Love it when you post these little gems, but why the "toe" of the Club, and not the Sweet Spot?
I used the phrase "Toe of the Club" because that is exactly the phrase Homer Kelley used. I wondered the same thing as I wrote the post and here would be my answer (not his):
Remember, during Release, both the Clubshaft and the Toe of the Club are rotating around the Sweetspot. And the Toe of the Swinger's Club is rotating counter-clockwise trying desperately to get 'in line' with the Sweet Spot and #3 Pressure Point for Horizontal Hinging through Impact. Hence, Homer's reference to the Toe causing the Release Bend.
Interesting sidelight:
That's why those old-timey wooden golf clubs were made with such long Toes. They were virtually impossible to Angled Hinge!
In a 1981 GSEM Class discussion, Homer Kelley referred to two types of Clubshaft Bend for Swingers. The first -- "Acceleration Bend" -- stresses the top of the Shaft during the Start Down. During the second -- "Release Bend" -- the stress is opposite the Acceleration Bend as the toe of the Club attempts to get in line with the #3 Pressure Point.
The Hitter's stress is at the back of the Shaft and does not vary.
Thanks Lynn! Great addition to this thread!
Just for my curiosity can you or someone else reference where he says the "wallop of centrifugal force" in the book- I believe it's there but am blanking out where to look.
Actually, never mind- I found it in 6-F-1 "Right" Timing...."Acceleration ceases when the speed it has produced equals that of the Thrust, and though the thrust is still present and able to maintain Velocity, it loses the flexed, stressed Clubshaft (Hitters) and the wallop of the Centrifugal Force (Swingers)."
Just for my curiosity can you or someone else reference where he says the "wallop of centrifugal force" in the book- I believe it's there but am blanking out where to look.
Actually, never mind- I found it in 6-F-1 "Right" Timing...."Acceleration ceases when the speed it has produced equals that of the Thrust, and though the thrust is still present and able to maintain Velocity, it loses the flexed, stressed Clubshaft (Hitters) and the wallop of the Centrifugal Force (Swingers)."
Mike-O-the-Psycho,
6-F-1 “RIGHT” TIMING Maximum Force is delivered by maximum Thrust (muscular and/or centrifugal) near – but prior to – full extension.
Acceleration ceases when the speed it has produced equals that of the Thrust, and though the Thrust is still present and able to maintain Velocity, it loses the flexed, stressed Clubshaft (Hitters) and the wallop of the Centrifugal Force (Swingers).
In a 1981 GSEM Class discussion, Homer Kelley referred to two types of Clubshaft Bend for Swingers. The first -- "Acceleration Bend" -- stresses the top of the Shaft during the Start Down. During the second -- "Release Bend" -- the stress is opposite the Acceleration Bend as the toe of the Club attempts to get in line with the #3 Pressure Point.
The Hitter's stress is at the back of the Shaft and does not vary.
It's interesting that he mentioned both of these bending features because some of the guys doing advanced shaft fitting take into account the bending characteristics at different points (zones) in the shaft. Specifically, the swing tempo may be considered for "Acceleration Bend" (using your terminology) and release quality for "Release Bend".
As I mentioned earlier the "Release Bend" is generally toward the target for almost all golfers (for full swings) and is caused by the centrifugal force due to the clubhead speed pulling outward on the shaft through it's center of gravity - thus, CoG wants to line up with the shaft axis bending the shaft forward. That's why offset heads tend to hit the ball higher and could slightly correct a fade because the CofG is further behind the shaft and the shaft will tend to bend more forward with these heads. Ok - maybe too much information there.
Still a little dubious on the impact deceleration concept - but it may be a "real vs feel" thing in that it helps to think about accelerating through impact to avoid quitting, throwaway, etc.
It's interesting that he mentioned both of these bending features because some of the guys doing advanced shaft fitting take into account the bending characteristics at different points (zones) in the shaft. Specifically, the swing tempo may be considered for "Acceleration Bend" (using your terminology) and release quality for "Release Bend".
As I mentioned earlier the "Release Bend" is generally toward the target for almost all golfers (for full swings) and is caused by the centrifugal force due to the clubhead speed pulling outward on the shaft through it's center of gravity - thus, CoG wants to line up with the shaft axis bending the shaft forward.
"'Release Bend' is generally toward the target for almost all golfers."
It's interesting that he mentioned both of these bending features because some of the guys doing advanced shaft fitting take into account the bending characteristics at different points (zones) in the shaft. Specifically, the swing tempo may be considered for "Acceleration Bend" (using your terminology) and release quality for "Release Bend".
As I mentioned earlier the "Release Bend" is generally toward the target for almost all golfers (for full swings) and is caused by the centrifugal force due to the clubhead speed pulling outward on the shaft through it's center of gravity - thus, CoG wants to line up with the shaft axis bending the shaft forward. That's why offset heads tend to hit the ball higher and could slightly correct a fade because the CofG is further behind the shaft and the shaft will tend to bend more forward with these heads. Ok - maybe too much information there.
Still a little dubious on the impact deceleration concept - but it may be a "real vs feel" thing in that it helps to think about accelerating through impact to avoid quitting, throwaway, etc.
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Some pictures showing these bends would be nice... or are they too subtle to see?
In a 1981 GSEM Class discussion, Homer Kelley referred to two types of Clubshaft Bend for Swingers. The first -- "Acceleration Bend" -- stresses the top of the Shaft during the Start Down. During the second -- "Release Bend" -- the stress is opposite the Acceleration Bend as the toe of the Club attempts to get in line with the #3 Pressure Point.
The Hitter's stress is at the back of the Shaft and does not vary.
I guess then, that the 7Th edition may explain this. Then the existing 6-C-2-A section is no longer completely applicable to a swinger.
I'll buy new clubs with extra flexible shafts to get that added "Kick" the shaft will supply as I stop moving my hands to allow the shaft to take over through impact. Hmm? Or I can change to a Hitting stroke pattern.
I guess then, that the 7Th edition may explain this. Then the existing 6-C-2-A section is no longer completely applicable to a swinger.
I'll buy new clubs with extra flexible shafts to get that added "Kick" the shaft will supply as I stop moving my hands to allow the shaft to take over through impact. Hmm? Or I can change to a Hitting stroke pattern.
I would have thought so too, and if only a good shaft fitting were that simple, but I probably should have added:
Wishon, "The Search for the Perfect Golf Club", 2005
Chapter 4 Myths-
Myth #3 - "The third myth to bury is that the forward flexing of the shaft just before impact (which some people mistakenly call "buggy-whipping" or "kicking") increases the speed of the clubhead"......
I started this thread by saying I'm much more up on clubfitting than TGM (trying to change that) and that is probably evident in my posts, but I think there's opportunity for incorporating concepts from both to increase one's ability to teach and/or learn to play this game.
What does HK mean in 2-E and 2-M-1 regarding a "prestressed" shaft? He seems to imply it's bent but I'm not sure in which direction. Also, the way I read it he is saying this condition will reduce Impact Deceleration(?).
The reason I ask is I've been into clubmaking a lot longer than TGM and on the face seems to conflict with my understanding of the physics of impact. For example, Cochran & Stobbs in "The Search for the Perfect Swing" showed that there was basically no influence by the player or shaft during impact and that the exiting ball speed is determined solely by the clubhead speed just prior to impact (assuming square contact etc.). This doesn't jive with the idea of "resisting impact deceleration" so I'm missing something.
Maybe I'm reading it too literally - he could be just trying to emphasize not quitting and reducing throwaway and such but he uses rather specific scientific terminology so I'm not so sure.
I have never read SftPS and don't know how C&S did their analysis. Basically, as far as I can tell, hitting the ball with a pre-stressed shaft should allow more momentum transfer to occur during impact. The shaft is just a spring. When a spring is compressed as far as it will go, it becomes effectively stiffer (up to the yield point of the material in question).
In addition, how a players hands brace the club at impact may provide a stiffer interface as well. That is one of the important aspects of the bent right and flat left wrists at and through impact.
Now for the kicker. All of this may not matter, from a momentum transfer point of view, if the speed of sound in the shaft is small enough such that the vibration or feel of impact occurs after the ball has left the face. At least in the case of steel rods (not exactly a shaft, but maybe a good approximation???), the speed of sound would allow the feel of impact to reach the hands roughly halfway through impact. As you can see, it is a very complicated interaction and highly dependent on shaft material properties, ball material properties, and clubhead speed at impact.
FWIW, regardless of how this impact momentum transfer stuff works out, in the book "The Physics of Golf" by Theodore Jorgensen, his model (matched against the swing of a tour player) showed that the most efficient transfer of clubhead speed to ball speed occurred when the club was at a 15* angle (ahead) relative to the ball at impact. That is essentially what one gets with a bent right wrist and flat left (more or less).
__________________ _________________________________
Steph
Distance is Magic; Precision is Practice.
Hybrid Mode
