Dave, >That manifests itself as a difference in flexibility, or pure >spine. It >will show up in a Neufinder, but will also show as FLO, and >will show from >differential deflection measurement.
Have you tested concentricity problems to verify how they manifest themselves in FLO, on a FM or a spine finder? How about when combined with a bend in the shaft or an out of round section. You seem to be saying these things aren't important, yet don't account for how you have determined that they are not or at what magnitude they are not and under what combinations they are not. Same thing for the out of round area. Just how big does an out of round area have to be before it can affect shaft performance? Is it usually the case that the out of round section is just local or is it more often extending down a good amount of the shaft, say the whole butt section, for example? If the whole butt section is out of round, do you still think it will not affect performance? Obviously, if the whole shaft out of round would effect performance. At what point would a section of out of round shaft effect the reading of a FM or flo? I have yet to see any study that answers these types of questions, nor a thorough study that indicates that these anomalies are not important and have no effect on shaft bending properties. > >What I was talking about when I said "out of round" -- and >what, I assume, >Alan meant as well -- was small out-of-round places on the outside >diameter, in the vicinity where the bearings rest on a >Neufinder (or other >bearing-based spine finder). That will affect the position at >which the >shaft "wants" to rest, but will have no effect on the >performance of the >shaft during a swing. How do you know it has no effect and how big does a "local" out of round have to be before it does? Have you tested your frequency meter theory for finding spines and flo out completely? For example, might the FM be reacting to the nature of a differential stiffness in the butt area only, or even and out of round in the butt section? If you find FLO when clamped at the butt end, are you sure it will have the same flo when clamped in the middle or by the tip? I've seen no studies of this. Under what amount of pressure on the clamp end, does the clamp cause a local out of round in the shaft and possibly effect flo results? These types of question could be endless. Because there are unanswered questions does that mean the theory is invalid? > >You have this interesting belief that flex asymmetry and shaft >bend have >the same effect on performance. I'm not sure where the belief >comes from, >but I know of no organized evidence to support it. The few >tests I've seen >to determine the effect of small bend on an otherwise >symmetric shaft have >not given the performance differences that folks have observed >from spines. I can't quote studies, but that does not make it invalid. There's just lots of guys anecdotal results and a few companies making money from the concept. What scientific studies of the effects that spines, NBP's, concentricity, out of roundness, shaft bend, or of flex asymmetry, for that matter, in a golf shaft can you quote? I'd like to read them. You and Alan make it sound as if your theory is the only one and has fully tested and found to be valid. I certainly don't see a preponderance of evidence on your side of the scale either. Dan
