I just beat my kids off the computer and got to read some of the answers. I understand but don't understand. MHO is that if a club is made longer, I would think it would play softer unless the clubhead is lighter than the previous one. BUT in the dynacraft shaft fitting addendum Example: a SKFiber PE (R) shaft would be rated for a swing speed for 81mph @43.5", but if you made the club longer @46" the rated swing speed would be 89mph. *^#%)@$#*#* SNAFU Pat ----- Original Message ----- From: "Burgess Howell" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, October 17, 2002 7:53 PM Subject: RE: ShopTalk: Shaft flex
> I thought he said that there are three determinants of shaft frequency -- > the spring constant, the shaft length, and the mass of the clubhead. The > spring constant is the component commonly referred to as flex. > > Therefore, the flex of a shaft is an intrinsic property. While you can > change the frequency of a shaft, you can't change its flex. I think this > is intuitive, no? For a given clubhead weight and shaft length, a softer > flex shaft will have a lower frequency than a firmer flex shaft. That's > what Royce said, right? > > What passage indicates that frequency is a definition of flex? > > Burgess > > At 11:25 AM 10/17/02, you wrote: > >Royce, > >Nice article. Your closing question, "does this all make sense?", is a > >good one. I am confused by the first sentence of your second paragraph, > >that says theoretically the longer and shorter shaft have the same > >flex. Then you go on to demonstrate how frequency is a definition of > >flex. Then you go and say changing the length changes the frequency. I > >have gone full circle and the ends don't meet. Help. > > > >Al > > > >At 09:00 AM 10/17/2002, you wrote: > >>I've been doing a lot of reading on materials mechanics lately (trying to > >>understand what the hell goes on in a golf swing...), and the following > >>is a summary of a chapter from "The Physics of Golf" by Jorgensen. > >> > >>Theoretically, the longer shaft is the same flex as the shorter > >>shaft. It may FEEL softer, but that's not what you are measuring with > >>the frequency analyzer. The frequency analyzer measures a property of > >>the shaft related to a spring constant of a vibrating rod. For a given > >>shaft, the frequency that it vibrates when you clamp one end and twang > >>the other is a function of the spring constant (a material property of > >>the shaft commonly called "flex"), the length of the shaft, and the mass > >>of the weight on the end of the shaft (i.e. the clubhead). For a given > >>flex, and a fixed clubhead weight, increasing the length of the shaft > >>will result in lower frequency. Likewise, for a fixed length and fixed > >>clubhead weight, a lower "flex" will result in lower frequency. > >> > >>Think in terms of an FM Precision plot...if you take a shaft, attach a > >>head, measure the frequency, then cut 1/2" off of the length, then repeat > >>the process over and over, you should get a straight line plot of > >>frequency vs. length. If you match the frequencies of an assortment of > >>shafts that are of equal lengths, then trim them to the lengths you need > >>for the clubs, and put the same clubhead on each shaft, you will again > >>get a straight line. If you decrease the clubhead weight by oh, say, 7 > >>grams each as you put them on shorter and shorter shafts, you should > >>again get a straight line, but of a different slope. The straight lines > >>on the FM Precision plots are based on incremental club weight of 7 > >>grams, a different increment will change the slope of the line. > >> > >>In the case you mentioned, there are other factors at work as > >>well. Increasing the length only will increase the swingweight, which > >>will make it FEEL different. The stiffness of a shaft can also vary > >>along the length of the shaft, and is a function of the material the > >>shaft is made of, the consistency or homogeneity of the shaft material, > >>the diameter of the shaft, the cross sectional area of the shaft > >>material. IN GENERAL, the "stiffness" of a shaft is mostly a function of > >>these properties at the tip end and the transition from the gripping area > >>to the tip area (i.e. the so-called bend point). Depending again on the > >>design of the shaft, it can be made more or less "tip stiff" or "butt stiff". > >> > >>Does this all make sense? > >>Royce > >>-----Original Message----- > >>From: [EMAIL PROTECTED] > >>[mailto:owner-shoptalk@;mail.msen.com]On Behalf Of Pat McGoldrick > >>Sent: Wednesday, October 16, 2002 10:28 PM > >>To: [EMAIL PROTECTED] > >>Subject: ShopTalk: Shaft flex > >>Does a 48" long shaft with a 195 gram head play stiffer than a 45" long > >>shaft with the same head? I assume the butt end is the stiffest part of > >>the shaft and whenever you trim the butt end of the shaft, the more > >>flexible the shaft becomes. Is this correct? Then why would the frequency > >>analyzer show the longer shaft with a lower reading? I have a hard time > >>trying to convince myself of this. Could anyone explain? Well it's that > >>time for me, be back tomorrow. TIA > >>Pat McGoldrick On Target Golf > > >
