[Rob2197]

According to Ralph Maltby (Golfworks), there was no difference in the performance of two sets of irons he built -- one with grooves and the other with no grooves.

On the other hand, I know that Jack Nicklaus and Arnold Palmer believe that square grooves give more spin on wedges than v-grooves.

Perhaps Billy McDonald of Henry Griffits could give us some insight.

I've seen testing done on it. I wish I could remember where, sorry. It was pretty substantial though. I think like 7-10% distance loss and as much as 15% spin loss on some irons.

It just makes since that if you are striking down with a descending blow and the ball actually rolls up the face of the iron that the grooves have to have some influence on that striking and rolling action. I know a lot of pros believe that square grooves give more spin and that many often have their clubs regrooved.