('Claw'). The 'Claw' is always pulling in to the center of the circle directed by the elbow trying to get to the belly button. This tension should increase with the beginning of the downswing thus increasing wrist cock.
I have not gotten to 'how you release' but this is a good description from the top to 6/100s.
Note that if your trail arm is above horizontal at the top of your backswing, the 'String-Ball' drill tells you that the initial motion of your lead arm is to the back away from the ball ala Dunigan. However the 'Claw' will not allow a release of wrist cock or anything like the motion Dunaway demonstrates. The 'Claw' will put the club onto a much flatter plane as the gap between elbow and side is eliminated.
So centrifugal force is 'used' to power the club and the 'Claw' retains that power until the proper delivery time. When you see Moe at clinics demonstrating how his swing is a perfect pendulum by holding the club at the grip and letting it swing note that the center of that swing is the butt of the club and not his shoulder. This is exactly what would happen with the string ball though the demo may make you think of Jones. Moe is just slowing it down but if you don't know about Bertholy and the 'String-Ball' you may not relate to the demonstration the way Moe may with his
extensive experience with Bertholy.
Peter
