Frequency is defined as the shaft “flex feel” of each club to the golfer. It is determined by the flexing characteristics of the club shaft. Frequency is a proven and accepted method of club assembly. Which can provide golfers with a set of irons or woods that will best control trajectories. The “frequency” of an assembled club is measured in CPM (Cycles Per Minute) on a special machine called a “frequency analyzer”.
We test for frequency, because not all shafts that are marked “stiff” are really stiff. Consequently, not all shafts marked “regular” are necessarily regular. This is true for all of the “stiffness” letter markings. The inconsistency can occur with both graphite and steel shafts, however, it appears more prevalent with graphite shafts.