Play Better Golf.
A number of years back (1997 or 1998 I think) I received a call from Corey Pavin. He was concerned with the grooves on his irons because he claimed he was hitting more fliers than he normally did. He also said he could not predict when it was going to happen, since a number of what he felt were normal fairway shots ended up as fliers. Corey sent his irons into me and the first step was to check out the grooves.
No player could play consistently well with the faces Corey once had.
Here is what I found: The groove type was a “V” groove but it was very shallow. The maximum groove depth allowed by the USGA is .020” and the maximum groove width is .035.” Corey’s irons had groove depths that ranged from .005” to .007” deep. This was a problem that was compounded by the fact that with this shallow a “V” groove depth, the width of the groove was also quite narrow. Finally, the face surface was smoother than normal because of a very light bead blast used to define the face area vs. a normal sand blast that is rougher. Also, after hitting quite a few balls, the surface was smoother yet. I also felt that his leading edges were too sharp.
Technical note here: The very shallow and narrow grooves created two problems. The first was that the grass juices or any water trapped between the club face and the ball could not escape. Think worn tires on wet pavement. Secondly, the friction component between clubhead and ball was seriously reduced because of the small grooves and also the very smooth face. Friction adds bite to the ball to reduce or eliminate the flyer effect. Corey was basically hitting some degree of flyer with every shot unless the playing conditions were perfectly dry at impact.
I called Corey back and explained the facts to him. Basically, no player could play consistently well with faces like this and I had definitely found his problem. I recommended the following solution to him: I would re-cut all the face lines to .018” deep (the PGA Tour checks depth on request, so a .002” cushion is advisable). I recommended that his #2 through 6 iron stay in “V” grooves but that I wanted to re-cut his #7 through sand wedge with “U” grooves. He finally agreed with the “U” groove thing after some convincing. I knew I had no chance on getting “U” grooves on all his irons, so I didn’t even try. I did however recommend to him that the leading edges on all the irons needed to be rolled slightly more and back up into the face and this he agreed with. Note that the GolfWorks has a special machine that I built that mills in the new modified grooves. Over the years hundreds of other Tour players have used this service including Jack Nicklaus, Raymond Floyd, Tom Watson, Tom Weiskopf and Lee Trevino.
So, Corey received his irons back and a few weeks later I received a very nice and long note explaining that the look and the playability of the irons was great. He simply could not believe the difference that proper grooves could make in hitting a golf ball the way he wanted to.
The lesson here is that one can never assume that the irons they are playing have correctly designed and manufactured grooves. We all need the best grooves to get the best playability.
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