The Rules Of Golf Copyright© 2005
The United States Golf Association

Rule Appendix II, 5, C (Current) Note: Exception regarding Punch Marks has been omitted from this article.

Impact Area Markings
Markings in the impact area must not have sharp edges or raised lips as determined by a finger test. Grooves or punch marks in the impact area must meet the following specifications:

(i) Grooves. A series of straight grooves with diverging sides and a symmetrical cross-section may be used (see Fig. 10).
. The width and cross-section must be consistent across the face of the club and along the length of the grooves.
. Any rounding of groove edges shall be in the form of a radius which does not exceed 0.020 inches (0.508 mm).
. The width of the grooves must not exceed 0.035 inches (0.9 mm), using the 30 degree method of measurement on file with the United States Golf Association.
. The distance between edges of adjacent grooves must not be less than three times the width of a groove, and not less than 0.075 inches (1.905 mm).
. The depth of a groove must not exceed 0.020 inches (0.508 mm).

The proposed Rule to replace Appendix II, 5, C regarding grooves on clubs, if adopted, will neutralize the spin benefit generated by U-grooves according to the USGA. Their position is that skill should be the predominant factor in golf competition, not equipment.

That position could transcend into a lengthy discussion about C.O.R. of driver faces and golf ball performance but we will leave that for another time. With regulations in place for both of those factors, the USGA now believes it is time to control spin from shots hit out of the rough.

Provisions call for current wedges to be grandfathered for 10 years but with a stipulation that tournaments for "elite players" will impose the use of the new Rule on wedges in 2009. Manufacturers will have to switch to the new regulation for all production on January 1, 2010.

We published the new USGA Proposed Rule in our April/May Club Repair News. You can view it here.

Most significant about the proposed change requires groove edges to have an effective radius of not less than 0.010 inches. Therefore grooves cannot have sharp edges or raised lips. This differs from the current rule, which calls for any rounding of edges not to exceed 0.020 inches but did not eliminate sharp edges. Essentially, the Rule change stays the same for groove depth, width and distance between edges of adjacent grooves.

So how do you know if you are playing with conforming grooves in your wedges? The USGA has published guidelines for measuring grooves. They call it the "Ink and Scratch Method". This test is designed to be performed in the field by rules officials using a black marker pen, carbide 'Marking Tool", magnifier, steel ruler and alcohol wipes.

The USGA Guidelines for this test is now posted in our TechReport Library.