[BerntR]

What do you mean that "This will move the sweet spot far up the shaft"? How does the Sweetspot move? Do you mean that CF is not pulling on the COG of the Club?

This is a fairly simple question I guess, but the answer requires quite a few clarifications.

First of all, the sweet spot of the clubhead is not the same as the sweet spot of the whole club. If you hit the sweet spot of the clubhead there will be less of a shock effect through the shaft to your hands. But the sweet spot of the whole club is not in the clubhead sweet spot, and you will get a shock in your hands, because you're basically hitting the ball outside the sweet spot of the whole club.

Second, mass and COG is not the appropriate approach to study sweet spot of rotating objects such as a golf club. You need to look at the distribution of kinetic energy (mass * velocity^2). The mass that moves faster counts more than the mass that moves slower. That is easy to feel by simply swinging fast and slow. The fast swing speed produces a much "heavier" club.

Mass is the mother of COG, and kinetic energy is the mother of MOI (Moment of inertia). More about MOI here: http://en.wikipedia.org/wiki/Moment_of_inertia

The COG of the whole club is by the way in the shaft a few inches above the hosel. If you move your hands as fast as the clubhead that's also where the MOI center will be.

Since the mass that moves faster counts more, the MOI center will get closer to the clubheads sweet spot (and beyond??) when yor clubhead speed /hands speed ratio is high. And it moves up towards the COG when this ratio is low.

If you don't have a proper release, the MOI center will be relatively high and you will feel a lot more impact resistance. I can still remember the first time I hit a 3 iron and the first time I hit a driver. I may not have the most vicious release now either, but back then it was really slow. The resistance at impact was massive.

Here's food for thought: Since the ratio of hand speed to clubhead speed changes throughout the swing, the MOI center will not be in the same place on the club from startdown to impact.

Fore left!