Subject: Dissimilar Bending and Twisting Properties in Golf Shafts

This Notice supercedes the Notice of Nov. 13, 1990, same subject.

Rule 4. Clubs (Preamble) states:
Where a club, or part of a club, is required to have some specific property, this means that it must be designed and manufactured with the intention of having that property. The finished club or part must have that property within manufacturing tolerances appropriate to the material used.

Form and Make of Clubs states in part:
a. General
... The club shall not be substantially different from the traditional and customary form and make ...
b. Shaft
The shaft shall be straight, with the same bending and twisting properties in any direction ...

Appendix II
DESIGN OF CLUBS states:
4-1b. Shaft
Bending and Twisting Properties
At any point along its length, the shaft shall: (i) bend in such a way that the deflection is the same regardless of how the shaft is rotated about its longitudinal axis; and (ii) twist the same amount in both directions.

As stated in the Notice referenced above, manufacturing tolerances together with intent in design have been considered to be relevent to the enforcement of this Rule. The language in the Preamble was added in 1992 to emphasize this point.

The intent of the Rule, as stated previously, is for shafts to perform symmetrically with respect to these properties, and the goal from a manufacturing standpoint should be to achieve this objective to the extent that it will make no difference how a particular shaft is oriented in a golf club.

Since the 1990 Notice, there have been several articles advocating the identification and orientation of irregularities in shafts. The stated purpose of such a process in most cases was to "neutralize" the potential effect of any such irregularities with regard to the intended performance of the shaft during the swing.

A few individuals have stated, either through patent design or claims based on such patents, that the process of identifying irregularities in shafts and orienting those irregularities in certain ways can produce results that are contrary to the intent of the Rule, e.g. correct hooks or slices.

The Implements and Ball Committee has reviewed this situation with respect to the intent of the Rule and the claims and practices of those who advocate or believe that maufacturing irregularities can be used to affect performance.

Previously, there was a reluctance to condone the advertising or other public acknowledgement to this effect by shaft manufacturers, other OEMs, and club makers. However, shaft manufacturuers have not yet been able to assure us that they can maintain tolerances which greatly minimize or eliminate asymmetries in twisting and bending.

The Committee has therefore concluded that the process of orienting a shaft with the intent of causing it to perform as if it were symmetrical would not be inconsistent with Rule 4-1b.

It would be impractical to formulate a standard that manufacturers could meet without revising their processes for making shafts. Consequently, the Technical Department will intensify its monitoring of shaft design and manufacture. If it appears that a manufacturer is maintaining wide tolerances for the purpose of affecting performance, the manufacturer will be asked to correect the situation.

Manufacturers are encouraged to contact the Technical Department with respect to any information regarding manufacturing process or tolerances that may be of assistance in the monitoring process.

Yours sincerely,

Frank W. Thomas
USGA Technical Director