The USGA is in the comment period for the proposed "zip-grooves" rule
It's not outlandish to suggest that many in the golf industry fear the world might come to an end Aug. 1. That's the deadline the U.S. Golf Association has set for receiving comment on its proposal to change the stipulations governing grooves on clubfaces. The proposed change would potentially reduce typical groove volume by half and double the radius of today's sharpest groove edges (such as these "zip grooves" on the new Cleveland CG12 wedges). Manufacturers are having tour players test clubs that feature prototype designs of the duller grooves, and as one insider says, "The tour players are saying they'll be able to adjust to it, but really they have no idea what this change will be like." Those are not idle estimates. The proposed groove rule has been called a rollback by some in the industry, but because today's golf balls generally spin less than the golf balls of the pre-1990s era of dull grooves, some shots could end up spinning much less than any current young player has experienced.
The bad news for tour players is that if the change happens as proposed, it will be implemented on tour with the start of the 2009 season, giving them only a year to figure out how to play shots from the rough.
The good news for us hacks, however, is that we could have at least 10 years (under a grandfather clause) to enjoy the current groove designs. Manufacturers haven't scaled back wedge performance yet even with the USGA's proposed rule looming.
The key element seems to be a microscopic design feature called groove-edge radius, which describes how sharp the edges of a groove are constructed. The newest wedges all have groove-edge radii that are about .010 inches, and many of the most aggressive grooves are near a radius of .005 inches. (A tip: If you want to take advantage of the latest groove technology, opt for the high-spin versions of multilayer urethane-covered balls. Anything less than that, and your ball might as well be a neatly formed piece of shale. The sharp grooves really do interact with the soft cover. Surlyn-covered balls are another story. The USGA's report on Spin Generation states that "For the Surlyn-covered ball, neither the edge radius nor the groove shape appears to influence spin.")
Equipment companies are still issuing comments to the USGA, and, not surprisingly, most companies seem opposed to the idea. They cite an increased manufacturing cost, an immediate devaluing of trade-in equipment and the difficulty of enforcing a rule that has no field test. In addition, there is a concern among manufacturers that the USGA is rushing through this rule, and that there is no direct evidence or connection that the proposed solution (duller grooves) will solve the perceived problem (a lack of a correlation between driving accuracy and success on the PGA Tour). Many, like Benoit Vincent, TaylorMade's chief technical officer, are urging more player testing. "Nothing in the rule says what is going to be the ideal result after this change," he says. "What is the USGA accountable for? How does the USGA know it's going to work?"
ENEMY NO. 1: A drill bit?
[#image: /photos/55adafbab01eefe207f8a51d]|||Drill Bit|||
A sharp groove is not so much club design as it is the manufacturing technique of your milling machine. Enter the drill bit (above) that Cleveland Golf is using on its new CG12 "zip groove" wedges. Cleveland's Scott Carlyle says the challenge wasn't cutting the groove: "We could do 10 or so wedges pretty easily, but if we got too aggressive, the bit would break off in the middle of a groove."