Uh; I didn't mention anything about NBP-GOG. What I said was its virtually impossible to assemble a club with the "hard spot" in a precise position. I have a spinefinder and a freq machine. I find hard spots - spines, and soft spots - NBP's easily. No problema. I don't deny the existence of spines, NBP's, or COG's. My argument is about marking and assembling.
TFlan ----- Original Message ----- From: "Dan Neubecker" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, October 09, 2003 6:44 AM Subject: RE: ShopTalk: NBP-COG > Hi Tom, > > It depends on what theory you believe in. If you believe that a spine > finder can find the correct NBP location as I do, then you absolutely can > get the NBP exactly at the COG. > > Bernie's post on NBP to COG alignment contained a quote from an experimental > set I made up. I did not have any high expectations for that set when I > made it up. Let me tell you that I was shocked by the difference in the > results. The results continue today after months with this set. I continue > to hit the best irons of my life. Now this set was a combination of new > things for me. First, I used a new shaft, PC Mach 22's, with R+, S- and S > shafts in the set. I used my NF2 to tip trim them to a matching profile of > .010" deflection between clubs, never having to trim more than 1/2" tip to > do so, and the find the NBP locations. Then I made up the clubs with a 3/8" > change between lengths, for a poor man's MOI match. Finally I assembled > them using the NBP (N1) to COG alignment. > > It could have any of those factors, or all of them that led to these > results, but I was literally shocked by how much better they played than any > set I've used. It was the most difference I have seen in at least 10 years > of experimenting with clubs, different lengths, different shafts, flexes, > torques, components, you name it, I've tried it. > > I can't ignore results like that, regardless of how tenuous the theory. > > Dan Neubecker > [EMAIL PROTECTED] > > > >-----Original Message----- > >From: tflan [mailto:[EMAIL PROTECTED] > >Sent: Wednesday, October 08, 2003 12:04 PM > >To: [EMAIL PROTECTED] > >Subject: Re: ShopTalk: NBP-COG > > > > > >Dr Tutelman: > > > >A question, por favor. When this subject was broached several > >months ago, > >and the thread unwound for about 3 weeks, I asked a question > >that got no > >universally agreed upon answer. The question was; is the spine > >found at the > >top of the shaft or at the bottom of the shaft when testing in > >Dick's spine > >finder? Responses were equally, and passionately, divided. > > > >I then asked another question; if when one finds the spine, > >the "hard spot" > >via the use of our arguably primitive methods, how can one > >accurately mark > >and then place the hard spot in a specific position? As I recall, you > >responded, correctly, that we'd be lucky to get the spine > >situated to within > >3 to 4 degrees. You mentioned the circumference of the .335" tip, when > >reduced to 360 degrees, would be virtually impossible to set > >accurately. I > >agree. An assembler would need to identify the spine at the > >shaft tip by > >marking it with a needle, then mark the hosel in the precise finished > >position. Then he'd need to mark the ferrule so the entire > >assembly could be > >stuck together in one operation. That's nearly impossible given the > >workplaces of most assemblers. > > > >So, this thread re; placing cog/spine in some specific location with > >accuracy is theoretically interesting but in practice its pretty much > >useless. I'm not knocking anyone, just making a point that's been made > >several times in the past. > > > >TFlan > > > >----- Original Message ----- > >From: "Dave Tutelman" <[EMAIL PROTECTED]> > >To: <[EMAIL PROTECTED]> > >Sent: Tuesday, October 07, 2003 10:49 AM > >Subject: Re: ShopTalk: NBP-COG > > > > > >> A few points I'd like to make concerning things that were > >brought up in > >> this thread: > >> > >> (1) As Alan Brooks and John Kaufman and I have said in the > >past, every > >> shaft will have the stiffest directions (that is, spines) at 180* > >> intervals. Similarly with the most flexible directions (that > >is, NBP). If > >> you measure anything else, there is something wrong with > >your measuring > >> equipment. (Others have already noted that residual bend > >affects a spine > >> finder's reading. That is probably the most common thing > >that is wrong > >with > >> your measuring equipment.) > >> > >> (2) FLO is important!!! It is not important because of > >anything the shaft > >> may be doing during the swing (unlike a fishing rod), but it > >is one of the > >> more reliable ways to find the REAL spine, untarnished by things like > >> residual bend. In other words, FLO is a more reliable > >spine-finder than > >> Colin's or Dan's. Slower perhaps, but it finds the real spine. > >> > >> (3) There are three theories that I have seen about why > >spine alignment > >> matters. NBP-COG is one of them. Here's the reasoning behind it: > >> * At the moment of impact, the major force bending the shaft is > >> centrifugal force. (That is probably true, but not > >universally accepted. > >> But let's proceed on the assumption that it is true.) > >> * That force will bend the shaft in the plane of the CG of > >the clubhead, > >> because centrifugal force acts through the CG of the clubhead. (In > >essence, > >> it is pulling the CG of the clubhead straight away from the hands.) > >> * If the shaft bends in a plane where the forces due to > >bending are not > >> in the same plane as the bending, there will be spurious > >torque on the > >> clubhead; you don't want that. > >> * But the only planes where the force and the bending are > >aligned are > >the > >> NBP and the spine plane. In other planes, there will be some > >small angle > >> between the bending and the force in the shaft. So you need > >to align one > >of > >> those planes (either the NBP or the spine) with the CG of > >the clubhhead. > >> > >> (4) If you build your clubs with nearly spineless shafts > >(like SK Fiber, > >or > >> the new Harrisons, or many filament-wound shafts), then it > >makes little > >> sense to say, "I used NBP-COG alignment [or any other > >alignment] and it > >> worked GREAT!" You were aligning an effect that probably > >didn't matter one > >> way or another. > >> > >> Hope this helps, > >> DaveT > >
