shoptalk-digest Friday, 6 September 1996 Volume 01 : Number
009
----------------------------------------------------------------------
From: mpace@juno.com (Morgan W Pace)
Date: Tue, 3 Sep 1996 02:28:21 PST
Subject: ShopTalk: Taylor Made Titanium Driver
This morning I tried a Ti driver and was very favorably impressed. I
decided to try to build a light weight club with a large head. Any
information on specs. of a Ti. Bubble Burner Driver w/R 80+ shaft
would be appreciated; i.e. total weight of the club, club head size,
weight, bulge, roll , shaft length, weight, bend point, torque (I have
no means of measuring shaft freq.)
Since hard data may be scarce any estimates on specs. or suggested
clubhead\shaft combinations available from component suppliers that you
think might produce a decent light weight chub w/large head would also be
appreciated. I am not trying to replicate any appearances or clone
the Taylor made club..
Thanks mpace
------------------------------
From: petef@moon.flanet.com (Peter Farris)
Date: Tue, 3 Sep 1996 18:38:28 -0400
Subject: Re: ShopTalk: Standard Weight Steel
>Any recommendations for a low bend point standard weight steel iron
shaft? TT
>Dynamic Gold / Dynamic has a high bend point ( and run too stiff for
me ) so i
>was looking @ Apollo and Brunswick.
>
>Does anyone out there play Rifle 5.0s -- do they flex closer to a Regular
or
>Average steel shaft ? My understanding is that the Rifle 5.5/6.0 runs
stiffer
>than the Regular flex of a standard/lightweight steel shaft. Any thoughts?
>
>Thanks again.
>
>
>
>
I play Rifle 5.5 with Chicago 944 heads[available right here in Clearwater],
they are IMHO very
soft. One will never part with them after trying them out for a couple
of
rounds.
Apollo are a little softer than TT. Just my thoughts.
------------------------------
From: mark kozu <markk@accessone.com>
Date: Tue, 03 Sep 1996 15:42:47 -0700
Subject: ShopTalk: Recommendations anyone?
I just finished assembling my first golf club (hooray!) It is a
Golfsmith XPC Plus 5 iron with XPC Plus R Graphite shaft. I hit it
about 5-10 yards farther than my existing 5 iron (SOTA, Dynamic Gold
S300 Steel shaft), but the SOTA feels much better on a good hit.
I like the lighter weight of the graphite shaft and the extra distance,
but the XPC just feels "harsher" (how's that for a scientific
term?)
I suppose I could get used to the way it feels, but if I am going to
spend the money to build the rest of the set, I would really like to get
the best of both worlds.
Any suggestions?
Thanks,
Mark
------------------------------
From: djmiller@wolf.co.net (Daniel J. Miller)
Date: Tue, 3 Sep 1996 22:16:48 -0500
Subject: Re: ShopTalk: Taylor Made Titanium Driver
You wrote:
>
>This morning I tried a Ti driver and was very favorably impressed.
I
>decided to try to build a light weight club with a large head. Any
>information on specs. of a Ti. Bubble Burner Driver w/R 80+ shaft
>would be appreciated; i.e. total weight of the club, club head size,
>weight, bulge, roll , shaft length, weight, bend point, torque (I have
>no means of measuring shaft freq.)
>
>Since hard data may be scarce any estimates on specs. or suggested
>clubhead\shaft combinations available from component suppliers that
you
think might produce a decent light weight chub w/large head would also be
>appreciated. I am not trying to replicate any appearances or clone
>the Taylor made club..
>
>Thanks mpace
>
Sorry I don't have specs on the Ti Burner Bubble Driver, but I have had
success with the Golfsmith Ti 260 head and the Grafalloy ProLite shaft.
I
put a 3 gm. tip weight in the shaft before assembly. I have 2 customers
using this club and they both give it rave reviews. One of them claims
20
to 30 yards gained in distance over his Callaway driver.
If you're willing to spend the money on this combination, I think you'd
find
it to be a great club. (I can't try it myself because I'm a lefty.
Anxiously awaiting the day when Golfsmith comes out with this head for lefties!)
Hope this helps!
Dan
djm
------------------------------
From: djmiller@wolf.co.net (Daniel J. Miller)
Date: Tue, 3 Sep 1996 22:28:02 -0500
Subject: Re: ShopTalk: Recommendations anyone?
You wrote:
>I just finished assembling my first golf club (hooray!) It is a
>Golfsmith XPC Plus 5 iron with XPC Plus R Graphite shaft. I hit it
>about 5-10 yards farther than my existing 5 iron (SOTA, Dynamic Gold
>S300 Steel shaft), but the SOTA feels much better on a good hit.
>
>I like the lighter weight of the graphite shaft and the extra distance,
>but the XPC just feels "harsher" (how's that for a scientific
term?)
>
>I suppose I could get used to the way it feels, but if I am going to
>spend the money to build the rest of the set, I would really like to
get
>the best of both worlds.
>
>Any suggestions?
>
>Thanks,
>Mark
>
Mark,
I had similar experience with the Harvey Pennick irons and the Golfsmith
Carbon Stick Filament Wound shaft. My guess is that the shaft is playing
a
little stiffer than you'd like. Some people like the "feel" of
a more
flexible shaft.
If you can, read the article titled "To Tip or Not To Tip" in
the Golfsmith
Clubmaker June 1996. It's very interesting for those of us that like to
"feel" the clubhead more.
I sold my Harvey Pennick irons and replaced them with Golfsmith Sterling
irons with Carbon Tour 5.0 graphite R flex shafts. The shaft is "cheap"
but
has pretty good specs at the price. The Sterling also has more "beef"
low
on the long irons. I trimmed 1/4" less from the tip than the chart
calls for.
My swing speed is clocked around 90-95 mph on the 5 iron, but a smooth swing
allows me to go with a more flexible shaft. I had intended to use these
clubs until I decided what to build next, but I may keep these for a long
time!
A recent posting by one of our Shoptalk members spoke highly of the
Grafalloy Attack-Lite shaft. This shaft may also be a great "feel"
shaft in
an Ultra-Lite. I've not tried it, but may do so next season.
I hope this helps a bit!
Dan
djm
------------------------------
From: ylwm0277@cyberstore.ca (Al McPhie)
Date: Tue, 3 Sep 1996 21:45:38 -0700 (PDT)
Subject: [none]
>To: shoptalk@conch.aa.msen.com
>From: ylwm0277@cyberstore.ca (Al McPhie)
>
>Please delete my name from your "send to" list. I sent this
same request
some time back, as directed by yourselves, yet continue to receive.
>
September 3, third request. I really do not want to receive any more
messages. For goodness sakes get me off the list. I need the room in my
mailbox for other things.
------------------------------
From: A02CSM1@MVS.CSO.NIU.EDU
Date: Wed, 04 Sep 96 05:39 CDT
Subject: Re: ShopTalk: (no subject)
*Sender: owner-shoptalk@CONCH.AA.MSEN.COM
*Precedence: bulk
*Reply-To: ShopTalk@CONCH.AA.MSEN.COM
*
*where can i get a sole plate for the 'ginty 7-wood? during a round of
golf the
* epoxy
*came loose and is now lost. i tried golfworks, dynacraft, golfworks, etc.
all
* said they
*can not help me unless i had the sole plate. where are these items available?
Since the company the made the Ginty line(Stan Thompson) is no longer
in buisness you have a problem. You might try Louisville Golf, they
have a head called a Niblic? that has a similar sole plate. Perhaps
they can help. Good Luck
Carl Mc Kinley
Carl's Golf Shop
------------------------------
From: Reg Hardy <datanet@earthlink.net>
Date: Wed, 4 Sep 1996 03:47:54 -0700 (PDT)
Subject: Re: ShopTalk: Recommendations anyone?
At 10:28 PM 9/3/96 -0500, you wrote:
>You wrote:
>
>>I just finished assembling my first golf club (hooray!) It is a
>>Golfsmith XPC Plus 5 iron with XPC Plus R Graphite shaft. I hit
it
>>about 5-10 yards farther than my existing 5 iron (SOTA, Dynamic
Gold
>>S300 Steel shaft), but the SOTA feels much better on a good hit.
>>
>>I like the lighter weight of the graphite shaft and the extra distance,
>>but the XPC just feels "harsher" (how's that for a scientific
term?)
>>
>>I suppose I could get used to the way it feels, but if I am going
to
>>spend the money to build the rest of the set, I would really like
to get
>>the best of both worlds.
>>
>>Any suggestions?
>>
>>Thanks,
>>Mark
>>
>
>Mark,
>
>I had similar experience with the Harvey Pennick irons and the Golfsmith
>Carbon Stick Filament Wound shaft. My guess is that the shaft is playing
a
>little stiffer than you'd like. Some people like the "feel"
of a more
>flexible shaft.
>
>If you can, read the article titled "To Tip or Not To Tip"
in the Golfsmith
>Clubmaker June 1996. It's very interesting for those of us that like
to
>"feel" the clubhead more.
>
>I sold my Harvey Pennick irons and replaced them with Golfsmith Sterling
>irons with Carbon Tour 5.0 graphite R flex shafts. The shaft is "cheap"
but
>has pretty good specs at the price. The Sterling also has more "beef"
low
>on the long irons. I trimmed 1/4" less from the tip than the chart
calls for.
>
>My swing speed is clocked around 90-95 mph on the 5 iron, but a smooth
swing
>allows me to go with a more flexible shaft. I had intended to use these
>clubs until I decided what to build next, but I may keep these for a
long time!
>
>A recent posting by one of our Shoptalk members spoke highly of the
>Grafalloy Attack-Lite shaft. This shaft may also be a great "feel"
shaft in
>an Ultra-Lite. I've not tried it, but may do so next season.
>
>I hope this helps a bit!
>
>Dan
>djm
>
>
Dan,
I have had real success equipping customers with the Grafalloy shafts, if
they can handle a slightly more flexible shaft. They are also helpful when
dealing with "baby boomers"
Recently I have been questioning myself as to why I "tip" shafts
following
mfg. guidelines since the mfg. knows little of the client's specific swing
characteristics
and has no idea what head I am shafting.
I didn't happen to see the Golfsmith article, it sounds like something I'd
be interested in.
Reg
Clubs Fit 4-U
------------------------------
From: cgdick <cgdick@freenet.calgary.ab.ca>
Date: Wed, 4 Sep 1996 05:36:34 -0600 (MDT)
Subject: Re: ShopTalk: (no subject)
> *Reply-To: ShopTalk@CONCH.AA.MSEN.COM
> *
> *where can i get a sole plate for the 'ginty 7-wood? during a round
of golf the
> * epoxy
> *came loose and is now lost. i tried golfworks, dynacraft, golfworks,
etc. all
> * said they
> *can not help me unless i had the sole plate. where are these items
available?
>
> Since the company the made the Ginty line(Stan Thompson) is no longer
I bought a 7metalwood from Golf Liquidators in Palm Springs in March. It
had a shaft label Apollo and Ginty logo.
More to the point, I run into a chap here that had one he had beaten to
pieces, simply wore it out.
I will ask him if he would part with the sole-plate if you like. It could
be a while before I see him again.
Colin
------------------------------
From: mark kozu <markk@accessone.com>
Date: Wed, 04 Sep 1996 09:28:36 -0700
Subject: Re: ShopTalk: Recommendations anyone?
Daniel J. Miller wrote:
>
> I had similar experience with the Harvey Pennick irons and the Golfsmith
> Carbon Stick Filament Wound shaft. My guess is that the shaft is playing
a
> little stiffer than you'd like. Some people like the "feel"
of a more
> flexible shaft.
>
I don't understand. The clubs that I have been using for the last
several years have TT Dynamic Gold S300 steel shafts, which I presume is
a stiffer shaft than the XPC Plus graphite R flex shaft that I built the
new club with.
> If you can, read the article titled "To Tip or Not To Tip"
in the Golfsmith
> Clubmaker June 1996. It's very interesting for those of us that like
Since I've only been interested in clubmaking for the past month or so,
I missed this article. Would you mind summarizing?
Thanks for your help,
Mark Kozu
------------------------------
From: "Gordon Olson" <G_Olson@mnsinc.com>
Date: Sat, 5 Aug 1995 15:38:56 -0400
Subject: RE: ShopTalk: Taylor Made Titanium Driver
Taylor Made's pamphlet "Find Your Game" says:
R-80 Plus has torque of 4.0, kickpoint is Mid-Low, and
has a weight of 73 grams
Head has 59 degree lie
Gordon Olson
- ----------
> From: mpace@juno.com (Morgan W Pace)
> To: ShopTalk@mail.Msen.com
> Subject: ShopTalk: Taylor Made Titanium Driver
> Date: Tuesday, September 03, 1996 6:28 AM
>
>
> This morning I tried a Ti driver and was very favorably impressed.
I
> decided to try to build a light weight club with a large head. Any
> information on specs. of a Ti. Bubble Burner Driver w/R 80+ shaft
> would be appreciated; i.e. total weight of the club, club head size,
> weight, bulge, roll , shaft length, weight, bend point, torque (I have
> no means of measuring shaft freq.)
>
> Since hard data may be scarce any estimates on specs. or suggested
> clubhead\shaft combinations available from component suppliers that
you
think might produce a decent light weight chub w/large head would also be
> appreciated. I am not trying to replicate any appearances or clone
> the Taylor made club..
>
> Thanks mpace
>
>
------------------------------
From: Kyle Stierwalt <kstierwalt@worldnet.att.net>
Date: Wed, 04 Sep 1996 16:09:14 -0500
Subject: ShopTalk: Re:
At 04:45 AM 9/4/96 +0000, you wrote:
>>To: shoptalk@conch.aa.msen.com
>>From: ylwm0277@cyberstore.ca (Al McPhie)
>>
>>Please delete my name from your "send to" list. I sent
this same request
>some time back, as directed by yourselves, yet continue to receive.
>>
>
>September 3, third request. I really do not want to receive any more
>messages. For goodness sakes get me off the list. I need the room in
my
>mailbox for other things.
>
Al,
I believe you can unsubscribe to ShopTalk by send email to:
majordomo@mail.msen.com
Type the following exactly in the body of your message (don't type anything
in subject field):
UNSUBSCRIBE shoptalk
------------------------------
From: djmiller@wolf.co.net (Daniel J. Miller)
Date: Wed, 4 Sep 1996 23:11:07 -0500
Subject: Re: ShopTalk: Recommendations anyone?
>Daniel J. Miller wrote:
>>
>> I had similar experience with the Harvey Pennick irons and the
Golfsmith
>> Carbon Stick Filament Wound shaft. My guess is that the shaft
is playing a
>> little stiffer than you'd like. Some people like the "feel"
of a more
>> flexible shaft.
>>
>
>I don't understand. The clubs that I have been using for the last
>several years have TT Dynamic Gold S300 steel shafts, which I presume
is
>a stiffer shaft than the XPC Plus graphite R flex shaft that I built
the
>new club with.
>
>> If you can, read the article titled "To Tip or Not To Tip"
in the Golfsmith
>> Clubmaker June 1996. It's very interesting for those of us that
like
>
>Since I've only been interested in clubmaking for the past month or
so,
>I missed this article. Would you mind summarizing?
>
>
>Thanks for your help,
>
>Mark Kozu
>
>
Mark,
I won't attempt to summarize the whole article since it covers a lot of
ground! It charts shaft frequencies using different tip trimming methods.
A relatively "normal" tip trimming recommendation yields a progressively
stiffer shaft as you go from long to short irons. If you trim in lesser
increments, the "slope" of the chart is not as steep, yielding
less
progression in the stiffness. Some people don't trim the tip at all,
yielding a "flat" slope. The bottom line is that this provides
more "feel"
in the short irons.
You might try calling Golfsmith to ask for a copy of the June '96 Golfsmith
Clubmaker. They may send you one!
Another very interesting article is in the July/August Golfsmith Clubmaker.
They explain how they fine tuned Scott Verplank's irons. I found it to
be
very informative!
Dan
djm
------------------------------
From: djmiller@wolf.co.net (Daniel J. Miller)
Date: Wed, 4 Sep 1996 23:14:01 -0500
Subject: Re: ShopTalk: Recommendations anyone?
Reg wrote:
>>
>>
>Dan,
>
>I have had real success equipping customers with the Grafalloy shafts,
if
>they can handle a slightly more flexible shaft. They are also helpful
when
>dealing with "baby boomers"
>
>Recently I have been questioning myself as to why I "tip"
shafts following
>mfg. guidelines since the mfg. knows little of the client's specific
swing
>characteristics
>and has no idea what head I am shafting.
>
>I didn't happen to see the Golfsmith article, it sounds like something
I'd
>be interested in.
>
>Reg
>Clubs Fit 4-U
>
Reg,
You might try to get your hands on the July/August Golfsmith Clubmaker.
They have a great article on how they fine tuned Scott Verplank's irons!
It
covers frequencies measuring from both tip and butt.
Dan
djm
------------------------------
From: A02CSM1@MVS.CSO.NIU.EDU
Date: Thu, 05 Sep 96 06:07 CDT
Subject: ShopTalk: Wilson Light X1 clubs 3i-pw
I'm trying to evaluate a used set of irons. They are Wilson
Light, X1. They look a little like the older staff(1960-70
vintage). The book I have doesn't list these. I suspect they
are the dime store version of the staff? Anyone have any
experience with these? I'm looking at taking them as trade-ins
and need to determine a value.
TIA
Carl Mc Kinley
Carl's Golf Shop
------------------------------
From: "Glaser Jonathan" <Glaser_Jonathan@bah.com>
Date: 6 Sep 1996 16:05:54 U
Subject: ShopTalk: Frequency Matching -- kind of...
Any recommendations on how to construct an almost-frequency matched set
of
irons using a lightweight steel shaft (Brunswick Microtaper) and NO frequency
analyzer? I know its a shot in the dark but I would really like to achieve
a
tigher slope than is achieved using the 1/2 inch tip trim rule. Too
cookie-cutter for me.
Questions:
Should I tip trim the shafts the same amount through the set or use a per
club
trim difference of 1/4" (or 3/8") (vs the 1/2" suggested
by Brunswick) to more
closely match the flex of each iron. What might this do to the long irons?
X-Sent-To: <jhm@ww1.msen.com>
Date: Fri, 6 Sep 1996 21:02:28 -0400 (EDT)
From: owner-shoptalk-digest@conch.aa.msen.com
To: shoptalk-digest@mail.msen.com
Subject: shoptalk-digest V1 #9
Reply-To: ShopTalk@conch.aa.msen.com
Precedence: bulk
Will my short irons be TOO flexible? What should I use as a starting point
--
its a combination flex shaft (R/S) -- the 5 iron, the 7 iron, etc? Id like
it
to be regular flex. Has anyone tried this and if so, were the results
satisfactory?
Thanks in advance and pardon the barrage of questions in a single posting.
------------------------------
From: miko <miko@julian.uwo.ca>
Date: Fri, 06 Sep 1996 21:00:26 -0400
Subject: Re: ShopTalk: Frequency Matching -- kind of...
This is a multi-part message in MIME format.
- --------------692026462917
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Glaser Jonathan wrote:
>
> Any recommendations on how to construct an almost-frequency matched
set of
> irons using a lightweight steel shaft (Brunswick Microtaper) and NO
frequency
> analyzer?
The issue of shaft flex is covered very well by Dave Tutelman
in his club design notes:
http://dunkin.Princeton.edu/.golf/clubmaking/clubdesn.4.html
He also has an article that addresses the idea of flex profile shaping
WITHOUT a frequency measuring device...
[article attached]
- --
| |
db miko
Mac Shack Golf
PCS-Class A Clubmaker
London, Ontario, CANADA
- --------------692026462917
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Content-Disposition: inline; filename="frequency profiling..."
FREQUENCY PROFILE SHAPING WITHOUT A METER
Dave Tutelman -- March 5, 1996
I'd like to thank Paul Nickles of Clubmakers' Heaven for providing
me with a lot of actual measured data that supports my
calculations. I know he won't agree with all my conclusions, and I
apologize to him in advance for that.
Here's a situation that may become common soon for amateur clubmakers, or
even custom shops that are too small to have a frequency meter.
You are willing to put up with the PRECISION of your favorite shaft
manufacturer, but you don't like the FREQUENCY PROFILE that you'll get if
you follow their tip-trim instructions. You want to choose your favorite
frequency profile for a set of irons, but you don't have a frequency meter
and don't have access to one? Well you can do it based on formula, to much
the same accuracy as if you had followed the tip-trim instructions.
The biggest problem is that you are at the mercy of whatever precision the
manufacturer builds into the shaft. Which shafts should you use, and which
should you stay away from, when you care about frequency and you don't have
a meter?
- The data in [WISH] indicates that the major-manufacturer steel shafts
are probably best for procedures like this.
- Don't use a sheet-wrapped graphite shaft for this, no matter how
expensive. There's entirely too much variation to be at all
predictable. [WISH]
- The data in [WISH] shows that filament-wound graphite from some
manufacturers can approach steel shafts in predictabilty. However, that
predictability can fall off for a tip-trim of more than 2 inches [NICK].
That out of the way, let's look at how we would determine the tip-trim to
get a particular frequency profile. To do this, we need two properties of
the shaft:
1. The tip-trim sensitivity of the shaft, in cpm per inch. This tells us
how many inches to tip-trim the shaft for each club, to effect a given
frequency change.
2. The frequency profile of a set of irons, given that they're all
tip-trimmed the same (for instance, not at all), instead of tipped
according to manufacturer's instructions.
If we have both #1 and #2 for a shaft, we can adjust the untrimmed profile
#2 by tip-trimming according to #1, to get any profile we want. (Caveat:
that's any profile until we run out of shaft. We can run out of tip to trim,
or we can trim so much tip that there isn't enough butt left for the length
we need. But this isn't a property of the method proposed here; it can also
happen when trimming frequency with a meter, or even when following the
manufacturer's instructions.)
As it turns out, both #1 and #2 above seem to be be relatively independent
of the shaft used.
The next sections will examine:
1. The tip-trim sensitivity of commercially available shafts.
2. The frequency profile of an untrimmed (or identically trimmed) set of
irons.
3. Using #1 and #2 to give clubs with "interesting" frequency
profiles.
4. Errors in the process.
5. Derivation of #2 for the analytically inclined.
1. Tip-Trim Sensitivity
The tip-trim sensitivity of a shaft is the number of cpm stiffer the shaft
becomes when tip-trimmed an inch. This assumes, of course, that the shaft
remains the same overall length, and is measured with the same clubhead.
The best way to find the tip-trim sensitivity of a shaft is to measure it
with a frequency meter. But this whole article is predicated on the fact
that you don't have one. So can we make use of published data to deduce
the
tip-trim sensitivity?
If a shaft is sold in a "combination flex" (e.g.- "R&S"),
then we can learn
enough to deduce its sensitivity. We can find out:
- The actual 5-iron frequencies of the shaft for the "R" flex
and the "S"
flex, which are published in the [SUMM].
- The tip-trim DIFFERENCE between the "R" and "S"
flex, in inches, which
is part of the manufacturer's trimming instructions for the shaft.
In all the numerical examples that follow, the frequency data is from [SUMM]
and the tip-trim data is from the manufacturers' instructions (as reprinted
in the Dynacraft and other catalogs).
For instance, consider the Brunswick Microtaper R&S shaft.
- Its "S" flex is 298 cpm for a 5-iron, tip-trimmed 4 inches.
- Its "R" flex is 287 cpm for a 5-iron, tip-trimmed 2 inches.
- The frequency difference is 11 cpm, and the trim difference is 2 inches.
Therefore...
- The sensitivity is 11/2 = 5.5 cpm per inch.
Below is a table I compiled for many of the currently-available steel
combination-flex shafts.
Higher Lower Freq Trim Sensitivity
Freq Freq Diff Diff (cpm/inch)
Apollo
AP44 R&S 314 301 13 2" 6.5
Shadow R&S 303 298 5 2" 2.5
?!?
Spectre A&L 295 290 5 1" 5.0
Spectre R&S 306 299 7 2" 3.5
?!?
Brunswick
LFA A&L 283 277 6 1" 6.0
MFA R&S 318 308 10 2" 5.0
Microtaper R&S 298 287 11 2" 5.5
True Temper
Dynalite A&L 290 280 10 1" 10.0
?!?
Dynalite R&S 317 304 13 2" 6.5
Dynamic A&L 278 273 5 1" 5.0
Dynamic R&S 323 310 13 2" 6.5
TT Lite A&L 297 293 4 1" 4.0
?!?
TT Lite R&S 323 312 11 2" 5.5
Note that more than 2/3 of the shafts show sensitivities in the range of
5.0
to 6.5. I've flagged the "outliers"; but note that the method
Dynacraft used
to determine their frequency was such that it could be explained by
relatively small sample-to-sample variation (3 cpm in all but one case),
rather than a large error in the tip-trim sensitivity. Indeed, if we look
at
the manufacturers' "intent":
- Most manufacturers want a 10-13 cpm difference between "R"
and "S".
- Most manufacturers (and ALL steel shafts that I've seen) specify
tip-trimming a 2" difference between R and S in combi shafts.
- This implies a tip-trim sensitivity between 5.0 and 6.5.
In the absence of reliable data to the contrary, I'd use a sensitivity of
5.5 cpm/inch for any of these shafts. Moreover, many of these combination
shafts have single-flex (i.e.- non-combination) cousins; for instance, the
Dynamic combi R&S is the same pattern as the Dynamic Gold R and the
Dynamic
Gold S. I'd use the same number for them, on the grounds that the shaft
pattern is so similar that the tip-trim sensitivity is probably the same.
I have a limited verification of this theory for the Dynamic Lite; I
tip-trimmed a sample shaft and measured its frequency for a constant length
and head weight, and tip-trims of 0, 1", 2" and 3". Each
inch of tip-trim
raised the frequency between 5 and 6 cpm on my frequency meter.
2. Frequency Profile of an Untrimmed Set
According to [COCH], the frequency of a club is proportional to:
- The square root of the stiffness of the material of the shaft.
- The square root of the stiffness of the geometry (the cross-section)
of
the shaft. This may have to be averaged in some way over the length
of
the shaft.
- INVERSELY to the 3/2 power of the club length.
- INVERSELY to the square root of the head weight.
- It is also affected by the shaft weight, but the effect is smaller than
the above factors.
The first two (especially the second) are a little difficult to deal with
if
you're trying to predict the frequency of a club based on measurement. But
if what you're trying to do is predict the VARIATION of frequency of the
same kind of shaft going from one iron to the next, you can lump the first
two parameters together in some easy way; they're the same for all the clubs
in the "series". It turns out that some nominal known frequency
for some
club in the set will be quite sufficient to pin down the shaft parameters.
So we're left with:
- Club length, and its variation between clubs.
+ We'll use a nominal length of 37 1/2" for a 5-iron.
+ We'll use 1/2" as the club-to-club variation; this is quite
standard.
- Head weight, and its variation between clubs.
+ We'll use a nominal weight of 256 grams for a 5-iron.
+ We'll use 7 grams as the club-to-club variation; this is very
standard.
- Shaft weight, and its variation between clubs.
+ Since this effect is much smaller than the others for reasonable
shaft weights, we'll ignore this for now and examine what we lose
in
the section on errors.
The frequency variation from club to club is a function of these variables,
and also of the frequency of the "base" club. We'll use a 5-iron
for our
base club (I hope nobody's surprised), and a nominal frequency of 300 cpm
(a
middling "R" shaft). In fact, the variation is directly proportional
to this
base frequency.
If we reflect the proportionalities above and use partial derivatives to
obtain the total differential, we're left with the equation:
1 dM 3 dL
df = f ( - --- --- - --- --- )
2 M 2 L
Plug in the values above: M=256 grams, dM=7 grams, L=37.5", and dL=-0.5",
and we get:
df = .0063 * f
For a set with a 5-iron frequency of 300 cpm, this gives a club-to-club
variation of 1.89 cpm.
If we look at the variation of the number as we change the assumptions,
we
get numbers like:
Club-to-club
Frequency
Conditions Variation
Nominal 1.89 cpm
Light head (253 grams) 1.86 cpm
Heavy head (263 grams) 2.01 cpm
Underlength club (36 inches) 2.13 cpm
Overlength club (39 inches) 1.65 cpm
Flexible shaft (280 cpm) 1.76 cpm
Stiff shaft (320 cpm) 2.02 cpm
There isn't all that much variation in simply assuming a nominal 1.9 cpm
or
so, unless we're talking about errors all building in the same direction.
But errors in the same direction aren't likely. For instance, the biggest
pair of errors would be a shaft that's very short and very stiff, not a
likely combination. Someone with a strong enough swing to need a very stiff
shaft would almost certainly go for the extra distance afforded by a longer
shaft.
The empirical data I've seen suggests that this number is something like
1.5
to 1.8, so this isn't far off the mark.
So let's use a nominal variation of 1.8 cpm per club. If we're off by 0.2
or
0.3 cpm, there are only four clubs each side of a 5-iron anyway, so the
maximum error will only be 1 cpm in the 9-iron and 1-iron.
What we've found is the frequency profile of the set if ALL the shafts are
tip-trimmed THE SAME. Not to the manufacturer's spec, but the same for all
clubs. Here's the frequency profile it gives for a set with a 300 cpm
5-iron.
2I 295 6I 302
3I 296 7I 304
4I 298 8I 305
5I 300 9I 307
Now that we know:
- What the profile looks like with CONSTANT tip-trim, and
- How much of a frequency change we get from a specific tip-trim...
We are ready to specify a tip-trim to give us any frequency profile we want.
3. Creating Your Own Frequency Profile
We know that:
- With no tip trimming, or the same tip trimming for all the shafts, the
club-to-club difference in frequency is 1.8 cpm, increasing as the clubs
get shorter. (If we have a sufficiently unusual club, we know how to
adjust this number up or down.)
- For the same shaft, clubhead, and club length, tip-trimming an extra
inch increases the frequency by 5.5 cpm. (This is a good estimate for
most shafts, though it's probably the least reliable shaft parameter.)
Using this, we can see how to tip-trim to get any frequency profile we want.
For example:
Sloped at 1.8 cpm per club:
This is just the club-to-club frequency variation of an untrimmed shaft.
For the shaft you're going to use, find the tip-trim that gives a 5-iron
the frequency you want; say that trim is 1.8" for the 5-iron. Then
trim
1.8" from EVERY shaft tip, and butt-trim the clubs to length.
According to Paul Nickles [NICK], this isn't a bad slope for people
who
aren't convinced either way between the sloped and the
constant-frequency schools, and therefore want to play it safe with
a
small slope.
Sloped at the "Brunswick grade" slope of 4.2 cpm per club:
This requires additional tip trimming, because the slope is more than
the constant-trim slope of 1.8 cpm per club. We need an additional
4.2 - 1.8 = 2.4 cpm per club
But we know the tip-trim sensitivity is 5.5 cpm per inch, so each
successively shorter club needs to be trimmed an additional
2.4 cpm per club / 5.5 cpm per inch = 0.44 inches per club
For all practical purposes, this is 1/2", which is the usual
tip-trimming instructions for the major steel shaft manufacturers. (I
consider it something of a vindication of this technique that it gives
the same tip-trimming instructions that Brunswick recommends for their
non-frequency-matched shafts.)
Suppose we want the same 5-iron frequency as above, so we know to
tip-trim the 5-iron by 1.8". Then our tip-trim chart would be:
1I 2I 3I 4I 5I 6I 7I 8I 9I
0" 0.3" 0.8" 1.3" 1.8" 2.3"
2.8" 3.3" 3.8"
Note that there isn't room on the shaft to get the full flexibility
we
want in the 1-iron. We are 0.2" short; that is, at zero tip-trim
the
shaft is still trimmed 0.2" more than we specified. By now we should
know that this means the frequency of the 1-iron is:
0.2" * 5.5 cpm/inch = 1 cpm
higher than we wanted. Since no golfer can feel a 1 cpm difference,
we
won't worry about it.
Constant frequency, zero slope
For this, we need to tip-trim to ELIMINATE the 1.8 cpm per club. That
means we do more tip-trimming on the longer clubs; this is backwards
from the way we usually think of tip trimming. Each longer club needs
to
be trimmed an additional
1.8 cpm per club / 5.5 cpm per inch = 0.33 inches per club
For all practical purposes, this is 1/3".
It is worth noting that Paul Nickles [NICK] has told me that 1/4"
is a
good rule of thumb for a first cut at a constant frequency. The
difference between 1/3" and 1/4" per club is at its maximum
in a 9-iron,
where the difference is 2/3", or 3.6 cpm. This is right at the
limit of
what a golfer can feel, so the difference probably isn't important.
If
you tune the frequencies with a frequency meter, you can tell the
difference -- but of course you wouldn't need a rule of thumb.
Suppose we want the same 5-iron frequency as above, so we know to
tip-trim the 5-iron by 1.8". Then our tip-trim chart would be:
1I 2I 3I 4I 5I 6I 7I 8I 9I
3.1" 2.8" 2.5" 2.1" 1.8" 1.5"
1.1" 0.8" 0.5"
This time we have enough tip to make the short irons flexible enough,
but we probably don't have room on the butt to make the long irons long
enough. For instance, consider that a 1-iron is usually 39.5" long.
Imagine we bought a shaft whose raw length is the common 41". Once
we
tip-trim 3.1", we are left with 37.9" Now, suppose the clubhead's
bore
ends an inch above the ground. That means we need a cut shaft length
of
39.5"-1" = 38.5". So we're 0.6" too short. We may
have to leave a little
more tip, and go for a slightly softer 1-iron.
One point is still a mystery, even to the careful reader: how did we know
that
our base 5-iron tip-trim was 1.8" to get the frequency we wanted?
In order to figure this out, we need to know our target frequency and the
frequency of the shaft for some known 5-iron and tip-trim. For instance,
suppose
we are using an Apollo AP-44 shaft to make clubs built 1/2" over length,
with
standard weight clubheads. We want a 5-iron frequency of 295 cpm.
Here are the calculations:
- - From [SUMM], we know that at standard length and 2" tip trim (standard
for
"R" flex), the club should vibrate at 301 cpm.
- - Frequency varies by 10 cpm for each inch of added length, assuming the
same clubhead weight and same tip trim. (This follows from the equation
in
the last section, but isn't obvious from anything that's been said so far.
Ten cpm/inch is pretty constant over the irons, and independent of the
shaft.) So 1/2" overlength takes us to 296 cpm.
- - We need another 1 cpm slower. Let's leave the tip 0.2" longer,
at 5.5 cpm
per inch of tip trim.
That gets us down to 295 cpm, with a tip trim of
2" - 0.2" = 1.8"
Let's end this section with a table of the frequencies of each of the tip-trim
strategies above. We'll go with the model we've been using:
- - Apollo AP-44 shaft
- - 5-iron trimmed 1.8" to give 295 cpm
Constant Constant Brunswick
Frequency Tip-Trim Scale
===================================================
Tip
Trim -1/3" All 1.8" +1/2"
Amount per club per club
---------------------------------------------------
Freq
per 0 1.8 cpm 4.2 cpm
club
---------------------------------------------------
1I 295 288 278
2I 295 290 282
3I 295 291 287
4I 295 293 291
5I 295 295 295
6I 295 297 299
7I 295 399 303
8I 295 300 308
9I 295 302 312
---------------------------------------------------
Range:
3I to 0 11 25
9I
===================================================
A few points about this table:
+ If you use a different shaft or a different base (5-iron) tip-trim, you
can simply assume the table "scales" by just finding adding the
same number
to all frequencies. (That number would be the difference between your 5-iron
frequency and 295.) Your errors won't be large compared to the other errors
in the process.
+ The constant-frequency column assumes the raw shaft is long enough to
take
all the trimming we need to do. This isn't the case; the AP-44, like most
R&S combi iron shafts, is 41" long. As we saw, this will give a
1-iron that
is either too short or too flexible.
+ The sloped systems give frequency differences that are very substantial
over the set. Remember that a difference of 5 cpm should make a difference
to most golfers, and a difference of 10-13 cpm is a full flex grade for
most
manufacturers. Even if you leave out the 1-iron and 2-iron, the range of
even the modest constant-tip-trim set is a full flex grade. Most sets
trimmed to manufacturers' instructions cover a range of two and a half flex
grades.
With this much variation across a set, I wonder why there isn't complete
agreement within the industry on whether frequency should be constant or
sloped. Oh, well......
4. Errors in the Process
Since the whole point of this exercise is to achieve a particular frequency
profile WITHOUT the feedback of measurement, we really need to have some
idea of how errors in the process are likely to propagate into frequency
errors. We also need some idea of what is an acceptable frequency error.
First, what should our target error be? It's generally accepted that
frequency differences under 3 cpm are not felt by the great majority of
golfers. On the other hand, differences over 5 cpm will make a difference
in
performance and feel for most golfers. A full "letter flex grade"
(say, the
difference between an "R" and an "S") is 10-15 cpm for
most shaft designs.
The process errors we'll have to take into account are:
- Shaft-to-shaft variations in stiffness and tip stiffness.
- Inconsistencies in the length of the club.
- Inconsistencies in the weight of the clubhead.
- Inaccuracies in the formula, including what we lost by ignoring shaft
weight.
Let's examine each in turn:
Shaft-to-shaft errors: This is the biggie. Data in [WISH] suggest that there
is a 3 cpm error at most in Apollo and True Temper steel shafts. This
number is a composite of raw shaft accuracy and tip-trim accuracy, which
is what we're depending on in this process.
However, clubmakers who have worked extensively with frequency meters
tell me the [WISH] data is hopelessly optimistic. They observe big
variations, especially in the tip-trim sensitivity (which is not
generally a specified or controlled parameter of the shaft). [NICK]
and
others have told me that every shaft model "has its quirks",
completely
aside from shaft-to-shaft repeatability; the tip-trim sensitivity isn't
smooth across the trim range in the same shaft.
The only solace I can offer is that the results are no worse than you
could expect from the same shafts following the manufacturer's tip-trim
instructions. But this way, you get to decide the overall shape of
the
frequency.
Whatever the actual number, it may be a little bigger for filament-wound
graphite, and is much bigger for sheet-wrapped graphite.
Club length errors: You are the clubmaker. You control these. This is
something you CAN measure. Don't let them happen!
If they do happen, the error is about 10 cpm per inch.
Clubhead weight errors: With reasonable quality control, a clubhead's weight
should match its spec within 3 grams. (This is the stated tolerance
in
the Golfsmith, GolfWorks, and Dynacraft catalogs.)
A 3-gram error in clubhead weight gives a 1.8 cpm error in frequency,
if
the iron vibrates at 300 cpm. The error is proportional to the
frequency, in case the 300 cpm assumption isn't a good approximation.
It's worth noting that a 2-gram difference in clubhead weight results
in:
- About one point of swingweight, and
- A bit over one cpm of frequency.
The message to me is that the first order of business is to make sure
that the clubhead weights are right for the swingweight you want. This
is one of the most important things you can do to get the frequency
right. Paul Nickles has told me this [NICK], but I have even more
dramatic evidence. After I built my frequency meter, I went back and
checked out the frequencies of several sets that I had built and still
had in the house. In all the sets built before I had a swingweight
scale, and none of the sets built after I was using a swingweight scale,
the biggest frequency error corresponded to the club with the biggest
swingweight error. Lesson: the maximum frequency error would have been
smaller if the clubs had been properly matched in swingweight or moment
of inertia.
Formula errors: There are three main sources of error in the "formula":
- We are ignoring the shaft weight.
- We use a single constant, 1.8 cpm, for the frequency difference.
- We "linearized" the frequency by using differentials.
Let's examine each of these in turn.
The basic formula for frequency in [COCH] accounts for shaft weight.
The
mass term, in which we included only head mass, is really:
M = H + .24*S
This assumes the shaft is of uniform weight (probably reasonable, if
not
absolutely precise) and uniform flexibility (not even close; we know
the
tip is much more flexible than the butt). The latter fact suggests that
a lot less than 0.24 of the shaft weight is participating in affecting
the frequency. Even so, I recomputed the formula using the shaft effect
suggested by [COCH], and came up with a club-to-club variation of 2.6
cpm, rather than 1.8. Since 1.8 is much closer to the actual empirical
data, I have to assume that an improper accounting for shaft weight
is
worse than none at all. So I went back to the formula with no factor
for
shaft weight.
Another source of error in the "formula" is that we are using
a single
constant, 1.8 cpm, for the frequency difference between clubs. This
ignores the fact that the frequency difference between clubs varies
with
a number of parameters, as we saw in an earlier section. The most
serious of these are the overall length of the set and the overall
frequency of the set. If the design of the set has the 5-iron very
different from 300 cpm and 37.5", then you'll want to adjust the
club-to-club frequency difference from the nominal value of 1.8. (There
is a table in a previous section that is a useful guide.)
There is another error implicit in the formula, due to the fact that
the
club-to-club frequency difference is actually proportional to the
frequency itself. We have "linearized" the frequency difference
between
clubs, when it is really proportional to the frequency. Assuming that
the club-to-club difference is a constant 1.8 cpm gives an error that
grows as you get further from the 5-iron. In the table below, we design
a set to a 5-iron frequency of 300 cpm, and see how the approximation
of
a constant 1.8 cpm per club varies from the actual frequency (as
computed by the exact formula for frequency [COCH], minus the shaft
weight component).
Actual Constant Error
2-iron 295.2 294.6 -0.6
5-iron 300 300 0
9-iron 309.2 307.2 -2.0
Thus the approximation of a constant frequency difference over the set
gives an error up to 2 cpm at the extreme, and less through the rest
of
the set.
5. Experimental Results
I am indebted to Paul Nickles for providing most of these measurements.
After most of the work for this article was complete, I finally got my own
frequency meter working and was able to add some measurements of my own.
The table below was obtained by taking frequency measurements for sets of
irons, and plotting them on linear graph paper. A straight line was drawn
to
give a "best fit" to the data by eye. Then I tabulated:
- The slope of the best-fit straight line.
- The maximum error of any club from that straight line.
- The average error (magnitude) over all clubs from the straight line.
This was done for expensive off-the-rack OEM clubs, both steel- and
graphite-shafted, and for several steel-shafted sets that I built before
I
had a frequency meter. My clubs were trimmed to manufacturers'
recommendations. It is also surmised that the OEM clubs were similarly
trimmed (1/2" per club), judging from the positions of the steps of
the
shafts.
I haven't identified the OEM clubs by name, because the purpose of this
data
isn't a "consumer reports" brand comparison but rather a sample
of what sort
of frequencies you get when you trim to manufacturers' specs.
Measured iron sets (all data in cpm)
Max Avg
Irons Slope Error Error
OEM Steel:
A 4.7 4 1.0
B 3.7 3 0.4
C 4.7 2 0.9
D 4.0 4 1.1
E 4.7 4 0.9
F 4.0 5 1.7
G 4.8 4 2.6
OEM Graphite:
H 3.3 8 5.6
I 4.7 19 5.3
J 3.3 5 2.0
K 4.3 18 3.9
My Homemade Steel
L 3.6 4 1.2
M 4.3 2 1.0
N 3.3 5 1.9
O 7.0 2 0.8
P 4.2 2 1.0
What conclusions can we draw from this data?
+ The general approach described in this paper is pretty good for steel
shafts, because it predicts a slope of 4.3 cpm per club and that is
pretty close to what the clubs are. (Ignore set "O"; those
are
True-Temper Flex-Flow shafts, which have very different characteristics
and trimming instructions from most steel shafts.)
+ Steel shafts lend themselves well to this approach. A few sets had a
single club that was as much as 5 cpm off; 5 cpm is the minimum that
most golfers can detect.
+ Graphite shafts do not lend themselves to this approach. The best set
of
the graphites was about as precise as the worst set of the steels. Half
the graphites had at least one club that was nearly two full flex grades
in error. That's like ordering an "S" and getting an "A"
flex.
I'll venture an editorial opinion based on this data. I will NEVER get a
set
of graphite-shafted clubs unless I know for a fact that it was
frequency-matched on a machine. The graphite OEM irons in the table that
gave such poor results were top-of-the-line sets from very respected
manufacturers, selling for big bucks. So people who say, "You get what
you
pay for," or "With the big OEMs, you're paying for quality,"
have a lot of
explaining yet to do. This data is the best argument I've seen yet for
custom clubmaking.
6. Acknowledgments
First and foremost, I'd like to thank Paul Nickles of Clubmaker's Heaven
(clubhvn@execpc.com), whose experimental data inspired much of this work,
and whose encouragement and detailed criticism greatly increased its
quality. I'd also like to express my gratitude to Dave Miko (now a PCS
Class-A Clubmaker; congratulations!) and to Normand Buckle for reviewing
drafts of the article and providing me with useful suggestions for its
improvement.
APPENDIX
Derivation of the Constant-Trim Frequencies
>From the appendix of [COCH], we know that:
9 EI
f = --- sqrt ( -------------- ) (1)
2pi L^3 (H + .24S)
where:
E = Material stiffness
I = Geometry stiffness (cross-section MOI)
L = Length of club
H = Head mass
S = Shaft mass
The conditions to make this true include an assumption of constant
cross-section, which is clearly an incorrect assumption for real shafts.
This figures into the equation in the factors of 0.24 and I. But we can
finesse this issue because:
- The .24 factor doesn't require the same shape of cross section, just
the
same cross-sectional area. Until quite recently, this was a good
approximation to real shafts. It still is, unless you get a shaft that's
deliberately tip-heavy, or deliberately "bubbled", or has
some other
deliberate manipulation of the weight distribution.
- The I factor can be replaced by some sort of "average I".
On the
surface, this would appear to mean we need to analyze every
diameter-reducing step. But we could just assume we know it, and see
what happens to it in our analysis. (It turns out to go away altogether
in the variational analysis.)
Let's re-express (1) as:
9 1/2 -3/2 -1/2
f = --- (EI) L M (2)
2pi
Where:
M = H + .24S if we want to include the shaft weight
M = H if we want to ignore shaft weight
This will make it easier to differentiate, and the next step is to take
partial derivatives with respect to the club parameters L and M. (In the
math below, the representation is handicapped by the lack of upper- and
lower-case "delta" on the standard computer keyboard. I use "d"
for itself
and both deltas. Math majors will miss it, but most others will probably
applaud the loss of a sometimes-confusing precision. :-)
df 9 1/2 -3/2 -3/2 1 f
-- = - --- (EI) L M = - --- --- (3a)
dM 4pi 2 M
df 9 1/2 -5/2 -1/2 3 f
-- = - --- (EI) L M = - --- --- (3b)
dL 4pi 2 L
We didn't take partial derivatives of E or I, because we're looking at the
variation with constant tip-trim. We don't need to know exactly what E and
I
are, just that they don't change. Since tip-trim is the thing that changes
the flexibility of the shaft, no tip-trim means no (EI) change. The actual
values of E and I make themselves felt implicitly; note that the actual
frequency (which includes an EI factor) is part of the derivatives.
We can find the total variation of frequency when we vary the other club
parameters, by combining (3a) and (3b) as a total differential.
df df
df = -- dM + -- dL
dM dL
1 dM 3 dL
df = f ( - --- --- - --- --- ) (4)
2 M 2 L
Equation (4) is our fundamental description of club-to-club frequency
variation. When we plug in nominal values for a 5-iron:
L = 37.5" dL = -0.5" (Clubs get 1/2" shorter
each club)
H = 256 grams dH = +7 grams (Clubs get 7 grams heavier each club)
f = 300 cpm (A nice round number, in the middle of the 5-iron range)
We get df = 1.89 cpm per club.
The table of other values in the text come from plugging other values of
club parameters into equation (4).
REFERENCES
COCH Alastair Cochran & John Stobbs, "The Search for the Perfect
Swing",
Lippincott, 1968.
NICK Paul Nickles, private communication, Dec 1995.
SUMM Jeff Summitt, "1995 Shaft Fitting Addendum", Dynacraft Golf
Products,
1995.
WISH Tom Wishon & Jeff Summitt, "The Modern Guide to Shaft Fitting",
Dynacraft Golf Products, 1992.
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End of shoptalk-digest V1 #9
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