Subject: Dissimilar bending properties in golf shafts

Rule 4-1b states:

"b. SHAFT
The shaft shall be generally straight, with the same bending and twisting properties in any direction, and shall be attached to the clubhead at the heel either directly or through a single plain neck or socket. A putter shaft may be attached to any point in the head."

Appendix II 4-1b covers this in a little more detail and states:

"BENDING AND TWISTING PROPERTIES
The shaft must be so designed and manufactured that at any point along its length:
(i) it bends in such a way that the deflection is the same regardless of how the shaft is rotated about its longitudinal axis; and
(ii) it twists the same amount in both directions."

Because manufacturing tolerances and intent in design were considered to be the bounds of enforcement, the Rule, as printed above and adopted in 1984, was not quantitatively specific.

It has come to our attention that shafts are being produced which possess a spine of sufficient consequence that it needs to be identified and oriented in the clubhead in such a manner as to make a difference in the club performance. The USGA believes that if there is need to identify the location of a spine in a shaft it is of sufficient consequence to violate the Rule quoted above.

Accordingly, we request that manufacturers review their production methods and take the necessary precautions and measures to eliminate the spine phenomenon, at least to the extent that it is no longer of sufficient consequence to need identification.

We invite your response to this request and hope that your cooperation will eliminate the need for further action.

Frank W. Thomas
USGA Technical Director