Golf Club Definitions

The Engine of the Golf Club:  The engine of the golf club is the golfer. The golfer is the entity that provides the power and creates the motion. The golfer is the engine… end of story.

 The Grip of the Golf Club:  The grip is what connects the golfer to the club. The grip must provide a comfortable, snug, and secure connection to the golf club. It must fit in such a way that it helps the golfer impart as much energy as possible into the rest of the club without distraction or interference. And of course, as many women golfers have informed me, the color must match their favorite decor! Yes ma’am I will do my best to make it so!

The Shaft of the Golf Club:  The shaft is the transmission of the golf club. The shaft determines the length, overall flexibility, and bend profile of the club. A properly fit shaft is geared to the golfers swing, just as a transmission is properly geared to the engine of a car. A shaft that properly fits the golfer allows the golfer to impart the maximum amount of energy into the club possible, with the proper trajectory, to produce the farthest distance, while achieving the best accuracy. Anything less is a waste of energy, time, money, and strokes.

 The Head of the Golf Club:  The head of the golf club is like a tire on a car. It is where the rubber meets the road, okay in this case where the steel meets the iothane or urethane cover, but the principal is the same. It is the main interface with the golf ball, and must achieve the best friction transfer with the ball possible, to produce the best energy transfer, to properly compress the ball, to create the best ball speed, with the proper launch angle, with the proper ball spin, to achieve the best distance and accuracy. Oh yes, and please note, that the grooves in a golf clubhead (NO MATTER THE SHAPE), do NOT create spin. Spin is determined by loft, angle of attack, and friction between the clubface and the ball. The grooves in a golf club perform the exact same function as the tread in the tires of a car (one reason I used a tire as a comparison). They channel away water and debris from the face (just like the tread in a tire does on the road), to allow the rest of the clubface to have as much friction with the ball possible. In fact (and it has been measured and proven), that in the case of a dry environment with little to no debris, a clubhead with no grooves at all will generate more spin than one with grooves. If you don’t believe this, then ask a drag race car driver why their rear tires have no tread, and they will tell you the same thing… better friction on dry pavement. Interestingly enough, a wedge with U-grooves is now illegal on tour, but a wedge with no grooves is not… go figure.

Shaft Spine:  The golf shaft spine (mainly applicable to steel shafts), is the seam or weld of a steel shaft, which is typically aligned with the target line of the club when assembled (perpendicular with the face of the club). A steel shaft begins as a flat sheet of metal and is formed into a tube, either graduated or in steps. The seam or weld where the resulting tube is joined together is referred to as the spine of the shaft. As the steel shaft flexes (bends) the spine wants to literally pop or twist itself toward the leading edge of the bend, sometimes violently. Graphite shafts however are typically wound around a mandrill, in different layers, with different shapes strategically placed along the shaft. This is how the manufacturer produces the graphite shaft’s desired bend profile. Therefore they typically do not have a defined spine like a steel shaft will, but graphite shafts do need to be pured for consistent performance (see Pureing below). While it is true that the bend or flexing of a shaft is actually turning during the swing, the unload point (the point where the shaft bends forward just before impact), should have the spine and clubface aligned with the target line. Therefore the theory is that if the spine is properly aligned with the target line of the clubface, there will be a minimal twisting effect of the head at the unload point (and at impact), resulting in a more consistent and accurate performance of the club. Please note however, that even after finding the spine of a steel shaft it should also be pured just like a graphite shaft. Most of the time the pure point of a steel shaft is located 90 degrees from the spine, but there are cases where this does not always hold true. Sometimes the spine of a steel shaft is not straight, and there can even be multiple spines in different segments along the shaft, therefore pureing of the shaft is necessary to ensure the club is assembled in the most consistent plane.

Shaft Pureing:  This is the process of finding the most consistent oscillation point (or plane) of a shaft. The butt end of an uncut shaft is clamped (typically in a frequency meter clamp), a weight of like mass to the head used in the final club is connected to the tip, and the tip of the shaft with the weight is then oscillated in a known plane. The desired effect is to have the tip stay perfectly in the same plane as it oscillates. If the tip does not stay in plane (i.e. does figure 8s as it oscillates), then the shaft is unclamped, turned a few degrees, clamped, and oscillated again. Once the proper plane of the shaft is found the 12 o’clock position is marked, and the shaft is assembled into the clubhead with the mark in the 12 o’clock position of the club (on top and parallel with the clubface). The theory here (as it is with spinning), is to achieve the most consistent and stable unload point of the club (the point where the shaft bends forward just before impact). The reason the pure point of the shaft is placed in the 12 o’clock position (parallel with the club face instead of perpendicular as with a spine), is to keep the head in the most stable plane at the unload point, thus having a more consistent and accurate performance of the club.

Shaft Frequency:  The frequency of a shaft is the measurement which equates to a shaft’s flexibility (or stiffness). It is the only true method of determining shaft flexibility. One point that should be made here is that there is absolutely NO standard of shaft flexibility among shaft manufacturers. What is meant by this is that the letters on a shaft indicating flexibility (L=lady flex, A=amateur (senior) flex, R=regular flex, S=stiff flex and so on), mean absolutely NOTHING except for how the letters relate to the other letters of the same model shaft. And even that does not always hold true. I can show you an L-flex shaft that is stiffer than an S-flex shaft. The only way to truly know the stiffness of a shaft is to use a frequency meter to measure it. To measure the shaft’s butt frequency, the shaft is clamped at the butt end (a butt clamp is approximately 5 1/2″ in length), and a known calibrated weight is attached to the tip end. The shaft is oscillated over a frequency counter and the cycles per minute (or CPM) are measured. A lower CPM indicates a more flexible shaft, and a higher CPM indicates a stiffer shaft. For example a 5 iron with a frequency of 295 CPM is more flexible than a 5 iron with a frequency of 305 CPM. One wouldn’t think that a difference of 10 CPM would make that much difference, but it does in fact make a very big difference based upon a person’s swing profile.

Shaft Bend Profile:  The bend profile (typically referred to as a shaft’s bend point, or kick point) is the area or section along the shaft where the shaft bends in the most consistent manner. Shafts are manufactured to have a certain bend profile for a certain type of golf swing. For instance a shaft that bends more toward the tip section (low bend point), will result in a much higher launch angle than a shaft that bends more toward the butt end (high bend point). Also a shaft with a low bend point will unload more slowly than a shaft with a higher bend point. The golfer’s wrist release is typically the primary determining factor for the bend profile that best fits the golfer’s needs. Although there are other factors that weigh in to help determine this, the wrist release is usually the starting point. A golfer with an early wrist release (i.e. more toward the top of the swing) needs a shaft with a lower bend point, and a golfer with a late wrist release (more toward the bottom of the swing) needs a shaft with a high bend point.  Most shaft manufacturers will list the shaft’s bend point in the shaft specifications, but again since there are no true shaft standards, even the specified bend point can be questionable. One of the best methods of determining a shaft’s actual bend profile is to clamp the shaft at predetermined lengths along the shaft (from the tip section backward), and measure its frequency from those areas. After the section frequencies are measured, they can be graphed and compared with other shafts. This gives a much better determination of how a shaft will actually bend. We use extensive shaft data tables, and shaft profiling software to select the best shaft for a customer. This data, and the associated software program contain hundreds of shaft bend profiles that can be graphed and compared. Selecting the proper shaft bend profile is one of the most critical factors when fitting custom golf clubs to a person’s swing. Anything less is nothing more than an expensive shot in the dark.

Frequency Matching:  This is a reference to the relationship of the flexibility between clubs in a set. Since the club flexibility (stiffness) is determined by measuring the butt frequency of the club (measured in Cycles Per Minute CPM), how the frequency differs from one club to the next is a very important parameter. For instance, in an iron set the clubs should be graduated in length by half an inch. As the number on the head of each club increases the club gets shorter by half an inch, and the weight of the head should increase by 7 grams. In a matched set, the frequency of each club should also increase by 3 to 5 CPM for each half inch it shortens (up to the wedges which are typically all the same length). This is necessary to ensure the clubs behave in a graduated manner (i.e. each club should feel, load, and unload in a graduated and predictable manner so that they behave correctly in accordance with your swing).  If the clubs in a set are not matched then they will not perform correctly or predictably. This is why most people have a favorite club in their set of irons, because that is the one club they can depend on to behave correctly. The other clubs in their set do not perform as predictably, because the set is not properly matched. In a matched set (with the correct lengths, frequencies, and properly graduated loft and lie angels), the clubs will ALL perform correctly and predictably. Name brand clubs are built randomly without regard to shaft differences, not to mention the lengths are many times not graduated, and the loft and lie angles are NEVER set. This assembly method can in no way render matching sets, and this is why a set off the rack is so unpredictable. It is also why it is not a good idea to buy different pieces of a set at different times from different manufacturers. The only way to properly match a set is to build a base club in the set to the specific frequency designed for the golfer, and then trim the other shafts in the set accordingly (also ensuring the head weights are exactly 7 grams apart). As a matter of practice, we always presort the shafts in a set by frequency and weight before trimming and assembly. This is done to help ensure the resulting frequencies will be correct. We also document this uncut frequency and weight (as well as the necessary trimming), of each shaft in the set. This is done so that a replacement club (or fill in club), built at a later date, can be duplicated exactly to fit within the set. Even after following these meticulous practices, it is also sometimes necessary to fine tune the head weights after assembly to ensure proper frequency matching. Custom assembly of a set of clubs is one of the most important deciding differences between a custom built set, and a set from off the rack. The ONLY way to end up with a matched set of clubs is to follow these types of assembly practices. So then in conclusion we can say this about a set of clubs off the rack, “they are like a box of chocolates… you never know what you’re gonna get!”

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