Abstract: The invention provides an insert for a golf club shaft that stiffens and strengthens the tip of the shaft and reduces oscillations in the shaft during the swing of the club and dampens vibrations due to impact with the golf ball and/or the ground. In preferred embodiments, the insert comprises a rod portion that increases stiffness and foam and adhesive portions that dampen vibration.

Abstract: A reconfigurable golf club head and a method for fitting a golf club to a golfer are described. Optimum club head design parameters are determined based on one or more of the following factors: the golfer's swing characteristics, ball flight trajectory tendency information, course and weather conditions, golf ball dynamic flight characteristics and personal preferences. Lookup tables or mathematical algorithms, such as impact and trajectory simulations, may be used. Features of the reconfigurable golf club head include a replaceable face plate to adjust the profile of the club face and a replaceable weight plate to adjust the club head center of gravity and inertia properties. Adjustable characteristics of the club face include the loft angle, bulge radius and roll radius.

Abstract: The preferred orientation, or planar oscillation plane, of a golf club shaft is located by measuring the oscillation of the shaft when an impulse is applied. Preferably, the out-of-plane oscillation is measured at a large number of angular positions about the shaft axis, and the principal planar oscillation plane is identified by that pair of opposed angular positions in which the out-of-plane oscillation is smallest. The location of the preferred orientation may be marked on the shaft and used to assemble a golf club with the planar oscillation plane in a predetermined orientation. The straightness of the shaft can also be determined by deriving its spring constant from its oscillation frequency and then measuring the restoring force when the shaft is deflected by the same nominal amount at different angular positions; differences in restoring force can be attributed to differences in actual deflection distance resulting from lack of straightness.

Abstract: The preferred orientation, or planar oscillation plane, of a golf club shaft is located by measuring the oscillation of the shaft when an impulse is applied. Preferably, the out-of-plane oscillation is measured at a large number of angular positions about the shaft axis, and the principal planar oscillation plane is identified by that pair of opposed angular positions in which the out-of-plane oscillation is smallest. The location of the preferred orientation may be marked on the shaft and used to assemble a golf club with the planar oscillation plane in a predetermined orientation. The straightness of the shaft can also be determined by deriving its spring constant from its oscillation frequency and then measuring the restoring force when the shaft is deflected by the same nominal amount at different angular positions; differences in restoring force can be attributed to differences in actual deflection distance resulting from lack of straightness.

Abstract: The preferred orientation, or planar oscillation plane, of a golf club shaft is located by measuring the oscillation of the shaft when an impulse is applied. Preferably, the out-of-plane oscillation is measured at a large number of angular positions about the shaft axis, and the principal planar oscillation plane is identified by that pair of opposed angular positions in which the out-of-plane oscillation is smallest. The location of the preferred orientation may be marked on the shaft and used to assemble a golf club with the planar oscillation plane in a predetermined orientation. The straightness of the shaft can also be determined by deriving its spring constant from its oscillation frequency and then measuring the restoring force when the shaft is deflected by the same nominal amount at different angular positions; differences in restoring force can be attributed to differences in actual deflection distance resulting from lack of straightness.