Dave
Just so we can appreciate the science and art of building golf clubs. I am a
senior mechincal engineer with General Electric. Have been for 33 years.
Hope to retire in May of this coming year. I also teach many courses for
machinist at our facility. I have made all my tools and equipment for golf
fabrications, except for the Kaufman frequency meter. I also made one of
those, but I wanted to see John's to see if it was better. I also made a
spine finder. I also built a inverted flex board. I already measure shaft
deflection with dial indicators and measure shaft load with a strain gage.
Just don't have enough time to test as much as I would love too. I really
rely on the expertise of this forum to (learn) all I can. There are some
very brilliant minds on this forum. You can't beat the years of experience
on this forum. I love to hear the many different views expressed. This is
the way we learn. All of us together collectivly can do as much if not more
testing as any OEM company. It all must start with minds thinking. I am very
appreciative of people like Tom Wishom and the Dave's and the Bernie's and
the so many others that take the time to share their insights. That insight
is what makes this forum worthy of its use.
Thanks to a group well done.Everyone please have a great holiday season and
be safe so that we can be back on this forum and learn (some) more next
year.
Reed
----- Original Message -----
From: "Dave Tutelman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Monday, December 23, 2002 9:03 AM
Subject: Re: ShopTalk: shaft flex v.s. frequency
> Reed,
> Just so you can get a somewhat balanced view...
>
> Bernie is retired from advertising.
> I'm a retired engineer and researcher.
>
> When Bernie describes something he likes, it's a full-court-press sales
pitch.
> When I describe something (I like or dislike) I can't bring myself not to
> present the other side as well.
>
> I am involved in the NeuFinder effort, and will be building one this
> winter, so I'm certainly a fan. But I feel Bernie's sales pitch leaves
> another side to be told.
>
> First of all, he answered the questions you asked ("how do I get one or
how
> do I build one?") but not the underlying "what is it?" It is a deflection
> board, with the following bonuses:
> (a) Readout on Dial Indicator, so you don't have to do major visual
> interpretation to do the reading.
> (b) Dan & Bernie have pioneered a way to use it to match a set of shafts
> for building a set of clubs. The matching is much faster and at least as
> accurate as frequency matching -- possibly more accurate.
> (c) Detailed plans are available to build it.
>
> My involvement in the effort is to help solve two shortcomings it has
> compared with the frequency meter approach:
>
> (1) Set up a calibration procedure and/or tolerance control so readings
> from one NF2 will be the same as for any other [calibrated] NF2 for a
given
> shaft. This is not a problem when matching shafts, but it is when talking
> with other NF2 owners about the stiffness of shafts. Which brings us to...
>
> (2) Relate NF2 reading to frequency. This is necessary because frequency
> is the current lingua franca of clubmakers. The catalogs of some of my
> favorite shaft manufacturers provide frequency numbers. The DSFI tables
> provide frequency numbers. I know my own clubs by their frequency numbers.
> Etc etc etc. We need to be able to cross-reference with NeuFinder
readings.
>
> I also have some problems with Bernie's statements about spines. A couple
> of days ago, Bernie and I agreed that we both believed in John Kaufman's
> statments about spines in his tech notes. Apparently we didn't agree on
all
> of them. You can see them at http://www.csfa.com/techframe.htm. Pay
> particular attention to the note on "Inverted flex board"; that has John's
> more rigorous and quantitative explanations -- and the important
> conclusions which are the ones I said I agree with. Here's a copy of those
> conclusions:
>
> BEGIN QUOTE___________
> Here's a summary of what I think about spines and stuff. (I could be all
> full of beans of course.)
> * In a spine finder a bent shaft will react just as a shaft with
> variable stiffness.
> * Steel and filament wound shafts may be bent and react in a spine
> finder but their true stiffness is very uniform.
> * The strong and weak axes are always 90� apart.
> * A shaft has two weak axes 180� apart and two strong axes also 180�
> apart. See the "bow-tie" in Plot 2.
> * I think one of the weak axes should be pointed at the target.
> * The weak and soft axes can be found with a frequency analyzer and
are
> the non-wobbling low and high frequency positions.
> * The better the shaft the less important is spine aligning.
> * Every shaft has two natural frequencies that are always 90� apart.
In
> good shafts these two frequencies are very close, 1 or 2 cpms.
> END QUOTE__________
>
> A couple of specific comments on Bernie's points...
>
> At 07:07 AM 12/23/02 -0500, Bernie Baymiller wrote:
> >With a frequency analyzer, you
> >have to locate the NBPs and spines on every shaft in a spinefinder first,
> >then frequency match and as you tip trim, the spine location can move and
> >you have to re-spine the shafts again.
>
> Simply not true!
> If you believe JK's tech notes, you get a more accurate spine location
from
> the frequency meter. If you use a spine finder, you can only consider it a
> starting point, to save you some time finding the REAL spine with the
> frequency meter.
>
> >The dial indicator also can tell you
> >the exact magnitude of the NBP-S1, simply by rotating the shaft and
watching
> >the dial indicator.
>
> That is mostly true, and it is a significant advantage over most spine
> finders.
>
> I say "mostly" because, like all mechanical spine finders, it can still be
> spoofed by geometric, rather than stiffness, imperfections in the shaft.
> Again, see JK's notes for more detail.
>
> >You have to unclamp and reclamp the shaft in a frequency
> >analyzer to do the same operation.
>
> Definitely true.
>
> But if mechanical spine finders (including the NF2) worked properly --
that
> is, they found true spine stiffness rather than a combination of spine and
> geometry -- they would have as time-consuming a process. Again, see JK's
> note on inverted flex board for the proper way to determine spine.
>
> Hope this helps.
> DaveT
>
>
>
