Alan said.... <snip> As far as 'toe bob' goes I am not sure that I know what you mean by this. I think it is probably the toe down deflection of the club head caused by the centrifugal force on the offset cg of the club head. This force increases very rapidly near impact (it's proportional to the square of the head velocity) and is resisted mostly by a relatively short section of the shaft near the tip.
</snip> As I understand it there are two forces acting here, both the result of the CG of the clubhead being offset from the centerline of the shaft. First there is a moment working to align the CG of the clubhead with the shaft, which has the effect of rotating the trailing edge of the clubhead under. This has the effect of increasing the loft of the club as it goes through the ball, and acts in the plane of ball flight, commonly called dynamic loft. According to Tom Wishon's book, moving the CG 1/8" further back from the face will add about 7 feet to the trajectory. What is commonly called toe bob is the result of a similar, but orthogonal moment trying to align the CG of the club with the shaft in the direction from the toe to the heel. The net effect is to rotate the toe of the club around the CG, which bends the tip towards your toes i.e. in a plane that is orthogonal to the plane of ball flight. This is the effect that causes dynamic lie angle to be different from static lie angle. All of which combines to make it amazing to me that any of us can ever hit the ball "on the screws".... Royce
