Pivot center

[Jeff]

Yoda - you wrote-: "Trust me, Jeff, that rope being swung by Jason Zuback had no trouble staying straight. If you had some footage of that event, I'm confident your 'captured images' would attest to that. Swing a pen knife 'round and 'round on a string, and you'll get the idea."

Jason had a lot of trouble keeping that flexible shaft straight at start-up - as one would when dealing with a pen-knife attached to a string. When the penknife is already in a state of circular motion, the string would definitely be straight. However, if the penknife was stationary at start-up, it has inertia, and when the penknife is first pulled by the the string, the string is not in a perfect straight line relationship between the hands centerpoint-of-rotation and the penknife. Jason's clubhead lagged far behind the hands and the flexible shaft was always curved until the clubhead's speed reached a certain level of speed that could then produce a CF that could balance the CP-force exerted by the hands. From that point onwards, the clubshaft was straight.

Another point - when Jason's timing was off the clubhead bypassed his hands in a flipping motion near impact, and the flexible clubshaft was no longer straight. That happened especially if his hands slowed down just prior to impact.

Try swinging a penknife at the end of the string and then abruptly stop the hand motion - the string will not remain straight and the penknife will no longer remain in its circular orbit!

Jeff.

[Jeff]

Yoda - you wrote-: "Try swinging the Clubhead without the "connecting" Clubshaft. Let's see what kind of orbit you can create."

I could retort - try swinging the clubshaft without the hands moving along a circular path and see what kind of clubhead orbit one can create.

Jeff.

[johnnyg]

can't jeff go and start his own web site and leave us alone? who gave him his own place here?

[Jeff]

Clarifying statements regarding the string-ball example.

When I state that an additional force can throw the ball off its orbit, the force doesn't come from the string. The force can occur when the hands do not constantly move along a circular path at a smooth rate of speed - which provides the centripetal force. So, the following factors can disrupt the ball in its orbit.

1) Sudden hand over-acceleration movement (equivalent to Hk's over-acceleration idea).
2) Sudden hand deceleration movement (equivalent to quitting on the shot).
3) Hand motion becomes non-circular (equivalent to HK's steering idea).
4) Sudden change in the radius of the hands' circular motion (which causes a sudden non-circular motion as the hands move to an orbit of different radius).

Also, when I state the clubshaft's flexibility causes the clubhead to move off its orbit, I mean that it allows it. The fundamental cause is the slowing of the hands pre-impact, and the shaft flexibility allows the clubhead to move out of its perfect circular path.

Here is a strobe photo of Bobby Jones swing.



What causes the clubhead arc to be circular? The answer - the circular motion of the hands. Anything that disrupts the smooth circular motion of the hands (over-acceleration, quitting, steering) will disrupt the clubhead's circular motion. An overly flexible clubshaft only makes these problems more apparent.

Jeff.

[12 piece bucket]

Clarifying statements regarding the string-ball example.

When I state that an additional force can throw the ball off its orbit, the force doesn't come from the string. The force can occur when the hands do not constantly move along a circular path at a smooth rate of speed - which provides the centripetal force. So, the following factors can disrupt the ball in its orbit.

1) Sudden hand over-acceleration movement (equivalent to Hk's over-acceleration idea).
2) Sudden hand deceleration movement (equivalent to quitting on the shot).
3) Hand motion becomes non-circular (equivalent to HK's steering idea).
4) Sudden change in the radius of the hands' circular motion (which causes a sudden non-circular motion as the hands move to an orbit of different radius).

Also, when I state the clubshaft's flexibility causes the clubhead to move off its orbit, I mean that it allows it. The fundamental cause is the slowing of the hands pre-impact, and the shaft flexibility allows the clubhead to move out of its perfect circular path.

Here is a strobe photo of Bobby Jones swing.



What causes the clubhead arc to be circular? The answer - the circular motion of the hands. Anything that disrupts the smooth circular motion of the hands (over-acceleration, quitting, steering) will disrupt the clubhead's circular motion. An overly flexible clubshaft only makes these problems more apparent.

Jeff.

If you want the hands to move in a constant consistent arc . . . then why would you want to move off the ball???? That's the WHOLE POINT OF THE CENTERED PIVOT . . .

[pistol]

can't jeff go and start his own web site and leave us alone? who gave him his own place here?

Yes cause he is entertaining..personally i use the right gonad as pivot center

[Jeff]

John

You wrote-: "who gave him his own place here?"

The answer is obviously Yoda. He made that decision independently. I suddenly found this "Golf By Jeff" section recently. If he wants to remove this section from his website at any time, he doesn't need anybody's permission because it is his website.

While this "Golf By Jeff" section exists, I will ask questions, freely debate issues, and never personally insult any forum member (by means of an ad hominem attack) for harboring a contrary point of view.

Jeff

[KOC]

Jeff,

A question for you. Do you believe in 10-23 different hand path?

[Jeff]

KOC - I don't really believe that the hands ever move in a straight line in a full golf swing. The hands obviously move in an U-shaped arc and during the "straight section" of the U-shape, the radius of the hand arc's circular motion is so large that it appears "straight".

Jeff.

[no_mind_golfer]

That a real golf swing in that add?

Certainly no hands slowing going into impact there...

(bobby jones's driver swing either for that matter)