Alan, How about shaft concentricity problems where the hole in the center of the shaft is offset a bit from center, resulting in different shaft wall thickness around the shaft. I'm sure you are aware that they can be slightly out of round, even if only for a portion of the shaft. Perhaps it is just a problem with inconsistencies in the sheet wrap. And of course there is the curvature issue that is very common. I assume it would not be unexpected to find several of these anomalies to occurring in one shaft. I've certainly seen my share of shafts without a curve in them that demonstrated something other than the standard type 2 shaft behavior. For example where the NBP's are 180� and equal in strength under flex, or where the spine plane is not 90� to the NBP plane. These shafts certainly have other anomalies than curve or flex differential in order to demonstrate these odd bending properties.
I guess if we could ask the engineers or manufacturing experts at SKFiber or one of the other companies that seemed to have solved the shaft spine/anomaly problem, we'd be able to find out what all the problems were they had to solve, and why most other manufacturers have not. The problems must be difficult ones to solve or we'd have many more shaft demonstrating limited consistency problems. Dan Neubecker [EMAIL PROTECTED] >-----Original Message----- >From: Alan Brooks [mailto:[EMAIL PROTECTED] >Sent: Thursday, October 09, 2003 8:20 AM >To: [EMAIL PROTECTED] >Subject: RE: ShopTalk: NBP-COG > > >Corey Bailey also referred to "other anomalies" in a shaft. Besides >curvature (or residual bend) what other anomalies are we talking about >here? How do they affect the behavior of a golf club when it is >swung? And how is it that a 'spine finder' identifies them? >The articles >I have read only refer to identifying stiffness variations >with a spine finder. > >Thanks, > >Alan Brooks > > > >At 07:55 AM 10/9/2003 -0500, you wrote: >>Dave, >> >>Well, that depends on how you define NBP. We've had this >discussion before. >>You choose to define NBP as the softest flex plane in a shaft >and the spine >>as the stiffest plane, excluding shaft geometric anomalies from >>consideration. >> >>A number of us disagree with that assumption and believe that >geometric >>anomalies might be just as important in shaft alignment as >stiffness. We >>feel a combination of differential stiffness and shaft >geometric anomalies >>in a shaft should be combined to determine the best >alignment, which is >>exactly what a spine finder does. >> >>Dan Neubecker >>[EMAIL PROTECTED] >> >> >> >-----Original Message----- >> >From: Dave Tutelman [mailto:[EMAIL PROTECTED] >> >Sent: Wednesday, October 08, 2003 5:35 PM >> >To: [EMAIL PROTECTED]; [EMAIL PROTECTED] >> >Subject: Re: ShopTalk: NBP-COG >> > >> > >> >At 04:49 PM 10/8/03 -0500, Don Flatgard wrote: >> >>NBP-COG alignment..... >> >>I posted this the other day and received no response so I'll >> >do it again. >> >>I agree with you on the difficulty of aligning the NBP and >COG to the >> >>degree. >> >>My method is to prepare the shaft, install the ferrule, find >> >the NBP with >> >>the NF. Take the DI off, turn the NF up-side down on the >> >bench and install >> >>the head and let it seek it own COG, let the epoxy set up >> >with the club in >> >>the NF. >> >>In my small mind I don't see how you could get any closer....df >> > >> >Don, >> >That will indeed get as close as you can measure it. (It's a >> >variant of an >> >approach I originally suggested.) Two flies in the >ointment, however: >> > >> >(1) The NF2 only finds the true NBP if the shaft is straight >> >and round. >> >Otherwise, there is an error (frequently a significant error) in the >> >position you find. >> > >> >(2) This approach only works for NBP-COG alignment. That's a >> >new theory, >> >and most of the anecdotal data (and all of the organized >> >published data) >> >use either NBP-target or spine-target alignment. >> > >> >Cheers! >> >DaveT >> > >> > >
